Cosmic Radiation Speeds up Aging in Space?

SpaceAdmiral writes "The Theory of Relativity tells us that the faster a person travels the slower time passes for that person relative to someone left on Earth. This means that traveling at high velocities in a spacecraft should reduce one's aging. However, recent research suggests that cosmic radiation may counteract that anti-aging effect. Iron-nuclei radiation affects the aging of cells, which is possibly one of the reasons astronauts who have been to the Moon tend to get cataracts about 7 years earlier than other astronauts."

Comments

So...

[op12]

...time to put on my tinfoil suit!

Re:So...

[Rei]

Sure, if you're fond of Bremsstrahlung radiation...

Re:So...

[cplusplus]

No, just your tinfoil goggles.

Re:So...

[thej1nx]

Don't!

Soak in that Cosmic Radiation(tm) baby!

You will get awesome ability to stretch... truths, become totally unnoticed/inivisible to the the rest of the world ... or at least the female population, generate a lot of hot air ...and get into flame-wars! On the downside, you will look really ugly, like a mile of bad road.

In other words ... you will become the average slashdotter!

Oh wait....:p

Re:So...

[VeryHotTopic]

A tin-foil suit is not enough. You need a layer of peanut butter between yourself and the foil!

Re:So...

[Cat_Byte]

Thank you Captain Obvious.

Dandy.

[Anonymous Coward]

The number of astronauts been to the moon is hardly a comparable figure to the ones who haven't, and therefore, difficult to make the hard-and-fast observation that they tend to get cataracts 7 years earlier.

Not much connection between those two things

[PIPBoy3000]

Going to the moon and back probably "slows down" time for an astronaut by a tiny fraction of a second.

Getting hit by a lot of hard radiation causes all sorts of cellular problems, not just cataracts.

How are the two connected again?

Re:Not much connection between those two things

[isometrick]

The article (and the summary) are merely speculating that when close-to-c travel is possible, the radiation might counter the "anti-aging" effect of Einstein's paradox.

It merely provided an example of the radiation possibly causing an acceleration of aging. This does not mean the astronauts in question were majorly affected by relativity.

Re:Not much connection between those two things

[heatdeath]

How are the two connected again?

Exactly what I thought when I read this article. The effects of relativity won't be "counteracted" by cosmic radiation any more than a diet of donuts and lard can counteract the effects of relativity.

Big surprise, radiation kills you.

Re:Not much connection between those two things

[shawn(at)fsu]

I think you might be taking it the wrong way. The going to the mooon was just to give an example of what happend to astronauts becuase of cosmic radiation with a control of Astronauts that stay in earth orbit, it had nothing to do with the effects of relitivity making them age slower.... Thats what I read from it.

Re:Not much connection between those two things

[Anonymous Coward]

There's nothing paradoxical about what Einstein proved.

Re:Not much connection between those two things

[Khashishi]

Until we have some kind of exotic radiation shields, you can forget about travelling at high speeds. I don't think accelerated aging is an appropriate description of burning to a crisp.

Re:Not much connection between those two things

[Andrew Kismet]

But the "Twin Paradox" is, and is clearly named as such. Many people have extended the word "paradox" to cover the entire anti-aging effect, as it TRIGGERS many paradox-scenarios.

Re:Not much connection between those two things

[SeeMyNuts!]

However, scientists in the 60s have shown conclusively that the proper intermix ratio in the warp core will reverse aging by at least three days. I think this will be sufficient to counter any radiation concerns.

Re:Not much connection between those two things

[Anonymous Coward]

Well, there are only really two different types of particles, for purposes of high-speed travel: charged particles and uncharged particles.

For charged particles, you merely need to produce an intense electromagnetic field (several thousand Tesla should do the trick, pretty easily produced if you've got the energy to get to near-C speeds)

The problematic fellows are the uncharged particles (photons, neutrons, neutrinos, etc) which obviously can't be repelled by that sort of electromagnetic shielding. For them, only substantial quantities of mass will work (although interesting mass dilation effects happen as you increase your speed close to C... so perhaps that would compensate for some of the increased shielding needed as speed increases)

Re:Not much connection between those two things

[DrFrob]

The "Twin Paradox," like most so-called paradox's, is not actually a paradox, as it was solved by general relativity.

Re:Not much connection between those two things

[isometrick]

I suggest that you consult your local dictionary.

"A seemingly contradictory statement that may nonetheless be true."

For instance, two identical twins who are of different ages might seem strange, but the situation might actually exist because of relativity.

Also, please consult this page so you can stop abusing the apostrophe. Remember, those in glass houses ...

Re:Not much connection between those two things

[aussie_a]

My understanding is that "Someone travelling really fast will age 1 year, for 100 years of Earth time. So if they leave Earth in the year 1900 and travel really fast, they will have aquired the experiences and aging of someone who travelled for 1 year. However when they land back on Earth it will be the year 2000." Bad example (no-one had spaceships capable of such speeds in the year 1900 ;)), but it simply shows the "paradox."

The "discovery" is that the radiation will take away the "1 year" portion of your aging, by making you age 100 years. But that doesn't do away with the paradox anyway, because (assuming the person survived of course, which they wouldn't in the 100 year example) they'll only have aquired the experiences of someone who lived for 1 year, rather then the experiences of someone who lived for 100 years.

I personally agree that this is all bollocks though. I'd like to know how they know that the "body" is aged, rather then just damaged. After all, what's the simplest explanation? That the cosmic radiation somehow causes you to age at an accelerated rate? Or it just damages your body to a large degree, like any other form of radiation?

Re:Not much connection between those two things

[TapeCutter]

"...as it was solved by general relativity"

Are you sure about that? It was introduced into Physics by GR but I'm not sure wormholes have been completely ruled out.

Re:Not much connection between those two things

[Mycroft_VIII]

What do wormholes have to do with the Twins Paradox?

Mycroft

Re:Not much connection between those two things

[Anonymous Coward]

Sorry to be pedantic, but radiation also keeps you alive! Afterall, what do you think heat is? I'm just getting a little tired of all the fuss over how bad "chemicals" (we're composed of them) and "radiation", are supposed to be. The type of chemical/radiation and the dose are the factors that determine lethality. Just thought everyone should keep that in mind.

Re:Not much connection between those two things

[Anonymous Coward]

I'm going out on a limb here and guessing you haven't had many physics classes...

Re:Not much connection between those two things

[hubie]

If we are still on the topic of traveling at relavistic speeds, that harmless heat radiation you mention gets blue-shifted up to not-so-friendly other radiation such as gamma and x-ray.

Re:Not much connection between those two things

[Thing 1]

Big surprise, radiation kills you.

Exactly! What I thought, when I read this article: perhaps our engineers will develop better radiation shielding by the time our spacecraft are able to approach the speed of light?

Re:Not much connection between those two things

[Thing 1]

Yes, and the AC GP said not only type, but also dose. So with the proper shielding, it doesn't matter what type of radiation it shifts into.

Re:Not much connection between those two things

[CheshireCatCO]

"Sorry to be pedantic, but radiation also keeps you alive! Afterall, what do you think heat is?"

Uh, thermal energy: random motions of molecules/atoms/whatever on a microscopic scale?

The energy I use to conduct metabolic activities and which provides that heat comes from the Sun via EM radiation. But heat? Not radiation.

Re:Not much connection between those two things

[CheshireCatCO]

NASA's press office apparently likes to sensationalize everything. You should have seen the headline that went on that story: "Was Einstein Wrong about Space Travel?"

The hell?

Re:Not much connection between those two things

[Schemat1c]

"Sorry to be pedantic, but radiation also keeps you alive! Afterall, what do you think heat is?"

Uh, thermal energy: random motions of molecules/atoms/whatever on a microscopic scale?

from wikipedia:
"Heat is a process quantity--as opposed to being a state quantity--and is to thermal energy as work is to mechanical energy."

and

"Infrared radiation is often linked to heat, since objects at room temperature or above will emit radiation mostly concentrated in the mid-infrared band"

Re:Not much connection between those two things

[TapeCutter]

"What do wormholes have to do with the Twins Paradox?"

Doh! Got my paradoxes mixed up, I was thinking of the Grandfather Paradox".

The Twins Paradox was inspired by Einstiens work and solved many years ago.

Re:Not much connection between those two things

[Anonymous Coward]

Wasn't it already solved within special relativity?

Re:Not much connection between those two things

[Anonymous Coward]

Sorry, to be precise I was refering to thermal radiation, not thermal energy.

Re:Not much connection between those two things

[CheshireCatCO]

So you're learning physics from Wikipedia, now? The distinction about heat versus thermal energy disagrees with every undergraduate and graduate course I've taken in physics. (Not to mention the OED and Webster's.) I'm inclined to believe those.

And "linked to heat" does not mean "is heat". Infrared is associated with warm objects because that's where things in our common experience tend to emit most of their thermal energy. (Hotter objects will shift that into the visible or beyond.) In much the same way, I associate red lights with stopped cars but red lights are not stopped cars.

Re:Not much connection between those two things

[CheshireCatCO]

I'd drop the "thermal" entirely. The Sun's light (which isn't usually thought of as thermal energy) is important for all kinds of reasons, including the heating it does. :-)

Re:Not much connection between those two things

[Tablizer]

The effects of relativity won't be "counteracted" by cosmic radiation any more than a diet of donuts and lard can counteract the effects of relativity.

Sounds like a fun experiment, though.

Perfect solution for clones

[shaitand]

All we have to do is bombard clones with the right kind of radiation and we can rapid grow them now.

Re:Perfect solution for clones

[Dr. Eggman]

...In addition to giving them all sorts of cancers, DNA and RNA transcribing errors, mutated and mutilated protiens.

If we assume that we can bombard them with x amount of quantity of y radiation to decrease maturation time by z, we must assume a disorder rate of (x*M)*z-21.

This means that x amount time M, which is the average Mutation count per quantity of y radiation. Then the decreased in maturation time, z, minus 21 which is the legally "mature"(adult) age for total bombardment time multiplied by the previous number to get total disorders.

Re:Perfect solution for clones

[SquadBoy]

Do you kill *every* joke you hear/read by picking it to death? Or is it just this one?

pkg_add sense-of-humour

Re:Perfect solution for clones

[Dr. Eggman]

Ehh, some people like dry, fake-math based jokes and some people don't...

Re:Perfect solution for clones

[zerus]

Or you could just say that an acute dose of 2 gray to the lens caused the cataracts. You're confusing a stochastic dose rate over a long period of time with a deterministic effect which is incorrect (cataracts for astronauts are a deterministic effect). Also you're leaving out the quality factor and tissue weighting factor, so you can't even get a proper committed effective dose to the lens.

Re:Perfect solution for clones

[hcdejong]

Ehh, some people like dry, fake-math based jokes and some people don't...

So there really are just 10 types of people....

Re:Perfect solution for clones

[shaitand]

Good doctor, are you suggesting that my suggestion suggests the possibility for breeding a new race of mutant clones?

Bah!

[GillBates0]

Bah! You young 'uns and your fancy schmancy "cosmic radiation". In my day, we didn't have this uppity "Iron-nuclei radiation". We got by with regular sunshine in the day, moonlight during the night and we liked it.

Re:Bah!

[Anonymous Coward]

Not to mention the wind burns on those days on the range looking in the far corners for calves to brand in the spring and summer.

Re:Bah!

[Anonymous Coward]

Er, yeah. Brand. That's it. I was trying to, er, brand them. Brand. Yes.

Re:Bah!

[Anonymous Coward]

Yeah, I remember those days well. Sunshine by the day, moonshine by the night... Like I said, I have good memories of those days, but for some reason a lot fewer memories of those nights...

Young..

[onion2k]

One way or another, NASA plans to keep their astronauts feeling young.

Miss Young was unavailable for comment.

Re:Young..

[Silicon Jedi]

For the love of all that is holy... Mod Parent UP!!!! +1 Teh Funny OMGWTFBBQ

Re:Young..

[Paradise Pete]

For the love of all that is holy... Mod Parent UP!

Miss Holy was unavailable for comment.

Re:Young..

[Anonymous Coward]

Miss? I thought they meant John Young. Always thought Gemini was a little cozy.

Yeah, but that won't alter time

[iced_773]

The aging does not "counteract" the relativity. For example, you may look like you aged 50 years, but only 20 will actually have passed for you. Meanwhile, 50 years may actually have passed on Earth.

Cosmic radiation may age you, but it will not accelerate time.

Re:Yeah, but that won't alter time

[SpaceAdmiral]

Oh, come on. I said "counteract this anti-aging effect" not "counteract relativity and slow down time. " Only an idiot would require your clarification.

Re:Yeah, but that won't alter time

[DirtEater]

The author clearly meant that from the perspective of the article, the artificial aging counteracts the results of relativity. Isn't nitpicking like this just a distraction from an actual discussion?

Re:Yeah, but that won't alter time

[grasshoppa]

If I may:

This means that traveling at high velocities in a spacecraft should reduce one's aging.

No it won't. I will reduce the appearance of time's progression on a person, from everyone outside that persons sphere of perspective. They will still have lived the same amount of relative time as someone else would have.

You weren't clear, and it sent shivers up a lot of people's backs.

Re:Yeah, but that won't alter time

[steveo777]

Think about it. Relativity makes great sense. If you traveled at half the speed of light (assuming time doesn't pass at warp 1): 50 years pass on earth, 25 for you. Problem is, it takes another 25 for you to get back. Now, relative to you, the earth is going back in time 25 years (provided you go the same speed back). Back to zero extra years.

Relativity is limited in its usefulness. Aging only stops/slows down for the visual perspective of the observer. You will still have aged 50 years if you speed of at light -1m/sec from earth. If they could 'see' with some sort of telescope, they would notice that you are moving very slowly, and not aging, mostly because so many of those photons carrying the information of your visual status haven't had the ability/time to reach the lenses.

If humans could only react to sound, then Einstien would likely have said that nothing goes faster than sound because we can't percieve it faster than sound. (And we'd be stupid to try, lots of things to bump into if sound can't head back faster than it got there).

Re:Yeah, but that won't alter time

[SpaceAdmiral]

That's a fair criticism, but I think in the context it's pretty clear. I mean, the previous sentence explicitly said it was a relative effect. I'm also assuming most /.ers have taken basic high school science. Having said that, the story isn't exactly as I wrote it (it was edited). So, um, I'll use that as my excuse for any further criticism that comes my way.

Re:Yeah, but that won't alter time

[Tharkban]

You got your twin paradox messed up:

http://math.ucr.edu/home/baez/physics/Relativity/S R/TwinParadox/twin_paradox.html

Re:Yeah, but that won't alter time

[Krazy Nemesis]

Did you just say 'warp 1'?

Back to zero extra years.

Ummm... but you just said that the Earth was traveling back in time. Does that mean I come back when I left, but 50 years older? So if I came back at a faster rate than I left, could I get back before I took-off?

they would notice that you are moving very slowly, and not aging

Since when was moving at the speed of light slow?

Re:Yeah, but that won't alter time

[brian0918]

"The author clearly meant that from the perspective of the article, the artificial aging counteracts the results of relativity. Isn't nitpicking like this just a distraction from an actual discussion?"

Not when it is presented as if there is some mathematical connection between living cells being damaged by high energy radiation, and the special theory of relativity.

Re:Yeah, but that won't alter time

[brian0918]

I'll laugh my ass off if this gets modded insightful. Although I've seen it happen before...

Re:Yeah, but that won't alter time

[dougmc]

Relativity makes great sense.

Obviously not, because your description shows that you're confused about how it works. Which isn't surprising -- most people are. I've got a degree in Physics, and I still find much of this stuff to be very counter-intuitive.

As for the situation of a guy travelling at 0.99999c for a while and then coming back to Earth at the same speed, the two trips do NOT cancel out. The difference is that the traveller was accelerated to that speed, then deaccelerated until he stopped relative to the Earth, and then accelerated back to 0.99999c in the opposite direction, and then deaccelerated again (we hope) when he reached the Earth. You can't just magically reach a given speed -- you have to be accelerated to that speed, and that's where the situation of the traveller is not the same as the situation of the Earth.

If you traveled at half the speed of light (assuming time doesn't pass at warp 1): 50 years pass on earth, 25 for you.

1) warp 1 is usually considered to be the speed of light, not 1/2 c.
2) time dialation is not linear. At 0.5 c, time would be slowed by a factor of 1/sqrt(1-0.5**2) or only about 15%, not 50%.

Re:Yeah, but that won't alter time

[ceoyoyo]

I'm not sure precisely what you said, but it is more than possible to go racing off into space at a high fraction of c, come racing back and arrive to find out that quite a bit less time has passed for you than for the people you left behind. Not only will you appear younger than would be expected, but you will BE younger because less time passed for you.

Re:Yeah, but that won't alter time

[osgeek]

To be honest, I found the article summary to be a bit misleading, confusing, and aiming to be too "clever" for its own good. The topic is interesting, but you were trying too hard to be funny or something. To each his own, I guess; but don't be too surprised if the technically minded at /. didn't get the point or joke or whatever you were trying to accomplish.

Re:Yeah, but that won't alter time

[dougmc]

1) warp 1 is usually considered to be the speed of light, not 1/2 c.

Scratch that -- I see what you meant. (The rest still applies, however.)

In any event, general relativity basically says that reaching 1 c is impossible. It doesn't say that you can't go faster than that (tachyons supposedly spend their entire life above the speed of light) -- it just says that matter can't go exactly the speed of light. As for what exactly happens at warp one, you'll have to ask Gene Roddenbery for the specifics, but from what I can tell, time continues normally, but your ship goes off really fast, leaving colored trails behind it, and a commercial usually follows very quickly.

Re:Yeah, but that won't alter time

[steveo777]

I've read the theorey of relativity in many forms. No degree, however. I've been through the formulas, and I understand them pretty well (was a math major, so I can crunch numbers). Problem is, this is still what I get out of relativity. I know that you can't just be accelerated to C or 1/2 without infinite force.

All I'm saying is that we won't know untill we try, and it makes no sense (to me) until it happens. I sure we all saw Flight of the Navigator. That's when I became intrueged with relativity, when I was 6. Didn't study it for another 10 years, though...

Re:Yeah, but that won't alter time

[dougmc]

I know that you can't just be accelerated to C or 1/2 without infinite force.

You can't reach 1 c, because it would require infinite amounts of energy ... that's one way of looking at it, and as accurate as any other. As for 0.5 c, you can reach that -- you'll just need massive amounts of energy to accelerate a macroscopic object to that speed, at least by our current 20th century standards.

All I'm saying is that we won't know untill we try

Until we try what? Try to accelerate Geraldo to 0.5 c out of the solar system? I'd pay a dollar to see that!

The effects of relativity have been measured experimentally. Atomic clocks put onto planes and flown around the world have been found to run very slightly slower, and subatomic particles that are known to last for X picoseconds have been found to last much longer when zipping about at 0.999c. Neat stuff -- coming up with theories like this is one thing, but actually showing the effects in the real world -- that's what's really neat.

Re:Yeah, but that won't alter time

[Anonymous Coward]

Something going at 1 c would never age. Also there is no proof that tachyons exist, and also the idea about tachyons says that above 1c its the reverse, it would take infinite energy to decelerate to 1c, though I don't know about what effects on time would be expected. Also if you go near 1c you wouldn't leave colored trails, you would just look like a blur to anyone watching that wasn't going at near relatavistic speeds. Also (from what I remember) in startrek they weren't traveling at warp in 'normal space' but 'sub space'. If your was going at .9999999999999999999999999999999999999999999999999 9c everything inside the ship would look completely normal, though when you looked out a window it would be rather odd since you wouldn't actually be able to see anything, and saying you could someone see something (your ship was going in circles around it maybe?), it would look pretty much like it was going insanely fast (though you would still probably not actually be able to see it, and the amount of photons coming into the window would probably blind you).

If you could instantly accelerate to a speed where on your ship for every second that passed, 2 seconds passed on earth (I'm not sure what that would be, and don't want to do the math), and on your ship you spent 25 years traveling away from the earth, turned around instantly and started heading back at the same speed, once you got back you would be 50 years older, and 100 years would of passed on earth. You can't go back in time by going at near relatavistic speeds, but you can somewhat leap frog ahead using that method.

Re:Yeah, but that won't alter time

[binarybum]

hey, thanks for clearing that up!

Re:Yeah, but that won't alter time

[binarybum]

D'OH!!

Re:Yeah, but that won't alter time

[steve_bryan]

If humans could only react to sound, then Einstien would likely have said that nothing goes faster than sound because we can't percieve it faster than sound.

If you are going to pontificate on a subject you might want to spend a little time actually studying it first. Einstein's idea that the speed of light was independent of observer had a lot to do with the results coming from Maxwell's equations and the null results of the Michelson-Morley experiment. Only a dilettante could think there was a useful analogy to the speed of sound in this context.

It is also worth noting that time dilation and lorentz contaction are effects of special relativity that are verified on a daily basis in particle accelerators everywhere around the world. It is not a subject on which one holds an opinion except insofar as how you want to explain the overwhelming amount of independently measured results.

This part of physics has now been around for over a century (Einstein's first paper on relativity appeared in 1905) and the math behind it has been around even longer. There aren't too many books on differential geometry for the layman but there are many good sources of information about relativity theory by Kip Thorne, John Wheeler and others.

Re:Yeah, but that won't alter time

[1u3hr]

All I'm saying is that we won't know untill we try

Particle accelerators "try" every day. They pump gigantic amounts of energy into protons, electrons and other particles, get them up to a hair below c, but never any hint of reaching or exceeding c (in vacuum, I know you can go faster than light does in glass, water, etc).

Re:Yeah, but that won't alter time

[charlesbakerharris]

Only an idiot would compare relativistic time dilation with cellular damage from radiation.

Also, only an idiot would think that any human has ever experienced anything more than a millionth of a second of time dilation, even from orbiting the earth.

Thanks for playing.

Re:Yeah, but that won't alter time

[Anonymous Coward]

Also, only an idiot would think that any human has ever experienced anything more than a millionth of a second of time dilation, even from orbiting the earth.

You are wrong.

See this figure from this journal article. The ISS is in a circular orbit with an altitude of about 360 km, hence a radius of about 6750 km. So clock aboard the ISS runs slower than it would on the surface of the earth by a factor of (1 - 300 * 10^-12). This comes out to about one millionth of a second per hour.

If you know the orbital speed of the ISS, you can estimate this yourself. Time dilation described by special relativity goes like gamma = sqrt(1-v^2/c^2) which is about (1 - 0.5 * v^2 / c^2) plus terms of order O(v^4/c^4). So we find that the fractional difference in rates due to time dilation is about about 330 * 10^-12.

This does not include the effects of gravity, which is not described by special relativity. That's why the previous answer was different. But you can also estimate this yourself, without really needing to know general relativity:

The frequency of a photon constitutes a clock. The energy of a photon is proportional to its frequency. A photon of energy E at radius 6750 km which travels downward to radius 6400 km will have suffered a loss in potential energy proportional to (1/r). So it's reasonable to guess that the energy of the photon at the earth's surface will have increased (a.k.a. gravitational blueshift) by an amount of about (1 + 306* 10^-12) So we recover (330 - 36) * 10^-12 = 294 * 10^-12 as the effective rate of time dilation for an astronaut on the ISS.

In fact, the gravitational redshift or blueshift predicted by general relativity is slightly different from the expression above, but for a small shift, this is a valid approximation.

These effects are real and have been observed. In fact, it is necessary to take them into account to design a working satellite GPS system. This article has more details.

Re:Yeah, but that won't alter time

[dougmc]

Also there is no proof that tachyons exist

... which is why I said supposedly, though perhaps theoretically would have been better.

and also the idea about tachyons says that above 1c its the reverse, it would take infinite energy to decelerate to 1c, though I don't know about what effects on time would be expected.

I think that a tachyon would exist backwards in time relative to us, and as it slowed and approached 1 c, time as seen by it would slow (but still be going backwards.) Of course, I'm not sure how tachyons would interact with normal, slower matter, so even if they did exist, they may not be detectable. Ultimately, they're just a theory, something suggested by the math involved in general relativity.

Apparantly the term tachyon is also used to describe constructs with imaginary mass (another interpitation of the same equations.) In any event, it's all theories for now, with little way to prove/corroborate or disprove them at this time.

Also if you go near 1c you wouldn't leave colored trails, you would just look like a blur to anyone watching that wasn't going at near relatavistic speeds.

In case it wasn't clear, that was a joke. When the Enterprise hits warp one, colored trails are left (usually by the sharp edges of the ship), the ship goes off the screen in a hurry, and a commercial almost always follows.

Also (from what I remember) in startrek they weren't traveling at warp in 'normal space' but 'sub space'.

I never really paid much attention to the techo-babble.

Either way, the NASA article is silly, and I'm surprised that somebody even bothered to write it. The idea of the effects involved are certainly sound, but the combination is silly. The idea of this radiation somehow counteracting the reduced aging? More likely is that you wouldn't age faster, you'd just die of cancer (if slow) or radiation poisoning (if fast.) You'd still be a young man, but still dead from radiation poisioning.

Re:Yeah, but that won't alter time

[ShadowBot]

To make an analogy between with the speed of sound you need to make a lot of assumptions (e.g. the uniformity of the medium through which sound is travelling) and it gets really iffy really quickly.

IANAPhycist but I have actually read up a lot on the subject. The book which explained it best, to me, started by describing a way to compensate for anomalies of observation due to the speed of light and then suddenly states a few chapters down the line that these are not 'observed effects' but 'real effects'.

IIUC Einstien's basic premise was that, since you cannot accurately compensate for the time between when and incident occurred and the time it is observed, and since Michalson Morley's experiment seemed to prove that the speed of light can always be assumed to be constant (in a vacuum), then you can simply treat your experiment as if the moment at which an incident is observed, is the moment it occured.

He goes on to design a series of formulas that will always let you compensate for the difference in observational timeframes (i.e. the apparent difference in timing due to the changes in distance which will cause light to take more/less time in travelling from incident to observer).

In all the material I read I never found any reason given for anyone to believe that these observational timeframes are actual timeframes (i.e. objects actually passing through time at different rates).

In fact, it seemed to me that if you looked at time as a vector, an object travelling away from you near the speed of light would seem to age more slowly, while one travelling towards you near the speed of light would age faster.

The interesting thing about proving/disproving the factuality of this theory is that it accurately describes how an object will be observed, at least when that observation is done using electromagnetic waves (or other light speed signals).

And the object will be observed to age more slowly or quickly (depending on direction of travel).

So, as far as I can tell, the only way to disprove it is to find a way of observing something at a speed faster than that of light, which isn't that easy, especially when practically every serious researcher begins with the assumtion that such things (tachyons) don't exist (Or that they are travelling backwards through time).

Re:Yeah, but that won't alter time

[jwdb]

IIUC Einstien's basic premise was that, since you cannot accurately compensate for the time between when and incident occurred and the time it is observed, and since Michalson Morley's experiment seemed to prove that the speed of light can always be assumed to be constant (in a vacuum), then you can simply treat your experiment as if the moment at which an incident is observed, is the moment it occured.

The basic premise of relativity is that you cannot define an absolute position, time or speed, not that you cannot compensate for time differences. Morley's experiment is relevant as it set out to measure our absolute speed versus the ether and proved that no such thing exists.

In all the material I read I never found any reason given for anyone to believe that these observational timeframes are actual timeframes

The point is that in relativity there are no actual time frames, only time frames of the observer. When you specify an event, you have to specify its position, speed and time relative to an observer or a fixed standard that is observable.

In fact, it seemed to me that if you looked at time as a vector, an object travelling away from you near the speed of light would seem to age more slowly, while one travelling towards you near the speed of light would age faster.

You're assuming that the direction of time is parallel to the direction of motion, which is again not what Einstein stated. In his theory time was a fourth dimension, perpendicular to all three dimensions of space, and thus completely independent of if you are moving forwards or backwards with the same speed. According to relativity, in both cases you will see the object age more slowly. In addition, you cannot talk about time as a vector as time is not moving in space but is a scalar value on the same level as the three scalar position coordinates. You can, however, talk about a space-time vector, which contains the three scalar positional coordinates and the one scalar time coordinate.

The interesting thing about proving/disproving the factuality of this theory is that it accurately describes how an object will be observed

Observation is all there is for us. It's like the question, "If a tree falls in the woods but nobody is aroud to hear it, does it make a sound?" You can't talk about a sound unless you also have a listener in mind. Likewise aging is a concept directly linked to our preception of the flow of time and has no meaning loose from an observer.
Looking at the flip side of the coin: the only thing we can do is observe, no more and no less, so anything outside that is completely irrelevant to humanity.

Jw

Re:Yeah, but that won't alter time

[ShadowBot]

The basic premise of relativity is that you cannot define an absolute position, time or speed, not that you cannot compensate for time differences. Morley's experiment is relevant as it set out to measure our absolute speed versus the ether and proved that no such thing exists.

Actually, what the Morley experiment specifically proved was that we have no relative movement to the luminous ether. There was a lot of debate about whether this meant such an ether did or didn't exist and Einstiens conclusion was that, whether it was everywhere or nowhere, as long as we couldn't detect it in anyway and it doesn't affect any of our observations, we could proceed by ignoring it in all our experiments.

While I'm not saying that it does exist, I think we should bear this caveat in mind when considering situations like the gravitational bending of light.

You're assuming that the direction of time is parallel to the direction of motion

Not exactly, I am actually working based on the initial observations that were described (in above mentioned book, which was recommended to me by a friend working on his maths PhD, and was the only source I found which actually went into the proofs of the theory) which led to the formation of the theory.

E.g. If an object is one light second away from you at time t and travels away from you at the 0.5 the speed of light for two seconds it will end up two light seconds away from you. Now, the light from it's first position will reach you after one second at time t +1, it will take time t + 2 to reach it's end point and the light from it's endpoint will reach you at time 2 seconds later at time (t+2)+2 = t+4. So the journey that appeared to take 2 seconds to the flying object, will appear to take 3 seconds to you! Hence the slower timeframe. This is the proof that was given, however, if the object flies towards you the time light takes to make the journey will be less at the end than at the beginning. Hence it will speed up!

As I mentioned this is the only proof of the formula i could find, however if you have any resources to a better source of info I'd be really interested in seeing it too.

Observation is all there is for us. It's like the question, "If a tree falls in the woods but nobody is aroud to hear it, does it make a sound?" You can't talk about a sound unless you also have a listener in mind.

That was exactly the premise Einstien was working from. So what he said was not "This is what will happen!" but "This is what you will see happening!"

These equations are great at helping us translate the effects we see from high speed particle accelerators and such. But I never saw any indication in there that we could use it to actually answer any questions about the nature of the universe, Spacetime, Wormhole physics, lorentz contractions, or any of the other conditions which are not actually a matter of observation but exprience.

Re:Yeah, but that won't alter time

[bcmm]

This isn't right. Sorry. The time difference can remain even once the two clocks/people are relatively stationary and in the same place.

Also, relativity is nothing to do with human perception and reaction times. Relativity is a set of real physical effects.

This has actually been measured experimentally: two identical atomic clocks have been put slightly out of sync by flying one of them around the world in a jet. They remained out of sync once they were stationary together on the ground. See Hafele-Keating_experiment for references.

I don't pretend to understand it properly, but your arguments against it have clear logical problems.

Re:Yeah, but that won't alter time

[bcmm]

If you've actually read and understood relativity (I admit I haven't), you would see that the slowing of time is real and is *not* counteracted by the return journey.

Re:Yeah, but that won't alter time

[jwdb]

E.g. If an object is one light second away from you at time t and travels away from you at the 0.5 the speed of light for two seconds it will end up two light seconds away from you. Now, the light from it's first position will reach you after one second at time t +1, it will take time t + 2 to reach it's end point and the light from it's endpoint will reach you at time 2 seconds later at time (t+2)+2 = t+4. So the journey that appeared to take 2 seconds to the flying object, will appear to take 3 seconds to you! Hence the slower timeframe. This is the proof that was given, however, if the object flies towards you the time light takes to make the journey will be less at the end than at the beginning. Hence it will speed up!

This is very true, but not the time dialation effect described by relativity. If that object, and let's say it is a clock, is moving left in your field of vision at an appreciable fraction of the speed of light, it will tick slower from your pov than a clock in your reference frame. This is the lorentz contraction you mentioned and is used in practice to adjust for errors in atomic clocks in gps satellites. I believe the lorentz contractions can be derived from one of the invariants in general relativity, but it's been a while for me so I'll have to go reread the relevant books.

That was exactly the premise Einstien was working from. So what he said was not "This is what will happen!" but "This is what you will see happening!"

These equations are great at helping us translate the effects we see from high speed particle accelerators and such. But I never saw any indication in there that we could use it to actually answer any questions about the nature of the universe, Spacetime, Wormhole physics, lorentz contractions, or any of the other conditions which are not actually a matter of observation but exprience.

I don't quite understand what you mean. For me, what I see is what I experience. In the case of a clock moving left, I see it ticking slower and if I stop it to bring it back into my reference frame, it will have recorded a shorter time interval than a stationary (to me) clock.
Relativity isn't a theory that explains much of the nature of the universe (although I believe gravity waves are somewhere in there) but is more like Newton's laws, in that it describes how we may calculate motion. In my eyes this is more than important enough.

In any case I'll go reread my books on the subject, as I feel I'm a bit rusty. What has helped me is not one specific book, but multiple books that all take a different approach to explaining. No one book will be able to explain it perfectly, but I find that others then pick up the slack.

Jw

Isn't this already known?

[caluml]

Isn't this a given? Just as if you expose your skin to UV radiation on the beach all day, it'll age faster. Isn't aging (and cancer) just the decay of the DNA in your cells - aging just making them not grow back properly, and cancer making them grow wrongly?

Re:Isn't this already known?

[Anonymous Coward]

Isn't this a given? Just as if you expose your skin to UV radiation on the beach all day, it'll age faster.

No, not really. UV is electromagnetic radiation, a.k.a. photons. Cosmic radiation is atoms travelling at relativistic velocities. The comparison might be like comparing a sonic shockwave to a bullet. They both cause damage, but they each do it in a different way. It's an apples to oranges comparison.

The article summary is basically saying this: When you accelerate to near lightspeed, relativistic time dilation means that you experience less time than things that have not been accelerated (like the rest of the universe). This means that to an outside observer, you will appear to age slowly. You might travel 100 light years and only 1 year passes for you. You experience one year, you age 1 year, while the people left back on Earth experience 100 years and age 100 years. But, space is filled with cosmic radiation, little atomic bullets that collide with you constantly, each one tearing through your cells and scrambling your DNA like eggs. If you yourself are travelling at close to lightspeed, then cosmic rays that happen to be travelling in the opposite direction from you will hit you with immensely more energy than they would if you weren't moving. More energy means more cellular mayhem, which in turn means accelerated aging. So, during 100 light-year journey, maybe you'll age several years, even though you only experience 1 year of time. Overall, you're getting screwed.

That same acceleration would doppler-shift mere UV up to a higher, more dangerous portion of the spectrum, maybe making it more like X-rays to you. However, it's much easier to shield a spacecraft from EM radiation than it is to shield it from cosmic radiation -- those little superfast atoms can tear through a lot of material.

Re:Isn't this already known?

[zenhkim]

This is precisely why the recently proposed "Mission to Mars" space program is such a stupid idea. It seems that Dubya Bush (I refuse to refer to him as President, because he isn't worthy of it) was looking for a quick pick-me-up in the polls, and thought that doing something similar to what JFK did in the 1960s (launching the Space Race against the former Soviet Union) would do the trick.

Ironically, his father, Bush Sr., pulled exactly the same stunt while in the White House, announcing his intention to send a manned expedition to Mars. However, the project was quietly (and wisely) scrapped when scientists pointed out that cosmic radiation would effectively doom everyone on the Mars ship to a premature and horrible death.

Somehow, Dubya hadn't been informed of that nasty little detail -- maybe he simply neglected to read the report, sitting on his Oval Office desk with a post-it on the front labelled "Re: Mars Mission -- Read This First" ? Oh well, being President is hard....

I'd be laughing if I wasn't so disgusted.

Re:Isn't this already known?

[Anonymous Coward]

moron

Re:Isn't this already known?

[Anonymous Coward]

Yes, one could also call Bush a moron. Thanks for pointing that out.

Isn't Einstein still correct?

[Zakabog]

Isn't Einstein still correct? You just need to travel faster, or get better shielding against space radiation and you'll still age slower.

Re:Isn't Einstein still correct?

[boldtbanan]

You always age at the same rate since age is a measure of the time passed (for you) with respect to the date of your birth. Relativity does not make you age slower, it just makes it appear so to people who did were not experiencing the same flow of time as you.

As for this story, it's moronic. It's like saying 'If you sit in a microwave for 3 days, that negates the effect of the thimbleful of SPF 1 suntan lotion you put on.' Duh. Show me someone who experienced a perceived loss of 7 years time to people on earth due to relativity (preferably travelling somewhere far away from a massive source of radiation such as THE SUN) and tell me what happens then. The whole premise of the claim made here is just stupid.

Sample size

[tdemark]

Iron-nuclei radiation affects the aging of cells, which is possibly one of the reasons astronauts who have been to the Moon tend to get cataracts about 7 years earlier than other astronauts.

I glad they can draw such conclusions given a sample size of 12.

Re:Sample size

[johnny cashed]

I agree, but you left out the other 6 who remained in orbit around the moon while the others went to the surface. And I'm leaving out Apollo 8,10,13 all of which ventured outside of the Earth's magnetic field.

Re:Sample size

[lysergic.acid]

What exactly was the conclusion that they drew? It seems to me that they've simply stated known data (astronauts who have visited the moon develop cataracts about 7 years earlier than those who haven't. That there were only 12 astronauts whom have visited the moon doesn't change this fact), and speculate that cosmic radiation may be the cause of these observed occurences since it affects the aging of cells.

If they would have said that visiting the moon causes you to develop cataracts 7 years earlier than usual, then that might be drawing conclusions based on insufficient observations. But just because they're talking about a small number of individuals doesn't mean they can't make a statement of fact.

WRONG

[Anonymous Coward]

The Theory of Relativity tells us that the faster a person travels the slower time passes for that person relative to someone left on Earth. This means that traveling at high velocities in a spacecraft should reduce one's aging

Who let this idiot on? This does not mean that one's aging is reduced, it means that their aging occurs slower than for someone on Earth. For example, a person travels on a space craft going almost light speed and another person hangs out here for one year. The person on the space craft at the end of earth's year will have aged less than the person on earth, but only because have not lived an extra year! Once they get a year older (with time passing at a reduced rate), they will have aged the same as the person on Earth.. But by this point, the person on Eaarth would have aged much further because they would have gone through more time.

So, time slowing down does not equal aging slowing down. It only equals time slowing down. Duh.

Re:WRONG

[From A Far Away Land]

The solution seems obvious. We must somehow increase the earth's orbit around the sun to nearly c, since the earth provides adaquate radiation shielding for human life. We'll just have to deal with the tendancy for the earth to fly away from the sun if we increase its orbital speed. That, and sunlight might have trouble reaching the surface of the earth reliably.

Re:WRONG

[feronti]

Well, then we'll just have to build a dyson sphere that encloses both us and the sun, and move that at c. Then we'll be ok.

Re:WRONG

[geekoid]

What object are we comparing our speed to?

Back In My Day

[Skeetskeetskeet]

We used to go to the moon in my front yard in a cardboard box covered in tin foil, and we never experienced any cosmic radiation or aging effects. The martians looked strangely like the neighbors golden retrievers, and the moon rocks we took home as samples smelled like dog poop, but it was all in the name of science.

Cataracts?

[Philip K Dickhead]

No! I drive Rincoln-Continentar!

Well that spoils it for me

[Bob3141592]

Considering the practical difficulties of accelerating to a high percentage of the speed of light, what's a little extra radiation exposure? A few extra meters of shielding ought to reduce that problem, though all that mass will take some extra energy to get up to speed.

How much would it cost to Lorentz contract my time so I can stop in the year 3006? A couple of gazillion? Would I even want to see how much more screwed up the world will be in another thousand years?

Maybe that radiation wouldn't be such a bad thing after all.

Re:Well that spoils it for me

[heinousjay]

Your positivity is overwhelming.

Perhaps I misunderstand

[Anonymous Coward]

I thought that the aging thing depended on frame or reference. In other words, the space traveler would only appear to age slowly to those of us still on Earth, while to the space traveler, his own aging would appear normal while the people he left on Earth would seem to age faster. TFA seems to suggest that the traveler would notice that he was aging slowly, too. Could a physicist explain this, please?

anti-aging effects?

[cowboy76Spain]

Travelling to great speed does not have an anti aging effect... It changes the "duration" of time, but the effects on the body related to the time spend does not vary. The classical effect of the astronauts who returns to earth 70 years before having aged only 7 years is due to the fact that the astronaut has spend only 7 years in the space (from his point of view).

How many astronauts on the moon?

[Anonymous Coward]

...and just how many astronauts have been on the moon to make a generalization?

Lying makes you go blind DOUBLE PROOF

[netsavior]

which is possibly one of the reasons astronauts who have been to the Moon tend to get cataracts about 7 years earlier than other astronauts So basically this proves what my mom said Lying makes you go blind. It also proves that the moon missions were fake.

Re:Lying makes you go blind DOUBLE PROOF

[zippthorne]

Hey! you're begging the question!

which begs the question,
why is it called "begging the question?"

Re:Lying makes you go blind DOUBLE PROOF

[fleisher]

why is it called "begging the question?"

"In logic, begging the question is the term for a type of fallacy occurring in deductive reasoning in which the proposition to be proved is assumed implicitly or explicitly in one of the premises."

http://en.wikipedia.org/wiki/Begging_the_question

Re:Lying makes you go blind DOUBLE PROOF

[zen-theorist]

So basically this proves what my mom said Lying makes you go blind. It also proves that the moon missions were fake.

i am inclined to think the blindness was caused by other activities, namely of the kind that slashdotters indulge in front of their monitors all night..

Word Choice

[Dr. Eggman]

Are you really aging slowly? All the reactions in your body are happening at the same rates, including aging. The difference is that the rates are happening at a different speed of time. So the same rates but different times means that you aren't aging slower, your creating a time illusion of sorts. You have not aged any more than you know you should in the time that you have, but other people see that you have aged less than they know you should in the time that you(they) have. Since you are both right, I contend that you have both aged slower and normally at the same time and thus we need to call it something else.

I suggest we call it 'spooky aging.'

From my cold dead hands

[climbon321]

So does this mean Charlton Heston would have already died of old age by the time he reached the Planet of the Apes?

Re:From my cold dead hands

[Anonymous Coward]

No, but it may explain the longevity of Mole-People

Re:From my cold dead hands

[aussie_a]

They had some sort of cryogenic freezing (which is why their female passenger died as hers was (of course) cracked) which I believe would protect them. If they were using a relativistic explanation for their trip (as in, they increased speed close to the speed of light) then I don't know why they needed to be frozen as well. Normally you have one, or the other not both (and I'm fairly certain at the start when Charlton Heston is making his speech he says that the year on Earth has already increased quite a bit compared to his own time).

Cosmic Radiation can also have positive effects

[LoverOfJoy]

In some instances it speeds up aging but in other cases it turns you into a superhero(tm). I'll take my chances!

Re:Cosmic Radiation can also have positive effects

[raider_red]

Hey, don't use the (tm) mark for that, and don't forget that Cory said we have to call them underwear perverts until DC and Marvell start behaving again.

It's hysterical, and the editors knew it

[jfengel]

From the very tail end of the article: "This story should not be construed to mean that Einstein's theory of Special Relativity is wrong."

Einstein was completely correct. What's wrong is the idea that you can use the time-dilation effect to get to another solar system safely if you can get close enough to light speed, since even short times in space cause health effects. Which has nothing to do with "aging" per se, and even less to do with relativity. And still less to do with NASA's immediate plans, since NASA only has solar-system travel in mind for the next few decades.

So the final tally is:
Space travel: still dangerous
Einstein: correct
Article author: dipstick

Re:It's hysterical, and the editors knew it

[Tackhead]

> What's wrong is the idea that you can use the time-dilation effect to get to another solar system safely if you can get close enough to light speed, since even short times in space cause health effects.

What everyone's overlooking here is this:

If you've got a power source capable of accelerating a spaceship to 0.99c for years at a time, you've got also a power source capable of deflecting the induced radiation from your travels, and you're probably not so worried about ship mass that you can't afford to build in shielding materials.

Consider that you encounter hundreds of times more mosquitoes on a cross-country drive than you do on a single evening barbecuing. You both may be clawing your faces off by Monday morning, but only one of you will be doing so because of mosquito bites.

Re:It's hysterical, and the editors knew it

[Rei]

you've also got a power source capable of deflecting the induced radiation from your travels

No, active shielding doesn't help much against GCR.

Re:It's hysterical, and the editors knew it

[jefe7777]

agreed. the headline made it sound like some inverse relationship existed, that was previously overlooked.

Re:It's hysterical, and the editors knew it

[BrokenStructure]

So what we need to do is construct our space-ships out of titanium and use view-screens, instead of glass, to view our surroundings... or other alien species that we may happen across...

Main screen on!

Re:It's hysterical, and the editors knew it

[Tackhead]

> > you've also got a power source capable of deflecting the induced radiation from your travels
>
>No, active shielding doesn't help much against GCR.

The paper you quote appears to be discussing designs for interplanetary flights using technologies achievable today. (A reasonable approach - I'm mainly addressing the folks who are talking about time dilation effects as related to space travel :)

2.1: Electrostatic requirements "exceed the state of the art by over an order of magnitude".

The paper was written in 2000. 2000's state of the art is better than that of the 60s and 70s. We're still several orders of magnitude away from spacecraft where relativistic/time dilation effects take precedence.

The radiation induced by flying headlong into whatever ionized crap happens to be in interstellar space (however thinly-dispersed it may be) at 0.99c almost certainly dwarfs the GCR effects. I'd also be pretty worried about shielding myself from the ship's own power source than either the induced radiation and the background radiation.

Long story short, by the time we've built a spacecraft flying at 0.99c (centuries, even if Moore's Law applied to spaceships), we'll have had plenty of time to solve the shielding problem (because we'll have had to make commensurate results in just about every other technology in order to build such a ship in the first place).

Maybe we solve it by building something that accelerates so quickly (and yet doesn't squash the crew to a pulp) that the crew only has to experience a few moments of ship-time, and the flight experience is less like spaceflight than like getting the galaxy's least-efficient chest X-Ray.

Maybe we solve it through passive shielding, and if that means our ships being size of small planets... why not use small planets? Enceladus and Europa would make lovely vacation spots if only they were closer to the Sun. But almost any star will do.

Re:It's hysterical, and the editors knew it

[shadowbearer]

Minutes before I caught this story, I read my email... and in there was the NASA Science News mailing for today. It is entitled: "Was Einstein Wrong About Space Travel?" While the article body wasn't quite as sensationalist, the title makes me wonder just who's penning articles for PR.

  Sigh.

SB

Re:It's hysterical, and the editors knew it

[Rei]

The paper was written in 2000. 2000's state of the art is better than that of the 60s and 70s.

In terms of achievable electrostatic potentials? Hardly. There haven't been any significant innovations in charge buildup since the 60s that I can think of. You're talking about launching a half kilometer long Van de Graaf generator and accelerating it to relativistic speeds. Not going to happen.

The radiation induced by flying headlong into whatever ionized crap happens to be in interstellar space (however thinly-dispersed it may be) at 0.99c .99 c? I think you better step out of sci-fi mode. That would require a preposterous mass fraction even on a pure matter-antimatter engine. But that raises an even bigger issue :) You're not going to be running into ions mostly: you'll be running into atoms. They're electrostatically neutral, so you're out of luck.

Long story short, by the time we've built a spacecraft flying at 0.99c (centuries, even if Moore's Law applied to spaceships), we'll have had plenty of time to solve the shielding problem (because we'll have had to make commensurate results in just about every other technology in order to build such a ship in the first place).

Faulty logic. Computers have gone from Eniac to your modern desktop in the same time that the method for tomato harvesting has gone from manual labor to... oh wait.

Not all technologies advance at the same rate, or even close to each other.

Maybe we solve it by building something that accelerates so quickly (and yet doesn't squash the crew to a pulp) that the crew only has to experience a few moments of ship-time, and the flight experience is less like spaceflight than like getting the galaxy's least-efficient chest X-Ray.

Bzzt. Just like how you mentioned collisions with relatively stationary interstellar particles being like encounters with high energy radiation, you're still going to ram through all of those particles anyways. Besides, stop and think for a minute: 1g is 9.8m/s^2. c is 300,000,000 m/s. Do the math as to how long it would take to reach just 1/10th C without crushing them (relativistic effects are pretty negligable at 1/10th C, so it's just division).

Maybe we solve it through passive shielding, and if that means our ships being size of small planets...

You don't need *that* much shielding. You're not trying to block neutrios here ;)

why not use small planets?

Because the mass ratios needed, even on antimatter engines, to accelerate up to relativistic speeds would mean that you'd be having an entire star's mass worth of antimatter. Not going to happen.

Re:It's hysterical, and the editors knew it

[timster]

Besides, stop and think for a minute: 1g is 9.8m/s^2. c is 300,000,000 m/s. Do the math as to how long it would take to reach just 1/10th C without crushing them (relativistic effects are pretty negligable at 1/10th C, so it's just division).

Technically, you must admit that this is relevant only for certain person-acceleration methods (such as today's favorite, mechanical force). If the ship could generate some kind of field that acted equally on all components of a person's mass, then arbitrary levels of acceleration are quite survivable. Of course this is sci-fi mode, but it is at least physically possible.

Re:It's hysterical, and the editors knew it

[Rei]

Hey, if you're willing to jump into sci-fi mode to work around the problem, you might as well just have them open up a wormhole and get around the problem in its entirity :) Of course, to do that, they'll have to recalibrate the phase coupling to emit a tachyon pulse at 3.14 THz to de-synchronize the harmonic vaccuum flucuations in the shield generator.

Re:It's hysterical, and the editors knew it

[timster]

Oh, it isn't THAT hard.

Our very own tiny Sun, despite its pitiful density (1.4g/cm3), manages gravitation of 28g at the photosphere. I can't be bothered to calculate the mass of an iron sphere required for the same strength of gravity, but the density of iron is 7.86g/cm3, so let's just assume that it's a LOT less. Denser materials are WAY better at making gravity.

So your ship consists of a propulsion module that is a huge ball of iron with engines, and a crew module that is much smaller. You have a tether between the two to provide an extra gee and a half or so (for more acceleration and the comfort of the occupants) but most of the pull on the crew module is gravity from the ball of iron.

It occurs to me though that a sphere is not the best shape. A proper shape would be more like a deflated ball, since that way your crew module could be closer to the center of mass (which greatly reduces the mass required).

At Earth gravity, you can make it to a tenth of c in a little more than a month. So if you can manage 30g, that's only a day, which is nothing. Besides, the giant piece of iron would help shield the crew module from collisions with random particles.

Re:It's hysterical, and the editors knew it

[Rei]

Well, lets see. The density of iron varies depending on how much it's compressed. Lets just handwave and say that iron on the ball is compressed to phi=10000kg/m^3.

U=GMm/(r+d)^2
V=4/3*pi*r^3
M=phi*V

So:
V=M/phi
M/phi=4/3*pi*r^3
M=4/3*pi*phi*r^3
U=4/3*pi*phi*G*r^3*m/(r+d)^2

Lets assume that tidal forces are low enough to allow d to be effectively zero:

U=4/3*pi*phi*G*r^3*m/r^2
U=4/3*pi*phi*G*r*m

Lets use a unit mass and get instead general gravitational acceleration

a=4/3*pi*G*r

We want 28gs, so:

1g=9.8m/s^2
28gs=9.8*28m/s^2=274.4m/s^2
274.4=4/3*pi*phi*G*r
r=274.4/(4/3*pi*phi*G)
r=1e8 meters

And its mass?
v=4/3*pi*r^3=4.3e24 meters^3
M=phi*v=4.3e27 kg

By comparison:
Earth's mass: 5.9736e24 kg
Sun's mass: 1.9891e30 kg (3.18e26kg of that is iron, given that it's 0.16% of the sun's mass)

I don't think all of the iron in our solar system would suffice.
I think we'd do better if we stuck to tachyons and phase decouplers :)

SAMPLE SIZE??? !!!

[Suzuki_SV_rider]

I mean c'mon. Is the sample size really large enough to make a call on the average number of years it takes for the onset of cataracts? How many people have walked the surface of the moon?

-sv rider

Re:SAMPLE SIZE??? !!!

[HTTP Error 403 403.9]

I mean c'mon. Is the sample size really large enough to make a call on the average number of years it takes for the onset of cataracts? How many people have walked the surface of the moon?

I did a survey at my cubicle and I conclude that 100% of the Earth's population agrees that the sample size is too small.

Relativity is not anti-aging

[�berhund]

Relativity will not make you live longer. It'll just get your time line out of sync with everyone else's.

Re:Relativity is not anti-aging

[geekoid]

It will, relative to everyone else. Which is the point of living lnger.

If I slept in a stasis field for 8 hour a night, I would live 33% longer.
Of course if it was a stasis field, it wouldn't count as sleep.

Small Sample

[SEWilco]

I'm all in favor of further study on a larger number of people who go at least as far as the Moon.

Sorry to disagree, but that's a ridiculous claim.

[Spy der Mann]

Space radiation helped my joints get more flexible, and all the wrinkles on my wife's face disappeared. If that wasn't enough, my brother-in-law can arrive to his job in practically no time, and my friend Ben got much stronger.

Sincerely,
Reed Richards.

It gets worse

[nizo]

When you travel near the speed of light just think of how many more cosmic rays you collide with since you are going so fast.

kudos to the austronauts and cosmonauts

[zr]

they knew then better than most of us do now the risks of going to outer space. but they went anyways, to advance science and explore farther frontiers.

i say we owe those pioneers mucho respect!

and just to make this post tad more useful, here's a link to the russian "buran" website: http://buran.ru/ with tons of interesting info.

And we're surprised?

[PhysicsPhil]

Why should we be surprised that hard radiation does enough cellular damage to increase the onset of aging? Is this really a shock?

The article submitter has watched way too many Star Trek episodes if he thinks that travelling to the moon is going to have a noticable time dilation effect. Light travels at 3e8 metres/second. The distance to the moon is ~1.3 light seconds (300,000 km). Unless the moon landing astronauts made that trip in under a minute, there will be no relativistic effects.

As a physicist, I can tell you that travelling in space is not by itself enough to slow time down. You need to be moving very fast indeed.

Re:And we're surprised?

[Anonymous Coward]

As a physicist, I can tell you that traveling at any speed is enough to slow time down, even just 1 m/s. It's just that the amount by which it slows down is incredibly negligibly small.

Faster than light travel

[Gogogoch]

Hmmm..... cosmic radiation counteracts 'that anti-aging effect' which is in turn due to relativity? So we have a way of counteracting relativistic effects? What inaccurate and imprecise physics reporting...again. Slashdot should stick to news on software if these stories can't be written with a bit more rigor. Or properly scrutinized.

This has got to be the most bizarre introduction

[Edmund Blackadder]

... ever.

I mean who writes these things? Can you talk about the aging effect of space rediation without going off on a tangent about relativity. The two are completely unrelated you know.

Also as others have said relativistic speeds do not really extend your life. From the point of view of the person travelling at a high speed his/her life will not feel any longer.

Cataracts?

[nightsweat]

I had heard the astronauts get Cadillacs earlier which, ironically, is also a sign of premature aging.

Space-aging

[Gilzors]

So now it's going to be harder to convince others to send people to the moon.

Statistical relevance?

[robogun]

I was wondering if the 25 or so astronauts who went to the Moon, including both lunar orbit and surface landings, was a large enough group to draw these statistical conclusions from.

This article is flawed

[ChowRiit]

The article seems to imply that increased aging through cellular decay, forced by radation, is somehow the "opposite" to decreased aging due to time dilation effects: this is clearly nonsence. One may have the opposite EFFECT to the other, but this is a very different thing...

And so I have heard from other scientists...

[Anonymous Coward]

Cosmic radiation also gives you Superhero (TM) powers, at least thats what this group of scientists told me...

speed of travel is important?

[mcguyver]

Using an astronaught is not a large sample and would make a highly speculative study.

Secondly, at the speed of light the aging process does not slow down. The rate at which I age is constant but you may view me as not having aged.

Lastly, would cosmic rays have a greater or lesser impact on your relative aging? If travelling at 90% instead of 50% of the speed of light increase my chances of being viewed as aging faster?

Maybe my questions are answered in the article but I tried to read it and my head exploded...

Another idiotic title/summary

[sk1tch]

What's with the latest string of intensely stupid articles on slashdot? First XBox downloads of apples outpaces iTunes downloads of oranges, and now a random fact of biology overrules an accepted theory of physics? Why do people write such retarded titles and how do they get posted?

Re:Another idiotic title/summary

[Anonymous Coward]

Because it's Slashdot?

Better things to worry about then aging

[dshade69]

I would think if you were in a space ship going fast enough for relativity to really matter, you would hopefully have shielding on said ship otherwise you would die pretty damn quickly.

Not just the traveller ages more slowly...

[brian0918]

"The Theory of Relativity tells us that the faster a person travels the slower time passes for that person relative to someone left on Earth. This means that traveling at high velocities in a spacecraft should reduce one's aging."

For a limited time, we will offer you the ultimate in longevity treatments. You'll fly off at ultra high velocities in one of our specially-designed rocket ships, which use certified Space Technology®. You'll be the envy of your friends, as they watch you age 50 or 100 times more slowly than them. It works better than any anti-aging cream on the market today. Call now!

Unfortunately, since there is no preferred frame of reference, the person travelling at a high velocity away from Earth will also see the people on Earth aging slower than him/her. But they'll be light years away by the time they realize that.

Re:Not just the traveller ages more slowly...

[Anonymous Coward]

Yes, but if the person traveling away from the earth turns around and comes back, then suddenly there is a prefered frame of reference (all that intertial stuff, you know), and so it really works. The twins paradox.

Re:Not just the traveller ages more slowly...

[brian0918]

"Yes, but if the person traveling away from the earth turns around and comes back, then suddenly there is a prefered frame of reference (all that intertial stuff, you know), and so it really works. The twins paradox."

Yes I know, but that's not what was stated in the submitted comment. The person who turns around and comes back breaks the symmetry of the situation. Also, "the twins paradox" is just a phrase. "Flux capacitor" and "warp drive" are other examples of phrases.

Re:Not just the traveller ages more slowly...

[Anonymous Coward]

Actualy, there is always a zero velocity frame reference. If you study the cosmic background radiation one side of the sky is blue-shifted, the other red-shifted. So this lets you find the proper motion of any object. The Earth and Sun move at a certain velocity relative to the Universe, not at a very relativistic speed, The guy on the rocket is moving at a high fraction of the speed of light. So the twin on the Earth will age more slowly than someone not moving in the Universe, but the twin on the rocket has a much higher speed and will age even slower.

The Start of Something New

[Quirk]

Others have commented on the nonsense of the story as posted but there is another angle. Much progress in biology and more especially in medicine has come from the study of pathologies. We assume a healthy organism then study a pathology to gain some insight into the changes the pathology has wrought. Further we reason from the state of the pathology to better improve our model of a healthy organism.

The classic example in neuroscience is the case history of Phineas P. Gage.

Space travel and Space Stations have provided us with a burgeoning catalogue of studies on the impact of extended stays in space on our and other metabolisms. The Biomedical Results From Skylab are an example of earlier studies. Space promises unique biological insights.

MOD PARENT UP; FUNNY

[Anonymous Coward]

Mod this up funny, it's ridiculous.

It's what you call...

[brian0918]

... bullshit. They're basically saying that radiation is not good for you. Big surprise there.

Eh?

[Anonymous Coward]

Relativity makes great sense

Well, it makes more sense than any of your post, at least

Think that's bad?

[Winlin]

Just wait until the first astronaut turns into a Protector. Now that's an aging problem.

You're kidding?

[Anonymous Coward]

Yet another thing that geeks like to do that makes you go blind.

Send in the Robots

[DumbSwede]

What a circuitous way to say that the Cosmic Ray and Solar Activity exposure of Space is bad for you. Scientific American had an in depth article on this just a month or two ago. As it turns out we have no really good ideas about how to adequately shield the human body from radiation in space and the problem only gets worse once you leave what little protection the Earth's magnetic shield provides. And before you suggest Magnetic Shielding or Material Shielding or Electrostatic Shielding, they crunched the numbers on all these things and the results were depressing. You can shield with a high enough Magnetic Field, but the Teslas involved are so high as to be worse that the radiation your trying to shield from (Earth's shield is effective because of size). Physical shielding requires a Meter or more of water all around (impractical because of weight). Etc., ect... We've made NO progress on really effective anti radiation measures in space. There are only coping strategies, so if you want to go to Mars just be prepared to give up 10-15 years off your expected life time on average or at best an early onset of senile dementia because you WILL loose quite a few neurons to radiation to realize your dreams of bounding around on Mars.

As a child I had been wildly enthusiastic about manned space flight or even becoming an astronaut myself some day. The fact that my 11th birthday coincided with the Apollo 11 Moon landing probably has something to do with this (I'll let you do the math to figure out my age). Anyway we've spent over 3 decades going basically nowhere and as it turns out space is a really hazardous place to stay for long periods of time. So while I'm still very much pro space exploration it is time to hand the baton to robots. Insisting that Man can do some things better is probably only true for the short term anyway. Better to embrace our robotic assisted lives by using the space program as a driving program to accelerate robotics instead of as a meat grinder for human flesh.

What NASA should REALLY focus on are sample return missions. That is where the real big bang for scientific buck will come.

Re:Send in the Robots

[khallow]

Physical shielding requires a Meter or more of water all around (impractical because of weight).

Ok. Use a meter of water then. The problem then reduces to the existing one of how to substantially reduce the cost of getting water (and other mass) there, which is a harder and more important problem.

Better to embrace our robotic assisted lives by using the space program as a driving program to accelerate robotics instead of as a meat grinder for human flesh.

I partly disagree. Ultimately, the point of our current space programs is to have people permanently living and doing useful stuff in space. At some point we have to put people in harm's way to get there. I find that quite acceptable giving the benefits. But at the same time, it's obvious that we get a lot more mileage currently from robotic missions. Sample returns are probably the highest value for the cost scientific missions we can run right now. But science isn't the only thing we should be doing in space.

Re:Send in the Robots

[Tablizer]

Better to embrace our robotic assisted lives by...

You forgot to say it in slashdotease: "I for one embrace our robotic overlords (roverlords?)"

Whoa...

[FusionDragon2099]

The Fantastic Four must be pretty old at this rate!

Chromosome damage is just Aging

[WillAffleckUW]

Error replications, and other fun things involving misfolds and fun usage of siRNAs and all, are just what aging is.

Radiation is just a way to do that faster. Most of aging's effects, other than the degredation/oblation/shortening of the telomeres, work out to the same thing.

Not quite correct.

[TiggertheMad]

When you travel near the speed of light just think of how many more cosmic rays you collide with since you are going so fast.

The speed at which electromagnetic radiation propagates is constant, regardless of your velocity. If you are 'standing still' relative to the universe, light travels at 300,000 km/sec. If you accelerate at 1 km/sec for 300,000 seconds and measure the speed of light, it will be traveling at 300,000 km/sec (and just to be clear, you will not be traveling at 300,000 km/sec at that point, as relativistic speeds can't be added linearly). Going faster will not cause you to 'collide' with more cosmic rays.

Re:Not quite correct.

[wanerious]

I don't think this is right. First of all, cosmic rays are particles, not radiation (as I think you are implying). But to the point, you would expect to collide with more cosmic rays since you are sweeping out a greater volume due to your velocity. Given some cosmic ray density in space (number of particles per m^3), the greater the volume swept out, the more encounters there will be. Each encounter would still feature relative velocities less than c.

Lightspeed reduces ageing?

[Andy Gardner]

Correct me if I'm wrong (and I know you will, this being slashdot :P) but a body travelling at relatavistic speeds would not experience a slower passage of time, a second would still be a second?

As far as I'm aware if your were 20 and traveled at reletavistic speeds for 10 years you would be 30 at the end of your journey. However many more years may have passed at some arbitrary fixed point (relatively).

So this article is basically saying radiation reduces lifespan?

Re:Lightspeed reduces ageing?

[drrngrvy]

You're exactly right about relativity, but wrong about the article: the article is in fact saying nothing . ;)

Re:Lightspeed reduces ageing?

[steve_bryan]

The article is really only about the pervasive threat of radiation that humans face if they leave the Earth and its protections behind. They genuflect about time dilation which is a consequence of relativistic physics but don't even try to explain. What we have known theoretically and have verified experimentally for about a century is that space and time are mixed together in a very algebraically specific way when viewed by different observers who are in relative motion. One consequence of this theory is called time dilation which means that each observer in relative motion sees the others' time as being dilated (slowed down) relative to what he experiences in his own frame of reference. I know this sounds paradoxical but it is nicely explained in Spacetime Physics by Taylor and Wheeler, Gravitation by Misner, Thorne and Wheeler and many other sources (maybe check Wikipedia).

What is quite incredible is that if we could build a ship capable of constant 1 g acceleration we could travel just about anywhere in the universe in what appears to be about 40 years to people on the ship (see chapter 6 of Misner, Thorne and Wheeler for the mathematical details). Of course it is worth noting that all our space exploration has been conducted with ballistic missles which are nothing like a spacecraft capable of constant 1 g acceleration. There is significant reason to doubt that it is possible to build such a device. But it is true that humans are quite comfortable with 1 g acceleration (that is equivalent to the force of gravity at the Earth's surface). I think that it is beyond merely remarkable that relativistic physics guarantees that if our range would be so great if only such a spacecraft could be built.

What this article and a much more complete similar article in Scientific American (March 2006 page 40)explain is that radiation puts a severe damper on the ecomonics of space travel. Pioneers of space flight have been flying by the seat of their pants when it comes to radiation shielding. Frankly I suspect it is a second order problem in the cosmic quest. If we could devise a starship capable of constant acceleration then just encase the whole thing in as sufficient water or something similar to duplicate Earth's protective atmosphere. Assemble it in space far up in Earth's gravity well with material mined from asteroids. Of course there is still the issue of inventing those darn dilithium crystals.

Imagine traveling to another galaxy and returning in less than one hundred years as experienced in your reference frame while the Earth has aged about 4 billion years. Who says we can't have time machines? The only problem is that they are all one way, into the far future. Check these musings in Kip Thorne's book Black Holes and Time Warps

Re:Lightspeed reduces ageing?

[Anonymous Coward]

I'm confused about the "travel anywhere in 40 years" part. Assuming you could accelerate at 1g for a year (about the time it would take to reach c), I thought you'd reach anywhere in the universe instantaneously after that, because the entire universe would be length-shifted to a distance of zero in your direction of travel. Am I missing something?

Astronauts on the Moon

[daigu]

How many astronauts have been to the moon? How did they isolate this population to determine that radiation was the cause? Perhaps there is a self-selection bias. Perhaps it is all the flashing bulbs from the pictures that are taken after a successful return. In other words, this causal connection is complete crap.

Re:Astronauts on the Moon

[Anonymous Coward]

How many astronauts have been to the moon?

None. As in zero. No human being has ever walked on the moon. Just because "they done showed it on the tee vee!" doesn't mean it really happened. How many more years need to pass before people come to realize they didn't have the technology to get people to the moon and back in 1969 and they still don't today? Are people in 2069 still going to believe that 100 years before, humans made it to the moon, but haven't been able to do it again since then?

That sucks

[Mad Ogre]

Sucks to be Major Tom.

Scientific Study?

[Anonymous Coward]

astronauts who have been to the Moon tend to get cataracts about 7 years earlier than other astronauts

Hhhmm. Been a while since I've been in a statistics class, but I didn't think there have been enough astronauts on the moon, in total to support such a study....

Oh, so that's why

[Anonymous Coward]

Captain Kirk had to get plastic surgery!

relativity?

[thisislee]

Relativity is just a buzz word to get people to read the article. This has no implications related to relativity except for the fact that you would probably have to be in space to go fast enough for fun relativity stuff to happen on a pereptible scale. Near speed of light travel is not anti-aging. It is forward time travel. Accelerated aging is a consequence of exposure to radiation and has nothing to do with relativity.

ROTFLMAO

[PortHaven]

Hey Slashdot,

"How LOWWWWWW can we go?"

This is "recent" research. Sheesh. I remember hearing about cosmic radiation's effect of aging when I was like 4 yrs old. (I just turned 30.)

Anyways, can someone please review the articles for some relanvancy to life. I mean, sheesh, this is a known issue. It's why one of the discussions regarding all deep space missions revolves around how best to shield the crew from cosmic radiation.

*yawn*

Oh yes, btw,...let me show you this great new revolutionary idea I've come up with.... I call it the "Space Shuttle"

No wonder why...

[Matarick]

Reed Richards has grey temples on his hair.

Apples and Oranges non-sequitor

[posterlogo]

"The Theory of Relativity tells us that the faster a person travels the slower time passes for that person relative to someone left on Earth. This means that traveling at high velocities in a spacecraft should reduce one's aging."

Then the article goes on to talk about cosmic radiation causing premature age-jaculation. Talk about apples and oranges... First of all, the obvious... sub-light speed travel does not reduce one's aging -- it would just appear that way (in theory) to a "stationairy" observer (as if there were such a thing). Second, actually using sub-light travel to let the world around you go by faster isn't really plausable, now, is it? Ok, those are the obvious ones. Something actually interesting (because it's real and verifiable) is that radiation does indeed cause telomere shortening. There is a correlation with increased age and shortened telomeres. The experiment should be relatively straightforward with model organisms sent to space, even in earth orbit, but one would have a difficult time proving causality: cosmic rays -> shortened telomeres -> premature aging.

What the article does not tell you, is that the amount of radiation that caused the telomere damage would necessarily also cause other DNA damage. In other words, the premature aging might be the last of your worries if you were actually exposed to cosmic radiation. One would probably die of cancer or radiation poisoning first.

Re:Apples and Oranges non-sequitor

[geekoid]

If you make two identical clock, and put one in a satallit, it's clock would appear slow compared the the clock left on earth. Hence not aging as much as if it had been on earth.

Point in fact, a clock on the top of mt. Everest would tick slower then one at sea level. Same thing if you had a clock on a pole, and one on the equator.

There are two factors, speed an gravity.

Re:Apples and Oranges non-sequitor

[posterlogo]

That's nice, you're talking about special relativity and general relativity. The point is that all inertial reference frames are equivalent. To step back from the gibberish for a second, that implies that all points of view are equally valid. I really hope we're disagreeing purely on semantics, because otherwise, you really think there is such a thing as slowed aging, and that would be sad. The clock on top of Mt. Everest would only appear faster than the one at sea level. Similarly, the one at the bottom of the Dead Sea would only appear slower than the one at sea level. Measuring the rate of something predictable, like radioactive decay, at each of those reference frames, by a person in each of those reference frames, and then later getting together and comparing the results...they would be identical -- all inertial reference frames are equally valid. You were on the right track until you said "Hence not aging as much as if it had been on earth."That clock sure feels like it's aging just like it's always been, and that's what matters.

P.S. The search for proof of general relativity by measuring phenomena super accurately, just like the clock experiment you describe, is ongoing, and by no means conclusive. But I believe the theory is valid.

Been there, done that

[Anonymous Coward]

It went like this:

T-REX: Dromiceiomimus, what have you done today? I'VE just made a machine that makes people age, with God's help!

DROMICEIONIMUS: So what's the symbolism there? Is it called "The Life Machine" or something?

T-REX: No. No, that would be good but this is actually just a machine that leaks invisible cell-decaying radiation.

UTAHRAPTOR: Holy cow! Why would you build something like that?

T-REX: B-Because God told me to?

UTAHRAPTOR: That's insanely dangerous, T-Rex! Geez!! I'm leaving. I don't want to be around a dude who has a LIFE-DESTROYING MACHINE nearby.

T-REX: Man, you're right! What was I thinking? Well, you can REST ASSURED that I'll be taking this up with God at my earliest convenience.

BUT LATER, ALL IS FORGOTTEN:

T-REX: So yeah! That's why I could never see myself using the word "twincest."

GOD: That's fair.

comic

large enough test pool?

[vingilot]

"which is possibly one of the reasons astronauts who have been to the Moon tend to get cataracts about 7 years earlier than other astronauts"

or because the sound stage they faked the landing on was contaminated with radiation from the manhattan project.

No, it's the radiation!

[Chemisor]

> Sheesh. I remember hearing about cosmic radiation's effect of aging when I was like 4 yrs old. (I just turned 30.)

Man, you must have absorbed quite a dose to age 26 years between reading the article and posting a comment.

Re:No, it's the radiation!

[PortHaven]

Yeah, I started reading Robert A. Heinlein in like 3rd/4th grade...

but...

[Anonymous Coward]

traveling at high velocities in a spacecraft should reduce one's aging

you age the same -- it's only when you get back that you realize what's happened (if you ever get back home!). So the effect of the cosmic radiation is not that complex -- it just reduces your chances of getting home later!

Well Duh

[falken0905]

Well Duh! Look what happened to Dr. Dave Bowman. Kubrick knew this in 1968.

What about shielding

[834r9394557r011]

I'm sure at this point, with the tchnology we have now for radiation shielding, there may be some truth to the article. But perhaps once the technology is available to block those rays, the "counter effect" they speak of would disapear.

I for one

[Anonymous Coward]

I for one welcome our (well, not so) new Radioactive Overlord!

Not quite correct, part Deux

[TiggertheMad]

Ok, lets think about it like this: You are traversing (for example) say twice the volume of radiation filled space in a givin time, therefore you are being exposed to radiation in any selected area for half the duration. Simple.

Re:Not quite correct, part Deux

[wanerious]

But we're not talking about a duration of radiation in a certain area, but integrating the total number of encounters. If you hang your head outside of a car and open your mouth, you'll swallow twice as many gnats going at 60 mph than you would at 30 mph (if the gnat density is constant in space).

You have it completely backwards

[drrngrvy]

You don't age slower when you travel faster: others age faster. The difference might seem superfluous but it isn't at all.

If you are travelling mightily fast you still only live 80 years or so - there's no way to prolong that according to Einstein. It's just that if you went back to where you started you'd find that everything else would have aged more than you; how much more would depend on how fast you were going.

In fact you'd probably live for less than normal due to the stress on your body from the rediculous accelleration you'd have to go through to make time dilation make any noticeable difference (I'd say you'd need to be travelling at about half a billion kph for that to happen).

Just because the article came from NASA doesn't mean they have 'their best men' working on it!

Re:You have it completely backwards

[edwinolson]

Wow. IANAP, but somehow I picked this up:

1. There are no preferred frames.

2. You can reach relativistic speeds quite quickly even at low accelerations. 1g acceleration for a year will get you 1.0 c. Somehow, I think your body might be able to tolerate 1g.

3. If 'units' hasn't let me down, half a billion kph is 0.46c. Relativistic effects are pretty boring at that speed. The Lorentz factor is only about 1.155.

Re:You have it completely backwards

[drrngrvy]

1. True. I'm not sure why you stated this in reply to my post though. Perhaps it was just for your other points ??

2. Good point, but stress is cumulative. It'd have an effect if you did it day and night for an entire year (but maybe not enough to shorten your life much). It was just an afterthought so that could well be wrong. Using 'rediculous' was definitely over-zealous on my part. Oops.

3. If you moved at 0.46c for a year you'd miss a month. You wouldn't notice that?

Re:You have it completely backwards

[edwinolson]

1. Because your post implied that there was a preferred frame when you argued that "you don't age slower (sic), others age faster". This is a meaningless distinction.

2. Hmm? Humans have evolved for 1g environments-- it's not like you have to add in the Earth's 1g. The passengers won't know the difference between whether they're at home on the sofa or on their space ship accelerating towards relativistic speed. No difference in stress.

3. I said it wasn't exciting, not that it wasn't noticable. Exciting is 0.99c :)

Re:You have it completely backwards

[drrngrvy]

1. "you don't age slower, others age faster" isn't a distinction in itself, it is only distinct from the way the title post is worded: "the faster a person travels the slower time passes for that person relative to someone left on Earth". Time never passes slower, only faster. Getting it the wrong way around is about as ignorant as you can be on the subject (that's aimed at the original poster btw :p).

2. I'm a spaz, ok, but I'm not wrong about the first one.

3. A month isn't exciting? Even when you're travelling at half the speed of light? One hell of a trip imho ;p.

This just in...

[Spamicles]

...radiation alters cells!

Iron nucleii radiation

[Omega Blue]

What on earth is that iron nucleii radiation?

There are three kinds of radiation: alpha, beta, and gamma. Alpha radiation is helium nucleii. Beta is electron and gamma is an extremely energetic form of electromagnetic radiation. I know of no iron nucleii radiation. That probably means iron ions travelling at some speed. Though that's more damaging to cells than gamma rays according to TFA, remember that alpha radiation can be blocked by a piece of paper. It seems that Iron ions probably don't have better penetration.

Relativity does not slow down ageing

[lithium100]

The whole point of relativity is that time is "relative". If I am travelling at 0.8c then I still age at exactly the same rate as I would on earth. Its just that 50 years to me might be 150 years to everybody back on Earth. We all still age exactly the same way in our own frame of reference. Its only when someone looks at me through a telescope that they realise I still look young whilst they have aged.

Confused?

[Geoff St. Germaine]

This is possibly the most confused article I've ever seen here. Somebody doesn't understand relativity, but decided to include implications of it in an article about the cellular effects of radiation.

so what?

[FirmWarez]

So, um, ok....travelling fast in a car means you have more time to do things other than travel, but iff you smack in to something and die, you don't? I mean WTF. Relativity and radiation are unrelated effects. So one counter acts the other. So? News that matters, to somebody.

that's putting it mildly

[penguin-collective]

Radiation in space essentially makes manned space travel beyond the moon impossible right now. Furthermore, there aren't even any good proposals for how to create viable shields.

Very, very wrong....

[brian0918]

"If you study the cosmic background radiation one side of the sky is blue-shifted, the other red-shifted. So this lets you find the proper motion of any object. The Earth and Sun move at a certain velocity relative to the Universe, not at a very relativistic speed, The guy on the rocket is moving at a high fraction of the speed of light. So the twin on the Earth will age more slowly than someone not moving in the Universe, but the twin on the rocket has a much higher speed and will age even slower."

Just... no.

Good study???

[Siberwulf]

astronauts who have been to the Moon tend to get cataracts about 7 years earlier than other astronauts.

How many men have been to the moon? Is this really a good control group?

Some Questions

[Nom du Keyboard]

Some questions:

Just what is iron-nuclei radiation, and how is it different from, say, tin-nuclei radiation? It's the term 'radiation' that's throwing me here. Is this like Alpha radiation' which are helium-nuclei? And if it's iron, why not stop it with a magnetic field?

Also, is there an 'At-Rest' speed in the universe where everything else is traveling faster than you against whatever reference the universe uses to measure speed, and hence time at this relative speed passes faster than at any other speed do to no time dilation at all? If so, then how fast is the Earth moving relative to this zero speed?

Re:Some Questions

[Detritus]

It's a bigger rock (13x larger than helium), and it causes more extensive damage in the cell when compared to helium nuclei. I don't think the exact element is too important. The damage is related to mass and kinetic energy. Iron is just a relatively common element, being the waste product of large stars.

obligitory

[Anonymous Coward]

The Fantastic Four are full of shit.

Misleading

[4D6963]

The resume and article is misleading. It sounds like cosmic radiations will counteract time dilation. It has however no connection, let's say you take a fast trip that to the relatively non-moving observer takes 1 year, but that because of time dilation it takes you the traveler live 1 hour, it will be about spending 1 hour and getting harmed by cosmic radiations, it will not make you take more than an hour.

Wow, what a fucked up resume and article.

"Was Einstein Wrong about Space Travel?" yeah right! Just put lead all around your near light speed space ship and laugh at this article.

Actually, those "news" are all about "Cosmic rays are bad for your health", did I get it right? I smell sentionnalism in the air, or something..

I know a spacecraft with radiation shielding.

[master_p]

It is called "Earth". It travels for millions of centuries in space, and people on it do not suffer radiation poisoning, even though they have no concrete shielding from it...

We're in space and we aren't dying?

[HaMMeReD3]

Can't they shield from the radiation, I would think while they are in the shuttle or iss they would be reasonably safe from radiation. I would think that this would be more an issue of being exposed to radiation on things like space walks. I would think if mankind ever got to interstellar travel we'd have solar radiation shielding figured out and this would probably be a non-issue. I doubt this will be a risk to the space tourism industry either.

does anybody take physics anymore?

[museumpeace]

The time dialation effect is apparent only to observers left behind on earth. To the astronaut, the clock ticks as fast as always and they live their three score and ten like anybody else. They return from their trip and find WE have aged faster. The radiation thing is certainly real and certainly unrelated to relativity. When you build your almost-lightspeed ship, be sure to lay on plenty of sheilding.

Questions about relativity

[cornlog]

OK. So answer this. If as Einstein's theory's seem to state, there is no "fixed grid" to space, then how come the person on the spaceship has time slow down. After all, if the spaceship moves away from Earth at .5c isn't Earth moving away from the spaceship at .5c? How do you know which one is moving at that speed, if they both are moving at that speed (relative to each other).

Also, if two bodies move away from each other, each at speed of light, what is the speed they are moving apart? Is it 2x speed of light?

Re:Questions about relativity

[museumpeace]

Relativity is not intuitive. Your questions demonstrate that much for sure.

The space traveler's DO NOT notice any change in the pace of time. Nobody will ever notice any change in the pace of their own clocks, chemical processes or entropy rates. The traveler will look back at earth and see that all its distances are foreshortened in the direction of travel. The earthlings will look at the space ship and think its clock is running too slow. The paradox is resolved by noting that one underwent acceleration and the other did not.

The question "two photons, L and R, head out from a lightbulb going in opposite directions, what is their relative speed?" is the classic question for separating the clued from the clueless. When you ask the question, you are acutally implying the fixed cartesian grid throughout space that you just said you knew to be a mistake. You're imaginging yourself in some priveleged observational frame seeing two photons but what question are you really asking? You are asking "what relative speed does photon L measure in trying to measure the speed of photon R?" The answer is always and only C no matter who takes the measurement. It was that observation, difficult though it was for others to accept it, that got Einstein thinking in the first place, it was like the proverbial apple that hit Newton on the head.
Try to think "space is squishy because of the time dimension"...not easy but it helps some people to visualize the physical world as relativistic observations reveal it to be.
Martin Gardener probably wrote some of the most accessible books on relativity for non physicists though he seems to leave some readers confused about GR...but then most people always will be. But if you are a really fast learner, you could try these lectures Space and Time in Special Relativity looks good but I have not read it...there are dozens of these. I got started with an introductory book by Bertrand Russell that is long out of print. Gamow was also a good popularizer.

At least

[WormholeFiend]

now we have an explanation why that guy in the movie Contact still had to die at the end...

early astronauts in the sun more

[peter303]

MOst of the 1960s astronauts were pilot and out in the sun alot more that the newer "office-scientist" payload specialists. Sun exposure is the biggest correlation with cataracts. (P.S. Sunlight is radiation too.)

GunBuster

[jfz]

http://en.wikipedia.org/wiki/Gunbuster

Big news: Being on the beach will let you live lon

[Saggi]

I have studied the effects of swimming on the beach, compared to swimming and diving in an active reactor. So far I have not been able to find any real subjects to test this on, but the theoretically studies are quite astonishing.

A 20'year old person who swims and dives in the sea will often live to be 70-80 years old. There are slight variations depending on the countrys average age and the number of sharks in the sea in question, but they are statistically neglible.

If the same 20'year old person would jump into a reactor and dive down to the core, his expected age would dramatically be reduced. The theoretically study indicate it would depend on the depth of the dive, and could potentially reduce his age to 20 years.

I have tried to get my studies into various magazines and journals, but so far no-one have accepted them. But now my hopes are up. NASA might accept them - so look out for my upcoming studies.

NASA needs to discard astronaut bodies

[Anonymous Coward]

If NASA would discard the bodies of astronauts and send just their brains on space missions, this whole problem would disappear.

See The Day You Discard Your Body for details. Chapter 15 has a whole section on NASA and the research they need to do to make this possible.

Ummm aging?????

[jameskojiro]

No they would age the relative time for them they spent in space, but would be suffering from Radiation exposure like somone working in a nuke plant.

Want to feel like an astronaut, go take a tour of cherynobyl

N-Acetyl-Cysteine

[aquadivina]

Will help prevent this. Especially if you take it with alpha-lipoic acid. Everyone should take them.