Interstellar Hydrogen Prevents Light-Speed Travel?

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Interstellar Hydrogen Prevents Light-Speed Travel?

Posted by CmdrTaco on Wednesday February 17, 2010 @04:33AM from the einstein-brought-in-backup dept.

garg0yle writes "As if relativity wasn't enough to prevent us traveling at light speed, Professor William Edelstein of the Johns Hopkins University School of Medicine is now claiming that the interstellar hydrogen, compressed in front of the ship, would bring the journey to a shocking end. 'As the spaceship reached 99.999998 per cent of the speed of light, "hydrogen atoms would seem to reach a staggering 7 teraelectron volts," which for the crew "would be like standing in front of the Large Hadron Collider beam."'"

30 of 546 comments (clear)

Fuckin' Noobs by jim_v2000 · 2010-02-17 04:35 · Score: 5, Funny

That's what the deflector array is for.

--
Don't take life so seriously. No one makes it out alive.
1. Re:Fuckin' Noobs by captaindomon · 2010-02-17 04:41 · Score: 4, Informative
  
  Not to mention the Bussard Collectors.
  
  --
  Just because I can hook a shark from a boat, I do no offer to wrestle it in the water.
2. Re:Fuckin' Noobs by Joce640k · 2010-02-17 04:55 · Score: 4, Insightful
  
  UM, I thought the plan was to scoop them up and use them for fuel, ie. you WANT those hydrogen atoms to pile up in front of the ship.
  
  --
  No sig today...
3. Re:Fuckin' Noobs by rssrss · 2010-02-17 06:01 · Score: 4, Informative
  
  The Bussard Collector is part of a Bussard Ramjet.
  The Bussard ramjet is a system of spacecraft propulsion proposed in 1960 by the physicist Robert W. Bussard. A moving spacecraft would use enormous electro-magnetic fields to collect and compress hydrogen from the interstellar medium. The hydrogen would be forced into a progressively constricted magnetic field, which would compress it until thermonuclear fusion occurs. The magnetic field would then direct the heated gas in the direction opposite to the intended direction of travel, thereby accelerating the vessel.
  More generally.
  
  --
  In the land of the blind, the one-eyed man is king.
Damn it, now they tell me by verbalcontract · 2010-02-17 04:35 · Score: 5, Funny

And I was just about to get into my 99.999998% lightspeed spaceship.
1. Re:Damn it, now they tell me by pla · 2010-02-17 05:48 · Score: 4, Insightful
  
  And I was just about to get into my 99.999998% lightspeed spaceship.
  
  Aside from the current nonexistence of such a craft, that really does count as the faulty premise with Edelstein's conclusion...
  
  Why would you go that fast (presuming you can't go much faster, of course)? It takes exponentially more energy to accelerate as you approach the speed of light, but that doesn't get you to your destination all that much faster. At a mere 99.9% of the speed of light, you spend less than one extra hour of travel (externally measured, of course) per month. For a "realistic" trip to nearby stars, that means an extra day and a half out of the 4.37 years to get to Alpha Centauri.
  
  For relatively local trips, the difference amounts to a triviality - And longer trips simply will never happen unless we have some breakthrough that makes Star-Trek-like warp engines a reality.
2. Re:Damn it, now they tell me by Fnkmaster · 2010-02-17 06:27 · Score: 5, Insightful
  
  Well, the only material difference is the time dilation factor for the person in the spaceship. At 99.9% the speed of light, that factor is about 22 - i.e. the 4.4 years seems to take only about 0.2 years, or 10 weeks. At 99.999998% of the speed of light, it is almost exactly 5000 - which means the trip would seem to pass in about 7 hours. This is ignoring the general relativistic effects of acceleration and deceleration.
  So, it's a material difference to the person traveling, but not so material to the observer stationary relative to Alpha Centauri.
Do keep up, dear boy... by Space+cowboy · 2010-02-17 04:35 · Score: 4, Insightful

After reading the article (yeah, I know...) tow thought spring to mind...

1) Warp drive doesn't posit a traditional "go-very-fast-through-normal-space" type of spacecraft engine - it warps[*] space-time (hence the name!) in front of and behind the spacecraft - see here for an explanation. The spacecraft itself is sitting in a bubble of normal space, possibly even at rest.

2) Um, ramjets, anyone ?

Seriously, any number of sci-fi authors have covered this problem in enormous detail over the last few decades

Simon

[*] And because this is /., I expect you all to forgive me for using the present tense here [grin]

--
Physicists get Hadrons!
1. Re:Do keep up, dear boy... by jgtg32a · 2010-02-17 04:44 · Score: 4, Funny
  
  You did not just link me to a astrophysics article of wiki that's worse than tv tropes for me
  
  I'm at 8 articles from just the first link you provided.
2. Re:Do keep up, dear boy... by confused+one · 2010-02-17 04:59 · Score: 4, Insightful
  
  Some of those authors have / had engineering and science degrees. That is part of what made them good at their job. Isaac Asimov and Arthur C. Clarke are classic examples.
3. Re:Do keep up, dear boy... by Space+cowboy · 2010-02-17 05:01 · Score: 5, Informative
  
  Let me recap for you (both of the below points taken from the links I provided...):
  
  1) Proposed by the physicist Miguel Alcubierre, popularised by Star-Trek.
  
  2) Proposed by the physicist Robert W Bussard (hence "Bussard Ramjet"), popularised by Larry Niven (the author), and even referred to by Carl Sagan on TV and in books...
  
  Various other authors have used the same ideas. Perhaps I ought to have mentioned that I'm a physicist too... And the gentle humour regarding tense was supposed to clue you in that I wasn't suggesting we had a practical solution just yet... I wish I'd spelt "two thoughts" correctly, though.
  
  Simon
  
  --
  Physicists get Hadrons!
4. Re:Do keep up, dear boy... by DerekLyons · 2010-02-17 05:04 · Score: 4, Insightful
  
  Seriously, any number of sci-fi authors have covered this problem in enormous detail over the last few decades
  Yes, any number of sci-fi authors have handwaved around these problems for the last few years. Actual scientists, not so much. And, as with TFA, the conclusions of the ones that have been less than sanguine. (From the POV of actually doing it.)
5. Re:Do keep up, dear boy... by Graff · 2010-02-17 05:24 · Score: 4, Interesting
  
  I wondered why they didn't run them in series. Cumulative thrust would have put the ship closer to light speed.
  Not necessarily. You are actually fusing those hydrogen atoms, turning them into helium. The output of one ramjet has less hydrogen than went into it. Yes, you could fuse that hydrogen/helium exhaust into heavier elements but it won't release as much energy. Basically you'll be adding mass to your spacecraft by putting another engine on but you won't be increasing your thrust as much as you may think.
  You might eke out a bit more acceleration with another engine in series but it's probably not worth it. You don't want to put them in parallel on a small ship either, for several reasons. For example, the magnetic fields that funnel material into the engine are supposed to extend in a cone far in front of the engine. Two engines that are close together will have their magnetic fields interact, complicating the management of those fields. Another concern would be properly adjusting those engines to maintain even thrust on both sides. When you're traveling at a significant fraction of the speed of light a slight variation in the hydrogen input of one engine could tear apart your spaceship pretty easily.
  
  --
  Sapere aude!
6. Re:Do keep up, dear boy... by DerekLyons · 2010-02-17 05:30 · Score: 4, Interesting
  
  And if you actually read the Wikipedia article you link to, rather than just drooling over the qualifications of the inventor, you'll find that as people have actually began to seriously study it - there are now significant doubts as to how well it will work. (Even assuming we figure out how to do the parts Bussard handwaved into existence, like the magnetic scoop.) In addition, even if it does work, it may be subject to the problems outlined in TFA.
7. Re:Do keep up, dear boy... by fatmonkeyboy · 2010-02-17 05:45 · Score: 4, Informative
  
  You are completely and absolutely wrong. Are you getting him confused with someone else? Asimov studied for and received his Ph.D. in biochemistry the standard way. He then worked for the Navy during WWII as a chemist and was later a professor of biochemistry at Boston University. I know all of this because I was a huge fan as a kid (and read his autobiography multiple times). But here's the wikipedia article: http://en.wikipedia.org/wiki/Isaac_Asimov
8. Re:Do keep up, dear boy... by Artifakt · 2010-02-17 06:05 · Score: 4, Informative
  
  Asimov worked specfically as a Munitions Chemist in WW2, alongside several other SF authors, including E. E. "Doc" Smith. Some of Isaac's war era work was classified well beyond that time (T.S. - 50 year to review at one time, according to Freedom of Information Act requests) and now seems to have become a matter of rumor and fallen from the official records, part of an interesting bunch of mostly unconfirmable claims suggesting that he, R A Heinlein, Jack Williamson, and maybe several other SF authors were consulted with regard to the Manhattan project just before Truman was informed. While that appears to be undocumented, There are Heinlein's own printed remarks about having two positions in the war, one of which he could talk about, and Larry Niven's comparison of what he and Jerry Pournelle did in advising the Bush administration after 9/11 to what a group of unspecified SF writers did in WW2, to make the rumors at least a trifle plausible.
  
  --
  Who is John Cabal?
Let's just hope... by Hognoxious · 2010-02-17 04:36 · Score: 4, Funny

Let's just hope the engine controls aren't made by Toyota, or it'll be hitting that speed whether the crew want or not.

--
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
simple solution: by notgm · 2010-02-17 04:36 · Score: 5, Funny

put a hydrogen-atom-splitter on the bow of the ship, they'll just get cut in half and fall out of the way.
1. Re:simple solution: by jbeaupre · 2010-02-17 04:57 · Score: 5, Funny
  
  You joke, but that might be an actual solution. If you can go that fast, why not postulate some other technology. Something that causes hydrogen to have a 50% probability of being on the left, 50% on the right. Just for a microsecond. Let it collapse back to the middle once you've gone past.
  Really you'd want to create some sort of probability donut. Fly right through the middle. I propose calling it the Homer-Schrodinger shield.
  
  --
  The world is made by those who show up for the job.
2. Re:simple solution: by Mr+Z · 2010-02-17 05:02 · Score: 4, Funny
  
  Hmmm.... something tells me that cutting a large number of single protons in half right in front of the ship would more than double their problems....
  
  --
  Program Intellivision!
Considering the energy required. . . by Salgak1 · 2010-02-17 04:38 · Score: 5, Insightful

. . .to GET to .99999998 c, this is unlikely to be a concern. And if you have the effectively-infinite energy to move a ship at this speed, providing sufficient shielding should be a trivial exercise in additional hand-wavium. . . .
easy solution by nomadic · 2010-02-17 04:40 · Score: 5, Funny

All you have to do is navigate around the hydrogen atoms.
True, But Irrelevant... by wintermute3 · 2010-02-17 04:41 · Score: 5, Insightful

I don't think anyone seriously contemplating relativistic or FTL travel expects to be physically accelerated to such speeds. After all, if stationary interstellar hydrogen is effectively hitting you at teravolt levels, it means that every particle in your body (and the ship) has actually been accelerated to velocities equivalent to the particles in the LHC beam. Not bloody likely. We need warp drive, subspace, wormholes, or something else to solve the problem, not ridiculous conventional acceleration.
- Michael
1. Re:True, But Irrelevant... by arielCo · 2010-02-17 05:26 · Score: 5, Funny
  
  Not bloody likely.
  
  Likely bloody. Very bloody.
  
  --
  This post contains no rudeness or derision of any kind. All arguments are friendly. Terms and exclusions may apply.
Economics by TrumpetPower! · 2010-02-17 05:05 · Score: 4, Insightful

Interstellar travel is fundamentally an economic paradox — ignoring, of course, such fantasies as Warp drives.
Sending a Shuttle-sized craft to Alpha Centauri in a matter of years would require roughly the current total energy consumption of humanity.
Only when our civilization advances to the point that we harness a significant portion of the Sun’s total energy output would the energy budget for interstellar travel approximate the same proportion of the energy budget we spend today on interplanetary missions.
One can suggest “sleeper ships,” but building mechanical devices that will survive thousands of years is as hard a problem as throwing them across light years of distance. Any gas will leak out of any container in such a timeframe, and no plastic or rubber seal would last a fraction of the time necessary. The next thought is to provide power to the ship during the long journey, but you need as much total energy as for getting there fast — and, if you can comfortably survive for millennia in interstellar space, why even bother with stars in the first place?
Oh — and the Fermi Paradox applies especially well. Assume that it takes even ten thousand years to colonize a remote solar system, and the entire galaxy would have been overrun by now if a colonizing civilization had started in the terrestrial Jurassic period.
Interstellar travel makes for great space opera, but it has no more bearing on reality than unicorns and dragons.
Cheers,
b&

--
All but God can prove this sentence true.
Re:Oh noes by NatasRevol · 2010-02-17 05:27 · Score: 4, Informative

10% of the speed of light is 67 million miles per hour.
Helios 2 - fastest manmade object ever - went about 150,000 mph.
http://www.aerospaceweb.org/question/performance/q0023.shtml
So, yeah even 1% of the speed of light would be 40x faster than anything else we've ever done.

--
There are two types of people in the world: Those who crave closure
Re:old news... by Geoffrey.landis · 2010-02-17 05:39 · Score: 4, Informative

They already figured this out nearly a hundred years ago.
In fact, erosion by interstellar matter (both hydrogen and dust) was a major plot element in Arthur C. Clarke's 1986 novel The Songs of Distant Earth.
A while back, at the old 1994 Planetary Society conference on Interstellar Flight, I had a paper proposing a plasma erosion shield to protect an interstellar spacecraft-- I ought to dig that one up and put it on the web somewhere, but New Scientist ought to know about it, since they mentioned it in an article back in 1995.

--
http://www.geoffreylandis.com
Re:old news... by Philip+K+Dickhead · 2010-02-17 06:01 · Score: 4, Funny

Thereby increasing, almost infinitely, the improbability of any FTL technology - thusly ensuring success for a system that harnesses improbability as a motive power.

--
"Speaking the Truth in times of universal deceit is a revolutionary act." -- George Orwell
Re:old news... by AmigaMMC · 2010-02-17 06:03 · Score: 5, Funny

>As the spaceship reached 99.999998 per cent of the speed of light, "hydrogen atoms would seem to reach a staggering 7 teraelectron volts," which for the crew "would be like standing in front of the Large Hadron Collider beam
...
Since most of the time the LHC is down that doesn't seem like a big problem :-p
Ok, big fan of the LHC, but just had to say it
You forgot to account for relativity. by microbox · 2010-02-17 07:39 · Score: 4, Informative

Actually you are missing something very important in your maths: relativity. It doesn't take much shorter to get to the destination from the perspective of someone on earth, but the tale is different for the people on the spaceship. The distance to the destination shrinks.

Sagan talks about this in Cosmos. If a theoretical spaceship accelerated constantly, it could traverse the entire universe in a mere 50 years -- but by the time it returned earth would be long gone.

Conceptually -- the universe has no "size" for a photon in a perfect vacuum. From the point of view of this theoretical photon, it is created in a distant star and intersects with your eye instantaneously. From our point of view it could take millions of years.

Considering that mass is what prevents light-speed travel (as well as the density of the medium being travelled through), that implies an interesting relationship between space-time and the higgs boson.

The universe is stranger than any fiction.

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Like all pain, suffering is a signal that something isn't right