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Looking for Life in Light
Gearoid_Murphy writes "Earth-like planets around distant stars may be too far away to be reached by spacecraft but scientists could still investigate whether they harbour life.
Telescope technologies are being developed that will probe the very faint light from these objects for tell-tale signs of biology.
These are the same "life markers" known to be present in light reflected off the Earth - so-called "earthshine"."
For some real signs of life, try a little moonshine.
Don't disappoint your bird dog. Go to the range.
Comment removed based on user account deletion
Telescope technologies are being developed that will probe the very faint light from these objects for tell-tale signs of biology.
I am guessing that they are talking about optical observations, since it appears to be an extra-atmospheric telescope they are designing. However, at those distances, how can they discern the difference between the shine from a planet and the light given off by the star(s) near the planet? I would think that we observe the earthshine from small enough distances that we can see it in spite of the Sun. I am curious how this would work for distant bodies.
If nothing else, it'll show up on the earth shine and indicate we're inhabited. On the other hand, they probably already know that...
An Indian-American Hindu committed to non-violent thought/speech/action alarmed by the global explosion of radical Islam
We may call it 'earthshine', but advanced extraterrestrials probably call it 'signs of parasitic infestation', and warn tourists to stay away in case they catch something.
You say albedo, I say libido...
Here come da fudge!
From the article:
...but not life!
"'This gives you some information on habitability,' said Wesley Traub, chief scientist on the US space agency's (Nasa) Navigator Program..."
How will this help? Radio telescopes can look at the absorbtion spectrum of the planet for the tell-tale lines of water, methane, oxygen (both O2 and O3), and other markers of highly reactive chemicals - especially when they will react with each other. When you have an atmosphere that is chemically violently unstable (as is the case on Earth), it must be being maintained by some process.
That's the first clue, but only the first. The second clue is that "dead" planets will be in equilibrium with their surroundings, but "living" planets will always be in opposition. (Organisms will always create a dynamic equilibrium that suits them, so must always counter any and all natural phenomena that would push the system away from that preferred state. Simple negative feedback.)
Simple radio telescopes can do all this now, no new optical technology need be developed, and no assumptions about the type of life need be made. (All the above assumes is that life can never be inert and that any specific organism cannot function equally under all potential conditions. That's broad enough, although there will probably be exceptions even then.)
The Km array proposed (and the hectare array already built) are just a huge stack of ordinary satellite TV dishes. This could be done by anyone at any time. A mile array would give you 2.5x2.5 pixels ast 100 lightyears - enough to discern if weather patterns exist, though not enough for any long-range forecasts.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
If you do an spectral anaysis of IR etc reflecting off the earth, you'll get certain signatures for trees, grasslands, sea, coulds cities etc. So if observers see the similar patterns they will assume that the distant planets will have a similar biology, cities,...
Of course these are all just assumptions. The scientists hope to make discoveries which they can publish for fame and glory. Luckily for them, they'll probably be dead long before they can be verified by eyeball technology.
Engineering is the art of compromise.
I can't understand why these guys are searching so hard for life in light. There have to be at least a dozen half-dead bugs in the ceiling light about 7 feet away from me.
Where's the news? NASA's had the Terrestrial Planet Finder in the works for years now. Is it a slow news day at BBC?
"Nasa's Jet Propulsion Laboratory suggest the technologies are getting close to the sensitivities required." Hey, Jet Propulsion Laboratory -- KEEP OUT OF OPTICAL SCIENCE'S BUSINESS. Go study jet's or something... geesh.
A computer once beat me at chess, but it was no match for me at kick boxing.
From what I hear these aliens are just non-stop lining people up on volcanos and nuking them. Maybe we don't want to go ringing doorbells just yet.
We want to:
A. attempt to detect life on a planet that is too far away for us to determine if we are correct any time in our lives
B. using a method that has an unknown accuracy
C. despite the fact that we don't even have an idea of the *order of magnitude* of the chances of life out there
What's the point?
That fact has always fascinated me. If we could travel faster than the speed of light with a huge telescope we could observe historic events. Thats pretty cool if you ask me.
Shine get!
Is communication from Commander Znetab of Zygort Interstellar Death Fleet:
Radio frequency wavefront from your planet is passing through our fleet causing much physical distress. Auditory awfulness of "Wayne Newton" voice recordings we are considering weapon of mass destruction. Is reducing all fleet radio operators to disembodied protoplasmic goo. If not stopping immediately, destruction of your insignificant planet will be accomplished. You have been warned!
Is ending communication.
Some mornings it's hardly worth chewing through the restraints to get out of bed.
Last time I checked, there exists a project already doing this. It's called SETI. They very thouroughly comb a large range of the EM spectrum for any data representing intelligent life. This proposal instead takes hazy samples from a very narrow band of data (the visible spectrum), to guess at the chemical composition of other planets. So we've replaced listening to white noise with looking at faint blue dots.
That's not AT&T, that would be PSU
"Earth-like planets around distant stars may be too far away to be reached"
May be?
and tried to find intelligent life by the light signature. All they'd see are the blue darters...
You keep using that word, I do not think it means what you think it means
If we have the ability to detect life on other planets, then surely if there were more intelligent life out there, they have the ability to detect us. Since no other life forms have detected us, we can therefore conclude that we are the most intelligent life forms in the galaxy.
Damn it.
My Karma is still positive.
Would some one please fuck up my slashdot id... its just too low... thank you!!!
asdf asdf (mushroooms usenet google)
It will just take a while to get there. Weapon systems are robust. Of course, we don't know when they detected us so we don't know how much time we have to set up defenses.
As an aside, your signature brought to mind the high school I went to. Some silly idea about "self-directed" learning, which actually just meant that the school only had to pay its staff to mark papers and yell at kids who brought slurpees to the study hall, rather than actually teaching anything. The graduation rate was about 20%, most of whom graduated a few years late. What an abomination. Not quite the same thing as "unschooling", but a potent demonstration of WHY schools are the way they are. As sucky as that model is (and it is undeniably sucky), we just don't have anything better yet.
Are you sure about the capabilities of such an array? There are two main properties to a radio telescope (or any telescope for that matter) and that is Resolution and Lightgathering. By increasing the diameter of the collecting dish you increase both the resolution and lightgathering capacity. By creating an array using interferometry you can increase resolution to create a "virtual" dish with a diameter equal to the distance from one end of the array to the other. This doesn't, however, increase lightgathering capacity the same way. Let me propose a crude analogy: think of dishes as buckets, you can put two buckets 50ft apart and infer how much rain fell between them by adding them and dividing by two, but if it was just a drizzle, your data wont be so hot. If however, you have a 50ft bucket, you're gonna collect a lot of water.
So an array of a bunch of teeny TV sattelite dishes wont have as much surface area as a dish a kilometer wide. So yes we could resolve a planet, but it would have to be bright enough to be seen.
If you are about to mod me down, keep in mind that this post was most likely sarcastic.
And with a really big single dish we could see planets that aren't bright enough to be seen? ;)
In practice, the Square Kilometer Array is intended to have a collecting area close to the physical area of one million square meters - requiring almost no gaps to exist between dishes.
My first calculation would be for dishes with a wider gap, which would give you much greater flexibility on pointing the damn thing, as you can't see through the other dishes. Personally, I consider this to be a much superior design, even though it would cost on the collecting area. Unfortunately, they are the ones being paid, even if I am the one who is right...
By way of comparison, Jodrell Bank Radio Telescope is a paltry 76 meters across, for a total collecting area of 4560 square meters, and that's one of the largest single steerable telescopes out there.
I'm going to guess that a collecting area about nine times that of Jodrell Bank, combined with a resolving ability that is, well, astronomical, you would get a very respectable image of Earth-like planets around other stars. If we accept the SKA group's claims, then you've a collecting area 250 times that of Jodrell Bank.
I first heard the 100LY=1 pixel resolution with SKA from Jill Tarter, head of the SETI Institute at a talk she gave at NASA Langley. From crunching the numbers, I can see nothing that could seriously contradict the claim. Even if you assume my model is the more reasonable implementation, the complete MERLIN network that has been detecting jovian planets for some time has only a fraction of that collecting area - probably something like a quarter or a fifth. (Aside from Jodrell Bank, the next-largest radio telescope in the UK is a paltry 32 meters across.)
If we go with SKA's claims, then we're talking about collecting possibly hundreds of times the total radiation, which would definitely be enough to spot even the tiniest of worlds - provided it had some characteristic reflected in the radio spectrum.
(It's also worth bearing in mind that networks such as MERLIN, which are hundreds of kilometers across, are set up for VLBI - very long baseline interferometry. That's fine, when you're talking about gas clouds or stars, but is probably none-too-hot for spotting very fast pulsars or rocky inner planets. On the other hand, a kilometer would let you use regular interferometry, which means these things would show up quite nicely.)
There are three drawbacks to all of this, and I'm surprised none of the posters has commented on them (so far). First, interferometry requires very exact timing of all the delays in the system, or it won't work. Let's go with the SKA estimate and say the dishes are 1 meter apart. Your clock must count an integral number of ticks for every meter the signal travels from the dishes, even after allowing for the natural variation in the data lines varying the speed of the signal. This is some astonishingly serious timekeeping.
The second problem is to keep the signal noise-free. Easy, for a giant single steerable dish - you plunk it in the middle of nowhere and surround it with a huge Faraday cage that only obscures the horizon. When you've a few tens of thousands - or millions - of very small dishes, the problem isn't so easy. The terrestrial radio sources will be far harder to screen out - not just
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
Well then they would be bright enough to be seen, since there would be much more light gathered
You just got troll'd!
"Parents who Unschool [wikipedia.org] should be charged with child abuse."
// contrary to popular belief, I had plenty of food, it was just not MacFood, it was healthy food :)
Strange, since it seems to me that its mostly an American thing... our children are lazier than hell. And public school teachers are coerced into standardizing a shitty education, instead of making it engaging, interesting, and possibly controversial (as in the case of history, politics, language, physics? I once had a physics professor who began class by explaining that explosions are really fast burns, and, in fact, that flour, as in the food ingredient actually does burn very fast and demonstrated blowing up flour. How's THAT for a controversial high school physics class?)
I came here with an eastern european education and found school easy, boring, and mostly a time sink for children, keeping me, personally from doing what I liked most... reading and researching for my own. (Keep in mind, most of eastern europe at the time had 6 day work weeks, and 6 day school weeks, but school was only about 4 hours a day and 2 or 3 days had also an after school gym class (mandatory, but VERY different than the lame duck gym we have here, most kids there were both limber, agile and rather thin.)
You have no idea how mind numbing our schools here in the USA can be, especially to someone accustomed to learning a lot on the outside on the extensive free time the "communist" education system offered (4 hours of mandated science, language, geography, history (oddly, I find that they taught relatively accurate world history, other than aggrandizing their own power plays as "wonderful displays of humanity, etc" At least the commies weren't racist where I lived (the russians are another issue, I hear they didn't get along with the jews too well)). Anyways, everything they teach here is cut and dry, and they have VERY few classes that facilitate discussion, controversy, and therefore, growth. The promulgation of heroification in history and political science is also extremely disturbing.
Imagine, if you will, going into 5th grade math, having the lady give you the american used sign for long division, and setting up some random 6 digit number divided by 3. Now imagine the child in question, being thought "about 4th grade in math skill" because he takes the cube root (by hand) of said 6 digit number. I guess the word "radical" doesn't enter into mathematical speech until about 10th to 12th in our fine country of SOL testing buffoonery.
So I promote, less the unschooling, and more the MORE FREE TIME FOR KIDS AND MORE FREE TIME FOR PARENTS. We had school from 06:30 to 10:30 in the morning. No more, no less. Gym was 2 hours x 2 days. We only had Sunday off, but school was FUN because it actually taught challenging things, and homework wasn't just busy work, it was relative, and usually short, mostly a cementing factor (as opposed to homework in the US which is at best bland, and worst busywork). My parents came home from work around 0400, they left around 0700 (I always left first) and we actually had time together, there was less shit on TV, except one hour of anime at 18:30 (6:30 PM) and that was my TV watching. And imported movies, once or twice a week. Other than that, I spent my time becoming acquainted with the works of the masters, from Master DaVinci to Jules Verne to Aristotle and Shakespeare. Strangely I also had time to go outside, play soccer both for fun and in a club, AND play chess (freestyle and tournament). I can guarantee less kids have time for this before they're 11 in our country, because we're pushed to "spend more time in school". Efficiency is something that is advertised but STRONGLY discouraged in America. Freedom is another one of those things, strongly advertised and COMPLETELY antithetical to the way of life Americans endure.
We just want to guzzle more gas, more food, more TV, more everything while having others think for us, since thinking is far more painful for the majority of Americans than even the other most painful thing... losing weight.
" What luck for rulers that men do not think" - Adolf Hitler
The light they can detect is the sun shining out of alien's asses.
Then which of geckos, termites or moss have you put below us?
I haven't given this topic a great deal of thought or investigation, but it seems to me very unlikely that there is anybody out there.
The problem is that electomagnetic waves, including radio waves, travel at the speed of light. Now correct me if i'm wrong on this but doesn't this mean that when we look out into space, in terms of lots of different ways in which communication might happen, we are looking at what is effectively a history of the universe?
So the question is, over the vast lifespan and stretches of the universe, is it really likely that not one single civilisation has broadcast one signal that is recognisably of intelligent origin, at some point in its history.
Even if it destroyed itself with nukes, or was very shy, at some point it will surely have broadcast some waves and these would still be bouncing around in space, and falling upon our detectors.
Now i wouldn't suggest that the plug be pulled on the seti program or anything but don't hold your breath. The chances are, ET is not home.
We may well find evidence of alien sludge, flora or fauna but intelligent alien life is a different matter. Its my belief that something very special happened in relation to humans. Whatever it was that led to the 'great leap forward' 40,000 years ago, we are very lucky to be on the right side of it.
I'm not sure I understand.
We, the "intelligent" inhabitants of our planet, are destroying our habitat, and killing each other in wars.
If, for example, we don't respect HUMAN life in the 3rd world (just 1000s of miles away) enough to help them to a long-term resolution, then what would we do to NON-HUMAN life?!?
I'm not only _expecting_ all SETI efforts to fail, I'm also _hoping_ they fail.
This whole thing is a waste of money. These people want to spend hundreds of millions of dollars to attempt to scan for possible "life markers" from very distant planets. We will never be able to visit these planets in the forseeable future. What sort of returns will we ever see from this astronomical sum of money if it is spent for this purpose? "Oh, XYZ planet 100 bazillion miles away could have conditions necessary for life (thank you for the cash)."
The hundreds of millions of dollars would be better spent right here on Earth: undersea exploration and settlement, energy mining, etc.; implementing technology to turn the deserts of the Middle East into lush gardens (one country there has a good head start). Even spending money to mine mineral resources from the moon, nearby planets, and the asteroid belt would be money better spent than this nonsense. At least spend the money on something that we can use both right now and in the near future to better the lives for life on Earth AND provide some sort of return on the investment. If we can actually make use of this sort of research later, then research it later.
We used models and satellite cloud data to simulate the Earth reflectance for a whole year. We then applied what we'd learnt from Earth to an extrasolar planet.
This means they are only "guessing" based on a "simulation" of what "life markers" look like from a distance. It's not even guaranteed to be accurate! They want to spend hundreds of millions of dollars looking for something based on a guess!
-M
There is no need to search space for ET life.
The ETs are already here.
Just watch this NASA footage
http://tinyurl.com/eslxh
Then watch this to see how and why it's done.
http://tinyurl.com/oxm2q
&
http://tinyurl.com/rvtc7
You light up my life
You give me hope
To carry on
You light up my days
and fill my nights with song
http://www.romantic-lyrics.com/ly6.shtml
This wasn't just plain terrible, this was fancy terrible. This was terrible with raisins in it. — Dorothy Parker
I'm all for looking for more earthshine, after all, that was the best song of of Vapor Trails.
No one got beat up more often than the mimes of the old west!
If we find oxygen in the atmosphere, we have found life. Oxygen is very reactive, without some process to constantly replenish it, any oxygen in an atmosphere would very quickly bind with other chemicals. The only process we know of that can do that is life. There could be others, but it is a very safe bet that where we find oxygen, there's life. Here's a link to the wikipedia article about earth's atmosphere, specifically the part about it's evolution.
P.S. Anyone else first learn about this stuff through SimEarth? Hehe. Fun game, very educational.
- None can love freedom heartily, but good men; the rest love not freedom, but license. -- John Milton
One of my buddies is working on this project. He had this to say about how the optics work:
"The basic idea is that under Fourier optics, a wavefront with electric field E that hits a lens with focal length f will produce the Fourier transform of that field E at a distance f from the lens. This location is called the image plane. The location of the lens is called the pupil plane, and the idea is that if you block part of the light at the pupil plane (say with a piece of material in a particular shape, called a mask), it can change the shape of the Fourier transform at the image plane. If we consider the incoming light to be from a star and a planet, we can design the mask so that there is very little light from the star in certain regions of the image plane, and we can see the light from the planet in those regions.
For a more rigorous introduction, I might recommend this paper from our group, which covers the basics of shaped pupils and shows some of our more interesting mask designs. The real challenges in this area now are eliminating the effects of tiny errors in our optics--the best we can get physically is to reduce the error in flatness of the various mirrors in the telescope design to on the order of 0.01 wavelength. (TPF will work in visible light, so that's on the order of a nanometer.) We need 0.0001 wavelength, though, and so we're trying to use adaptive optics (mirrors that we can shape) to cancel these errors. Researchers in this area are very close to achieving the "10 billion times brighter" from the article, we just need to show we can deal with these errors. Very interesting stuff."
m0nstr42.blogspot.com
1903 Called. It wants to know why the Wright Brothers had this idiotic need to fly across a field. After all, perhaps time travel would have been more useful, than say moving people from place to place......
Huh?
Your resolving power, however, should be pretty damn amazing at 20 miles diameter. Ok, so what's wanted here is something nice and noisy, where your ability to isolate a region of sky and/or track an object would be of value.
You could probably track the storms on Jupiter - you can detect those with even a trivial dipole and a receiver in the right range, so you've certainly got more collecting power than necessary. Not sure how accurate your measurements would be, but that would make a fascinating experiment.
GnuRadio will turn your computer into a suitable receiver (provided you either have a soundcard that works at the right frequency, OR you have a suitable analog-to-digital converter plugged in somewhere). You then need to process the streams into something interesting. I believe AIPS is what you'll want for this. It is "professional" Open Source software for interferometry (read: the interface is crappy, but the logic is superb).
The nearer satellites - such as those orbiting Mars - should be well within your ability to receive and track. I doubt there will be any encryption on the data being sent to Earth, so you might be able to get real-time(!) images from the probes. The only question there is whether the signal would be strong enough to correctly interpret. The same would be true of anything sent by the Cassini probe, although it is much further away and therefore would be far fainter, so you might be restricted to just knowing where it was. Which would be pretty damn good, even so.
I would certainly encourage you to give it a try and see what you can do, and also to diary what works. You may well be able to do far better than I expect - it depends on how big the dishes are and how well you are able to sort signal from noise.
You get your Real Ultimate Power badge if you can intercept a message from either Voyager probe, and an honorary lifetime membership of the Q Continuum if you can get any kind of signal at all from one of the Pioneer probes.
(Note to the humour-deprived: If NASA can barely achieve the former, and can't achieve the latter at all, on the Deep Space Network, there is no friggin' way an amateur is going to on three dishes... unless they ARE in the Q Continuum, in which case the prize is easy.)
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)