Slashdot Mirror
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.
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?
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?
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.
Yeah, and if we could go back in time we could prove jesus never existed.
Oh, I come here for the witty conversation.
A blog about stuff.
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.
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)
"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
I agree that the chances of detecting a signal are very, very small indeed. However I see a different problem, that being the length of time that high-power broadcast signals are being used by a civilisation.
It seems likely that in the next couple of decades a lot of our brodacast signals on the lower frequencies that can escape the ionosphere will have been turned off in favour of internet based tv/radio, microwave signals from satellites directed at earth and spread-spectrum technologies that are indistinguishable from background noise.
So that means we will have had about 120 years of broadcast that has escaped into space. So, assuming we are in anyway typical (BIG ASSUMPTION), we are trying to find a transmission from a planet that went through this 120 year phase at exactly the right time thousands of years ago so that the signal arrives at earth now while we are listening.
I think the universe is big enough for there to be life out there, it's just that we won't find it, and we definitely won't hear it's radio transmissions.
Art is the mathematics of emotion
Very true.
Things that don't work on the small scale, will never work on a large scale. Can't make your family happy? Don't try to be a leader of your country (i.e. politician). Don't care about keeping your world in shape? Then stop dreaming about exploring other worlds.