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Could An ExtraTerrestrial Find Earth with a Telescope?

Zonk posted more than 6 years ago | from the helloooo-up-there dept.

Space 179

Active Seti writes "If aliens were hunting life outside their own planet, could they peer through the vastness of space and lock onto Earth as a likely home for life? Researchers say with a roughly Hubble-sized array observers could measure Earth's 24-hour rotation period, possibly leading to observations of oceans and the chance of life. 'They would only be able to see Earth as a single pixel, rather than resolving it to take a picture,' said Astronomer Eric Ford. 'But that could be enough for them to identify our planet as one that likely contains clouds and oceans of liquid water.' The research will be useful to astronomers designing the next generation of space telescopes on our planet, because it provides an outline of the capabilities required for studying the surfaces of Earth-like worlds."

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Well then... (1)

Dragon By Proxy (1063904) | more than 6 years ago | (#21788364)

Phoning home wouldn't cost that much after all!

I've got an idea (4, Funny)

ILuvRamen (1026668) | more than 6 years ago | (#21788368)

We should totally arrange some stars into a smiley face or big arrow pointing at us then (yes I know that would only look right from certain angles, it's a joke). But you've got to wonder why some other super advanced civilization didn't move some stars around to circle themselves or something and make it really obvious where they lived.

Re:I've got an idea (4, Funny)

edwardpickman (965122) | more than 6 years ago | (#21788436)

They probably did it's just their smiley face has five eyes and no mouth. The stars spelling out "We Are Here" are tough to read given the language differences and they use a pentagon to point instead of an arrow given they never developed archery. Celapods have trouble with bows. There is hope of translating the "Free Beer" part of the sign if we can only figure out the translation for beer. We do know there's an exclamation mark like symbol at the end of what's thought to be the word Beer. We know it as Orion's Belt.

Intergalactic quarantine symbol (5, Funny)

Hognoxious (631665) | more than 6 years ago | (#21789228)

Rings around a gas giant means "keep the hell away from this system and don't, whatever you do, let the inhabitants get out".

A pentagon-shaped smiley? (2, Funny)

haraldm (643017) | more than 6 years ago | (#21789246)

Whoa - if their smiley were pentagon-shaped I'd definitely run! Other civilizations with pentagon-shaped things aren't famous for being friendly towards people who are "different".

Re:A pentagon-shaped smiley? (2, Informative)

Rhinobird (151521) | more than 6 years ago | (#21789452)

What the hell. Most of the Wiccans I've met are perfectly ok people. Wierd, but nice.

Re:A pentagon-shaped smiley? (1)

tyrione (134248) | more than 6 years ago | (#21789634)

Wiccan wear Pentacles and use ritual Pantacles.

Pentagons are a sound dig at the Pentagon of the USA.

Re:I've got an idea (4, Interesting)

AKAImBatman (238306) | more than 6 years ago | (#21788450)

But you've got to wonder why some other super advanced civilization didn't move some stars around to circle themselves or something and make it really obvious where they lived.

Impracticality? I mean, moving a star takes a tremendous amount of energy. Either that, or a massive gravitational mass that can be moved through more conventional means. (One of the drawbacks of stars is that you can't exactly setup thrusters on the surface of a flaming, gaseous body.) If they were even close to such technology, it would actually be easier to send out explorers than to muck around with the position of stars.

Assuming that such a civilization could even exist. Which is (unfortunately) somewhat doubtful. Everything we know so far suggests that life is exceedingly rare in the universe. Rare enough to make it difficult to find another civilization that used to exist, much less one that you can actually contact. (Don't even get me started on the incredible time scales by which the older civilization would be long dead before we could even see each other.)

Re:I've got an idea (1)

WallyDrinkBeer (1136165) | more than 6 years ago | (#21788708)

Everything we know so far suggests that life is exceedingly rare in the universe.
Um, they told you that in bible school, right? We are not so special. There are 10^21 stars out there - there must be many civilizations out there.

Re:I've got an idea (4, Interesting)

AKAImBatman (238306) | more than 6 years ago | (#21788784)

Um, they told you that in bible school, right?

No, basic scientific principles told me this. While the Drake Equation [wikipedia.org] is not accepted by all scientists as a valid computation, the Fermi Paradox [wikipedia.org] is still a difficult problem to solve.

We are not so special. There are 10^21 stars out there - there must be many civilizations out there.

To throw an equally unfounded accusation back at you, you're a fan of Carl Sagan, right?

Let me put this in simple terms: The size of the universe is known to be at least 93 billion light years across, and is estimated to be ~13.7 billion years old. In a universe that big and that old, there is a strong chance that any other civilization(s) that may have formed are extremely far apart from one another. So far apart that there is a good chance that the civilization(s) will "miss" each other's existence.

Like it or not, if there was a civilization coexisting in our neck of our galaxy, we'd have some inkling of it already. Unnatural radio transmissions would stand out against the background radiation and give us a sense that another civilization is there. We have been scanning the skies with powerful equipment and so far have come up with little to no evidence of such transmissions.

The long and short of it is that from what we know today, there's an infinitesimal chance that we humans will ever meet another civilization. The best we can hope for is that we find planets that support more basic forms of life.

Re:I've got an idea (2, Informative)

esper (11644) | more than 6 years ago | (#21789020)

It's only been about 100 years since Marconi invented the radiotelegraph. Even if we assume that they would be 100% certain to pick up any signal we've sent, no matter how weak, and that they would be 100% able to recognize it as carrying meaning, any civilization more than 100 light years or so away would still have no inkling of our existence based on unnatural radio transmissions. A 100 light year sphere is a pretty small chunk of space compared to the rest of our galaxy. Much too small of a chunk to draw strong conclusions from, IMO.

Re:I've got an idea (2, Insightful)

sweet_petunias_full_ (1091547) | more than 6 years ago | (#21789260)

The other way to look at this is that it would take 100 years for signals emitted from within this (mostly empty) 100 light-year sphere to get here.

If we extend it to 1000 LY in order to increase our chances, that means that any signal we get now is from a civilization 1000 years ago -- which is now 1000 years more advanced than when they sent that signal. Assuming they will receive /our/ signals in 1000 years, that gives us about 2000 to evacuate and go mum before we would expect their 1000-year advanced disintegrator ray to hit these coordinates. :)

To sum up, either we have to be really, really lucky to find aliens "nearby" who haven't figured out how to stay quiet, or, the aliens are so far away that we might be luckiest if they don't find us.

Re:I've got an idea (1)

KDR_11k (778916) | more than 6 years ago | (#21790462)

That, or we might already have destroyed ourselves in some way by the time the signals get anywhere. Same for the other civilizations, who's to say that even if we get their signals, that they are still alive by the time we read them or even worse, get there?

Re:I've got an idea (1)

SamP2 (1097897) | more than 6 years ago | (#21789762)

This has nothing to do with bible school, but a simple knowledge about rudimentary statistics.

The there is life on OUR planet (by itself) says absolutely nothing about an increased chance it would be on other planets. For the simple reason - in the hypothetical scenario where there was only one planet in the universe to harbor life, the inhabitants of that planet would be in a similar position to us - they know life exists on their planet, and nothing about the rest. But what about the billions of other planets? Well, since there is no life on them (in that scenario), there is nobody there to compare.

If there was even one OTHER planet than our own that has life, we could deduce an average statistics based on the distance between the planets and the size of the universe (e.g. if our max visibility is 100 light years and we found one planet in that bubble, and the universe is 100 billion light years across, then statistically there is (even if a very very very crude approximation which may be way way way off) about a billion planets that have life (in a given 1-D vector actually, if you look at it from visible volume vs invisible volume, the number will be even much larger).

But you need at least one other planet for this to work. If there is only one planet you know that has life, and you are sitting on that planet, the fact your planet has life makes absolutely no statistical difference on the chance of life on other planets (other than of course knowing it's POSSIBLE for life to exist, and estimating favorable conditions for it to happen). But you can't say that since we have life here, it must exist somewhere else, without having at least one other comparison point.

Re:I've got an idea (1)

myth_of_sisyphus (818378) | more than 6 years ago | (#21788732)

I don't think an advanced civ. would even want to talk to us. They have their shit sufficiently together to travel interstellar distances so why would they even want to talk to a planet that can't even provide food to all its people and who kill each other and who have come close to complete annihilation not once but twice?

They might send some exo-sociologists and maybe beam up a few cows and hicks but that's it. We would be poison to them. They might even set up a few quarantine beacons outside the solar system. Maybe that's why those Pioneer probes are slowing down. They'll hit a barrier right outside Pluto.

Re:I've got an idea (1)

GooberToo (74388) | more than 6 years ago | (#21790178)

a planet that can't even provide food to all its people and who kill each other and who have come close to complete annihilation not once but twice?

Because maybe they just found food and water for their people? And space to expand? ;)

Re:I've got an idea (1)

WhatAmIDoingHere (742870) | more than 6 years ago | (#21790484)

Why would they want to talk to us? Because we're here.

Re:I've got an idea (1)

statemachine (840641) | more than 6 years ago | (#21789572)

One of the drawbacks of stars is that you can't exactly setup thrusters on the surface of a flaming, gaseous body.

But while we're talking about impracticalities, you could have an easier time extinguishing the side facing the direction you want it to move.

Re:I've got an idea (1)

vertinox (846076) | more than 6 years ago | (#21790160)

(One of the drawbacks of stars is that you can't exactly setup thrusters on the surface of a flaming, gaseous body.)

Well if such a civilization had reached a technological singularity event, most likely they've got a lot of time on their hands since they would have figured out how to avoid mortality by old age and would most likley use something like a gravity well to shift the stars slightly over billions of years.

Rather than push the start, they could move it in the direction of said gravity well over time. Of course that might be mini black holes or neutron stars.

Re:I've got an idea (1)

keithmo (453716) | more than 6 years ago | (#21788458)

Maybe they did, but their "smiley face" looks like a random collection of stars to us.

Re:I've got an idea (1)

explosivejared (1186049) | more than 6 years ago | (#21788556)

You're onto something there. Their smiley face would probably not be anthromorphic, as they probably don't look like humans. If I were a super advance civilization that could move stars and such, I would move black holes around me as to cloak my existence. If I have the power to move stars, there is a good chance that someone else does and could use it to blow me up.

I say we start looking for constellations that resemble our imaginations of aliens. After that we look for black hole clusters and then wipe out those galactic hide and seek playing wimps for being galactic hide and seek playing wimps. You can move stars have some courage!

Re:I've got an idea (1)

Martin Blank (154261) | more than 6 years ago | (#21788758)

Cloaking yourself with black holes may well end up drawing attention to you. It's a decidedly unnatural arrangement, the poles tend to spew X-rays, and even without that, a hole in space could well draw curiosity. I heard tell of stories of the early days of the Ohio-class boomers which were so quiet that the Soviets looked for dead spots in the water. It wasn't a perfect method, but it sometimes gave more clues as to the location than the US ever planned. Eventually, some method of combating this with white noise or some other similar method was integrated, and the loose tracking stopped.

Re:I've got an idea (1)

Double_Duo_Decimal (1104907) | more than 6 years ago | (#21789596)

There is an arrangement of singularities in the Star Wars universe called the Maw. In the (incredibly hard to reach) middle of which sat the developing grounds of the Death Star and the Sun Crusher. Because the black holes were put in relatively close proximity to each other(by an unknown force) there was a veritable maze of gravity to hide the center.

Re:I've got an idea (2, Insightful)

ILuvRamen (1026668) | more than 6 years ago | (#21788612)

well then they're dumb cuz just looking at the galaxy, it's not that hard to come up with a formation that would look incredibly unnatural. Like groups of stars forming the first couple prime numbers or a giant perfect circle that are 1/100 of a lightyear apart. Or even just a simple line of them spaced really close to each other and perfectly equidistant.

Re:I've got an idea (0)

Anonymous Coward | more than 6 years ago | (#21788482)

If there existed a "super advanced civilization" I doubt they'd be willing to make their location obvious to other regions of the universe without doing a background check on other "civilizations" first.

A Space Ship to Visit the Space Alien (2, Interesting)

reporter (666905) | more than 6 years ago | (#21788532)

A space alien peering at us is a quaint idea. What does his ogling us accomplish? He can never reach the earth, and we cannot reach him in that neighboring galaxy.

If we really want to explore the stars, we must focus on high-risk projects that bust the fundamental notions of science. One such project is the hyperdrive [newscientist.com] . Burkhardt Heim developed a unique (almost incomprehensible) field of physics. If he is right, then we can build a space ship to visit the space alien peering at us.

Note that one deduction from Heim's work is a formula for calculating the mass of fundamental particles. The formula has been subjected to review by esteemed physicists and is 100% accurate. Could the hyperdrive be another valid consequence of Heim's work? The possibilities are quite tantalizing.

"To boldly go where no one has gone before ..."

Re:A Space Ship to Visit the Space Alien (1)

raving griff (1157645) | more than 6 years ago | (#21788560)

The mere fact that such technology is becoming feasible to us suggests that alien beings may have similar technological advancements, allowing them to visit us.

Re:A Space Ship to Visit the Space Alien (2, Interesting)

Free_Meson (706323) | more than 6 years ago | (#21789068)

The kind of "visit" an alien intelligence would pay us would be most unwelcome.

No civilization is crossing the vast emptiness of space for any reason other than settlement. The investment of resources required for such a journey would be too massive to be undertaken for any other reason.

Re:A Space Ship to Visit the Space Alien (1)

KDR_11k (778916) | more than 6 years ago | (#21790506)

Depends. We're spending a lot of money to get pictures of the different planets in our solar system despite most of them being completely unsuitable for habitation or even terraforming. If we saw another civilization we'd send some probes there out of sheer curiousity.

Re:A Space Ship to Visit the Space Alien (0)

Anonymous Coward | more than 6 years ago | (#21789306)

Why has his post been modded as troll? Here's an interesting article about Dr. Heim's hyperdrive: yro.slashdot.org/article.pl?sid=07/07/24/174240 [ripway.com]

Re:I've got an idea (0)

Anonymous Coward | more than 6 years ago | (#21788686)

...yes I know that would only look right from certain angles...
Not quite as hard as moving stars, but it is totally within our abilities to fill our part of space with an orbiting cloud of corner reflectors. This way, any civilization sending out a PING would get an immediate echo of the very same signal regardless of which angle they're broadcasting from. Of course, they would have to be actively searching rather than passively listening.

Re:I've got an idea (0)

Anonymous Coward | more than 6 years ago | (#21789538)

Ya they did... it's called constellations.

Re:I've got an idea (3, Insightful)

RAMMS+EIN (578166) | more than 6 years ago | (#21789904)

``Sometimes I think the surest sign that intelligent life exists elsewhere in
the universe is that none of it has tried to contact us.''

Re:I've got an idea (1)

Peter Lake (260100) | more than 6 years ago | (#21790050)

They did. But after centuries of politicizing the project they ran out of bugdet and instead of 42 it came out as number 37 [nasa.gov] . The other super advanced civilization had a competing project, but after their religious fundamantalists came to power they decided it should send a deeply spritual message - voila: a coathanger [nasa.gov] .

Too much work.... (1)

ColdWetDog (752185) | more than 6 years ago | (#21788388)

I, for one, would just wait for the Instructional Videos to arrive.

Doesn't that mean.... (1)

markswims2 (1187967) | more than 6 years ago | (#21788396)

Shouldn't we have the same odds looking the other way? for all we know, we can be looking at an alien civilization that's looking at us right now. The problem is the planet renders to a single pixel. Good luck SETI.

Single pixel? Not a problem... (1)

LynnwoodRooster (966895) | more than 6 years ago | (#21788778)

All we need to do is get one of those really cool computer programs like they have on CSI where we can zoom in even further, enhance, and make out their continents...

Re:Doesn't that mean.... (2, Insightful)

Bartab (233395) | more than 6 years ago | (#21789270)

Exactly, which is why the occasional "SEE, NO OTHER EARTH LIKE PLANETS!!!" as proof for everything from "life is rare" to "ghod created us" are all silly noise.

Star Trek already did it (0)

Anonymous Coward | more than 6 years ago | (#21788410)

Episode #8 of the original series, titled "Miri." Captain Kirk and company land on a duplicate of Earth inhabited only by prepubescent children. In a search for a cure for aging, scientists unleashed a virus making anyone beyond puberty go absolutely mad, mutate, age rapidly, and die. When the crew lands and becomes infected, they have to find a cure while dealing with the mutated "greps" and the horde of adult-fearing children simultaneously.

Too many assumptions? (4, Insightful)

RobertM1968 (951074) | more than 6 years ago | (#21788422)

The article makes a lot of assumptions such as:
(1) Life on other planets has the same requirements for existence as us (Class M
        planet, water, air like ours, gravity like ours, etc)
(2) Extra-terrestrials will be using technology similar to ours (as opposed to more advanced tech)
(3) (Basing off #1 being true as they did) there are planets suitable for life such as ours that
        we haven't yet discovered that are looking in our direction.

Re:Too many assumptions? (1)

calebt3 (1098475) | more than 6 years ago | (#21788546)

Class M [wikipedia.org] ? Since when did we move to the Star Trek universe?

Re:Too many assumptions? (1)

RobertM1968 (951074) | more than 6 years ago | (#21788620)

Well, I live in the Star Trek Universe quite often lately (check out http://www.startreknewvoyages.com/ [startreknewvoyages.com] )...

But, that aside, this IS Slashdot... I'm pretty sure every geek... I mean Slashdotter here knows what a Class M planet is... and if not, you just provided them with the necessary explanation ;-)

Re:Too many assumptions? (4, Informative)

Liquidrage (640463) | more than 6 years ago | (#21788604)

There's a lot to that discussion. We tend to assume that the laws of physics will work pretty much all over the galaxy. And in places where our current understandings break down, life isn't likely to exist (black holes, Planck scales, etc...).

Given this assumption, there aren't a lot of options for different types of life. The chemistry just doesn't work. Biology is chemistry, chemistry is physics, and physics is mathematics. It basically puts in some ground rules for life. There's a decent little wiki on this: http://en.wikipedia.org/wiki/Alternative_biochemistry [wikipedia.org]

As you can see in that wiki (there are pro's and con's for each of the alternates), based on our understanding life either does need most of the same things we do, or at least our biochemistry should be the most common in the universe. The math just makes it that way. There are some variables sure. And some alternatives. But for the most part, looking for stuff life us seems to most likely scenario.

Now, given this, #1 and #2 should fall somewhat in line with what they're thinking. Sure, the minutia of evolution could lead to exotic live from our perspective. Something other then DNA based life even. But they (the aliens) should still come up with e=mc And their biochemistry should, at least, be something comparable to ours.

Re:Too many assumptions? (0)

Anonymous Coward | more than 6 years ago | (#21790156)

"The math just makes it that way." While I basically agree with you I still think that math and what have you could work completely different in another part of the universe. You just never know. The universe is so mind-bogglingly immense.. I'm so used to dealing with things that fit inside other things. You know.. your car fits in the garage, your house in your city, your city in your country, your country onto a continent, and a planet into a solar system.. but solar systems fitting inside something.. and what always gets me to the point where I feel like I'm on an acid trip and about to hit a wall... what's the universe inside of? What could possibly be big enough to contain the universe? How? OK I'm getting off topic. My other point is that there's already examples of alternative biochemistry in bacteria and what have you here on Earth, especially in environments that really promote unique conditions, such as the bottom of the ocean. I can honestly see a possibility of say, a sulfur based life form existing on another planet.. possibly even intelligent life based on another source/form. Who knows.... it's too early, I'm going back to bed.

Re:Too many assumptions? (1)

Scotman (1126481) | more than 6 years ago | (#21789844)

I just want to add to that. We have microscopes that can see things that lensed based scopes can not see. The ones I am referring to use magnetic fields to control the light and bring it up to something a camera can see. There is no reason this can not be revered for a telescope to see details at much greater distances. We have no need for them here on Earth and have not got such a thing working yet (not that I know of). However if life on another planet had a higher level of technology, and more importantly a reason to make such a thing that could see that far) there is no reason it could not be made. We still have no idea how good such a system would be. Perhaps if an alien had this, he could have Google Earth like pictures of Earth.

Re:Too many assumptions? (0)

Anonymous Coward | more than 6 years ago | (#21790012)

I'd add an assumption myself: we didn't yet take a photograph of the (relatively small but way near) apollo mission remains on the moon with our hubbles and telescopes. So a significant tech progress is needed by an alien to see us light years away.

Re:Too many assumptions? (1)

SirLurksAlot (1169039) | more than 6 years ago | (#21790042)

Keep in mind that the article also stated that this is an exercise in considering how we can improve our own observational abilities, and not just "would aliens be able to detect us." I also don't think it's unreasonable to want to search out life that is similar to our own, and which has similar technology. Of course any life would be an astounding discovery, but to find a civilization that is similar to our own, that would be truly amazing. It's a lonely thought to consider that we are alone in the universe (one which I reject, considering the enormity of just the galaxy alone), and I think it is in our nature to want to search out others like us.

Re:Too many assumptions? (1)

Wormholio (729552) | more than 6 years ago | (#21790430)

Given the statistics of the available data that is the best you can do.

And unfortunately when you divide by (N-1) in computing the error bars you find they are rather widely spaced.

I, for one... (1)

Debello (1030486) | more than 6 years ago | (#21788442)

Welcome our galactic colonizing telescope-toting alien overlords!

Re:I, for one... (0)

Anonymous Coward | more than 6 years ago | (#21788610)

You don't care about your Slashdot karma at all, do you.

Re:I, for one... (0)

Anonymous Coward | more than 6 years ago | (#21790810)

brilliantly executed and totally hilarious!!!
how you think these jokes up I wish I knew hahahahahhh

oxygen, man (4, Informative)

Quadraginta (902985) | more than 6 years ago | (#21788454)

Phoo, once you've detected O2 in the atmosphere, you're done. Only life could produce that much free oxidizer in a strongly reducing universe.

Re:oxygen, man (1)

$RANDOMLUSER (804576) | more than 6 years ago | (#21788942)

Indeed. That's what started James Lovelock [wikipedia.org] down the road to the Gaia hypothesis [wikipedia.org] .

The Earth would look like a Quasar (0)

gelfling (6534) | more than 6 years ago | (#21788466)

The earth throws off so much man made electromagnetic radiation that it would have to look like anomalous object. Now, how many of those do we see in 'near' interstellar space? None.

Re:The Earth would look like a Quasar (1)

gardyloo (512791) | more than 6 years ago | (#21788542)

1/r^2, plus being near a far, FAR more powerful start will tend to do that.

Re:The Earth would look like a Quasar (1)

imasu (1008081) | more than 6 years ago | (#21788572)

Nice guess, but incorrect. The inverse square law pretty much pwns any EM radiation we make normally, stuff like Tsar Bomba being an exception.

http://www.faqs.org/faqs/astronomy/faq/part6/section-12.html

Scroll down to the table, and you'll see that detection ranges for something like Arecibo at more than a couple LY requires transmitters in the terawatt range.

Re:The Earth would look like a Quasar (0)

Anonymous Coward | more than 6 years ago | (#21788622)

No, it wouldn't. Do you have any idea how much radiation a quasar throws off compared to Earth?

Re:The Earth would look like a Quasar (1)

PPH (736903) | more than 6 years ago | (#21788674)

Primitive civilization broadcasting megawatts into space in order to transmit a message a few dozen kilometers.

Nothing to see here. Move along.

Omygod (1)

no-body (127863) | more than 6 years ago | (#21788468)

- been there, looked at it, nice place... and, looking at the primitive abundant upright walking livings there, quite funny what they do and how long they keep doing this. Quite amusing, actually. Looks they are on a turning point right now. Not sure if they self-destruct or get it together....

Might have water (1)

huxrules (649822) | more than 6 years ago | (#21788470)

Hmm I wonder what that blue pixel is made out of. SEND IN THE ICE PIRATES!!

Heh heh haven't seen that abe lincoln photo huh (0)

Anonymous Coward | more than 6 years ago | (#21788500)

We all know a single pixel can't represent more than just a dot. duh.

This assumes..... (2, Insightful)

ezratrumpet (937206) | more than 6 years ago | (#21788524)

........that aliens see things the same way we do. What if they "hear" on the same spectrum that we "see"? We could what-if this to death, but it's important to remember that listening might be just as important as looking, and not just for SETI.

Re:This assumes..... (1)

Liquidrage (640463) | more than 6 years ago | (#21788678)

Interstellar sound waves...Brilliant!

Now, how to go about building a giant concrete ear. Hmmm.....

OK, honestly. Me thinks that anything that would produce sound waves that made it through interstellar space and was able to be detected on Earth would most likely be easier to detect looking for photons. Whether that be radio waves, visible, gamma, etc...

Sound is just the movement of energy through matter in waves. While I have no doubt it's possible that in some alien world hearing would be more important then eyesight (think of bats and sonar for example), that type of sense does not lend itself to being spotted from across vast differences. The medium to carry it is horrible, it absorbs the energy on it's way, and it distorts it. It would be like shoving the hubble behind a gazzilion miles of concrete then trying to take pictures.

Re:This assumes..... (1)

glarbl_blarbl (810253) | more than 6 years ago | (#21789148)

I think what the GP was trying to say was: what if alien species have evolved to perceive spectra we can only detect with technology? Of course they wouldn't call it "hearing" or "seeing" since they probably don't speak english.. and if we could wire our brains directly to radio telescopes I bet we'd come up with a whole new word for perceiving those frequencies.

My guess, though, is that the only entities which would evolve those abilities would actually live in deep space -- negating the need to search for M-Class planets.. The whole scenario strikes me as extremely unlikely even on cosmic timescales... But it's fun to think about, anyway.

Re:This assumes..... (2, Insightful)

danilo.moret (997554) | more than 6 years ago | (#21790194)

If they "hear" on the same spectrum that we "see" then just change the words, because to us they "see" but call it "hear". These words just label our senses, they don't define them. We label one way the sensors set to receive the "visible light" electromagnetic spectrum, they label it different. Big deal.

Unless the label change also implies that the "audible electromagnetic spectrum sensors" don't dominate their senses as ours, it hardly matters what label gets used.

It's OK if they can see us with a telescope (0)

Anonymous Coward | more than 6 years ago | (#21788540)

as long as they don't have a Illudium PU-36 Explosive Space Modulator to go with it.

Who was it... (0)

Anonymous Coward | more than 6 years ago | (#21788616)

...who wrote that methene would show up in a spectograph as the marker for life on Earth? Might have be Issac Asimov, I don't recall.

Still, I think a radio telescope would have a better chance. See the beginning of "Cosmos", the film.

In thy own image. (0)

Anonymous Coward | more than 6 years ago | (#21788632)

"'But that could be enough for them to identify our planet as one that likely contains clouds and oceans of liquid water.'"

Which might be as meaningless to them as hot arid environments is to us. We all see life based around our own experiences. Clouds and water equalling life* may not even occur to them.

*Let alone, civilization.

Do we want to be found? (3, Insightful)

brassman (112558) | more than 6 years ago | (#21788636)

"Yet across the gulf of space, minds that are to our minds as ours are to those of the beasts that perish, intellects vast and cool and unsympathetic, regarded this earth with envious eyes, and slowly and surely drew their plans against us."

And then there is the possibility (5, Interesting)

elgee (308600) | more than 6 years ago | (#21788652)

That ET will find us with a microscope.

Lightspeed is slow (4, Insightful)

GeneralCC (1206630) | more than 6 years ago | (#21788656)

Well, if extraterrestrials were able to see earth using electromagnetic radiation (ie light, radio waves, ect) depending on their distance they would not see a modern earth. If they were over 5 billion light years away then if they looked at this solar system the Sun and the Earth would just be forming. This is because light speed is too slow. By the time the light reaches the extraterrestrials a large amount of time would have passed. They would have to use something other than a telescope to see a modern life sustaining Earth.

Re:Lightspeed is slow (1)

sethanon (26295) | more than 6 years ago | (#21788908)

The Milky Way Galaxy is just 100,000 light years across and contains 200 billion stars. The Virgo Super Cluster is 200 million light years across and contains thousands of galaxies. The nearest exoplanet that we have detected is about 10 light years away.

Meanwhile animals and land plants are believed to have started showing up around 500 million years ago on a presumably "life sustaining Earth".

The universe is big but there are a lot of places nearby from which you could observe using only light that Earth has an interesting chemical and physical makeup.

Re:Lightspeed is slow (0)

Anonymous Coward | more than 6 years ago | (#21789416)

They just watched the dinosaur extinction event last week and gave up hope of anything more interesting evolving here.

Earth at Night (0)

Anonymous Coward | more than 6 years ago | (#21788664)

Since the Earth has so much light pollution at night, wouldn't aliens notice the bright magnitude and spectrum?

Short answer (1)

iminplaya (723125) | more than 6 years ago | (#21788696)

Yes [lollipopanimation.com]

Simple! (1)

Tablizer (95088) | more than 6 years ago | (#21788720)

They would only be able to see Earth as a single pixel

How about we launch some giant pixels so that they see more.

It worked with Google push-pins [blogspot.com] .
       

They don't need to see us (1)

wrmrxxx (696969) | more than 6 years ago | (#21788728)

All they need is a smelloscope. If they can pick up the smell of cats, they'll find their way here.

only just starting to brainstorm in 2007? (1)

xPsi (851544) | more than 6 years ago | (#21788790)

This is a great line of inquiry and I certainly enjoy reading about such things, but wasn't the technical end of this "what if" scenario mapped out pretty extensively back in the 90s when the extrasolar planets started being detected? I'd be surprised if researchers are only just now getting around to asking cute generic "how could we directly detect earth-like planets by thinking like an alien measuring earth" brainstorming questions.

Re:only just starting to brainstorm in 2007? (0)

Anonymous Coward | more than 6 years ago | (#21788838)

Yes, astronomers knew the Earth would be variable. The new part of the study is performing calculations to determine whether it would be possible to determine Earth's rotation rate, despite the highly chaotic nature of weather. The conclusion is that the Earth's rotation period could be determined fairly accurately, even with a telescope only a few times larger than HST.

Determining the rotation period is important, so that you'd know when a given surface feature had rotated into view again, allowing you could collect photons for several weeks or months and coherently average to build up information about regional features (e.g., continents or oceans).

The real question is... (0)

Anonymous Coward | more than 6 years ago | (#21788836)

Can ET detect his extra testicle with a microscope?

we'd better ask ... (1)

thephydes (727739) | more than 6 years ago | (#21789126)

Can the extra-terrestrial see uranus with a telescope?

mind boggling (1, Insightful)

sugarmotor (621907) | more than 6 years ago | (#21789150)

It is mind boggling how limited these people's imagination is in regards to how other life could exist, see the universe, or interact with it. As far as I'm concerned life could exist within the sun itself. And then what use is a telescope??

Nice day to you all!

Stephan

pixelization (1)

Quiet_Desperation (858215) | more than 6 years ago | (#21789174)

'They would only be able to see Earth as a single pixel, rather than resolving it to take a picture,' said Astronomer Eric Ford. 'But that could be enough for them to identify our planet as one that likely contains clouds and oceans of liquid water.'

Wow. That's one hell of an information packed pixel. Maybe he means one of those spooky, hyperadvanced alien pixels. I hear they're super effective.

If they are hostile aliens, we can only hope they do a lot of image processing. I hate to think the only thing standing between us and being driven into hellish alien slave pits is a antialiasing filter. I hate to think that, but I have brain issues that make me think things like that. :(

Re:pixelization (0)

Anonymous Coward | more than 6 years ago | (#21789234)

I hear they're super effective.
Aliens are pokemon?

Re:pixelization (4, Informative)

imsabbel (611519) | more than 6 years ago | (#21789294)

I see your humor, but...

A single pixel can provide a hell of a lot of information: Do spectroscopy, and you can get the typical absorption lines (O2 for example should be easy to detect, and be a sure way for _anybody_ who detects it to tell something is odd about that planet).
Track the intensity over time, and you can get the rotation period.

What a pointless question. (1)

Ihlosi (895663) | more than 6 years ago | (#21789364)

We already have the technology to image planets in other star systems, it's just that no one is willing to spend the money on it. By throwing enough money at the problem, we could already detect and analyze Earth-like worlds around other stars.

So, if the aliens have our level of technology or better, and are willing go through the effort, they could easily find Earth.

Idiots (1)

dementedWabbit (675528) | more than 6 years ago | (#21789448)

It never ceases to amaze me how scientists always think that, if there is life out there, it's as limited as us in creativity/science/life/etc.

Re:Idiots (1)

Baron_Yam (643147) | more than 6 years ago | (#21789648)

It never ceases to amaze me how people always think that, if there is life out there, it isn't as limited as we are by the laws of physics.

Re:Idiots (1)

farkus888 (1103903) | more than 6 years ago | (#21789782)

actually I am going to have to second gpp here. think for just a moment about the vision of an eagle compared to ours. their vision is developed similarly to ours only with more "sensors". I've never even seen any indication that eagles are at the high end of what an eye of similar basic design can do. if we were to conjecture that they might have vision based on an eye of superior design, it becomes downright stupid to make assumptions about what the world looks like to them. from where we sit its nearly impossible to comprehend what the world looks like to the eagle. I think there is far more room for variations in life within the laws of physics than you are willing to imagine because you are limited by things like that and have never been without those limits.

Re:Idiots (1)

tsjaikdus (940791) | more than 6 years ago | (#21789770)

It never ceases to amaze me how scientists always think that, if there is life out there, it's as limited as us in creativity/science/life/etc.
They are trying to find out how others may see us, so we know what to look for ourselves. If you just assume this superintelligence can do everything already and not question how, than it's not possible to learn from it, duplicate a result or make a prediction, hence then it's not science. Then it's a interesting as a sf book.

We've Already Been Discovered (5, Funny)

DavidD_CA (750156) | more than 6 years ago | (#21789476)

We've already been discovered, twice.

The first time: they discussed us using irrelevant analogies, took a senseless poll, said things like "imagine a Beowulf cluster of these" and "itsatrap!", and one alien remarked "I, for one, welcome our new Earthling overlords."

The second time: they just shouted "DUPE!" and moved on.

Re:We've Already Been Discovered (1)

tsjaikdus (940791) | more than 6 years ago | (#21789792)

What an incredible rude remark to make!

How far? (1)

damburger (981828) | more than 6 years ago | (#21789960)

The article doesn't appear to mention at what distance they could detect us with a Hubble-like device, and so it doesn't really tell us anything seeing as we don't know how many sun-like stars are in that range.

Except that... (1)

HouseArrest420 (1105077) | more than 6 years ago | (#21790024)

They're basing these ideas on a new telescope on the fact that other worlds hosting life would be hosting life that requires the same needs as our own to survive. I think these smart scientists are forgetting a very simple fact. We're creating these telescopes to find ALIEN life. They are called aliens because they are alien!!! And as anyone knows (or at least can imagine) when your looking for nothing but quartz, that diamond in the ruff doesn't shine so bright.

Simple and short, if your employing means that would be benificial to finding worlds humans can inhabit....your going to miss the ones with life that we can't survive on, all because you've already ruled out the fact that they can't possibly sustain life. Living organisms on THIS planet are 90% water so of course WE need water to survive, but whose to say the only other living aliens in any galaxy aren't 90% rock, or gas for that matter? Debate that idea all you want...for as long as you want....but have you ever met an alien? And I know that example is a bit contrived.....but it does raise an interesting question. How are you going to find something when your not really looking for it?

Hell, for a real basic example look to the cartoon series Ben10, one of his alien forms is a fire based alien....yeah I bet he lives on a planet that's 90% water lol. I know its a cartoon and isn't real...but who's to say it's not correct in some form. Every scientific advancement started out as a theory, and most were thought of as impossible or ridiculous in their own time. With that said, I'm done with voicing my opinion and have only one thing left to say. Have fun sailing your ship off the edge of the world!

I always wondered ... (1)

LaughingCoder (914424) | more than 6 years ago | (#21790148)

... what aliens, observing the electromagnetic patterns emitting from earth, would make of the odd modulo-7 component that derives from our 7 day week. It wouldn't seem to make much sense to them given that 7 does not divide evenly into a single orbit of the planet around the sun. Of course the 24 hour pattern the would also detect would align with the planet's rotation (pretty closely), so that would make the modulo-7 thing even more odd to them.

Its a pointless discussion (1)

bradbury (33372) | more than 6 years ago | (#21790400)

While there may be a high probability that there are Extraterrestrial Civilizations, the probability that they are now at the state of the Earth's 21st century development is extremely low. It is much more likely that they are far behind us or far ahead of us. If they are far ahead of us then the development of nanotechnology will allow them to build telesopes 100, 1000, 10,000 m in diameter with mirrors accurate to the atomic scale. They will be able to launch (or build) arrays of these in space. They will be able to connect them as interferometers. They will be able to observe the Earth in great detail. The article cited is an extremely anthropocentric article focused on perhaps the next 10-20 years of our own development which fails to take into account what our capabilities will be in 50 years.

It is also not true that one needs a "protective atmosphere". One can easily engineer biochemical systems which are highly tolerant of UV radiation and have much better DNA repair capabilities than those which currently exist. The problem is to be able to evolve such systems. One might expect that the process of climbing out of the oceans would be a bit slower in such environments.

SETI is more likely to get them to listen (1)

Doug52392 (1094585) | more than 6 years ago | (#21790508)

It's a wildly accepted fact that, somewhere out there, there is another civilation out there. But why, if an extraterrestrial race is so advanced, would they use a telescope? I think that, if an intelligent race were out there, they would be more likely to find us through the Search for Extra-Terrestrial Intelligence (SETI), or a similar effort. The real question, however, is if they ever find us, will they come? Will they be friendly?

Yes (0)

Anonymous Coward | more than 6 years ago | (#21790714)

Yes, I can.
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