Could An ExtraTerrestrial Find Earth with a Telescope?

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."

Comments

Well then...

[Dragon By Proxy]

Phoning home wouldn't cost that much after all!

I've got an idea

[ILuvRamen]

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

[edwardpickman]

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.

Re:I've got an idea

[AKAImBatman]

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

[keithmo]

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

Re:I've got an idea

[Anonymous Coward]

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.

Re:I've got an idea

[explosivejared]

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

[ILuvRamen]

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

[Anonymous Coward]

...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

[WallyDrinkBeer]

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

[myth_of_sisyphus]

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

[Martin Blank]

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

[LynnwoodRooster]

Well then, screw them... I mean, if they aren't going to follow the stinking RFC standards about smilies and emoticons then why do we even want their standards-breaking butts here anyway?

Re:I've got an idea

[AKAImBatman]

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

No, basic scientific principles told me this. While the Drake Equation is not accepted by all scientists as a valid computation, the Fermi Paradox 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

[esper]

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

[sweet_petunias_full_]

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

[Anonymous Coward]

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

Re:I've got an idea

[statemachine]

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

[Double_Duo_Decimal]

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

[SamP2]

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

[RAMMS EIN]

``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

[Peter Lake]

They did. But after centuries of politicizing the project they ran out of bugdet and instead of 42 it came out as number 37. 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.

Re:I've got an idea

[vertinox]

(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

[GooberToo]

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

[KDR_11k]

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

[WhatAmIDoingHere]

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

Re:I've got an idea

[ring-eldest]

We have been scanning the skies with powerful equipment and so far have come up with little to no evidence of such transmissions.

This is an ignorant argument http://en.wikipedia.org/wiki/Argument_from_ignorance. Absence of evidence is not evidence of absence. Perhaps radio communication is not as ubiquitous as we believe it to be.

Re:I've got an idea

[Brother Seamus]

... 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.

What, like a bullseye or something?

Re:I've got an idea

[General Wesc]

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.

I'm going a bit off-topic here, but isn't a Big Bang-based universe n light years across going to be n/2 years old?

Re:I've got an idea

[thief_inc]

If we assume that there are 1000's or even millions of civilizations out there at different stages of development and a different distances from the earth we should receive transmissions eventually. Follow me for a second.
Imagine a civ that is on a parallel development track as us but they are 2000 LY(light years) from us. We won't receive their transmissions for another 2000 years. They would have to be 2000 years ahead of for us to receive their transmissions. If the universe does support a variety of civilizations we should eventually receive a transmission sometime of the course of a 100 year period. Also even if there are civilizations a million years more advanced than us as long as they are a million light years away we would have received their transmissions. Of course we are kind of threading the needle here but if the universe is abundant in life forms than we should have transmissions from somewhere by now or at least in the next 100 years or so.

If we don't find a transmission in my lifetime I will have to come to the conclusion that life is in fact rare in the universe. And if there is other civilizations out there they are so rare that it may be many 1000's if not millions of years before we make contact, if ever we just may miss each other in the end.

Re:I've got an idea

[Ihlosi]

We have been scanning the skies with powerful equipment and so far have come up with little to no evidence of such transmissions.

Erm, hate to bust your bubble, but we've scanned part of the sky, and in a very narrow frequency range, for transmissions that must have been meant for crossing interstellar distances. If there was another Earth circling around Alpha Centauri, we'd have no idea it was there.

Re:I've got an idea

[crazyeddie740]

Expansion of the universe. Objects at the edge of the observable universe were 13.7 billion light years away when they emitted the light that is reaching us now. At present time, they are now 46.5 billion light years away. (Assuming something really funky hasn't happened to the expansion of the universe outside of our past light cone, I guess.) See observable universe and comoving distance over at the 'pedia.

Re:I've got an idea

[Liquidrage]

"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"

That part is not true. Typical radio transmissions virtually disappear well short of a single light year. And by "virtually" I mean our own giant radio antennas wouldn't hear them.

We would really have a very hard time detecting ourselves just a light year away. Other transmissions that have a longer range are so infrequent from us, we'd miss them with our own scans, and they'd be nothing but noise that gives no reason to take notice.

So it's possible there's "something" in our neck of the woods and we don't know it.

Re:I've got an idea

[14erCleaner]

Unnatural radio transmissions would stand out against the background radiation and give us a sense that another civilization is there. As technology advances, our radio transmissions are looking more and more like background noise (tighter encoding, less redundancy). Also, a more advanced civilization would probably all have cable TV.

Re:I've got an idea

[Xonstantine]

This is an ignorant argument Actually, not it isn't.

Absence of evidence is not evidence of absence. Um, yeah it is. Particularly when you are looking for evidence. Said another way, your argument can be applied to argue that there might be invisible pink elephants flying overhead. Which is to say, it's useless and not an argument at all.

There are a couple of solutions to the lack of evidence problem, but the most probable one is that there simply is not technological life besides us within our visible light cone. Like another poster said, the Fermi paradox is basically insurmountable. If there was advanced technological life in the galaxy, they would be here (and everywhere else) by now. The fact that they aren't strongly suggests that we're it.

Re:I've got an idea

[4D6963]

Unnatural radio transmissions would stand out against the background radiation and give us a sense that another civilization is there.

The background radiation, really? You mean that? Oh yeah do you see that little spot, right next the big blue blob? Might just be them..

Seriously, you seem to think that all our telescopes put together form some sort of super fish-eye that monitors the entirety of the sky permanently. If it was the case, then we would know a lot more than the small fraction of asteroids we estimate we know (about a tenth of how much we estimate there are in total, depends on which figures you look at). Telescopes have an extremely narrow field of view, so narrow you could try every night for a year to catch a commercial airplane with one of these with no success.

Actually I think it's a good analogy. You couldn't find find an airplane in the nightly sky with a 10-meter telescope if you tried hard. They are there tho! Just not too often, and in a small part of the sky you're not looking at.

Re:I've got an idea

[rbowles]

Everyone knows the invisible elephants aren't pink.

Re:I've got an idea

[smurgy]

We should totally do that, but make the arrow point at Alpha Centauri.

That would be a prank worth pulling off!

Re:I've got an idea

[Xyrus]

Our galaxy is over 100,000 light years in diameter. We barely started listening to the universe.

In fact, there are few installations that could detect an "unnatural" signal against the background radiation unless it was generated very close by (in galactic measure), or was specifically directed at us with enough power. As I'm sure others will mention, any advanced civilization capable of SOME space travel would be using mainly directed transmissions which would severely limit our chances of detecting them unless by chance we were somehow in the path.

And then, of course, there is a travel time.

You're also equating life with "intelligent life capable of generating detectable transmissions". Life could be quite prevalent, but intelligent life less so. Then there is also the chance that a civilization arose and fell long before humans ever walked the earth.

Then, for the tin foil hatters out there, an advanced civilization may be monitoring us or even participating. A civilization sufficiently advanced will have abilities indistinguishable from magic and all that.

~X~

Re:I've got an idea

[Anonymous Coward]

>There are 10^21 stars out there

Um, you know the exact number how?

>there must be many civilizations out there.

Why must there?

Re:I've got an idea

[s20451]

As I'm sure others will mention, any advanced civilization capable of SOME space travel would be using mainly directed transmissions which would severely limit our chances of detecting them unless by chance we were somehow in the path.

But if such civilizations were even reasonably common, we should have coincidentally observed at least a few such signals by now.

You're also equating life with "intelligent life capable of generating detectable transmissions". Life could be quite prevalent, but intelligent life less so. Then there is also the chance that a civilization arose and fell long before humans ever walked the earth.

But this is exactly what the original poster is arguing (a point with which I agree): civilizations may exist but may be so far apart in time or space that they never see each other. Also, if such a civilization was spacefaring, there's no evidence that they ever visited Earth: no anomalous artifacts or fossils.

Then, for the tin foil hatters out there, an advanced civilization may be monitoring us or even participating

Wouldn't such an advanced civilization be indistinguishable from the Abrahamic God, who observes and participates but never reveals Himself?

Re:I've got an idea

[ring-eldest]

Maybe you have a different idea of what science is than most people, but we should not be looking for evidence of ET, we should be looking for evidence which will refute the theoretical underpinnings of ET (at least in Poppers vision of science). So no, absence of radio transmission != evidence of no ET, it's simply an absence of unusual radio waves.

The trouble is, falsifying the existance of ET is difficult (mostly unfeasable) and expensive. It's cheap to scan for radio waves, so we've convinced ourselves that radio is the most likely form of interstellar noise produced by intelligent life.

I'll happily agree with you that pretty much any theory surrounding ET, or the universe as a whole in such aspects that are difficult to measure/quantify, are pretty shakey. You have to draw the line at saying "no radio transmissions = evidence of no ET," if you want to stay objective, though. Otherwise you might as well jump on the other non-scientific theory bandwagons, ala intelligent design.

Re:I've got an idea

[Anonymous Coward]

There are 10^21 stars out there Um, you know the exact number how? http://www.google.com/search?source=ig&hl=en&rlz=&q=stars+in+the+universe&btnG=Google+Search

there must be many civilizations out there. Why must there? Statistics.

Re:I've got an idea

[jc42]

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.

Because they don't consider where someone lives to be especially important. You don't know or care where I live, right? The important thing is the ability to communicate, and they do that simply by having the ubiquitous robot probes install gateways to the galactic network wherever they come across a world that has advanced sufficiently to have its own local network.

If you haven't noticed them on our network, that simply demonstrates that you're not very observant. And some of them here have pretty low user ids.

Of course, there is a fairly strict policy of not saying things that explicitly identify oneself as non-human. It's funny how few humans are totally unwilling to even consider that someone else may not be just like them.

Re:I've got an idea

[HumanPenguin]

Err if we have 93 Billion light years of space to play with. Then given that all of our current communications technology travels at the speed of light. And we have no real idea how to get around that. Then any unnatural radio waves that happen to be in our neck of the woods are still very unlikely to reach us during the time a civilization exists. and would have been sent out at the very least 1000s of years ago. We have only been listening for about 75 years. So the lack of unheard unnatural emissions really dose not point to the non existance of a current civilization. The simple answer is we really have no idea if there is or even if there is likly to be other civilizations out there or if they ever have been. And until we get a letter saying Dear Earthling please come to the party. Opps sorry you are 1 billion years to late. I am not going to vote either way. Because everything else is just cool speculation.

Re:I've got an idea

[HumanPenguin]

The problem is they did do this millions of years ago. The reason we cant see it is we were an insignificant solar system and got moved into the middle of the smile. Either that or they had the plan and the technology but a bunch of environmentalist said. You cant do that one day life may evolve in those baron solar systems.

Re:I've got an idea

[MBGMorden]

Intelligent life could be rare without life as a whole being rare. It could also be that intelligent life that ever reaches a level of technology capable to sending a radio transmission is rare. The universe could be teaming with roughly medieval level civilizations and so far we're the only ones who figured out this whole electrical transmission thing. People tend to look at our problems in the world and hope for there to be something "better" so that we can look at ourselves and have something better to strive for, but it could very well be that as far as even intelligent life goes, we could be some of the smartest little critters the Universe has ever seen.

There could also be another issue: what if there is something fundamentally better to use than radio signals? Say we "outgrow" radio communications within another 500 years. At that point we will have had a 600 year window where radio communications were usilized by us. Now, that 600 year group of transmissions will continue to radiate outward, but each planet it passes will still only have 600 years worth of time to listen, find it, and do something about it. If that's the case, we might not be finding any transmissions because we might simply be outside of the window of any nearby civ's radio communications era.

Lastly, life can be INCREDIBLY rare yet we could still have numerous advanced civilizations in the universe. There are more galaxies in the Universe than there are people on Earth (on the order of about 10 galaxies to each person). Each contains BILLIONS of stars (small galaxies a few billion - large ones several dozen billion). So, if we were to assume that even though all galaxies have billions of stars, most of them are dead as can be. Only one in every BILLION galaxies (so say about one in every 20 billion billion star systems) has intelligent life. Even with that rarity we should still have several dozen advanced civilizations in the entire universe. The problem with that is that if it's THAT rare, even though there should be NUMEROUS civilizations, even if they were all active at the same times, they could never communicate using anything remotely resembling current technology. Effectively, they'll never be able to prove each other's existence.

Re:I've got an idea

[Feanturi]

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.

They just did, about 5 days ago. But we won't see the changes for several thousand years.

Re:I've got an idea

[jc42]

Typical radio transmissions virtually disappear well short of a single light year. And by "virtually" I mean our own giant radio antennas wouldn't hear them.

Not true at all. Back in 1978, Science published an article on the topic. Its title was "Eavesdropping: The Radio Signature of the Earth". If you're not a subscriber, you can find several copies of it online, as well as several other articles that cite it and do further analysis. The authors studied what could be learned about our planet by an astronomer with our level of technology (as of 1978) living on a planet within the sphere of roughly 50 light-years that our broadcasts had reached. They assumed that no program content could be deciphered by the remote astronomer, and only the Earth's changing spectrum over time could be measured.

Their conclusions were fairly impressive. They started by explaining the nature of the received signals, and how those could be used to determine our planet's orbit, its day length, the orbit of our large moon, and the rough temperature zone in which we live.

They went on to point out that our radio broadcasts are mostly done with hardware that puts its energy into a narrow frequency band, and mostly horizontal to the surface, so that from a remote viewpoint each broadcast station would appear briefly and fade. That is, the radio spectrum received from the Earth would come mostly from the limb, and not from the disk. This could be used to draw a map of the broadcast stations. The Doppler shift of each station as it appears 12 hours apart on opposite sides would give the station's latitude, the time would give its longitude. The resulting distribution would show that there are two different kinds of surface on our planet, and we live mostly on one of them (and mostly along the boundaries). Knowing the planet's temperature zone would tell the astronomers that we're on a water world, and our stations are on land.

As the stations' frequencies drift over the year, it would become clear that we are diurnal, and also active during the evening, but not active between midnight and dawn. Further analysis of the signals would show the use of several different kinds of hardware, and these are distributed in patches over the planet. This shows our ability to organize on a large scale, but not on a planetary scale. The use of the same broadcast hardware in different areas would show our ability to form distant alliances between our "nations".

Anyway, the article was an interesting illustration of what our broadcasts have been telling to any distant astronomers with technology as good as ours. They left it to the readers' imagination what could be deduced by more advanced astronomers. And, of course, our signals have propagated another 30 light years since then.

Re:I've got an idea

[jc42]

Wouldn't such an advanced civilization be indistinguishable from the Abrahamic God, who observes and participates but never reveals Himself?

Nah; we've found that we can talk openly about the "anthropologists" visiting Earth to study its civilization. And you can talk about us all you like. Who's gonna believe you? Do you really want to be considered one of those nutcases that believe in visiting aliens?

It's sorta like that "Abrahamic God", y'know. Actually, he was one of the first wave of anthropological visitors, soon after the regular visit of a robotic probe found that an intelligent species had evolved on this planet. He did reveal himself to lots of people. Look at the results: The "rational" humans today totally discount all those uncorroborated reports. Rightly so, of course, since humans routinely make up all sorts of fantasies about revelations, visitations, etc. The real ones just disappear into the fog of fantasy.

It's always that way with a new intelligent species. They always think they're unique in the universe. So a member of a physically-similar species can easily pass as a local from the next valley. As they develop, you may have to pretend to be from somewhere remote on the planet. But they never believe you're from much farther away than the edges of their conceptual world.

This usually turns out to be good for our studies. The visitors can walk freely among the natives, and can subtly guide them toward membership in the galactic civilization. It does usually take millenia for this to happen. But that's ok; we really want each new species to bring their own outlook and capabilities, and overtly directing their development would just make them subservient.

We really don't want to be welcomed as overlords ...

Re:I've got an idea

[CarpetShark]

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.

It's when they start using pentagrams that you need to worry.

Re:I've got an idea

[HaMMeReD3]

There are several reasons I think seti is a failure

1. Universe expanding, objects moving farther and farther, would cause a stretching of the signals
2. We are listening for anything that doesn't look like noise, that would pretty much be a well defined analog signal, lets say you went out 100 million light years from earth and tuned 95.3fm and pointed it at earth (assuming that would work), you would receive 1000 95.3 stations at the same time, since they are sprawled all over the planet. It would come in as one giant multiplexed mess, essentially it would look like noise, and due to the sampling the more signals the more it'll look like background noise.
3. Digital signals look like noise when they are good, the idea of compressions etc is to remove any uniformity from the stream. You won't open a zip and see 100 0's then 100 1's, that's not a compressed file. I think any civilization capable of transmitting digital signals through the cosmos would be able to compress and encode that data semi-efficiently.
4. If it was a digital signal, and we did recognize it, do you think we have the codecs installed? Maybe the aliens are conveniently sending us vlc streams.

Point is, I think it's a lot harder to recognize signals from space then we think it is. If we were ever going to communicate on intergalactic levels, it would need to be based on some sort of quantum entanglement. I don't think the aliens are using RF, and if they are it's probably harder to find then we think. We've been using RF for about 80 years as a species, and it's adapted and changed a lot, in 100 years maybe we will be using quantum entanglement and optical circuits everywhere and rf will be obsolete, it is a finite and shared spectrum.

We are not just looking for life on other planets, we are looking for life that is trying to send us clear and easy to understand signals from space. That may be in a 400 year phase of their civilization where RF is a major component. All of a sudden the chances get a lot slimmer.

Re:I've got an idea

[Liquidrage]

No, what I wrote was true.

http://www.faqs.org/faqs/astronomy/faq/part6/section-12.html
I haven't completely read what you linked yet, though I will at some point to give this a more proper reply. But was that article just drawing the bubble around the Earth in light years and commenting on the reach our radio signals? Or coming up with a cherry picked scenario to show how it could work? If you read what you quoted of me it says "typical radio transmissions virtually disappear well short of a single light year". And that is 100% accurate.

If you look at the bottom of the link I just posted you'll see that even using Arecibo AM signals vanish at less then 1 AU. FM at a few AU. To get into lightyears you're getting into much higher frequencies and the signals have a lot more power behind them. Which aren't "typical". "I love Lucy" isn't going to make it to our nearest stellar neighbors, nor is 100.9 KISS FM. Unless they have a dish the size of a small moon powered by a star.

So yes, what I wrote was true. The most logical frequencies for local communication do not lend themselves to be pick up from far away. Now, if our goal was to send signals far away, and someone at the other end knew it was coming and listened for it, yeah, we could send signals no problem. That's basically SETI on our end looking for it. But now you're into a needle in a haystack unless the other end is doing nothing but spamming the galaxy with high frequency "here we are" signals. Which we aren't doing, so I don't believe we should assume anyone else is either.

Re:I've got an idea

[sploxx]

Impracticality? I mean, moving a star takes a tremendous amount of energy. Correct, but maybe we're closer in moving stars than we may think (Yes, I'm speculating... but I always thought about this idea and I never saw it discussed, so please tell me where I'm wrong in the following: :-)

Maybe we could exploit the chaotical movement of stars (or other big masses) and, with a really powerful
simulator, could predict which small nudge could change the positions of the stars in a (short timescale) predictable way. This maybe would
enable us to produce large scale patterns in the universe - Exploit the amplification bvehaviour of chaos to yield something useful.
I'm thinking about something like the 'planetery superhighway' for space probes, just the other way around.

Re:I've got an idea

[dfgchgfxrjtdhgh.jjhv]

even if there are aliens 100 light years away, how could we communicate with them?

any further & they might as well not exist.

Re:I've got an idea

[cbiltcliffe]

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

Calvin, it's getting late. Time to come in!

I can't Mom. I've got to kill snow goons!

Re:I've got an idea

[sweet_petunias_full_]

"If we don't find a transmission in my lifetime I will have to come to the conclusion that life is in fact rare in the universe."

Your argument seems to depend on finding a civilization that has developed radio but which has not yet developed the good sense to keep its radio beams from escaping into space. That provides a very tiny window of opportunity in which to get a signal, and as late bloomers in this universe, that window may already be past us by a billion years and all of the aliens so advanced that they are invisible for all intents and purposes.

Also, what makes you think that all intelligent life has to have developed long-distance broadcast radio technology? We may be the only ones that wanted or needed to invent it, for cultural or physiological reasons. Even supposing that there are enough aliens physiologically similar to us (thereby needing some understandable sort of audio communication), it could easily be the case that everywhere else the telephone was invented first, lessening the need for radio to be developed, or only developing much later in a very different format. If the phone system were not culturally top-down and profit-driven, the ability to make one-to-many broadcasts could have developed long before radio, and radio might only be used for mindless things (like garage door openers, presidential debates, that sort of thing). Technology doesn't have to develop everywhere else the same way.

That's why, if nothing is detected for 100 years, I won't be surprised.

It's fully possible that life is abundant, but intelligent life rare, and intelligent life with radio tech rarer, and intelligent life with radio and willing to let it reach us rarer still. (You have to factor in that if they are smart, they may not be willing to be detected by psychotic warmongers.) Rarest is if they *want* to reach us, are not especially afraid of the consequences and are actively trying with focused beams. Even in such a case, we would have to be listening on all frequencies, in all directions, all of the time and be able to distinguish it as something non-random. That's a tall order.

Then you may want to take signal blockage into account, as there may be sporadic clouds or outbursts from natural radio sources in the foreground, orbiting asteroid belts, gravitational bending, etc.

Yes, there are a lot of stars out there, but we're kind of dependent on a very specific radio standard that may not be as universal as people think...

Re:I've got an idea

[fzuccaro]

Amen. A comedian once commented that "Earth is the Alabama of the universe."

Re:I've got an idea

[CTachyon]

BTW, the whole superluminal expansion thing, mentioned by another poster, is called "Inflationary Big Bang Theory". It was proposed to explain why the cosmic microwave background is so uniform, because a slow (light speed or slower) Classic Big Bang would've produced a very lumpy universe. It stuck around because it explained a lot of other stuff, too.

Since the expansion of the universe is a property of space-time itself, not of the matter within space-time, this doesn't violate Einstein's Special or General Relativity. Essentially, for any two points A and B, new space is constantly popping up in between them, which is what causes the Hubble expansion of the universe. If the new space is being created quickly enough, as happened during Inflation, a light beam sent from A to B will never reach B, because for each second the beam travels, more than a light-second of new space has appeared between the beam and B. At that point A and B are "causally disconnected".

Re:I've got an idea

[Xonstantine]

If something isn't falsifiable it really isn't science. That's the problem with the search for technological ET life. No matter how far, high and low you search, the universe is too large to "prove" the non-existence of ETs. And there is always some hidden other parameter the true believers can bring out like "maybe we're not looking for the right kind of life". The universe is an extremely violent place, and the more we discover, the more it's apparent exactly how lucky we are. I think if and when we manage to get to other stars we'll discover life is relatively plentiful, but technological ETs non-existent.

Re:I've got an idea

[instarx]

Everything we know so far suggests that life is exceedingly rare in the universe.

Face it - that was a really dumb thing to say. We have no way to know how common or rare life is in the universe. Hell, we don't even know how common or rare life is in our own planetary system.

Stop stubbornly trying to prove you were right by using convoluted semi-logic.

Too much work....

[ColdWetDog]

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

Doesn't that mean....

[markswims2]

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.

Re:Doesn't that mean....

[Bartab]

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.

Re:Doesn't that mean....

[danlock4]

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. We CAN be looking at an alien civilization which is looking at us right now, but we see it as it was a long time ago, as many years ago as it took for light from that star to reach us, which is probably before that civilization existed. They'll see the Sun as it was the same number of years ago.

Star Trek already did it

[Anonymous Coward]

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?

[RobertM1968]

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?

[calebt3]

Class M? Since when did we move to the Star Trek universe?

Re:Too many assumptions?

[Liquidrage]

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

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?

[RobertM1968]

Well, I live in the Star Trek Universe quite often lately (check out http://www.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?

[Scotman]

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?

[Anonymous Coward]

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?

[SirLurksAlot]

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?

[Anonymous Coward]

"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?

[Wormholio]

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.

Re:Too many assumptions?

[Anonymous Coward]

Well, I live in the Star Trek Universe Go fuck a rug.

Re:Too many assumptions?

[batquux]

Besides, we really only care about life that's similar enough to us that we can eat it.

Re:Too many assumptions?

[Anonymous Coward]

Good point

Re:Too many assumptions?

[raju1kabir]

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.

I'm no rocket surgeon, but this seems to me like an incredibly narcissistic set of assumptions.

It took us thousands of years to get some basic grasp of how life on this planet works, and that's with a big head start - we have it right here to experiment with.

Isn't it a bit shortsighted to conclude that our efforts to understand life have been so thorough as to exclude any other fundamentally different basic approaches?

Sentient life - autonomous entities with motivation and self-awareness - could take forms radically different from those we've had the opportunity to study (namely, ourselves). Simplistically put, such entities could be larger, smaller, slower, or faster than we are mentally prepared for or perhaps even technologically capable of observing. For that matter, they could have been right here all along, and might not even know we're here either for the same reasons.

I may be guilty of the same limited thinking. Perhaps there are forms of awareness that I can't even conceive of. To us the resultant behaviours may seem deterministic and dull, while from their perspective we might appear the same.

Re:Too many assumptions?

[Liquidrage]

Those aren't actually a different biochemistry.

Their energy source isn't the sun, and they're able to thrive in water that's very hot, in very high pressure, and with a lot of sulfur. But they're still carbon based life, they still take oxygen from the water. They're extreme, but still fall into line with "looking for us".

I, for one...

[Debello]

Welcome our galactic colonizing telescope-toting alien overlords!

Re:I, for one...

[Anonymous Coward]

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

Re:I, for one...

[Anonymous Coward]

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

oxygen, man

[Quadraginta]

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

[$RANDOMLUSER]

Indeed. That's what started James Lovelock down the road to the Gaia hypothesis.

The Earth would look like a Quasar

[gelfling]

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

[gardyloo]

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

[imasu]

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

[Anonymous Coward]

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

[PPH]

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

Nothing to see here. Move along.

Omygod

[no-body]

- 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

[huxrules]

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

[Anonymous Coward]

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

This assumes.....

[ezratrumpet]

........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.....

[Liquidrage]

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.....

[glarbl_blarbl]

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.....

[danilo.moret]

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.

A Space Ship to Visit the Space Alien

[reporter]

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. 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

[raving griff]

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

[Free_Meson]

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

[Anonymous Coward]

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

Re:A Space Ship to Visit the Space Alien

[KDR_11k]

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

[palegray.net]

I don't generally agree with the idea that advanced civilizations would travel across the galaxy in the first place, at least not in any recognizable biological form. That said, our society may very well reach a point where discrete beings are encapsulated in pure information, as opposed to being represented by self-aware sacks of bio-soup.

This mode of existence makes it much easier to travel long distances, as it drastically reduces the requirements for "life support" as it were. Charles Stross explores this idea in his book Accelerando, which is written in a Gibsonesque style in my opinion. If only for fun, give it a read.

It's all about the lobsters and their slow takeoff. Oh, by the way... why do you insist on attaching human failings to hypothetical alien intelligences? Dude, the Matrix has you.

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

[Anonymous Coward]

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

Who was it...

[Anonymous Coward]

...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.

Re:Who was it...

[Javagator]

. . bovine flatulence -- the intimate intestinal activities of cows, reindeer, elephants, and elk -- is detectable over interplanetary distances, while the bulk of the activities of mankind are invisible. We would not ordinarily consider the flatulence of cattle as a dominant manifestation of life on Earth, but there it is.
--Carl Sagan, Cosmic Connections, pg 150

In thy own image.

[Anonymous Coward]

"'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.

Re:In thy own image.

[Anonymous Coward]

Everything in the universe works a certain way. You've got all these crazy physics that dictate how the physical part works; what if the life part has to work this way, too, just because the rules are set up that way?

Do we want to be found?

[brassman]

"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."

Re:Do we want to be found?

[Asky314159]

Wait, so does that mean that Al Gore is really an alien, trying to stop us from ruining the planet before the rest of the armada shows up to take control?

Re:Do we want to be found?

[Anonymous Coward]

Nice quote, but why would an alien race be at all interested in the Earth and our resources? Water? There is far more water in the outer solar system which would take less energy to snag than to come all the way here into the inner system. Besides, for an alien race to cross that vast gulf of space, wouldn't they need to be able to bring their resources with them anyway? The whole idea of alien invasion based on Earth as a piece of real estate, resource mine, or new colony for their own purposes is utterly silly.

On the other hand, if said alien invaders think that humans might eventually advance to the point where we become a problem, well, in that case, I can see them wiping us out...

Re:Do we want to be found?

[ichigo 2.0]

Why is it utterly silly that aliens would want to conquer Earth and it's resources but not utterly silly that they would want to wipe us out (presumably to prevent us from conquering their planet and it's resources)?

And then there is the possibility

[elgee]

That ET will find us with a microscope.

Lightspeed is slow

[GeneralCC]

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

[sethanon]

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

[Anonymous Coward]

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

Earth at Night

[Anonymous Coward]

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

Short answer

[iminplaya]

Yes

Simple!

[Tablizer]

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.

They don't need to see us

[wrmrxxx]

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

Single pixel? Not a problem...

[LynnwoodRooster]

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...

only just starting to brainstorm in 2007?

[xPsi]

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?

[Anonymous Coward]

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...

[Anonymous Coward]

Can ET detect his extra testicle with a microscope?

we'd better ask ...

[thephydes]

Can the extra-terrestrial see uranus with a telescope?

mind boggling

[sugarmotor]

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

[Quiet_Desperation]

'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

[Anonymous Coward]

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

Re:pixelization

[imsabbel]

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.

Re:pixelization

[kryliss]

That's nothing.. On CSI they can get a 1 pixel picture and *insert CSI technology* turn it into a high res 1600x1200 full color display capable of identifying any of the criminals in the picture with full visual ID and their entire life's history.. all within about 12 seconds of getting the 1 pixel image.

Re:pixelization

[Quiet_Desperation]

I see your humor

Thanks. I don't think anyone else did. :-(

Intergalactic quarantine symbol

[Hognoxious]

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?

[haraldm]

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?

[Rhinobird]

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

Re:A pentagon-shaped smiley?

[tyrione]

Wiccan wear Pentacles and use ritual Pantacles.

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

What a pointless question.

[Ihlosi]

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

[dementedWabbit]

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

[Baron_Yam]

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

[tsjaikdus]

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.

Re:Idiots

[farkus888]

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

[imsabbel]

What ever eyes they have, they still wont violate physics.
Diffraction limit==One pixel earth.

Re:Idiots

[Anonymous Coward]

But what if their eyes are 10's of kilometers in diameter?

We've Already Been Discovered

[DavidD_CA]

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

[tsjaikdus]

What an incredible rude remark to make!

Extraterrestrial life - oblig webcomic

[Anonymous Coward]

http://pbfcomics.com/?cid=PBF162-Executive_Decision.jpg

How far?

[damburger]

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.

Re:How far?

[Anonymous Coward]

The article says "Therefore, we estimate that there are ~11 such stars included in the possible TPF-C target
list of Brown (2005) around which an Earth clone's rotation period could be measured to ~2%. If we were to scale up the primary mirror of TPF-C by a factor of two (16m x 7m), then... there are ~35 stars in the sample target list of Brown (2005) for which an Earth clone's rotation period could be measured to ~2%. If a bandpass of ~400nm were practical, then the limiting host star magnitude might increase by roughly one magnitude, making it possible to measure rotation periods for Earth-clones around ~35 or ~90 stars, for the two mission scenarios. We caution that..."

Except that...

[HouseArrest420]

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!

Re:Except that...

[tomz16]

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. ... Nobody is forgetting that fact. It's just that we are playing the odds. So far, 100% of life we know has the same basic set of requirements (with some very good fundamental bio/chem/phys reasons for those requirements). 0% of life we know are your hypothetical rock creatures... It only makes sense to look for the former.

Furthermore, we are only focusing on what is possible. Since you cannot define a set of criteria measurable with our current technology for locating a "rock creature" or some other exotic intelligence, there is no way to even start a search for them!

Re:Except that...

[HouseArrest420]

Since you cannot define a set of criteria measurable with our current technology for locating a "rock creature" or some other exotic intelligence, there is no way to even start a search for them! My point exactly. Our current technology is no where near what would be needed to search for another "exotic intelligence" (your words), which is what ANY alien species would be. If it was...we'd have found them by now. The simple fact that we're looking, for the lack of a better phrase, for life forms like ours speaks loudly for the fact that we don't even know what we're looking for or what to look for when it comes to another species. If they were like us, they wouldn't be alien. But the notion that they're like us is exactly why we're looking for planets we would be able to inhabit. In my eyes that leaves a very small chance of us finding anything more than another world we'd be able to colonize. But who knows, I'm no scientist. Just a dreamer.

Re:Except that...

[Anonymous Coward]

Yes, they could be very different. But we have to start somewhere. This study performed detailed modeling of the Earth. Hence the claim is not "We now know how to find all type of ET life.", but rather "It would be possible for ET to measure Earth's rotation period, identify continents, oceans, and weather." Those observations would suggest that the planet was capable of harboring life like us, but not prove that it does or say much about life that was extremely different than us.

Re:Except that...

[HouseArrest420]

Those observations would suggest that the planet was capable of harboring life like us, but not prove that it does or say much about life that was extremely different than us. My point exactly....again. Are you guys reading what I'm writing or just argueing to argue...because you've both argued my exact point in a part of yours.

I always wondered ...

[LaughingCoder]

... 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

[bradbury]

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.

Re:Its a pointless discussion

[Demonweed]

For the most part I concur. It is conceivable that a civilization might develop astronomy yet not deploy a vast interferometry network. For example, the inhabitants of a high gravity world would face much greater challenges in developing their earliest spacecraft. Inhabitants of a perpetually cloudy world might become very advanced before developing curiosity about astronomy and astrophysics. That said, the technological gap between Hubble-like capabilities and a much more powerful platform is narrow. In fact, deploying a constellation of space telescopes capable of detailed observations of extrasolar planets is already a human possibility. The GPS constellation(s) provide proof of concept in terms of the logistics, and existing space telescopes demonstrate the viability of that technology. It would certainly be a less ambitious effort than sending humans to Mars, and it might even be less challenging than a return to the Moon. I've long supported a global space interferometry network because one end result of these efforts -- detailed images of extrasolar planets -- could revive an aspect of human imagination and inspiration that seems to have fallen dormant since the Apollo Program came to an end.

SETI is more likely to get them to listen

[Doug52392]

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

[Anonymous Coward]

Yes, I can.

Some problems

[ardor]

Its not as easy:

1) As another poster pointed out, we have been sending and receiving EM transmissions for only a hundred years. The amount of star systems with a distance of less than 100 ly to the sun is not high.
2) It is very well possible that advanced civilizations this close to our own star system existed, but perished or moved long ago. Or, they are no longer using EM transmissions, but another way of communication we do not yet know or understand. For example, it is not unthinkable that a civilization ceases to use satellites and long-distance EM communications and broadcast, instead relying on a sophisticated fiberoptic wire network. In fact, its something that has been considered by several countries already. (Easier to fix, packet-based data transfer generalizes transfers so the same wires can be used for all kinds of data etc.)
3) As a possible consequence of (2), it is possible that they ARE aware of us, but simply refuse to reply. Many reasons are possible; they may be very reclusive, xenophobic, or simply not interested in us.
4) Another consequence of (2) is that they may have been sending out EM data as well - but ceased to do a long time ago. We may have missed their transmissions.
5) Maybe we just don't understand them? What if they are sending laser pulses but we do not recognize them as information?
6) Another idea is that the civilizations closest to us are in a far more primitive state than us. They may be in their equivalent of a stone age. It is interesting how everybody instantly thinks of alien civilizations being ancient and advanced - the opposite is possible as well...

Now, a lot of this is speculation. In sum: EM transmissions are not the holy grail. Their absence alone indicate very little, and prove nothing.

Re:Some problems

[s20451]

Why focus on EM? We have been "listening" in the form of archaeology and recorded history for millennia. No artifacts or other evidence of landings have been found yet. Maybe "they" visited and cleaned up after themselves perfectly, but it is somewhat hard to believe.

You're wrong that the absence of EM evidence (or archaeological evidence) "prove[s] nothing". It certainly constrains the possible ways in which extraterrestrial intelligence could exist or operate. We have pretty much ruled out any nearby intelligence that operates in ways that we could detect or that would be meaningful to us.

If we based it on Hollywood

[Provocateur]

Hey if we can make out a mustache by zooming in on somebody's 2-pixel wide face (see Enemy of the State or any episode of The Unit or 24, oh wait that's IP address) or a backpack among millions of New Yorkers (Peacemaker), they should be able to make out the inhabitants of this Mostly Harmless planet.

Re:If we based it on Hollywood

[DanJ_UK]

Of which most are far from mostly harmless.

Google Earth is your friend..DRMed, but still good

[wikinerd]

When I see Earth with Google Earth (by the way, FSF, where I am a member, has called the creation of a free compatible client a high-priority project, and if you have free time please try to help, and if you need hosting for your project I can give you), I hardly can detect life, let alone humans, on Earth. Visually it's very difficult to detect it (and nothing suggests that an alien would expect a green planet to be filled up with plants, in fact a scientist would expect plant life to be red-coloured and in fact that's how it was in the past as red-colour has greater absorption efficiency... Earth plants became green only after changes in the atmosphere). I can see, of course, that the planetary atmosphere is a very dynamic system (clouds go and come every day), but all the rest is nothing but white places over the poles (ice), vast blueness (oceans), a few greenie plains (jungles, where remained by the human effects), and some light brownish-yellowish regions (deserts). That's all. I would need to analyse the Earth's spectrum or possibly other means to find out what chemistry this funnily coloured vastness has.

But wait, there's more: I can zoom in a little and see mountains etc. And if I zoom more I see that some oceans have little green islands in them, so perhaps I could start to understand that this bluish abyss could be some kind of liquid and the greenish spots could be areas of higher elevation. But still, it could very well be a dead planet with no life, let alone humans. So I have to zoom more. Oh, now I can see that there are some grayish spots near the greenery, as if someone had vomited on the Earth's plains. Yea, it certainly looks like vomit, but what is it? Zooming more... oh, it looks different from anything else, it has some kind of structure, lines etc. Still looking like vomit, though... structured vomit. Who the hell vomited on the planet we, the alien scientists, discovered? How can we write a paper on a vomited planet? Everyone will laugh, our academic reputation is at risk because of this vomit on this extra-Gliese planet.

But let's move away from this freaking vomit and look closer at the green plains and the brownish-yellow regions to see what there is there to be seen. Zoom a bit... oh what's this? Some kind of lines in the desert? Oh, it looks like other aliens visited this dead planet earlier and played some earth games on it, eh? Perhaps they were having some kind of planetary football games or something and this was their soccer field... But wait, some lines are quite intriguing. Nah... these aren't lines, these are complete drawings. Let's move away a bit and zoom closer... Hm, here these look like symbols. Ok, there may once have been some intelligence on this planet, but now it must be dead, probably, as it is too far away from its star (we the aliens like hot stuff so we live near our star, and this is what we consider the only habitable zone possible, for us if it feels hot it's good and we believe the whole universe is somehow made for us to explore and play in, so any planet outside our habitable zone must be dead because that's what the big scientists here say).

Where did this intelligence come from? Maybe it came from the vomit, so let's go back there and zoom more. Wow, what's that? It looks like the lines that divide the vomit in little rectangles have little ant-like things running over them. Oh, and by these lines there are big boxes. But what these boxes contain? Maybe there's more vomit in there! Ok, our scientists found the truth, these running things transfer the vomit from box to box! And maybe this vomit is intelligent! But not much, as it probably has not discovered telecommuting or work-from-home yet. And that's what we would expect from a planet outside the habitable zone, it must be so cold these (15-25C, which for us is too cold) that this vomit has its intelligence sabotaged by the tem

Re:Google Earth is your friend..DRMed, but still g

[wikinerd]

It's funny how I wrote all this vomit stuff and cockroach fiction while eating and am still able to safely finish my food

Just check the radio

[JimDaGeek]

Seriously, any ET just needs a radio telescope and would hear all our transmissions, Jerry Springer, Oprah and even Riki Lake.

No wonder we have not been visited yet!

Re:Just check the radio

[Samgilljoy]

And what if they've been recording those transmissions and sharing them with their friends - with only implied and not written consent? What if they found the musical recordings on Voyager and have been sharing those files?

I can see a whole fleet of RIAA Battle Cruisers in Earth's future. The brave heroes of legal departments worldwide launching themselves into space to protect our precious intellectual property.

we are the aliens' pixels

[wikinerd]

Forgot to add that if you really want to see how our planet looks like from the vastness of space, just fire up google earth in skygazing mode. Every pixel now is a whole world full of action, with many of them having other smaller worlds in orbit around them, and perhaps on some of these there are creatures like us calling their little pixel their home, and arguing, making love and war, playing with their gadgets (oh yeah there are surely geeks out there!), trying to find new theories of everything (surely there are also nerds out there as well!), or just losing their time going from home to office and back everyday instead of setting up as self-employed/freelancers. They are experiencing their world as the most real and important thing, and yet their world for you is a tiny unimportant pixel.

They probably can see the planet but not us, which is a good thing IMO if they are like us.

Re:Google Earth is your friend..DRMed, but still g

[imsabbel]

Maybe you should stup sniffing shit, because reading even half your post did only archive two things:
a) a slight headache
b) the feeling that there is somebody out there who's totally fucked up (and not me)

Isn't anyone going to make a "both hands" joke?

[Anonymous Coward]

I mean, c'mon folks!

I couldn't resist

[scooter.higher]

So what you're saying is: anything could have happened a long time ago in a galaxy far, far away?

What comes after /

[Leuf]

.

The above post is likely only visible as a single pixel from your vantage point, but it should be enough for you to determine what I think of this article

Single pixel, eh?

[ScrewMaster]

Okay, so now suppose we have aliens that truly understand the value of a (ahem!) "manned" space presence and have built really large astronomical arrays.

let's hope they're not nearby

[treebeard77]

I fear if they are, Charlie Pelligrino might have been right in The Killing Star http://sites.inka.de/mips/reviews/TheKillingStar.html

that is:Paraphrased from the book:

1. Any species will place its own survival before that of a different species.
2. Any species that has made it to the top on its planet of origin will be intelligent, alert, aggressive, and ruthless when necessary.
3. They will assume that the first two rules apply to us.

Add to this the facts of relativistic bombardment. A missile approaching at a speed close to that of light is hard to detect, leaves very little time to react, is next to impossible to intercept, and is utterly devastating on impact. In short, once a civilization has achieved the technological level necessary for relativistic bombardment it can erase a neighboring civilization in a single strike.

This book scared the hell out of me. And from such a neat, amusing fellow.

Who says

[Anonymous Coward]

Who says aliens would be looking for a place with water? Who says they would even know what water is?

I mean, if they even exist, what are the chances of them needing the same atmosphere and life support system we need?

In other "news"

[wilsong]

...scientists have confirmed that aliens have CCD imaging technology, they have a concept of "pixels", and it's exactly the same as ours.

I have the answer...

[OwlWhacker]

We found you back in 1863.

Soon you shall all die.

I know

[Anonymous Coward]

I'm much more interested in the purplis colored one. What's it's name again?
The people seem very kind to eah other, and aren't trying to find new ET's to pass on and peddle their corruption too!

it's mind boggling

[Anonymous Coward]

how so many are sure that the ET's should be THAT different to us. It just so happens that there is a reason for our visible spectrum, that ought not to be too different on Mars for example. There is a reason we should look for O2. It happens to allow combustion! There is a reason to look for water. It has an anusually abrupt boiling point making it very stable. Spirituality suggests it is deeply intertwined with life. eg. hidden messages in water. The human form, including all our fingers, together with our excellent balance with 2 appendages etc. is highly practical and reason for why we are dominant species on Earth. The way we communicate now eg. wireless microwave is highly practical and may well still have practical use into the next millenia. The likelihood is that there are far more reasons to look for these characteristics than not look for them. The only irrelevant thing I can think of is human hair, and we already negate the importance of that! It seems that a) we are alone or b) we are being left alone, or even a strange subconscious c) we don't really want to find or be found. Bottom line: We are NOT together now. WE are NOT ONE. How can we expect to be taken AS ONE

The Fermi Paradox Explained

[BigBlueOx]

They already detected Earth and decided not to come here.

Well, I'm glad you asked. Their instruments, much more sophisticated than ours, were able to detect that our atmosphere is highly poisonous being almost 25% free oxygen!! On top of that, the air is freakin saturated with water!! Hell, a good piece of steel wouldn't last 10 vorlecs there. Even if we sent robots, they'd just rust away!! And that's not to mention that the whole place could erupt in a giant fireball any minute if that free oxygen mixed with methane and something sparked!! The whole place probably burns flat every smagdar or two.

Total waste of time and resources to go there especially with all poor and hungry Aretards to care for here at home. No more goddamn government boondoggles!

Actually, that's a single moon

[CarpetShark]

Actually, I think you'll find that a single moon around a water planet is the intergalactic quarantine symbol. Why do you think no one comes to see us? ;)