Article in the Independant

[China Doll]

Hi All,

I was reading an article in the Independant earlier about life on other planets and whether or not we should actually be advertising our presence or not.

I just wondered what anyone else thought of that really? Personally I think if there was life out there then why do we always presumme that it will be cruel/evil or indeed smarter than us anyway? I've always had the idea that if there is life out there then it's most likely little single cell things or something like that. If you think life exists on other planets then what sort of form do you think it would take?

I'm not entirely sure this belongs in science but I'm not sure we have a sci-fi category... sorry!

China xx

[jake-the-peg]

Life started early on the Earth - almost as soon as the heavy bombardment of meteorites stopped, but it was billions of years later that complex life arose.

Whether complex life is inevitable once life starts is unknown but yes we may well be surrounded by billions of planets populated by amoebae with just the odd civilisation thousands of light years away.

I guess we draw analogies from our own history of what happens when civilisations meet - generally it's not pretty and I'd not be too optimistic about the outcome either.

I think though we're protected by the vast distances involved. There's a slim chance that one day we may be able to exchange messages with an alien race but it could well be a case of asking questions that we want our children to get the answers to.

There are some problems that seem solvable and that you can easily envisage an advanced civilisation overcoming - lfree clean energy for example, very long lifetimes etc. the problems involved in interstellar travel are not like that and I think it's very unlikely we'll ever get to meet an alien face to face.

As to what form it will take, I think it's biochemistry will be very similar, there are probably only a few chemical solutions (sorry bad joke) to the life problem, maybe only one. Their physical form will be a combination of the type of planet they evolved on and chance. But there are other limiting factors. They will need to be a certain size, they could be very large but I doubt intelligent life could exist on a very small scale (excluding the social insect kind of solution I guess).

They'll probably also be symetrical - possibly bisymetrical - it's a real advantage to have sensory organs in pairs as you can tell distance. I can't think of any one-eyed creatures to have existed and I don't think that's a coincidence.

Anyway this is Nasa's exobiology page you might find it interesting: <

[jake-the-peg]

sorry:

http://exobiology.nasa.gov/

[Loosehead]

It is statistically certain that life exists all over the universe. Our own galaxy is no doubt teeming with it but due to the vastness of space we will never meet and it's very unlikely that we could communicate. signals would be lost in the vastness of space. Imagine if we could communicate to say the nearest system to our own, even at the speed of light it would take 8 years for an answer to come back.

Now someone will no doubt say that it is only our understanding that limits speed to c, yes that's true but until some future "Scotty" can come up with warp speed, we are stuck with it!

Now as to form, who knows, we tend to imagine life as carbon based but science fiction has flirted with the idea of very different forms, who knows or dares to speculate but I'd imagine there are a huge variety of life from amoeba type cells to ultra intelligent beings, we just don't know.

[wildwood]

I really don't think that there is any life out there at apart from possibly some very simple molecule clusters. It is unlikely that anyone will ever know for sure.

The nearest galaxy to Ours is the Andromeda galaxy which could have exploded [imploded] 2 million years ago and we'll still be able to see it for another 200,000 years before it disappears from our sight. This will give you some insight of the immensity of outer space.

It has been said that there are one billion galaxies out there, but that is only an estimate. It could just as easily be countless trillions, we just don't know what's out there because their light hasn't reached us yet.

[wildwood]

Anyway, what I really wanted to say before being waylaid is that the Americans have already send a probe with Men's identity and Earth's info on it into outerspace that is supposed to keep traveling [forever?] in case aliens want to know what humans look(ed) like and where Earth is situated in this galaxy.

Sorry, I can't remember if it had a name, it was a few years ago.

[jake-the-peg]

It was the Voyager Golden record
http://voyager.jpl.nasa.gov/spacecraft/goldenr ec.html

A possible candidate for primitive life is Europa. It's one of the moons of Jupiter and has liquid water under ice.

So obviously it has an internal temperature able to sustain life. Unfortunately the mission planned to investigate this was canned a couple of years back when the focus shifted to manned Mars expeditions.

It's a shame but there is very srong evidence that Mars once had liquid water on it's surface and an atmosphere and so there is the possibility that we might find micro-fossils of primitive life on Mars - but I do mean primitive - I wouldn't expect any roaring trade in Martian T-Rex bones.

[China Doll]

There's a Calvin and Hobbs cartoon strip where Calvin states that the surest sign of life out there is that it hasn't tried to contact us. I've always liked that idea. Anyway...

I think it was Blue Planet I was watching and they were saying that we always thought that without the sun no life could exist; however, right at the bottom of the sea where the sun can't get to there are these little eco systems forming and proving us wrong. Could this be the type of life that might be out there? Or am I just confused again?

(Thanks for the links Jake; I've had a look through and think I'm a little out of my depth there though!)

[China Doll]

Does a chaos unit just mean that the structure of an area differs to other areas on the planet/moon?

[ryepie]

Well just to put a different spin on this; there is one school of thought that thinks it is far more likely that IF we did encouter another species from far far away in the sense that they travelled to us, that they would actually be quite benign (one of the main champions of the theory being Carl Sagan).

This is because it is assumed (and we can only have an earthly perspective on this reasoning of course) that any race that manages interstellar travel will have done so through global co-operation in many aspects, such as economy, peace-time etc. In other words, if we as a planet were to ever succesfully start interstellar travel, it will only happen when global resources (materials, man-power, money etc.) are no longer being used on global-wide things such as war, and the idea of an 'economy' radically changes; as such an task would only be successful if it was a global effort. And when this point comes, we would probably consider ourselves pretty friendly I imagine, and using the same reasoning the same would go for other races.

Of course if an alien race visited us now, we would probably be considerably less friendly. So the best chances for two civilizations meeting are those who are both technologically advanced beyond a certain point.

I just thought I'd add that perspective to the mix.

[jake-the-peg]

Of course the greatest advances in space technology were actually always driven by military pressures.

The Moon race through the cold war and then Shuttle would never have been built were it only a civilian project.

The blue planet business is what are referred to as "blake smokers" volcanic plumes deep under water in which we discoverred ecosystems independant of the sun. This totally blew away preconceptions that we had about where life could survive and possibly arise which is wht we think that places like Europa could harbour life forms despite their distance from the sun.

Europa has an icy surface that seems to be moved in various flows by convection currents below - think of a planet entirely coverred by rivers of ice.

I think the chaos unit is an area where these ice flow interact and become chaotic instead of steady flows

[Bazile]

Why do we consider that if there is intelligent life out there , they would want to bother contacting us ?

For all we know there could be civilisations out there ( with the technology to transmit their presence quickly over vast distances ) that are so advanced compared to us - that it would be like comparing where we are now on the earth , to the stone age period - or earlier .

Re wildwood's post - I'm always in awe of the vastness of the universe - and we are only talking about the nearest galaxy to our's - mind boggling distances - eh?