Is there another Earth out there?

USA Today ^ | Staff Writer

[bedolido]

[snarkpup]

"The space people will contact us when they can make money by doing so." - David Byrne

[ConservativeDude]

"The real space sequel guaranteed to capture public attention, astronomers say, is the discovery of another planet like Earth in our own starry neighborhood -- and it is likely to happen within a decade."

I'll bet ANYONE a million bucks that we don't discover another "planet like Earth in our own starry neighborhood within a decade". ANYONE.

What a load of hooey. I stopped reading after that sentence.

[LiteKeeper]

read later

[Skywalk]

Well, before the invention of superluminal transportation, this would be the perfect way to escape a totalitarian world government.

[B-Chan]

I'd be willing to wager a smaller amount -- say ten bucks. (I'm poor.) If interested, FRmail me a proposal.

[BillCompton]

I think it is highly unlikely there is intelligent life in the galaxy and maybe in the entire universe...excepting earth, of course.

It seems so obvious. Suppose, for example that it takes us 10,000 years from now to produce a space station that can travel to the stars. Further more, assume that each space station finds the resources to split into two space stations every 10,000 years. In only million years, that is 100 doublings. That would be hundreds of trillions of space stations for every star in the galaxy. To quote Enrico Fermi: "Where are they?"

If they were only a million years more advanced, they would have populated here already. Of course, there could be other explainations: Suppose there is something hostile to life in the space between stars. Who knows? But life explodes geometrically. There is no reason to think that truism about life is limited to non-technologically advanced life, right? So if they exist, where are they?

[PatrickHenry]

Old topic, new thread. [This ping list is for the evolution side of evolution threads, and sometimes for other science topics. FReepmail me to be added or dropped.]

[glorgau]

So if they exist, where are they?

How do you know they aren't here already? If said civilisation was one million years more advanced than us, say at the level of Homo Sapiens to Homo Erectus, what makes it so obvious that they would be detectable? Heck, stealth aircraft would be magic to people living in the 1500s. Multiply that by 1000.

[Dimensio]

I think it is highly unlikely there is intelligent life in the galaxy and maybe in the entire universe...excepting earth, of course.

I agree, except for the "excepting earth" part.

[Lonesome in Massachussets]

Somewhere in a parallel universe the Red Sox win the World Series more than once every 100 years.

[BillCompton]

How do you know they aren't here already?

My point is that if there were 100's of trillions of colonies of them around our sun, we would probably know about them. And our well-being would probably not be on their list. Ultimately, it will be a race to consume resources...biological systems always become that.

[AntiGuv]

FWIW, in my estimation of The Drake Equation, there should only be some half dozen communicating civilizations at present in the Milky Way.

[BillCompton]

I think it is highly unlikely there is intelligent life in the galaxy and maybe in the entire universe...excepting earth, of course.

>I agree, except for the "excepting earth" part.

You have obvously forgotten about the indisputable fact that Hillary Clinton is intelligent.

[BillCompton]

FWIW, in my estimation of The Drake Equation, there should only be some half dozen communicating civilizations at present in the Milky Way.

This assumes that these civilizations, once they reach the ability to travel in space, don't go. If they go, and they multiply, they quickly consume the galaxy.

[alnitak]

Within a decade you may be right, within 2 decades you're very probably wrong. Note that by "Earthlike" astronomers mean small, dense and rocky, orbiting close in to the star, like Earth, Mars, Venus and Mercury. We may have to examine 100's or 1000's of such planets before we find one with an oxygen rich atmosphere.

The exo-solar planets that have been found so far are gas giants - Jupiters and super-Jupiters.

Oh and btw, given the size of our galaxy, I would consider anything within 1000 light years to be "our neighbourhood" :-)

Further reading in case you're interested (it's a bit technical):

The Extrasolar Planets Encyclopaedia: http://cfa-www.harvard.edu/planets/

and their extra-solar planet catalog (108 current candidate planets): http://cfa-www.harvard.edu/planets/catalog.html

[B-Chan]

Good point.

Although I don't think there are any hnau (C.S. Lewis' term for beings with souls) other than humans, there's no reason to assume that if there were any they'd be recognizable as such, either in appearance or in behavior.

My guess: If we ever did encounter a truly "alien" intelligence, odds are that their/its behavior and motivations would make to sense whatsoever to us. They might invade the Solar System, ignore all attempts at contact, and then leave as suddenly as they came -- after carving the entire surface of Mars into one huge, mysterious abstract sculpture. To my mind the actions of a truly alien intelligence would make no more sense to us than badminton makes sense to an amoeba.

A real alien species would probably be something more like a tiny virus than a giant lizard anyway. Any race or being capable of travelling between stars is going to be highly optimized for survival -- which means small, lightweight, and redundant, like a virus. If we as Earthlings were creating an organism designed for space travel, we'd do well to create a whole bunch of tiny, identical, fast-replicating virus-like Critters rather than One Big Thing. Big things are hard to get going, for one thing, and would require all sorts of complicated engines and things to get anywhere in any kind of reasonable time. Critters, on the other hand, could simply drift through space on plasmas or magnetic fields or be pushed along by a microwave laser beam from the Earth until they ran into something interesting -- an inhabited alien world, say. Instead of invading the alien planet, our Critters would instead let us invade the bodies of the aliens themselves, conquering them at the cellular level, injecting them with our RNA, and turning Them into Us from the inside out. Sounds like a Twilight Zone episode, doesn't it?

Come to think of it, no one really knows where real viruses get their start. How do we know SARS isn't an alien invader, bent on our destruction somehow?

I once saw a cartoon in which a scientist is looking through a microscope at a colony of bacteria, when suddenly the bacteria line up in formation and spell out the words TAKE ME TO YOUR LEADER, HUMAN. Maybe the real aliens have been here among us all along...

[e_engineer]

When they say "planet like Earth in our own starry neighborhood within a decade", they mean an Earth sized planet within a few hundred light years.

There are millions of stars in our "neighborhood", and it is almost certain that some of them have earth sized planets. (Our star has several)

[AntiGuv]

That is an assumption which is not necessarily true. Your essential argument is a fallacy. It is the supposition that: because intersolar travel appears uncommon, extraterrestrial sentience is nonexistent.

First of all, it's worth noting that by 'communicating civilizations' I do not mean civilizations in contact with one another, but rather civilizations that emit any signs of their existence into extraplanetary space (i.e. radio waves, etc.)

Secondly, you assume that any extraterrestrial intelligence would have personality characteristics similar to our own (reproduction rates, exploration impulses, etc).

Third, you assume that hyperadvanced civilizations will operate in a manner similar to our own (corporeal, competitive, expansionary, etc).

Fourth, you assume that the rise of sentient lifeforms is evenly distributed across the lifespan of our galaxy, rather than steadily concentrated toward later (from our perspective, more recent) eras.

Fifth, you assume that superluminal or near luminal travel is something that is an eventual inevitability, for any given civilization. Moreover, that it is an attractive option for great numbers.

I could go on. The point of the matter is that your original thesis is a fallacy.