Patrick C.

Many Fundamentalist Christians believe that the Earth is the only planet in the Universe that has intelligent life. They use science to support this belief.

However, there is a book by two scientists called Rare Earth: Why Complex Life is Uncommon in the Universe. They make their case without a religious and ideological agenda.

What do secularists think of the Rare Earth Hypothesis?

Jesus Tap-Dancin' Christ

Bullcocky.

We'd NEVER see them. Ever. Because the universe expands proportionately to the distance between things, and the limitation of the speed of light for any form of communications, any communciation sent would take centuries at the bare minumum to reach us, with millenia or longer being more apt. This signal would be distorted due to Doppler shifts, and would be recieved most likely long after the other civilization perished.

We are not alone--it just looks that way.

Godbert

Rare in regard to the universe means by no means just once.
Assuming we have 10^22 stars in the universe you could have 10 billion earths and they still would be extremely rare (1 in a trillion).

djmullen

Here are a couple of URLs that discuss Rare Earth:

http://www.seti.org/science/rare_earth.html

http://www.space.com/scienceastronom..._1_020715.html

Executive summary: we're rare, but it's a big universe.

Jobar

The vital variables which are used to justify this thesis- numbers of planets, numbers of suns which can support life, the conditions under which intelligent life can evolve- are still unknown, so the argument is basically just arm waving.

In fairness, it is certainly not impossible that it is correct- but at this point no one knows.

Valentine Pontifex

I don't think using the term "universe" is the best term to use here.

It would be far better to ask: How many other other technological civilizations are there in our Galaxy?

Astronomers tend to think the number is large, while evolutionary biologists tend to think that number is small. Obviously this is only a trend and there are exceptions.

As for myself, I would be surprised if we share the Galaxy with another technological civilization. But I still am running SETI@Home on the idea that it does not hurt to check. But for the universe as a whole, I think it is safe to say that there is one out there somewhere since the universe as a whole is just that big. And if inflations is even remotely close to the mark and the observable universe is trivially small compared to the whole then there is a LOT of civilizations out there though forever out of contact.

If we drop the request for technological civilizations and settle merely for life than I would suspect that life has appeared thousands of times (if not millions) of times in our Galaxy.

Shadowy Man

Which astronomers are those?