Rare Earth

[otseng]

Imagine there's no spacemen except the ones we launch
No alien rock n' rollers to listen to Sagan's hunch
Imagine we're all stuck here and must confront ourselves

.. uh oh!

Imagine now that Star Trek is just a TV show
No cosmos full of life forms just earthlings here below
Imagine there's no 'contact' to make 'cause no one's there

... uh oh!

You may say I'm a realist but I'm not the only one
Who knows there's zero data from SETI - or anyone!
Imagine your dream's over no Yoda to soothe you
And your only choices left then boil down to two
Imagine you're unique here and must opt for love or hate

... uh oh!

You may say I'm religious but I'm not the only one to say if you seek communion
it's the heart that must be won!

From the Rare Earth Song

In the book Rare Earth, the authors make two main points:
- Microbial life is common in planetary systems.
- Advanced life (animals) is rare in the Universe.

The arguments they give can be found at wikipedia.

But, in the book, they don't really explore the implications of their hypothesis.

So, what I'd like to ask is:

What are the implications if earth is the only planet with advanced life on it?

[QED]

But, in the Rare Earth scenario, there is no "luck of the draw". There is only one stick to draw from - Earth. It is not the fact that we picked out that one stick called Earth that is special. But the fact that there is only one stick to draw from.

As it was beginning to dawn on me a few posts back, It does very much hinge on there being other Goldilocks planets which refuse to bear life. We have to make this clear as a part of the scenario as we might otherwise be looking at the case where the only remarkable thing is that it is only this planet that has suitable conditions.

[otseng]

As it was beginning to dawn on me a few posts back, It does very much hinge on there being other Goldilocks planets which refuse to bear life. We have to make this clear as a part of the scenario as we might otherwise be looking at the case where the only remarkable thing is that it is only this planet that has suitable conditions.

This is what the authors argue for in their book. Though I will add that they don't go so far as saying that the Earth is the only Goldilock planet. They offer a formula to calculate the odds of find another Goldilock planet, but do not offer a final value to the formula. But, they do seem to strongly imply that Earth is the only planet.

[Galphanore]

As it was beginning to dawn on me a few posts back, It does very much hinge on there being other Goldilocks planets which refuse to bear life. We have to make this clear as a part of the scenario as we might otherwise be looking at the case where the only remarkable thing is that it is only this planet that has suitable conditions.

This is what the authors argue for in their book. Though I will add that they don't go so far as saying that the Earth is the only Goldilock planet. They offer a formula to calculate the odds of find another Goldilock planet, but do not offer a final value to the formula. But, they do seem to strongly imply that Earth is the only planet.

Is this it? Click the equation to view it's explaination :
[center][/center]

[Cathar1950]

I watched the guy show it on either pbs or NGC. But the problem was the numbers are unknown for what counts. I hope we are not the first or moest advanced because the universe will have a long wait. But I guess some one has to be first.

[Galphanore]

I watched the guy show it on either pbs or NGC. But the problem was the numbers are unknown for what counts. I hope we are not the first or moest advanced because the universe will have a long wait. But I guess some one has to be first.

Yeah, the link says that the reason they don't solve the equation is because they can't fill in some of the numbers, so their whole hypothesis is based on what they want the result to be. Interesting they neglect to mention that particular part.

[Cathar1950]

I watched the guy show it on either pbs or NGC. But the problem was the numbers are unknown for what counts. I hope we are not the first or moest advanced because the universe will have a long wait. But I guess some one has to be first.

Yeah, the link says that the reason they don't solve the equation is because they can't fill in some of the numbers, so their whole hypothesis is based on what they want the result to be. Interesting they neglect to mention that particular part.

The program I saw did mention that problem.
Still it does seem like it would not take much to fill in a few numbers.
The result might be weaker but it is still nice to think to think about.
I just hope we are not first.
We might find out planets and life is common and has little little value beyond life.

[Galphanore]

I watched the guy show it on either pbs or NGC. But the problem was the numbers are unknown for what counts. I hope we are not the first or moest advanced because the universe will have a long wait. But I guess some one has to be first.

Yeah, the link says that the reason they don't solve the equation is because they can't fill in some of the numbers, so their whole hypothesis is based on what they want the result to be. Interesting they neglect to mention that particular part.

The program I saw did mention that problem.
Still it does seem like it would not take much to fill in a few numbers.
The result might be weaker but it is still nice to think to think about.
I just hope we are not first.
We might find out planets and life is common and has little little value beyond life.

Here are the parts of the equation :

• * fg is the fraction of stars in the galactic habitable zone. 0.1 at most.
  * fp is the fraction of stars in the Milky Way with planets. All extrasolar planets discovered to date orbit stars that are fairly metal-rich, suggesting that planets may be peculiar to metal-rich stars.
  * fpm is the fraction of planets that are rocky ("metallic") rather than gaseous.
  * fi is the fraction of habitable planets where microbial life arises. W&B believe this fraction is unlikely to be small.
  * fc is the fraction of planets where complex life evolves. For 80% of the time since microbial life first appeared on the Earth, there was only bacterial life. Hence W&B argue that this fraction may be very small. Moreover, the Cambrian Explosion, when complex life really got off the ground, may have been triggered by extraordinary climatic and geological events.
  * fl is the fraction of the total lifespan of a planet during which complex life is present. This fraction cannot be high because complex life takes so long to evolve. Complex life cannot endure indefinitely, because the energy put out by the sort of star that allows complex life to emerge gradually rises, and the central star eventually becomes a red giant, engulfing all planets in the planetary habitable zone. Also, given enough time, a catastrophic extinction of all complex life becomes ever more likely.
  * fm is the fraction of habitable planets with a large moon. If the giant impact theory of the Moon's origin is correct, this fraction is small.
  * fj is the fraction of planetary systems with large Jovian planets. This fraction could be large.
  * fme is the fraction of planets with a sufficiently low number of extinction events. W&B argue that the low number of such events the Earth has experienced since the Cambrian explosion may be unusual, in which case this fraction would be small. Such a low number again requires a very stable planetary system, with outer planets having nearly circular orbits, no gravitational perturbations from passing stars, and no nearby supernovas, quasars, or gamma ray bursts.

So some of the things are rather hard to figure out any time soon, and if we fill them in with guesses then we can, depending on what guess we make, come to a result anywhere from earth being the only one to millions of possibilities just in our galaxy.

[Furrowed Brow]

Hi Osteng

Personally, that is what I predict. No complex life, or any life form, will be found that originated outside of Earth. Even on Goldilock planets.

Ok. Do you think it is possible to turn some kinds of religion into a testable predication, or is that just a personal view.

I'd also say low level life i.e bacteria, simple cell organisms don't count either way. I think we would need to at least see stuff as complex as fish, reptiles, mammals, hominids etc, in that rising order.

Would a hominid found on another planet necessity a radical reinterpretation of scripture? In a similar way as the Copernican Revolution brought about.

[otseng]

Personally, that is what I predict. No complex life, or any life form, will be found that originated outside of Earth. Even on Goldilock planets.

Ok. Do you think it is possible to turn some kinds of religion into a testable predication, or is that just a personal view.

This is my personal stance. Primarily because I believe abiogenesis is impossible.

Would a hominid found on another planet necessity a radical reinterpretation of scripture? In a similar way as the Copernican Revolution brought about.

It would depend, if they independently believe in a Jesus and God, no, there would be no radical reinterpretation.

Seriously though, I'm not sure if there would be any reinterpretation, but I would abandon debating against evolution, since that would be proof to me that it is true.

[otseng]

Speaking of goldilocks, Paul Davies has a book out - The Goldilocks Enigma: Why Is the Universe Just Right for Life?

I haven't read the book, but I've read some reviews of it. I think the interesting thing is now scientists pretty much accept that the universe happens to be "just right". But, the problem now is, why?

The main options, then, are: first, that the Universe is a fluke; second, that it is one of many and happens to be, much like Goldilocks' porridge, just right for us; and third, that conscious observers bring the universe they inhabit into existence simply by observing it, although their teleological actions would have to reach back into the past, forcing the right conditions to be selected at the Big Bang.

BOOK REVIEW: The Goldilocks Enigma: Why Is the Universe Just Right for Life? by Paul Davies

Given the three choices, I kinda like the fourth one the best, "God did it."