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Freeflyhawk88

SPitZer

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Spitzer sees far-off planet light

http://news.bbc.co.uk/1/hi/sci/tech/4379007.stm
http://news.bbc.co.uk/1/hi/sci/tech/4411865.stm
http://www.futurepundit.com

I agree with the Rare Earth hypothosis. I think that Earth-like worlds are rare and that ETs are even rarer. The rare earth hypothosis adds the following factors to the famous Drake equation:

1) The presence of gas giants in the right orbits to screen out comets and asteriods to reduce the amount of impacts on the Earth-like world.

2) The presence of a large moon orbiting the Earth-like world (double-planet system). The moon stabilizes the axial tilt of the Earth-like world. Also the moon creates tides, which probably helps in the emergence of life from the sea up onto the land.

3) Plate-tectonics: These are essential for the reprocessing of the atmosphere as well as geo-cycles. However, I suspect that any Earth-size planet will have these.

Factors 1 and 2 probably drop the number of Earth-like world candidates by a factor of a thousand.

The other way to calulate the probability of ETs for any given number of Earth-like worlds is to calculate the ratio of time of human civilization (about 10,000 years) to the time that life has been on the Earth (about 4 billion years). This gives a factor of 1 in 400,000. This means to me that one out of every 400,000 Earth-like worlds, with the right sized moon and the gas giant planet being in the right place, is likely to have an ET civilization.

If you assume that 10% of the galaxy's stars are F, G, or K-type and 10% of those are in the galactic habitable zone. You get about 4 billion stars. If 10% of those have an Earth sized planet in the right orbit, that drops it down to 400 million worlds. So, there are probably 400 million "garden worlds" in the galaxy. Lets say that one out of a thousand of these garden worlds has a large moon and gas giant planets in the right orbits, this drops the number of garden worlds suitable for the emergence of ET down to 400,000. Since the time ratio of civilization to life on Earth is 1 in 400,000, this comes out to one civilization in the galaxy, which is us!

So, we are alone in the Milky way.

If the current csmological theories are currect, there are 10 to the 75 number of galaxies in our universe (the observable universe being a very small part of the total universe) and that there are probably an infinite number of other universes. So, the probability of ETs existing is unity.

To sum up, ETs exist and there is probably an infinite number of them. Its just that they are a lot further away from us than current SETI expectation calls for (the nearest ET civilization is probably in Andromeda - 2 million LYs away from us).

Posted by: Kurt on July 28, 2004 05:06 PM

The criticism of this group has been to say that we've looked for intelligence for close on half a century and nothing has turned up, therefore there has to be nothing.

Drake's equation

N = R * fs * fp * ne * fl * fi * fc * L

N is the number of intelligent civilizations able to communicate within our own galaxy.

R = average rate of star formation in the galaxy, equal to about 20 stars per year
fs = fraction of stars that are suitable suns for planetary systems, approximately 0.1
fp is the number of suitable suns with planetary systems
ne is the mean number of planets that are located within the Continuously Habitable Zone (assuming liquid water is necessary for life).
fl is the fraction of such planets on which life actually originates
fi represents the fraction of such planets on which, after the origin of life, some form of intelligence arises
fc is the fraction of such intelligent species that develop the ability and desire to communicate with other civilizations (e.g. they construct radio telescopes or laser systems).

Clicky pleeze

ETs PLAN 51 wayz to bring an ICBM down;):ph34r:

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