The Search for Life: The Drake Equation - BBC4, 20:00

[klr]

A quick heads-up. This is not a new program - it was first broadcast in Dec. 2010 - but I've not seen it before, that I can recall.

http://www.bbc.co.uk/programmes/b00wltbk

For many years our place in the universe was the subject of theologians and philosophers, not scientists, but in 1960 one man changed all that.

Dr Frank Drake was one of the leading lights in the new science of radio astronomy when he did something that was not only revolutionary, but could have cost him his career. Working at the National Radio Astronomy Observatory in Greenback in Virginia, he pointed one of their new 25-metre radio telescopes at a star called Tau Ceti twelve light years from earth, hoping for signs of extra-terrestrial intelligence.

Although project Ozma resulted in silence, it did result in one of the most seminal equations in the history of science - the Drake Equation - which examined seven key elements necessary for ET intelligence to exist, from the formation of stars to the likely length a given intelligent civilisation may survive. When Frank and his colleagues entered the figures, the equation suggested there were a staggering 50,000 civilisations capable of communicating across the galaxy.

However, in the 50 years of listening that has followed, not one single bleep has been heard from ET. So were Drake and his followers wrong and is there no life form out there capable of communicating? Drake's own calculations suggest that we would have to scan the entire radio spectrum of ten million stars to be sure of contact.

The answers to those questions suggest that, far from being a one off, life may not only be common in the universe but once started will lead inevitably towards intelligent life.

To find out about the equation's influence, Dallas Campbell goes on a worldwide journey to meet the scientists who have dedicated their lives to focusing on its different aspects.

The program is repeated at 01:00 tomorrow morning - all praise the DVR "record program" button.

EDIT: Wrong time, dammit ...

[Gawdzilla Sama]

Tell us when it hits Youtube, somebody?

[Animavore]

It's already on YouTube. Start here http://www.youtube.com/watch?v=UzRirEcx-GQ

[Gawdzilla Sama]

It's already on YouTube. Start here http://www.youtube.com/watch?v=UzRirEcx-GQ

Danky!

[Coito ergo sum]

The Drake Equation -

Arbitrarily create a list of variables. Assign more or less arbitrary values to said variables. Alter values as needed to obtain result desired.

[Gawdzilla Sama]

The Drake Equation -

Arbitrarily create a list of variables. Assign more or less arbitrary values to said variables. Alter values as needed to obtain result desired.

The values assigned are arbitrary, but the conditions described are pretty well sussed out.

[Coito ergo sum]

The Drake Equation -

Arbitrarily create a list of variables. Assign more or less arbitrary values to said variables. Alter values as needed to obtain result desired.

The values assigned are arbitrary, but the conditions described are pretty well sussed out.

Ultimately, any number derived is meaningless because we don't know most of the information. We can estimate the number of starts in the universe, but we don't have enough information to know the number of planets that is typical, or the number of planets capable of sustaining life, or the number of planets that sustain life that would evolve intelligent life, etc. Basically, an application of high-low possible variables results in the conclusion that there can be something like between 1 and N-X intelligent civilizations in the universe. One being the known quantity, Earth, and N being the number of stars in the universe, and X being the unknown number of stars without intelligent life revolving around them.

The Drake equation states that:

where:
N = the number of civilizations in our galaxy with which communication might be possible;
and
R* = the average rate of star formation per year in our galaxy
fp = the fraction of those stars that have planets
ne = the average number of planets that can potentially support life per star that has planets
fℓ = the fraction of the above that actually go on to develop life at some point
fi = the fraction of the above that actually go on to develop intelligent life
fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
L = the length of time for which such civilizations release detectable signals into space.[3]

R can be estimated with some large range.
fp is not known
ne is somewhere between just over 0 to some percentage greater than 50.
f[ is wholly unknown, and may be 1/Z where Z is the number of planets in the universe.
fi is wholly unknown, and may be 1/Z where Z is the number of planets in the universe.
fc is wholly unknown, and may be 1/Z
L is wholly unknown.

Conclusion - N may be anywhere between 1 and a lot.

[Gawdzilla Sama]

Yes, yes, yes, they know that. However, it gives parameters to search for likely planets.

[Coito ergo sum]

I'm thinking N = 1-ish.

1 in 100 sextillion chance of a planet having intelligent life doesn't sound far fetched. A lot of random opportunities. Law of large numbers, and whatnot.

[Gawdzilla Sama]

There's a problem with "L" of course.

[Coito ergo sum]

There's a problem with "L" of course.

Well, and time scales are hardly imaginable in human terms. It seems reasonably conceivable that civilizations just like ours lived and died a billion years ago. Maybe we are the beginning or end of the bell curve, wherein the peak represents the most intelligent/communicative civilizations existing at any given time in the life of the universe. I.e. there was a time when the universe was too new, and there was no life, for like a billion years, then the bell curve begins, as civilzation one pops into existence, then 2 more, than 3, than 10 than 100, then 1000 then 1000s, then the peak of civilization-births occurs, and then the rate of new civilizations starts to come down. We could be the first, or the last, conceivably.

Or, it may well be so rare to have life, that Earth could just be freak of nature. Maybe universes aren't all that life-oriented. It's a solipsism to think that the universe is all about us, meaning humanity. But, since really all life is just part of the same family tree, the same analysis can be extended to all of life on Earth and life in general. Maybe universes are rock, gas and energy focused, and life is just an aberration.

[Gawdzilla Sama]

Not what I meant. Those are other variables. The amount of time civilizations can generate detectable signals depends on what we are listening for, in deed what we are capable of listening for. If they used gravity waves to communicate we might not spot them at all.

[Coito ergo sum]

That too, of course.

[TonyBelch]

Not what I meant. Those are other variables. The amount of time civilizations can generate detectable signals depends on what we are listening for, in deed what we are capable of listening for. If they used gravity waves to communicate we might not spot them at all.

Neutrinos could be the future FTL technology.

[Gawdzilla Sama]

Not what I meant. Those are other variables. The amount of time civilizations can generate detectable signals depends on what we are listening for, in deed what we are capable of listening for. If they used gravity waves to communicate we might not spot them at all.

Neutrinos could be the future FTL technology.

Why not tachyons?