Are We Alone? - [A PBS/Nova interview from July, 2004]

PBS.org ^ | July, 2004 | Neil deGrasse Tyson & Peter Ward

[snarks_when_bored]

Paleontologist Peter Ward does a masterful job of helping astrophysicist Neil Tyson understand why it is quite likely that intelligent life (as opposed to, say, microbial life) is extremely rare in the cosmos.

In addition to the photos of Tyson and Ward (posted below), there are five other nice (but generic) photos viewable in a Javascript slide show on the PBS website.

Astrophysicist Neil deGrasse Tyson (top) and paleontologist Peter Ward square off in a friendly debate about the odds that intelligent life flourishes beyond Earth.

[snarks_when_bored]

Ping

[maestro]

Are we alone?

Nope....

Resurrected Jesus of Nazareth and His Holy Angels ARE coming from Heaven!

HAPPY EASTER!

:-)

[joshhiggins]

"when we get too hot, we pull greenhouse gases out of the atmosphere and turn them into coral reefs."

One of those little inconvenient factoids that messes up all the calculations of the "global warming" crowd.

[glorgau]

"when we get too hot, we pull greenhouse gases out of the atmosphere and turn them into coral reefs."

The arguement seems to ignore the fact that life itself formed the biosphere of the planet. The carbon cycle is intimately linked with life - hence the stable temperatures. The whole planet is one big continuous feedback loop. Could have a point about the asteroid impacts though...

[Grut]

It's a basic rule of thumb that when you have only one example, you assume it's the average. Therefore, intelligent life is presumably typical for Sun-like stars the age of the Sun: all this havering about local conditions and the difficulty of matching them elsewhere just ignores this.

So Fermi's question "So, where is everyone?" is still a good one. There ought to be radio civilizations all over the place. Debates like this one are just 'begging the question'.

[Drango]

FReeper SETI list....I'm #42....Whooooooooooooo

http://setiathome2.ssl.berkeley.edu/stats/team/team_15327.html

[marktwain]

Debates like this one are just 'begging the question'.

Not really, the debate was all about answering the question. It is true that we have really explored only one planet, and that planet has intelligent life.

The answer to Fermi's question may well be that we are really rare, for all the reasons given above.

The other side of this, given that we are rare, is that the whole universe is available to us for our use. We could colonize much of the galaxy in a couple of hundred thousand years.

[IronJack]

intelligent life beyond Earth must be exceedingly rare.

Do I need to say it? Intelligent life is not all that common ON Earth.

[carlr]

Interesting article.
Whether one believes in ID,which I do for the record but not looking for an arguement on that point,or if they believe in a long evolutionary process it is refreshing to see it laid out how unique we may be in the universe.
No offense to the deceased but I long felt Carl Sagen became more of a political activist than a scientist.I remember hearing him say once that we should stop all spending on national defense and use the money to send a man to Mars.The need for this is debatable but Sagens motivation appears to have been political not scientific.

A couple of questions.Is it possible to have a star different than our own,white dwarf,red or blue giant if those terms are still used,that could have a planet proportional to size of the star. That is,located at a proper distance based on the gravitational pull of the star and have the proper heat for life at least similar to that which we know.
What would be the ideal distance from a red giant based on its heat output and what would be the size of the planet required to deal with the higher gravity of the larger star?I ask this because all the planets that have been found outside the solar system are giants.Would the size of the planet itself even if in ideal distance to its star for heat have an adverse effect on life forming due to the high gravity of the larger planet?
I have kind of forgotten the life cycle of a star.Are all the giants considered to be old stars having expanded in size from one similar to ours.If that is the case they of course would have engulfed any planets similar to our own.

[JimSEA]

Thanks for an excellent atrticle posting.

[PatrickHenry]

Science Ping!

An elite subset of the Evolution list.

See list's description in my freeper homepage. Then FReepmail to be added/dropped.

[eno_]

It means we owe it to the universe to get off this rock before some random rock or blast of x-rays wipes us out.

[AntiGuv]

My personal values for the Drake Equation calculate 3.84 civilizations in the Milky Way detectable at interstellar distances. We're one of them..

[AntiGuv]

Well, 100 years ago our known number of civilizations with radio communication were zero. So, did the number of radio civilizations jump since then from nowhere to all over the place ?

Obviously the 'basic rule of thumb' is inadequate. You are falling into the inverse gambler's fallacy.

[OSHA]

I came up with 1.25. I know where the .25 is that means there is one more out there somewhere.

[MainFrame65]

Your questions were at least partially addressed in the discussion.

Large stars burn out much faster, and emit excessive radiation that might sterilize any planets that form. Also, they are far less stable over the long periods of time that Earth took to produce its abundant life.

Small stars - 60% of our galaxy - would require the planet to be so close that they would be locked, like our moon, into a synchronous rotation. One face to the sun, burning hot, the other frozen. The thin border zone would be hardly more hospitable.

Sagan was more interested in his daily dose of cannabis than in scientific pursuits.

[doc30]

It's a basic rule of thumb that when you have only one example, you assume it's the average.

This article doesn't say Earth is an average. It basically talks about the stable conditions to allow life, and ultimately, intelligent life to form. If you don't have a stable environment for a long enough time, things go extinct and there is insufficient time for recovery. This could be from asteroids, temperature variations, changes in the central star's intensity, etc. The point is that most astronomers don't think in terms of ecosystem stability and geology. This article hits home those points.

[Sam Cree]

I'm going to say that the arguments for rarity of planets with civilizations are good ones. But if something exists once, it probably exists more than once, IMO. Rarity within a space as unimaginably huge as the universe can still translate into large numbers.

However, it's probably OK with me if aliens are out of reach.

[BillCompton]

I find Fermi to be entirely persuasive.

If we developed technology that allowed us to build colony ships and we sent one out per 10,000 years. And if each of the colony ships, on average, split every 10,000 years, in a million years, we would completely dominate the galaxy. There would be trillions of colonies around each star.

And a million years is nothing.

If we can manage speeds a thousand times faster than Voyager, Most of the Milky Way is reachable in the million years.

I think this is what life means: filling the ecosystem.

Perhaps intersteller travel is not possible. That would certainly change things.