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Fraser
2007-Feb-12, 05:20 PM
If you're wondering how many extraterrestrials there are in our galaxy, you just have to use a simple equation developed by astronomer Frank Drake in 1961. Just find out how many stars there are, how many support life, how many advanced societies form, and a few other details and we'll be set.
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<a href="http://media.libsyn.com/media/astronomycast/AstroCast-070212.mp3"><strong> Episode 23: Drake Equation (18 MB)</strong></a>
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Read the full blog entry (http://www.astronomycast.com/solar-system/episode-23-the-drake-equation/)

EvilEye
2007-Feb-12, 07:10 PM
His equation looks great on the surface, but it made too many assumptions (in my opinion).

It assumes that many places can have habitable planets. We have found "many" planets outside of our solar system already, and none of them were good candidates. It also assumes that life will always evolve. That's not neccessarily true. Life can come into existence, and then be obliterrated before it ever has a chance. Then he assumes that life can evolve to "intelligence". While that may be true... our dogs, cats, primates, and dolphins etc... are "intelligent", but they have no interest other than to satisfy their needs.

All that said...

Why do we need an equation?

If there was even just ONE single form of any kind of life found on another planet (or moon).... everything we know would change.

Oh... and Just because we can't find it doesn't mean its not there.

GREAT topic!

jamini
2007-Feb-12, 07:30 PM
His equation looks great on the surface, but it made too many assumptions (in my opinion). It assumes that many places can have habitable planets. We have found "many" planets outside of our solar system already, and none of them were good candidates. It also assumes that life will always evolve. That's not neccessarily true. Life can come into existence, and then be obliterrated before it ever has a chance. Then he assumes that life can evolve to "intelligence". While that may be true... our dogs, cats, primates, and dolphins etc... are "intelligent", but they have no interest other than to satisfy their needs.
Actually, we are only able to indirectly observe the larger planets outside our solar system by the wobble they create on their respective suns. More habitable planets such as ours have not been found simply because our current technology is unable to detect their presence. The next generation of space telescopes may reveal more planets than anyone has ever imagined.

That life can and will evolve on planets suited for life is IMO very high. Whether we evolved because of or despite all the obstacles we overcame is debatable; regardless, we did evolve from extremely basic and common elements that are common and prevalent throughout the observable universe.

In my opinion, our greatest challenge as a species will be to survive technology without destroying ourselves. Given the current state of world affairs, I’d assign this parameter the lowest number of probability.



Why do we need an equation?
We are curious. In the absence of firm data and direct observations, we make estimates.


If there was even just ONE single form of any kind of life found on another planet (or moon).... everything we know would change.
There very well may be. We have as yet only landed on the moon and sent rovers to Mars. We have barely yet begun to explore our solar system. Personally, I’m kind of curious about what may exist below the ice on some of the moons of Jupiter and Saturn. Perhaps some day a probe will provide some answers.


Oh... and Just because we can't find it doesn't mean its not there.
Isn’t this statement incongruent with everything else you’ve just said? I interpret the rest of your post to say that you feel it’s exceeding unlikely that there are any extraterrestrial life forms and that thinking about it (or at least trying to ‘guestimate’ it) prior to any firm evidence is a meaningless effort. But maybe I just read your post too fast, I do that sometimes.

If anyone’s interested, here’s a site with an interactive Drake calculator, where you can enter your own estimates:
http://www.seti.org/site/pp.asp?c=ktJ2J9MMIsE&b=179074

EvilEye
2007-Feb-12, 10:28 PM
I wasn't arguing whether there might be life out there. I'm almost certain that there has to be.

My argument was with Drake's equation.

There are too many variables to consider when trying to create a technologically capable living thing.

Even just the fact that we have fingers is key to our technolgy. If dolphins had hands they may well have developed beyond us. (I know.. Hitch-hiker's Guide)

I don't doubt that there may be tons of other weird forms of life, that maybe we didn't even recognise as life. Maybe because we have restricted ourselves by our own defining of it.

Our planet is exactly the right distance from our exactly right sized star, with a perfectly placed moon to keep us steady, we're tilted perfectly to give us the seasons we need for agriculture, we have exactly the right mixture of nitrogen and oxygen to keep us from blowing up in thin air. And on and on....

No doubt it is possible to have life out there, but I don't see Drake's equation taking in anything more than baseline possibilities.

Still .... it's fun to think about! :)

SingleDad
2007-Feb-13, 05:31 AM
One thing I find weird about Drake's equation, it assumes ALL "life" is carbon based. True the life we know of is carbon, but we are makeup of almost proportionally of the same thing we are. Remember, we are not special... we are not the norm... we just are. As far as we know, these hot Jupiters could have some non solid life form made up of plasm and gases.

Brian

Blob
2007-Feb-13, 12:28 PM
Hum,
it is only an equation.
there are certain numbers that are fairly well estimated.
R = 10-20 new stars per year
Fp = 30%

There is no one forcing you to choose the number of habitable planets or the type, or likelihood, of life that arises on the planet.

Ne -Number of habitable planets per planetary system
Fl - Fraction (percentage) of those planets where life develops
Fi - Fraction (percentage) of sites with intelligent life
Fc - Fraction (percentage) of planets where technology develops
L - "Lifetime" of communicating civilizations (years)

R * Fp * Ne * Fl * Fi * Fc * L = N

(N= at least 1)

spent
2007-Feb-15, 06:50 AM
I agree in that I think there are too many variables to even come close to forming an equation.

But as a guess I would say that Life in and of itself is common yet extremely rare.
Intelligent (like us or better), even rarer.

If our own planet was even a smidgen farther from the sun. We would not exist.
Most life would have frozen to death or dehydrated.

I think we take for granted in a very large way just how fragile we really are.

Already. If you alone on this planet earth. Just you. Living in chicago. Right now.
No shelter. No animals to hunt. You would freeze to death. ONLY and ONLY because we have houses and heat and can go to jewel do most exist.

You will not survive very long on your own as a bird or skunk can.

Now. image the earth being just half the distance closer to Mars we would be frozen. Just a little 23 degree pitch turns summer to winter.

Our exact material and amount of it, distance and size between sun and earth are indeed so very incredibly perfect for life to exist at all.

A celestial duplicate just in degrees of pitch or minute distance alone would be soo incredibly rare.
And any slight deviation from it kills almost everything.

Common? If life can be duplicated. I think the basics would be very similar. Some species might duplicate and some be
very very different. I bet the dinosaurs never thought an animal like us would exist. And what did the first human who ever dug up a dinosaur think?

And that's just here.

llarry
2007-Feb-16, 07:13 AM
Hmmm,

Well I agree, great topic. To the question why do we need an equation, I believe Pamela stated that it is an attempt to determine the mathematical probability that intelligent life other than our own exists. I'm not a mathematician ( as I may inadvertantly prove with the content of my post), but I don't believe mathematical modeling of this type is an attempt to prove anything so much as it is a starting point, or tool for developing a hypothesis which then may be disproven or not. For this purpose I believe maybe Drakes Equation has proven quite effective. We are still talking about it and the serious search for planetary systems similar and suprisingly dissimilar to ours has proven very interesting.

The most interesting question too me is whether there is a technicological
culture old enough, near enough or both for us to detect the radio signals. It seems unlikely we could directly observe an earthsize planet, let alone detect life on it,anytime soon.

Larry

EvilEye
2007-Feb-16, 11:46 AM
Let's imagine that every earth sized planet did have humans walking around on it. And let's suppose that none of them use any type of radio frequencies to communicate. (basically that they are happy being where they are and are like the 1700's)

We still would never know about them. Even if they were only a light year away.

The resolution you would need to see life on a planet would be about 3 meters.

Sure, you might get to a close enough resolution to see green and surmize that there could be plant life, which would make you more curious, but the reality is that we could never prove anything in time for us to know.

We are still making advances in technology, but in reality, the pay-off won't come for hundreds if not thousands of years.

formulaterp
2007-Feb-18, 08:46 PM
If our own planet was even a smidgen farther from the sun. We would not exist. Most life would have frozen to death or dehydrated.

Define "smidgen". Instead of 93 million miles, what if a planet were 90, or 88, or 95? Would that prevent life from existing?


If you alone on this planet earth. Just you. Living in chicago. Right now. No shelter. No animals to hunt. You would freeze to death. ONLY and ONLY because we have houses and heat and can go to jewel do most exist. You will not survive very long on your own as a bird or skunk can.

You do realize people DID live in the Chicago area long before houses and heat or the Sears tower was built. We call then Native Americans. Of course there were animals to hunt and they weren't alone. People would survive, they did before.


Just a little 23 degree pitch turns summer to winter. Our exact material and amount of it, distance and size between sun and earth are indeed so very incredibly perfect for life to exist at all.

A celestial duplicate just in degrees of pitch or minute distance alone would be soo incredibly rare.
And any slight deviation from it kills almost everything.

How would an axial tilt of 22 degrees or even 17 degrees prevent life from existing? What if the planet had a mass which was 10% greater or smaller? Would that exclude the possibility of life? Would it be different? Sure, but I don't see how it would have prevented life, even intelligent life from existing.

formulaterp
2007-Feb-18, 08:52 PM
We still would never know about them. Even if they were only a light year away.

The resolution you would need to see life on a planet would be about 3 meters.


Not really. You can get fairly good indirect evidence of life without having to see individual houses or dinosaurs.

http://tpf.jpl.nasa.gov/earthlike/earth-like.html

EvilEye
2007-Feb-18, 09:59 PM
Not really. You can get fairly good indirect evidence of life without having to see individual houses or dinosaurs.

http://tpf.jpl.nasa.gov/earthlike/earth-like.html

As I stated... you would have to see the life to prove that life existed.

Merely seeing evidence is not proof. Find a dropping... that is evidence. Find evidence of a dropping... not proof.

Find the life... that is proof.

And what I said is that we cannot see actual life on any planet outside of our solar system. And we won't know enough to look harder at any of the millions or billions of planets we may find, because they are too far away.

We may see the planet, but it will still be just a ball. You can use spectrometers and all the other instruments you want, but you are not ever going to get close enough to find life.

Evidence? maybe...

Proof? No

formulaterp
2007-Feb-18, 10:22 PM
As I stated... you would have to see the life to prove that life existed.

Merely seeing evidence is not proof. Find a dropping... that is evidence. Find evidence of a dropping... not proof.

Find the life... that is proof.

I think your standards are unreasonable.

So we have no proof dinosaurs existed? We certainly have fossil evidence, but nobody has ever seen a dinosaur. We have no proof the War of 1812 occurred? We have historical evidence, but nobody alive ever "saw" the war occur.

ev·i·dence: noun

1. that which tends to prove or disprove something; ground for belief; proof.

proof: noun

1. evidence sufficient to establish a thing as true, or to produce belief in its truth.

Zeta
2007-Feb-19, 01:05 AM
I was wondering if there were certain radio wavelengths where due to our multitude of communications where the earth would actually outshine the sun, or approach some significant fraction of total solar system radio emisions? If so, alien astronomers might think there is something unusual about our sun, even if they were not able to detect any coherent communications coming from us, even if they couldn't see earth directly.

The same thought could be applied in reverse. We could analyze the spectrums of millions of stars near or relativley far to see if there are more radio transmissions than predicted by theory, and any nearby could be a target of increased study.

Any thoughts if this is feasible or even possible?

eric_marsh
2007-Feb-20, 04:18 AM
There are obviously lots of unknowns that can sway the Drake numbers significantly one way or another. A couple of things that I've not heard mentioned which I think are significant are whether or not the planet has a magnetic field and some sort of a prediction of how long a technological society can survive. We've been a technological society for what, about 100 years now? In that time we have come up with plenty of ways to do ourselves in and in some cases it's been not much more than luck that we have not done so.

EvilEye
2007-Feb-20, 04:34 AM
There are obviously lots of unknowns that can sway the Drake numbers significantly one way or another. A couple of things that I've not heard mentioned which I think are significant are whether or not the planet has a magnetic field and some sort of a prediction of how long a technological society can survive. We've been a technological society for what, about 100 years now? In that time we have come up with plenty of ways to do ourselves in and in some cases it's been not much more than luck that we have not done so.

That is another great example. Michio Kaku talks about this.

If we do not destroy ourselves using our own technology we may evolve to the next "type". But given our rate of advancement, we are unlikely to survive to see it. (this is me talking...not Michio)

The point I am trying to make that you and Michio support is that even if an intelligent society did exist, it would last for such a short time, that no-one would have time to discover them. OR... that they will have advanced so far beyond us that they would purposely avoid us to allow us to advance.

Anything out there at our level will never find us without us finding them at the same time.

formulaterp
2007-Feb-20, 11:20 PM
We could analyze the spectrums of millions of stars near or relativley far to see if there are more radio transmissions than predicted by theory, and any nearby could be a target of increased study.

Any thoughts if this is feasible or even possible?

Definitely feasible/possible. Whether or not it would be successful is another matter. One of the factors that work against you is sheer distance. Despite the fact we (or ET) may be pumping out all sorts of telecom transmissions, their ranges are limited, and would require massive antennae to detect at astronomical distances. You can listen in to this podcast from a presentation at the recent AAS meeting on this very subject.

http://podcast.aas.org/AAS%202007%20Seattle%20Presentations/Select%20Plenary%20Sessions%20and%20Press%20Confer ences/F696F4F5-695A-4ACC-8540-89BF3D4F24DF.html

formulaterp
2007-Feb-20, 11:28 PM
A couple of things that I've not heard mentioned which I think are significant are whether or not the planet has a magnetic field and some sort of a prediction of how long a technological society can survive.

Well they are certainly good points, but they are covered by the Drake Equation.

If your supposition is that a magnetic field is necessary for life to develop, then that would be included in the term F(l). The final term L, is in fact the lifetime a technological civilization can survive before it destroys itself or something else happens to it.

eric_marsh
2007-Feb-22, 02:17 PM
Well they are certainly good points, but they are covered by the Drake Equation.

If your supposition is that a magnetic field is necessary for life to develop, then that would be included in the term F(l). The final term L, is in fact the lifetime a technological civilization can survive before it destroys itself or something else happens to it.

I think that life could evolve without a magnetic field, but not necessarily intelligent life. For example, bacterial could grow in soil and be protected from radiation. You are correct, I missed the term L.

Ilyas
2007-Feb-22, 04:34 PM
I agree with you totally. What's the need for an equation?

Ilyas
2007-Feb-22, 04:37 PM
His equation looks great on the surface, but it made too many assumptions (in my opinion).

It assumes that many places can have habitable planets. We have found "many" planets outside of our solar system already, and none of them were good candidates. It also assumes that life will always evolve. That's not neccessarily true. Life can come into existence, and then be obliterrated before it ever has a chance. Then he assumes that life can evolve to "intelligence". While that may be true... our dogs, cats, primates, and dolphins etc... are "intelligent", but they have no interest other than to satisfy their needs.

All that said...

Why do we need an equation?

If there was even just ONE single form of any kind of life found on another planet (or moon).... everything we know would change.

Oh... and Just because we can't find it doesn't mean its not there.

GREAT topic!

I agree with you completely. What's the need for an equation? Like you say just because we can't find life does not mean there is none. If they are so advanced, they should be able to hide themselves!

Fraser
2007-Feb-23, 12:33 AM
I think the purpose for the equation is to try and break the problem down into parts. If you can figure out every single piece that make up the whole, maybe you stand a better chance of finding alien life. Science works by reducing something complicated into simpler parts to try and understand how they work. An understanding of the parts gives you an insight into the whole. Not always, but it does help sometimes.

EvilEye
2007-Feb-23, 02:32 AM
I think the purpose for the equation is to try and break the problem down into parts. If you can figure out every single piece that make up the whole, maybe you stand a better chance of finding alien life. Science works by reducing something complicated into simpler parts to try and understand how they work. An understanding of the parts gives you an insight into the whole. Not always, but it does help sometimes.

Thank you so much for responding. I LOVE your shows.

I was just raising a question.

I also believe that if we don't question "experts", then we may never have any new ideas.

I had a wonderful conversation with a future son-in-law who is much more eductated than I over Space & Time, and he actually raised an eyebrow when I gave him some of my non-traditional personal theories.

There is nothing like thinking.

Sometimes it keeps me awake for hours.

Math is good, but....

Math also says you can keep cutting a distance in half and never reach a wall while still moving forawrd.

A.DIM
2007-Feb-23, 05:51 PM
That is another great example. Michio Kaku talks about this.

If we do not destroy ourselves using our own technology we may evolve to the next "type". But given our rate of advancement, we are unlikely to survive to see it. (this is me talking...not Michio)

The point I am trying to make that you and Michio support is that even if an intelligent society did exist, it would last for such a short time, that no-one would have time to discover them. OR... that they will have advanced so far beyond us that they would purposely avoid us to allow us to advance.

Anything out there at our level will never find us without us finding them at the same time.

Lonely Planets by Grinspoon discusses this.
Actually, he makes a rather well reasoned case why the Drake Equation could be considered a Rate Equation; that is, at what Rate do species reach Intelligence that allows them to become immortal?
Obviously we ourselves as a species are getting smart enough to cheat biological death as well as geologic and cosmic threats to our planet and species.

So, as a species, what do you do forever?

:)

EvilEye
2007-Feb-23, 11:06 PM
Lonely Planets by Grinspoon discusses this.
Actually, he makes a rather well reasoned case why the Drake Equation could be considered a Rate Equation; that is, at what Rate do species reach Intelligence that allows them to become immortal?
Obviously we ourselves as a species are getting smart enough to cheat biological death as well as geologic and cosmic threats to our planet and species.

So, as a species, what do you do forever?

:)

Well a least for us as a species, we have to move from our own differences to survive. We may kill all of us before we discover a way to survive forever.

We have to become one global cosciousness... but on our planet, that is controlled not by people, but by governments, and they have different interests collectively.

Remember the old coke commercials where everyone of every race was holding hands and singing? That is what we need to achieve any advancement for the human race, no matter how corny it seems.

When we finally realize that all people here on earth are the same race, will we ever advance to the next level, where we can save each other from total destruction.

I feel (fear) this way....

By the time another planet finds ours, and tries to contact us... they will find nothing but bacteria and viri trying to (re-)evolve.

lb8848
2007-Mar-07, 02:36 AM
Frasier
Have enjoyed your programs with Pamela very much. Would like another episode on the SETi research: what exactly have they found, where have they been searching, have they found any signals they thought looked promising but turned out to be nothing, where will they search next, will the equipment be upgraded, if so what improvements do they expect, when will the upgrades be installed, and so on. Would be a great show.
Regards
lb8848