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> Predict Kepler's Production ..., How Many Earthlike Exoplanets?
 
The Kepler Telescope will soon begin it's 4 year survey of 100,000 stars. How many rocky planets will it find in the habitable zone?
None [ 0 ]  [0.00%]
Less than 10 [ 7 ]  [22.58%]
10 to 50 [ 4 ]  [12.90%]
50 to 100 [ 1 ]  [3.23%]
100 to 500 [ 2 ]  [6.45%]
500 to 1000 [ 5 ]  [16.13%]
More than 1000 [ 4 ]  [12.90%]
Thousands [ 2 ]  [6.45%]
Tens of Thousands [ 6 ]  [19.35%]
Total Votes: 31
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uaafanblog
Posted on Jul 10 2009, 07:25 PM


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I too think the number will be high. Hopefully, such findings will be exciting enough to everybody to fully fund the next generation telescope which I understand will be able to measure the spectra of each candidate planet that Kepler finds.

I certainly feel lucky to have been alive during this period in human history. I often look forward tot he future and am envious about some things that await us, but to have been alive when mankind's greatest accomplishment (walking on the Moon) occurred and looking forward to a definitive announcement of a true "Earth II" in my lifetime is pretty nice.


--------------------
I been stuffed in your pocket for the last hundred days, when I don't get my bath I take it out on the slaves. So grease up your baby for a ball on the hill, I'll polish them rockets now and swallow those pills and say ....
Ahhhhhh .... Spacelord mutha mutha.
-- Monster Magnet --

It is offensive and ruinous, something to be avoided at all cost, for a nonbeliever to hear a Christian talking about these things as though with Christian writings as his source, and yet so nonsensically and with such obvious error that the nonbeliever can hardly keep from laughing.
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Quantum_Conundrum
Posted on Jul 18 2009, 02:34 AM


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I said 100 to 500.

The reason for this is our own solar system has 1 planet that is in a habitable zone and 2 that are bordering that zone.

The orbits of planets tend to obey a harmonic sequence, so one would expect a planetoid in many stars "habitable zone". I figure most of these will be dwarf planets or gas giants, however.


In addition, finding 100 to 500 planets in "habitable zones' in now way implies life is on any of them. There's about a zillion other "variables" to determine whether they might have life.
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gocrew
Posted on Dec 29 2009, 03:48 AM


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Does the question ask how many the Kepler Telescope will directly find, or how many will be inferred from its findings? The KT will only detect planets transiting across their sun in our line of sight. This is a rare event. If memory serves, KT will find 465 Earth-like planets... if every single star of the 100,000 has a rocky planet in the habitable zone.

Going on how the question is asked, any likely answer has to be below 1,000 to be plausible. I think it will find about 20, based on the following assumptions:

1) Most systems will form planets.

2) The current percent of known planets with stable orbits - 5% - holds more or less true across the universe, and that unstable orbits will eject their smaller planets from the system.

That would still leave several thousand earth-like planets in that field alone.

Also, be careful in assuming that every system is going to display our nice geometry of planet spacing. It could well be that only such a result will give us stable orbits, but that this result is still a bit rare. The fact that our system displays this pleasing sort of mathematics doesn't mean that it is common out there.
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adoucette
Posted on Dec 29 2009, 01:49 PM


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QUOTE (uaafanblog @ Apr 20 2009, 11:16 PM)
The poll is not whether we think any of those will have life much less intelligent life. The best tool you can use to answer the intelligent life question isDrake's Equation.

This poll question is more about the "fp" and "Ne" variables in that equation.

By the way ... Frank Drake reports that the "average" of people making guesses puts the number of technological civilizations in our galaxy around 10,000. Remember ... that's in the 100 billion stars that are in the Milky Way. Kepler will be looking at only 100,000 in a specific portion of the sky.

The Drake equation can also be used to determine how many Unicorns play after dark in parks:

N* = the number of parks on the Earth:

fp = fraction of parks with unicorns living near by:
Current estimates range from 100% (where Unicorns can live they do) down to close to 0%.

ne = number of parks ecologically able to entice Unicorns to play after dark:
Estimates range from 100% (Playing in the park is such a survival advantage that it will certainly evolve) down to near 0%.

fl = fraction of those parks where Unicorns actually live nearby: .

fc = the fraction of fi that has Unicorns that allow themselves to be seen:

fL = the fraction of the park's life during which these less bashful Unicorns survive:

fi = the fraction of parks where Unicorns who will allow themselves to be seen actually play after dark:

CALCULATE

N = the number of unabashed Unicorns in the world


Arthur

This post has been edited by adoucette on Dec 29 2009, 02:32 PM


--------------------
"We cannot prove that those are in error who tell us that society has reached a turning point; that we have seen our best days. But so said all before us, and with just as much apparent reason. On what principle is it that, when we see nothing but improvement behind us, we are to expect nothing but deterioration before us?"

Thomas B. Macaulay
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uaafanblog
Posted on Dec 29 2009, 10:33 PM


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Arthur,
Your point besides the obvious?

This post has been edited by uaafanblog on Dec 29 2009, 10:35 PM


--------------------
I been stuffed in your pocket for the last hundred days, when I don't get my bath I take it out on the slaves. So grease up your baby for a ball on the hill, I'll polish them rockets now and swallow those pills and say ....
Ahhhhhh .... Spacelord mutha mutha.
-- Monster Magnet --

It is offensive and ruinous, something to be avoided at all cost, for a nonbeliever to hear a Christian talking about these things as though with Christian writings as his source, and yet so nonsensically and with such obvious error that the nonbeliever can hardly keep from laughing.
-- St. Augustine --

I laugh a lot in the Evolution/Creation section of this forum.
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adoucette
Posted on Dec 29 2009, 11:56 PM


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Only that the Drake equation can not be used as a tool to answer any question about the likelihood of intelligent life in the universe any more than it can be used to tell us how frequently one will find the elusive Unicorns playing in parks after dark.

Why?

Because we don't know the answers to ANY of the questions it asks.

Even the simplest one, as in how many stars are in the MW Galaxy:

The Milky Way system is a spiral galaxy consisting of over 400 billion stars

http://casswww.ucsd.edu/public/tutorial/MW.html

the Milky Way galaxy - a spiral galaxy of at least 200 billion stars

http://www.atlasoftheuniverse.com/galaxy.html

How many stars are in the Milky Way Galaxy?
Answer: Current estimates are 100 billion.

http://www.activemind.com/Mysterious/Topic...uation.html#Try

the Milky Way, contains maybe 400 billion stars (plus or minus 200 billion)

http://www.nova.org/~sol/chview/chv5.htm

the Milky Way, there is a predicted 3 billion to 100 billion stars.

http://hypertextbook.com/facts/2000/MarissaWager.shtml

The Milky Way is the galaxy which is the home of our Solar System together with at least 200 billion other stars (more recent estimates have given numbers around 400 billion

http://messier.obspm.fr/more/mw.html

Thus in just these few references, the number of stars in our Galaxy is estimated to be some number between 3 Billion and 600 Billion, but we have NO CLUE as to what the right number is, and it could in fact be outside of that range.

For ALL the rest of the questions, like the fraction of planets where life evolves or fraction of life where intelligent life evolves, ANY guess is as good as the next one, and thus ALL values are equally valid.

Thus NO answer is any more likely to be true than any other answer.

Arthur


--------------------
"We cannot prove that those are in error who tell us that society has reached a turning point; that we have seen our best days. But so said all before us, and with just as much apparent reason. On what principle is it that, when we see nothing but improvement behind us, we are to expect nothing but deterioration before us?"

Thomas B. Macaulay
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uaafanblog
Posted on Dec 30 2009, 01:15 AM


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To say we have "no clue" is a bit disingenuous. As with much science there are variable conclusions ... I'm comfortable that there are more than 3 billion stars in our Galaxy and I'm equally comfortable to say there are less than 600 billion. As with many other issues in science, we must look to consensus for the "best" answer unless and until some other data arises to reject that consensus. The accepted consensus (you may argue) is around 100 billion.

I've never seen Frank Drake (or any other reputable source) indicate that his equation was anything but full of guesses. Kepler will help us narrow down one of those parameters and aside from the broader surveys (such as those you listed) estimating the number of stars in our galaxy, yes ... they're all guesses.

Kepler will definitely give us more data about how likely other systems similar to ours exist. With the discovery of "nnn" exoplanets in the last decade (sorry ... didn't want to put an exact number since a couple of dozen are disputed), it is IMnsHO the most exciting and promising space mission we've undertaken since landing on the moon.

And yes, none of that means we're any closer to finding any intelligent life "out there" than there was yesterday. But finding a candidate planet that could actually harbor life entralls me.

This post has been edited by uaafanblog on Dec 30 2009, 01:19 AM


--------------------
I been stuffed in your pocket for the last hundred days, when I don't get my bath I take it out on the slaves. So grease up your baby for a ball on the hill, I'll polish them rockets now and swallow those pills and say ....
Ahhhhhh .... Spacelord mutha mutha.
-- Monster Magnet --

It is offensive and ruinous, something to be avoided at all cost, for a nonbeliever to hear a Christian talking about these things as though with Christian writings as his source, and yet so nonsensically and with such obvious error that the nonbeliever can hardly keep from laughing.
-- St. Augustine --

I laugh a lot in the Evolution/Creation section of this forum.
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flyingbuttressman
Posted on Dec 30 2009, 01:35 AM


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Any meaningful use of the Drake equation requires a significant sample size.
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uaafanblog
Posted on Dec 30 2009, 02:14 AM


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And the Kepler results will be one small step toward building such.


--------------------
I been stuffed in your pocket for the last hundred days, when I don't get my bath I take it out on the slaves. So grease up your baby for a ball on the hill, I'll polish them rockets now and swallow those pills and say ....
Ahhhhhh .... Spacelord mutha mutha.
-- Monster Magnet --

It is offensive and ruinous, something to be avoided at all cost, for a nonbeliever to hear a Christian talking about these things as though with Christian writings as his source, and yet so nonsensically and with such obvious error that the nonbeliever can hardly keep from laughing.
-- St. Augustine --

I laugh a lot in the Evolution/Creation section of this forum.
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adoucette
Posted on Dec 30 2009, 03:27 AM


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QUOTE (uaafanblog @ Dec 29 2009, 08:15 PM)
To say we have "no clue" is a bit disingenuous.


No it's not,
We have no clue, and Drake's formula gets us no closer to having one.

QUOTE
As with much science there are variable conclusions ... I'm comfortable that there are more than 3 billion stars in our Galaxy and I'm equally comfortable to say there are less than 600 billion.  As with many other issues in science, we must look to consensus for the "best" answer unless and until some other data arises to reject that consensus.  The accepted consensus (you may argue) is around 100 billion.

I've never seen Frank Drake (or any other reputable source) indicate that his equation was anything but full of guesses.  Kepler will help us narrow down one of those parameters and aside from the broader surveys (such as those you listed) estimating the number of stars in our galaxy, yes ... they're all guesses.

Kepler will definitely give us more data about how likely other systems similar to ours exist.  With the discovery of "nnn" exoplanets in the last decade (sorry ... didn't want to put an exact number since a couple of dozen are disputed), it is IMnsHO the most exciting and promising space mission we've undertaken since landing on the moon.

And yes, none of that means we're any closer to finding any intelligent life "out there" than there was yesterday.  But finding a candidate planet that could actually harbor life entralls me.



Even if you are comfortable with the level of imprecision of the first variable being any number between 3 Billion and a number 200 times larger and even if Kepler helps us get a reasonably decent answer to the second question, the fraction of stars with planets around them.

This still leaves us with little but wild guesses for the next 5 variables, so even with good data from Kepler, any computed value from 0 to Billions is still possible and we have no way of using the equation to tell us the likelihood that any given answer is better than any other answer.


I'm not dissing the Kepler mission, just pointing out that the Drake equation is nothing more then a list of the obvious things we need to know to get the answer to the question, not a means for determining anything at the present state of knowledge.

Arthur

This post has been edited by adoucette on Dec 30 2009, 04:14 AM


--------------------
"We cannot prove that those are in error who tell us that society has reached a turning point; that we have seen our best days. But so said all before us, and with just as much apparent reason. On what principle is it that, when we see nothing but improvement behind us, we are to expect nothing but deterioration before us?"

Thomas B. Macaulay
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uaafanblog
Posted on Dec 30 2009, 04:52 AM


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QUOTE

No it's not,
We have no clue, and Drake's formula gets us no closer to having one.

Yes it is. "NO CLUE" is entirely disingenuous. We have PLENTY of clues. They may (as I said) be variable but there are many many many more than none; so saying "no clue" couldn't be characterized as anything other than disingenuous ... unless one perhaps calls it hyperbole. Take your choice.

QUOTE
Even if you are comfortable with the level of imprecision of the first variable being any number between 3 Billion and a number 200 times larger and even if Kepler helps us get a reasonably decent answer to the second question, the fraction of stars with planets around them.

This still leaves us with little but wild guesses for the next 5 variables, so even with good data from Kepler, any computed value from 0 to Billions is still possible and we have no way of using the equation to tell us the likelihood that any given answer is better than any other answer.

At the risk of repeating myself ... I said that neither Frank Drake nor any reputable person ever suggested the equation was anything but a bunch of guessing.

QUOTE
I'm not dissing the Kepler mission, just pointing out that the Drake equation is nothing more then a list of the obvious things we need to know to get the answer to the question, not a means for determining anything at the present state of knowledge.

And in context the Drake Equation only came into the discussion when a tangential question to the OP was being answered. The thread really has nothing to do with the Drake Equation (which is admittedly mental masturbation and nothing else), excepting that again, as I said, Kepler will begin to get us to a place where we can start to fill in one of the equation's variables.

This post has been edited by uaafanblog on Dec 30 2009, 04:53 AM


--------------------
I been stuffed in your pocket for the last hundred days, when I don't get my bath I take it out on the slaves. So grease up your baby for a ball on the hill, I'll polish them rockets now and swallow those pills and say ....
Ahhhhhh .... Spacelord mutha mutha.
-- Monster Magnet --

It is offensive and ruinous, something to be avoided at all cost, for a nonbeliever to hear a Christian talking about these things as though with Christian writings as his source, and yet so nonsensically and with such obvious error that the nonbeliever can hardly keep from laughing.
-- St. Augustine --

I laugh a lot in the Evolution/Creation section of this forum.
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adoucette
Posted on Dec 30 2009, 02:18 PM


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QUOTE (uaafanblog @ Dec 29 2009, 11:52 PM)
Yes it is. "NO CLUE" is entirely disingenuous. We have PLENTY of clues. They may (as I said) be variable but there are many many many more than none; so saying "no clue" couldn't be characterized as anything other than disingenuous ... unless one perhaps calls it hyperbole. Take your choice.



I don't think we are very much in disagreement.

You originally posted:

QUOTE
The best tool you can use to answer the intelligent life question is Drake's Equation


The point of my posts has simply been to show that as a tool it can't begin to answer that question, since with our present state of knowledge you can equally make a case for virtually ANY answer.

Which is what I mean by "No Clue".

Why?

Well regardless of your choice of inputs, no one could use FACTS to dispute you.

Because no input would be based on any known facts.

Meaning it's not a tool for anything.

For instance consider the 3nd through 5th variables:

Ne = number of planets per star ecologically able to sustain life:

While the site says the lowest number is .33, there is no basis at all for this high a number (since we have found no other planets that in fact do sustain life), and it could in fact be quite a bit lower, for instance there is the Rare Earth Hypothesis, that concludes one also needs a number of somewhat improbable other attributes in a life sustaining planet. So the reality is this number could easily be between .0001 and possibly 1.

http://en.wikipedia.org/wiki/Rare_Earth_hypothesis

or

Fl = fraction of those planets where life actually evolves.

While the site says the lowest number is .0001% , it could easily be lower. We have no idea what the likelihood of abiogenesis occurring on a given planet is, but we think that over 1 billion years passed from the time the Earth formed until the most primitive life forms arose, so at best we can assume is it takes a long while. Still a high percent of stars are over 1 billion years old, so this number could also be a many thousand times higher.

or

Fi = the fraction of Fl that evolves intelligent life

The site says the lowest number here is .0001% as well, but again it could be even lower. There is no certainty that even if abiogenesis occurs, that evolution will result in intelligent life. On the Earth, we think this took something over 3.5 billion years to occur, so at best we can assume is it also takes a long long while. Given the time frame for Fl and then Fi, a lot of bad things can occur to stop this process in its tracks. But once life started on earth, it survived some pretty nasty events, and still managed to get to the present state, so if it turns out that abiogenesis is common, then the number could also be thousands of times higher.

To put it in perspective, if all three of these turn out to be in the low end of the spectrum, then these variables alone could equate to a multiplier of .000000000000001, but if all were on the high end of the spectrum then these could be a multiplier as high as .001, or a factor of 12 greater than the low end.

So now we multiply the low value by the low end estimate of the number of stars and we get the incredibly low estimate of 0.000003 planets in the galaxy with intelligent life and multiply the high values and we get 600,000,000 planets with intelligent life.

Any formula which gives this wide of an answer is of no predictive value and we still have two more variables to consider, whose range of answers will further widen the range of possible answers.

QUOTE
I said that neither Frank Drake nor any reputable person ever suggested the equation was anything but a bunch of guessing.


Which I'm in agreement with, which is why I disagreed with the "tool" reference.

QUOTE
The thread really has nothing to do with the Drake Equation (which is admittedly mental masturbation and nothing else), excepting that again, as I said, Kepler will begin to get us to a place where we can start to fill in one of the equation's variables.


I agree, but as shown above, even with the first two variables filled in, the equation is still useless.

Arthur




--------------------
"We cannot prove that those are in error who tell us that society has reached a turning point; that we have seen our best days. But so said all before us, and with just as much apparent reason. On what principle is it that, when we see nothing but improvement behind us, we are to expect nothing but deterioration before us?"

Thomas B. Macaulay
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uaafanblog
Posted on Dec 30 2009, 07:53 PM


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As you say, there's no real disagreement here then. Though I do think we differ with regard to the use of the word "tool". I think it is one. It's just that it's a tool for speculation. That said, allow me to add a few thoughts.

In one sense, "Rare Earth" is not much more than an intellectual pissing on Drake's parade. It acts as a reasonable counter-argument. All well and good.

Essentially, it comes down to optimism versus pessimism or perhaps more accurately hope versus skepticism. I'm obviously in the "sure would be a waste of space" camp and I think it's safe to characterize you as skeptical. Either view (at this point) could be "more" correct than the other.

I will say that I'm skeptical that any discovery of intelligent life will come relatively soon. So I don't sit around with my fingers crossed anticipating such an event. On the other hand though, my fingers are crossed that we get some positive indication of relatively nearby potentially habitable earth-analogue during my lifetime. Kepler probably won't reveal such a candidate but it is likely to give us many targets to investigate with the next generation devices that are planned to follow it.



--------------------
I been stuffed in your pocket for the last hundred days, when I don't get my bath I take it out on the slaves. So grease up your baby for a ball on the hill, I'll polish them rockets now and swallow those pills and say ....
Ahhhhhh .... Spacelord mutha mutha.
-- Monster Magnet --

It is offensive and ruinous, something to be avoided at all cost, for a nonbeliever to hear a Christian talking about these things as though with Christian writings as his source, and yet so nonsensically and with such obvious error that the nonbeliever can hardly keep from laughing.
-- St. Augustine --

I laugh a lot in the Evolution/Creation section of this forum.
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adoucette
Posted on Dec 30 2009, 10:12 PM


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I don't know what you mean by "relatively nearby".

In cosmic terms that can mean some pretty far distances.

Yes, I'm very skeptical.

I believe that most of the Rare Earth hypothesis is likely to be true, to varying degrees, such that the likelihood that we will ever find evidence of life on another planet is remote and that we will ever encounter intelligent life is next to nothing.

Nor do I believe that we will ever send a probe to another planet with the ability to tell us what it finds there, simply because even to the nearest star the mission would be monumentally expensive and even then would likely take far longer than a human lifetime to accomplish. Damn hard to get funding for a mission when no one alive will ever see the results.

It's highly unlikely that anything Kepler finds will alter this, as less than 1% of the stars it's looking at are less than 600 LY from earth.

Kepler has been looking at the star field for almost a year and AFAIK, hasn't found any new planets (it did look a bit closer at one that we already knew about).

This is somewhat disappointing considering their expected results:

Expected Results

The Kepler Mission begins to collect data immediately after launch and checkout and begins to produce results in a progressive fashion shortly thereafter.

The first results come in just a few months when the giant inner planets are seen, those with orbital periods of only a few days.

Objects that are in Mercury-like orbits of a few months are detected within the first year.

http://kepler.nasa.gov/sci/basis/results.html

Arthur

This post has been edited by adoucette on Dec 30 2009, 10:21 PM


--------------------
"We cannot prove that those are in error who tell us that society has reached a turning point; that we have seen our best days. But so said all before us, and with just as much apparent reason. On what principle is it that, when we see nothing but improvement behind us, we are to expect nothing but deterioration before us?"

Thomas B. Macaulay
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gocrew
Posted on Dec 30 2009, 11:18 PM


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The Kepler scientists are going to make an announcement in January of what they have found so far. Apparently, they have found some things, and some of what they have found, to paraphrase one of them, is beyond anything he had expected or could have predicted. I am keen to see what it could be.

As for the Drake Equation, I think the best description is that it is a good way to organize our ignorance. That doesn't make it any less fun.

And I think the Rare Earth Hypothesis is probably not far from the truth.
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