How Many Sentient Life Forms are in the Milky Way?

[N2NH]

Yes, we have a good idea. In fact we have scientifically known for around a half century. It's the SCIENTIFIC formula known as the Drake Formula. It helped to get Star Trek on Television, well, sorta. It's also the way SETI operates and why they listen the way they do.


The Drake equation states that:http://upload.wikimedia.org/math/4/a/c/4ac1a1c3e0f903e8ed70359a4bb99466.pngwhere:

N = the number of civilizations (http://en.wikipedia.org/wiki/Civilization) in our galaxy with which communication might be possible;and

R* = the average rate of star (http://en.wikipedia.org/wiki/Star) formation per year in our galaxy
(http://en.wikipedia.org/wiki/Milky_Way)fp = the fraction of those stars that have planets
(http://en.wikipedia.org/wiki/Planet)ne = the average number of planets that can potentially support life (http://en.wikipedia.org/wiki/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 (http://en.wikipedia.org/wiki/Intelligence) 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 (http://en.wikipedia.org/wiki/The_Drake_Equation#cite_note-2)] (http://en.wikipedia.org/wiki/The_Drake_Equation#cite_note-3)

It has alternatively been expressed as:


The number of stars in the galaxy now, N*, is related to the star formation rate R* byhttp://upload.wikimedia.org/math/9/1/0/910753167fad20256dacdd8983101e7d.pngwhere Tg = the age of the galaxy.
Assuming for simplicity that R* is constant, then
http://upload.wikimedia.org/math/e/5/9/e59241ca83723b5b603e2d22b39c6ad8.png and the Drake equation can be rewritten into an alternate form phrased in terms of the more easily observable value, N*.[4]
(http://en.wikipedia.org/wiki/The_Drake_Equation#cite_note-3)
http://upload.wikimedia.org/math/8/4/6/846953db691bd7f2123caa767626d2af.png

Regarding SETI (and in the past Carl Sagan):


In 1960, Frank Drake conducted the first search for radio signals from extraterrestrial civilizations at the National Radio Astronomy Observatory in Green Bank (http://en.wikipedia.org/wiki/Green_Bank,_West_Virginia), West Virginia (http://en.wikipedia.org/wiki/West_Virginia). Soon thereafter, the National Academy of Sciences asked Drake to convene a meeting on detecting extraterrestrial intelligence. The meeting was held at the Green Bank facility in 1961. The equation that bears Drake's name arose out of his preparations for the meeting:


As I planned the meeting, I realized a few day[s] ahead of time we needed an agenda. And so I wrote down all the things you needed to know to predict how hard it's going to be to detect extraterrestrial life. And looking at them it became pretty evident that if you multiplied all these together, you got a number, N, which is the number of detectable civilizations in our galaxy. This, of course, was aimed at the radio search, and not to search for primordial or primitive life forms.

— Frank Drake[1] (http://en.wikipedia.org/wiki/The_Drake_Equation#cite_note-0)

This meeting established SETI as a scientific discipline. The meeting's dozen participants — astronomers, physicists, biologists, social scientists, and industry leaders — became known as the "Order of the Dolphin". The Green Bank meeting has been commemorated by a plaque (http://www.setileague.org/photos/miscpix/drakeqn.jpg) at the site.

As far as Star Trek...




The equation was cited by Gene Roddenberry (http://en.wikipedia.org/wiki/Gene_Roddenberry) as supporting the multiplicity of inhabited planets shown in Star Trek (http://en.wikipedia.org/wiki/Star_Trek), the television show he created. However, Roddenberry didn't have the equation with him, and he was forced to "invent" it for his original proposal.[31] (http://en.wikipedia.org/wiki/The_Drake_Equation#cite_note-30) The invented equation created by Roddenberry is:
http://upload.wikimedia.org/math/1/6/3/163f4b0e90c76794df4097dbc199fc47.png

Drake has gently pointed out, however, that a number raised to the first power is merely the number itself. A poster with both versions of the equation was seen in the Star Trek: Voyager (http://en.wikipedia.org/wiki/Star_Trek:_Voyager) episode "Future's End (http://en.wikipedia.org/wiki/Future's_End)."

One equation, drawn up for one meeting in 1960 and it has changed our world and our view of the universe. In both mass media and scientifically. Well, IMHO, of course. I'm sure some will say this is unscientific, but there you go. :lol:

The Drake Equation. (http://en.wikipedia.org/wiki/The_Drake_Equation)

[NQ6U]

The Drake Equation is meaningless. Depending on how you choose the data, you can make it come out however you choose.

[N2NH]

The Drake Equation is meaningless. Depending on how you choose the data, you can make it come out however you choose.

It's a starting point. It implies nothing, merely gives the parameters and was useful in changing the viewpoint of scientists and the general public to the idea that there could be other civilizations on other star systems. It changed the picture of aliens from Little Green Men from Mars and The Blob to Klingons and Starman. A quantum jump in thinking.

It has been modified and extrapolated into other, sometimes more useful functions.

As with anything, if you are a pessimist, you will get an abnormally low number of Sentient Civilizations in the galaxy.

If you are an optimist, you will get an abnormally high number of Sentient Civilizations in the galaxy.

The truth is in-between as with most things.

Now, the real question is, did a pessimist discover fire? If not, then he's unlikely to discover extra-terrestial civilizations also.

[KC2UGV]

The best sign of intelligent life in our galaxy, is that none have tried to contact us...

[N2NH]

The best sign of intelligent life in our galaxy, is that none have tried to contact us...

That we know of. If the Southwestern Indians are to be believed, they have.

[KG4CGC]

42. The answer to the number of sentient life forms is 42.

[KC2UGV]

That we know of. If the Southwestern Indians are to be believed, they have.

If they have tried, then I would rule them out as intelligent.

[kc7jty]

Michele Bachmann says life exists only on earth, and if you continue in your disrespect for God's truth you will burn in eternal hellfire.

[W3WN]

Strictly speaking, of course, when Gene Roddenberry was first pitching Star Trek (TOS), while he had the Drake Equation in mind, he didn't have it with him and had to make up something on the fly.

I also understand that the equation was modified for The Big Bang Theory to extrapolate the odds of the show's protagnists in hooking up with the opposite sex.

A variation of which is now employed by my nephew, as he prepares for his freshman year at college. (Need I explain that his name is Drake?)

[suddenseer]

They probably drive by everyday. "What's that planet?"
"Carbon burning lower life forms, nothing to see here."

[W3WN]

Michele Bachmann says life exists only on earth, and if you continue in your disrespect for God's truth you will burn in eternal hellfire.
Since microbes and other microorganisms have been discovered off the planet, I think that (with proper extrapolation that I leave to you as an intellectual exercise) tells you all you need to know about Michele Bachmann.

[KJ3N]

They probably drive by everyday. "What's that planet?"
"Carbon burning lower life forms, nothing to see here."

Now, THAT I would believe. :rofl:

[KJ3N]

Michele Bachmann says life exists only on earth, and if you continue in your disrespect for God's truth you will burn in eternal hellfire.

Bat-Shit Bachmann can go fuck herself. :roll:

[kb2crk]

I think they should try finding sentient life on this planet first.

[KJ3N]

I think they should try finding sentient life on this planet first.

Oh, good luck with that one. :roll:

[NQ6U]

Since microbes and other microorganisms have been discovered off the planet [...]

Can you cite some evidence of this discovery? If true, I think it would have been big news, yet I never heard about it.

[kb2vxa]

Like pi, no matter how far they work out the equation they'll never figure out how many angels can fit on the head of a pin.
Now if you want to know how many can fit in a ballpark the answer is here: http://mlb.mlb.com/team/roster_active.jsp?c_id=ana

[N2NH]

Can you cite some evidence of this discovery? If true, I think it would have been big news, yet I never heard about it.

There's this. Dunno if it's beyond any doubt, but it is tantalizing. (http://aquapour.com/alien-bacteria-fossils-found-in-meteorite-by-nasa-scientist/556290/)

And there's this too. Recent NASA findings.


(http://www.france24.com/en/20110808-meteorites-carried-lifes-building-blocks-earth-study)

[NQ6U]

There's this. Dunno if it's beyond any doubt, but it is tantalizing. (http://aquapour.com/alien-bacteria-fossils-found-in-meteorite-by-nasa-scientist/556290/)

And there's this too. Recent NASA findings.


(http://www.france24.com/en/20110808-meteorites-carried-lifes-building-blocks-earth-study)

The first example is questionable, the second is not a discovery of extraterrestrial life, just speculation on how the amino acids that comprise DNA may have arrived on Earth.

[W5GA]

I think they should try finding sentient life on this planet first.
They'd take one look at our Congress, and decide it wasn't worth further effort.

[K7SGJ]

They'd take one look at our Congress, and decide it wasn't worth further effort.

Actually, that would certainly indicate no intelligent life there.

[kc7jty]

So, how many of you guys that bitch about congress vote?
It's like smearing shit all over yourself then complaining about the stink.

[n2ize]

The Drake Equation is meaningless. Depending on how you choose the data, you can make it come out however you choose.

In a purely mathematical sense it is correct because it's basically the "multiplication rule" for probabilities which is mathematically valid.. But that doesn't mean that the result obtained by plugging in values will be correct because most of the values that you plug in are themselves probabilities that are measured in terms of guesses rather than experiment. So, all in all the equation (at least for now) is a probabilistic measure of belief. The result is going to be subjective depending on the person applying the equation and whatever guesses they make for the probabilities.

As it stands now I would call the formula "mathematically valid" but not necessarily "scientifically valid". However, that may change over time if a more scientific means of experimentally determining the necessary probabilities Nonetheless, it is a cute formula to play around with in a dark room on a rainy night, provided of course that there is nothing else available to play around with in a dark room on a rainy night. :-D

I would hardly say it has changed our view of the universe. However, science and astrophysics has and ironically as it does the Drake Equation may become more relevant as time goes by. On the other hand it may not.

[ad4mg]

So, how many of you guys that bitch about congress vote?
It's like smearing shit all over yourself then complaining about the stink.
I vote, and I bitch plenty. That you choose to be a slacker doesn't elevate you above the fray. Piss on your "holier than thou" bullshit, Bill.

[W3MIV]

I vote, and I bitch plenty. That you choose to be a slacker doesn't elevate you above the fray. Piss on your "holier than thou" bullshit, Bill.

While I may have chosen a more delicate manner of phrasing the response, I confess a certain identification with the emotion that fired it. My vote is the only voice remaining to me; the others all have been diminished or taken away. I shall not yield it willingly, and I shall continue to wield it until they wheel me to the dumpster.

[W1GUH]

I'm pretty sure I read, or heard someplace that we got the Drake Equation form Tralfamadore.

http://www.glogster.com/media/3/14/16/52/14165292.jpg

As for voting....how many Obamas is it going to take til it becomes obvious that voting makes no difference whatsoever? That it's pretty much a fairy tale promulgated while they're sticking it in our nether regions? That's it totally a charade?

[K7SGJ]

So, how many of you guys that bitch about congress vote?
It's like smearing shit all over yourself then complaining about the stink.

I do. Sometimes I wonder why, but I have voted every single election, local, State, and Federal, since I was eligible. I can understand why many have quit, but as frustrating as it gets, there is always hope. (The eternal optimist)

[W5GA]

The only elections I haven't voted in were those where I was unable to by virtue of being under water (another military benefit).

[kb2vxa]

AAAaaahhh............ da gubmint is like a wish sandwich; two pieces of bread and you WISH you had some meat.

[W3WN]

Bat-Shit Bachmann can go fuck herself. :roll:Anatomically impossible without mechanical aids. And why would we want her to pleasure herself?

[W1GUH]

"Around and round went the monstrous wheel..."

She should only wind up like the poor maiden in that fable.

[NQ6U]

Anatomically impossible without mechanical aids. And why would we want her to pleasure herself?

Not only that, she might make more little batshit Bachmann babies. She appears to be preternaturally fertile.

[kc7jty]

I vote, and I bitch plenty. That you choose to be a slacker doesn't elevate you above the fray. Piss on your "holier than thou" bullshit, Bill.
Brilliant response Luke.

[kc7jty]

While I may have chosen a more delicate manner of phrasing the response, I confess a certain identification with the emotion that fired it. My vote is the only voice remaining to me; the others all have been diminished or taken away. I shall not yield it willingly, and I shall continue to wield it until they wheel me to the dumpster.
...and that voice compares to that of a mouse on one of Jupiter's moons.

[kc7jty]

I'm pretty sure I read, or heard someplace that we got the Drake Equation form Tralfamadore.

http://www.glogster.com/media/3/14/16/52/14165292.jpg

As for voting....how many Obamas is it going to take til it becomes obvious that voting makes no difference whatsoever? That it's pretty much a fairy tale promulgated while they're sticking it in our nether regions? That's it totally a charade?

No use Paul, the children have been pumped into believing being part of the charade is necessary to be a real American.

[kc7jty]

Anatomically impossible without mechanical aids. And why would we want her to pleasure herself?
Opportunity now present:
There is a wind blowing around (and it's most prevalent in the area where they live) that Michele's hubby is gay, and she pleasures in not having to receive. They're not a couple but an act.

[W1GUH]

No use Paul, the children have been pumped into believing being part of the charade is necessary to be a real American.

Sigh...you're right about that.

[W3WN]

Opportunity now present:
There is a wind blowing around (and it's most prevalent in the area where they live) that Michele's hubby is gay, and she pleasures in not having to receive. They're not a couple but an act.That's sad on so many levels. But it does explain a lot, doesn't it?

[n2ize]

...and that voice compares to that of a mouse on one of Jupiter's moons.

That woman looks scary !!

[N2NH]

Anatomically impossible without mechanical aids. And why would we want her to pleasure herself?

To spite Lesbians.