Slashdot Mirror
Study Estimates 100 Billion Planets In the Milky Way Galaxy
The Bad Astronomer writes "A new study finds that there may be 100 billion alien planets in the Milky Way alone, with 17 billion of them the size of Earth. Announcements like this have been made before, but this new research is more robust than previous studies, using data from the Kepler planet-hunting spacecraft over a longer period and analyzing it in a more statistically solid way (PDF). They also found that smaller planets are not as picky about their host stars, with terrestrial planets forming around stars like the Sun or as small as tiny, cool red dwarfs with equal ease."
So are they saying there is 100,000,000,001 total planets? Thats some accuracy!
Are planets in our Solar System "Alien" or are we claiming ownership over them?
I think they just wanted to use Alien in the summary.
But only a few million will be suitable for life-as-we-know-it, Jim
Comment removed based on user account deletion
17 billion in the Milky Way. There's a metric shit ton of other Galaxies.
"Two possibilities exist: Either we are alone in the Universe or we are not. Both are equally terrifying."
I wonder if there is any way to statically guess the number of planets in the Goldilocks zone, the approximate distance from a star for liquid water to be possible. That would be a very interesting number but I'll just throw out a guess there will be more than one. It's remarkable to think of all the possible life that could be out there. We are probably destend to never meet, but it's interesting nonetheless. I think one of the greatest things finding life elsewhere would accomplish if it ever were to happen, is to study evolution on a completely different scale. The diversity on Earth alone is remarkable, to think what an entirely different planet might produce makes my imagination go wild.
You mean you were a kid before they discovered the planets in the solar system? O_o
The Keppler field of view is only a couple of thousands lightyear deep. That means the results are based on our neck of the woods only. Now, it may be ok to assume that other outskirts of the Milky Way are similar, but there is no reason to assume the same applies for the center of the galaxy, where most of the stars are, very closely packed.
Lestat, is that you?
So you're the other highlander... There can be only one!
100 billion planets and I have to be stuck on this one.
How long before we get visitors from the red-dwarf terrestials, flying around and zapping people with their heat vision? Dicks.
"Love heals scars love left." -- Henry Rollins
Ass U Me
John McAfee 'It was like that time I hired that Bangkok prostitute; to do my taxes, while I fucked my accountant'
that's cuz he's dead
Seems reasonable, until you try to figure out where the 1%'s came from.
Everybody lives on a street in a city
Or a village or a town for what it's worth.
And they're all inside a country which is part of a continent
That sits upon a planet known as Earth.
And the Earth is a ball full of oceans and some mountains
Which is out there spinning silently in space.
And living on that Earth are the plants and the animals
And also the entire human race.
It's a great big universe
And we're all really puny
We're just tiny little specks
About the size of Mickey Rooney.
It's big and black and inky
And we are small and dinky
It's a big universe and we're not.
And we're part of a vast interplanetary system
Stretching seven hundred billion miles long.
With nine planets and a sun; we think the Earth's the only one
That has life on it, although we could be wrong.
Across the interstellar voids are a billion asteroids
Including meteors and Halley's Comet too.
And there's over fifty moons floating out there like balloons
In a panoramic trillion-mile view.
And still it's all a speck amid a hundred billion stars
In a galaxy we call the Milky Way.
It's sixty thousand trillion miles from one end to the other
And still that's just a fraction of the way.
'Cause there's a hundred billion galaxies that stretch across the sky
Filled with constellations, planets, moons and stars.
And still the universe extends to a place that never ends
Which is maybe just inside a little jar!
It's a great big universe
And we're all really puny
We're just tiny little specks
About the size of Mickey Rooney.
Though we don't know how it got here
We're an important part here
It's a big universe and it's ours!
If telephones are outlawed, then only outlaws will have telephones.
you do realize Obama hasn't spent 1 dollar more than necessary. The trick is Bush put two wars, and 8 years of tax cuts on credit cards and Obama got stuck with the bill.
Sooner or later quitting your job and living off a second mortgage on your house is going to catch up to you. Then again I don't expect anyone else to realize that is exactly what both parties have been doing for the last decade.
Gravitational Lensing does allow us to see along the arms of our galaxy though. While this may not let us see everything, it does allow us to see more than just our local cluster.
The numbers associated with the universe are just amazing. The universe is so big that anything possible becomes probable... you might even say "anything possible is guaranteed to happen somewhere... and probably a lot of somewheres".
You think the odds against intelligent life around any random star are one in 10^12? Then there should be at least 10^10 stars with intelligent life.
The universe really is that vast.
Well that's the big question. We already know the chances of life developing in the universe, it's 1, it's happened, we exist. This study (cool as it is) actually adds no new information in the question of whether life exists elsewhere, what it does is give us an idea of how many potential habitats like ours there are. We could find evidence of extrasolar life tomorrow, or never. It's still entirely possible (some would say probably) that the Sol system is the only one harbouring life in the universe despite a plethora of suitable environments.
All this actually does is narrow down one of the variables in the Drake Equation, which is a bit of a napkin based Fermi Problem idea anyway. We need to answer the Fermi Paradox first.
Please consider this account deleted, I just can't be bothered with the spam anymore.
The Fermi Paradox isn't exactly the sort of thing you can answer in the traditional sense, rather it highlights an apparent contradiction in what we could reasonably expect from the universe given it's size and age, and what we actually observe (or fail to). The Drake Equation is actually a sort of partial "answer" in that it attempts to at least formalize the specific unknowns that affect the number of potentially detectable civilizations that might currently exist in our galaxy
Initially we fed it entirely with wild speculation, now we're starting to be able to peg down some of the variables within reasonable limits. We're getting a pretty good idea of the rate of star and planet formation, starting to get a sense of the probability of Earthlike planets, and realizing that if we're any indication the window in which a civilization is "loud" enough to be detected from another star is potentially extremely short - it's questionable whether we were ever above the threshold, and our transmission strength is already beginning to fall due to more efficient technology.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
it would have taken 60 days to create them that's why he went with 640K and 6 days,
by TheSpoom (715771) Uncaring Linux user here. I have nothing to add to this but please continue. *munches popcorn*
We have developed a system called mathematics that allows us to work with numbers, even ones so large that we have a difficult time conceiving of them in any practical terms. Using that system and given the proper input data, we can make reasonable predictions, which can lead to practical knowledge. This is a refinement of the input data.
Shame they didn't say that about the number of movies they made.
I assume he means Richard Dawkins http://en.wikipedia.org/wiki/Richard_Dawkins not Richard Dawson from Hogans Heroes http://en.wikipedia.org/wiki/Richard_Dawson
If you don't look, you won't find.
I sincerely hope this won't turn out to be like the martian canals. I'm not an astrophysicist so please correct me if I'm wrong, but we're assuming the only thing that can cause regular and periodic brightness changes in a star is a planetary transit. I know we've a very few blurry visuals of at least a handful of planets, but could it be that not all these are transits? Is there a secondary method that can be used to verify the result?
Assuming that our solar systems layout is pretty average in the galaxy that puts about 11 Billion planets in the (current) habitable zone, assuming 1% of those have life that leaves 110 Million planets, assuming that 1% of those have complex life, that is about 1 Million planets, and assuming that 1% of worlds where complex life develops intelligent life follows that suggests about 10,000 planets. Sounds about right.
Yes, because "1%" is a magic formula for discovering the truth.
Love the "sounds about right" conclusion too. Do you base that on some extrapolation from Star Trek or something?
To have a right to do a thing is not at all the same as to be right in doing it
Indeed there is - in fact the brightness changes are only the original method used to detect planets and are restricted to detecting the tiny fraction of planets with an orbital plane that we happen to be looking at edge-on (otherwise the planet would never pass between us and the star) More recent techniques involve detecting the slight wobble in a stars motion due to orbiting planets - the sun is not actually the exact center of the solar system, it too orbits the barycenter (center of mass) of the entire system. In our case this point is actually varies between about 2/3 and 1 solar diameter away from the center of our sun as the alignment of the outer planets changes. Smaller planets can also be detected by the much smaller but higher-frequency (because they're closer and orbit faster) wobble they introduce. Obviously the easiest planets to detect this way are large planets orbiting close to their star (large, high-frequency wobble), distant planets like our own gas giants will take an extremely long time to detect because you need to wait for them to complete a few orbits (many centuries) to confirm their existence. They're not particularly relevant in the search for Earth-like worlds though.
The original dimming detection technique does have a couple of big advantages though - for one you can watch a really wide area of the sky at once, so even though you'll only be able to detect a tiny fraction of planets it still averages out pretty well (detecting tiny wobbles requires much greater magnification/tighter focus). The second, and really exciting, advantage is that we can potentially tell what the atmospheric composition is like. The recent Hubble observation of the transit of Venus across the sun was a proof of concept and calibration test for this: a tiny percentage of the starlight that reaches the telescope has passed through the atmosphere of the planet, and by detecting the miniscule change in the light spectrum we can perform a spectral analysis on the planet's atmosphere. Heady stuff.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
sorry, stupid math error - the barycenter varies between about 1/6 and 1 solar diameter away from the center of the sun
--- Most topics have many sides worth arguing, allow me to take one opposite you.
Thanks for taking the time to explain this! I suppose a brightness variation along with a lateral wobble pretty much confirms a planet. And if you consider the percentage of occlusion against the calculated mass, you get the planet's density! (I think).
The important part is the ability to form long, complex chains. Only two elements can do that: Carbon and silicon. Carbon is better at it. Silicon may be good enough.
It's not just the the chain of base atoms, it is the geometry of the entire molecule. Silicon, being a significantly larger atom than carbon puts the atoms attached to it in a different spacial pattern than if they were attached to carbon. Therefore, what is attached to them is also in a different location. It just doesn't work with silicon as the base because the silicon based organic molecules don't allow things to align in a way that is condusive for the processes that would lead to life. The most abundant atom on earth is silicon and yet there is no evidence of self replicating silicon based molecules. The geometry simply doesn't work out.
You're welcome. You 're quite right about the ability to calculate density if both methods can detect a planet (at least if you assume the planet is passing fully in front of its sun) , and you got me curious as to whether they could both detect the same planets. Looks like they can, and that I was wrong about exactly how the stellar wobble is detected - they actually use an extremely sensitive spectrometer to detect the slight doppler shift in the starlight as the star moves towards and away from us in it's orbit. So it's not so much a matter of magnification as being able to filter out one star's light from all the others in the area. And it still works best for detecting planets orbiting edge-on to us, it's just not nearly so critical - apparently the odds of a planet the size and orbital distance of Earth orbiting close enough to edge-on to be detected by the transit method is only ~0.47%.
Lots more interesting details, including an interesting picture of the orbital path of our sun (it looks rather like a spirograph tracing).
http://en.wikipedia.org/wiki/Methods_of_detecting_extrasolar_planets
Hmm. now I'm wondering how the doppler method distinguishes between a small planet orbiting almost edge on to us, and a much larger planet orbiting almost perpendicularly. In either case the in velocity towards us would show the same sinusoidal variation... Aww, looks like they actually can't, they can only determine the minimum mass, if the planet is orbitting edge-on. At least it provides us a solid mass estimate for those detected via transit as well. And apparently the transit method is accurate enough that they can actually detect all sorts of other things as well, even indirectly detect additional planets by the perturbations they cause in the detected planet's orbit. Fascinating stuff, thanks for getting my curiosity piqued.
--- Most topics have many sides worth arguing, allow me to take one opposite you.