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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
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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
If we're not, there's a good chance that the aliens are too far away for it to matter. That whole "1 light-year per year" speed limit and all tends to keep 'em away.
I am officially gone from
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.
Shame they didn't say that about the number of movies they made.
"I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space."
Oliver's law of assumed responsibility: If you're seen fixing it, you will be blamed for breaking 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.