My God, it's full of dots!

September 26, 2013 8:24 AM

New Scientist magazine has posted a nifty interactive infographic that illustrates how many Earth-like planets might exist, based on observations from the Kepler Space Telescope. The orbital observatory has catalogued 151 exoplanets based on examination of 0.28% of the sky.

"Given that the Milky Way is thought to contain between 100 and 200 billion stars, our best estimate of the total number of such planets in our galaxy is 15 to 30 billion," writes New Scientist's Adam Becker and Peter Aldhous. (Kepler previously)

posted by Gelatin (34 comments total)

Appropriate soundtrack
posted by The Whelk at 8:31 AM on September 26, 2013 [1 favorite]

This is really cool!
posted by showbiz_liz at 8:35 AM on September 26, 2013 [1 favorite]

We have come so far and are here now. Please don't send us away.

You have no idea what it is like away from this place. You search, and search in the sky for answers.

Here is your answer: there are others out there, far poorer than you, who searched as well.

And you are all we have. Please do not ruin this for us.

We have come so far to be with you, to live here. It is cold and vast and empty.

What you see in the sky now is despair.
posted by Lipstick Thespian at 8:46 AM on September 26, 2013 [3 favorites]

The Kepler project is super amazing science. 15 to 30 billion earth-like planets is a fantastically specific result. Let's hope it stands!

But shame on New Scientist for editorializing "From this perspective, the chances that we're alone in the cosmos seem very slim, indeed." There's a whole different problem, estimating the likelihood that life will spontaneously originate on an Earth-like problem. And then a third problem, the likelihood of intelligent life, whatever that means. The science on these two questions is very shaky. The Kepler results are quite specific. Then again maybe a little poetic license is appropriate to go with an easy-to-understand visualization.
posted by Nelson at 8:58 AM on September 26, 2013 [3 favorites]

Always worth linking to the Exoplanets database. Their plotting tools are nice - try a histogram plot of "Date of discovery" to see how sharply the number of discoveries rises between 2000 and 2010. Amazing stuff.

(And Kepler has many many more "planet candidates" - we don't know for sure which of ~3500 candidates are not planets, but well over 90% (guessing) of them are certainly planets.)
posted by RedOrGreen at 9:00 AM on September 26, 2013 [1 favorite]

Nelson: shame on New Scientist for editorializing.

Not sure why you'd say that. Yes, they're editorializing, but they're editors...
Seriously, this statement seems more than fair:

How many of these worlds harbour life? We don't know, but if we are alone in our galaxy, it's not for a lack of accommodation.
posted by RedOrGreen at 9:04 AM on September 26, 2013 [2 favorites]

I hope that within my lifetime optics will have advanced enough that we can directly image the features of the closest exoplanets.
posted by ymgve at 9:06 AM on September 26, 2013

Why use Kepler at all when you can just extrapolate all the planets you need?
posted by swift at 9:28 AM on September 26, 2013 [2 favorites]

shame on New Scientist for editorializing "From this perspective, the chances that we're alone in the cosmos seem very slim, indeed." There's a whole different problem, estimating the likelihood that life will spontaneously originate on an Earth-like problem. And then a third problem, the likelihood of intelligent life, whatever that means.

It's like in their excitement they jumped several places in the Drake equation.
posted by Gelatin at 9:39 AM on September 26, 2013 [2 favorites]

...our best estimate of the total number of such planets in our galaxy is 15 to 30 billion
They never call, they never write...
posted by Thorzdad at 9:43 AM on September 26, 2013 [2 favorites]

They never call, they never write...

"All we ever see of stars are their old photographs."

--Doctor Manhattan, Watchmen
posted by Gelatin at 9:50 AM on September 26, 2013 [1 favorite]

That was really well done.

For the nerds, I feel obligated to link to both the xkcd comic and exoapi which "provides access to exoplanet data through a simple RESTful API."
posted by gwint at 9:53 AM on September 26, 2013 [3 favorites]

estimating the likelihood that life will spontaneously originate on an Earth-like problem.

Certainly this is shrouded in the anthropic principle, but on Earth; simple one-celled life arose pretty much instantaneously once heavy bombardment ceased. The general idea is that a significant fraction of Earth-like worlds (of which we know at least three; Venus, Earth, Mars, maybe Titan, as well) will harbor simple life as soon as conditions cease preventing it. Complex life like plants and animals? smaller again, but non-zero. Still very probable, though. Dinosaurs had a really nice run of things without inventing radios. Intelligent, tool-using, physics-mastering life that doesn't wipe itself out? Again, non-zero, but vanishingly small. Geologically speaking, the instant there were Homo Sapiens, there were radios, lasers, nukes, and space probes.

If you ballpark the numbers with the Rare Earth hypothesis (extension of the Drake equation), you end up on the order of 0-100 intelligent civilizations in the lifespan of the Galaxy. The odds on there being an overlap of civilizations is starting to look problematic. Either we're the first (or belong to the first wave of Smart-Enough-For-Radios civilizations) or the one or two waves before us are all gone except for artifacts; most likely.

On edit: all Kepler and the like are really doing here are refining the veracity of terms of the Drake equation. Necessary, but not sufficient.
posted by Xyanthilous P. Harrierstick at 9:57 AM on September 26, 2013 [4 favorites]

Whether the habitable zone planets have life is something that we may be able to determine relatively soon because of extra solar spectrometry. Free oxygen = life.
posted by Mitheral at 10:11 AM on September 26, 2013 [3 favorites]

Metafilter.com: providing access to internets through a simple html-based RESTful API.
posted by blue_beetle at 10:12 AM on September 26, 2013

15 to 30 billion earth-like planets is a fantastically specific result

Yeah that's a number worth remembering. Helps 15 billion is close to the age of the universe, about 14 billion. Also that's just in our Galaxy, there are 170 billion other galaxies in the observable universe. Let's see, 177 billion * 15 billion = it's full of planets.
posted by stbalbach at 10:18 AM on September 26, 2013

15 to 30 billion earth-like planets...

And his majesty, Dominar Rygel XVI will rule them all.
posted by Brandon Blatcher at 10:53 AM on September 26, 2013 [3 favorites]

By MeFi's own Adam Becker, the Freelance Astrophysicist.
Username:"freelanceastro."

Who, incidentally, I have played roaring-drunk-rockband with on more than one occasion.
posted by Myca at 11:15 AM on September 26, 2013 [3 favorites]

It's like in their excitement they jumped several places in the Drake equation.


I enjoy snark and name-dropping as much as the next guy, but did you RTFA? The Drake equation is:

N = R*fp*ne*fl*fi*fc*L

where:

N = the number of civilizations in our galaxy with which communication might be possible (i.e. which are on our current past light cone);

and

R = the average rate of star formation in our galaxy
fp = the fraction of those stars that have planets
ne = the average number of planets that can potentially support life per star that has planets
fl = the fraction of planets that could support life that actually develop life at some point
fi = the fraction of planets with life that actually go on to develop intelligent life (civilizations)
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

So far as I can see, there are seven variables at work here. The first one doesn't enter into what we are talking about (we know there are stars here), and the presentation says absolutely zero about the last four. There remain two, the second and third, and the point of the article is that we have a much firmer idea about the second and third variables than before.
posted by ricochet biscuit at 11:50 AM on September 26, 2013 [1 favorite]

Hi all! Thanks for the link, Gelatin, and the shoutout, Myca. Glad you like our piece. If anyone's got any questions about it, I'm happy to answer them here.

As for whether we've jumped a few places in the Drake equation -- I don't feel we have. We're simply stating, as richochet biscuit points out, that we have a better idea of what's going on with more of the variables in the Drake equation than we did before, thanks to Kepler and other surveys. A couple of decades ago, nobody knew how common it was for planets to form at all -- much less in habitable zones. It was a totally open question in science. Now we know much more.

For what it's worth, we showed this to Frank Drake himself before launch, and he liked it.

gwint: we used the Exoplanet Archive API in creating this graphic.
posted by freelanceastro at 12:03 PM on September 26, 2013 [8 favorites]

I hope that within my lifetime optics will have advanced enough that we can directly image the features of the closest exoplanets.

We recently determined the color of one. Baby steps...
posted by XMLicious at 12:17 PM on September 26, 2013 [2 favorites]

the presentation says absolutely zero about the last four

But the article (of course I read it; it's my first link) says that "From this perspective, the chances that we're alone in the cosmos seem very slim, indeed," which does seem to go from ne to fl if not fi.

But I don't want to get bogged down about it; it's still awesome, and well worth a bit of exuberance. I don't doubt Frank Drake liked it; I surely did.
posted by Gelatin at 12:53 PM on September 26, 2013

Speaking of exuberance, from XMLicious's link:

The world, known as HD189733b, has a deep azure hue - probably the result of silicate (glass) rain in the atmosphere, which scatters blue light.

Glass rain. We live in a cool universe.
posted by Gelatin at 12:57 PM on September 26, 2013 [1 favorite]

It seems that in the atmospheres of some brown dwarfs it rains molten iron.
posted by XMLicious at 1:15 PM on September 26, 2013

RedOrGreen: "Nelson: shame on New Scientist for editorializing.

Not sure why you'd say that. Yes, they're editorializing, but they're editors... "

Nelson's wording is a bit off. How about: "Shame on New Scientist for pulling numbers out of their ass and calling it science."

Because that's what any application of numbers to the Drake Equation really is.
posted by IAmBroom at 1:19 PM on September 26, 2013

IAmBroom: Shame on New Scientist for pulling numbers out of their ass and calling it science. Because that's what any application of numbers to the Drake Equation really is.

Our numbers in the extrapolation are all pulled from peer-reviewed publications - specifically, the 15% figure comes from Dressing and Charbonneau 2013. If you want to know where the rest of the information came from, try our About page.
posted by freelanceastro at 1:28 PM on September 26, 2013 [2 favorites]

Is the search grid really spaced out like that, or is that just done in the graphic to make them more visually distinct? If so, any ideas why? Really interesting presentation, by the way, good work.
posted by feloniousmonk at 3:06 PM on September 26, 2013

feloniousmonk: they really are spaced out that way! We got the data for the Kepler field directly from the Kepler team. They're spaced that way because that's how the CCDs (light detectors, same thing you've got in your digital camera) are arranged in the telescope. Here's a picture of the CCDs before they were placed in Kepler; you can see they're arranged in the same pattern.

As for why the CCDs are arranged that way: not sure, but I'm guessing it's got to do with the assembly process. For the science Kepler is doing, they don't need a single continuous field, as long as they can hold the telescope steady on the same part of the sky for long periods. Unfortunately, that's exactly what they can't do anymore. :-(
posted by freelanceastro at 3:43 PM on September 26, 2013 [2 favorites]

And thank you! Glad you like it - we had fun putting it together.
posted by freelanceastro at 3:46 PM on September 26, 2013

Yeah, CCD chips need a gap around the edge, not least for read-out electronics and so on, and there's a limit to how big you can make a single chip (although an astronomical instrument, especially of Kepler-grade will naturally be close to the forefront of what can be engineered).

All big CCD cameras on telescopes have these gaps between chips, but usually you make multiple exposures to fill in the gaps. As freelanceastro notes, with Kepler it's better to just keep observing on target.

I believe CMOS sensors (as in most digital cameras) have a lot of the circuitry per-pixel and might arguably reduce the chip gap as a result, but CMOS sensors (as I understand it anyway) also suffer from having somewhat less area per pixel that is light sensitive, so it's not a great trade-off. I believe this is being worked on though.
posted by edd at 4:27 PM on September 26, 2013 [1 favorite]

fleelanceastro, thanks for coming to answer questions here. As always I already regret my snarky tone about "shame on..". I appreciate the comment about not being alone as a bit of poetic enthusiasm for what is a fantastically specific result from Kepler. I'd love to read some more about the other variables in the Drake equation some day, particularly fl and fi. But that's a different question than what your article / visualization is about.
posted by Nelson at 4:39 PM on September 26, 2013 [1 favorite]

My pleasure, Nelson - and don't worry about it. We'd all like to know more about fl and fi, but that's still beyond our reach. We might know more soon, though: NASA approved the Transiting Exoplanet Survey Satellite (TESS) mission back in April, which will find habitable exoplanets that are much closer to Earth than most of the ones that Kepler found. And once we have the results from TESS, we will hopefully be able to use the James Webb Space Telescope (if it ever actually launches) to get spectral information about the atmospheres of those planets, which could give us some indications about life on those worlds. That would give us a handle on fl, at least.
posted by freelanceastro at 5:12 PM on September 26, 2013 [2 favorites]

Basically, what Mitheral said.
posted by freelanceastro at 5:16 PM on September 26, 2013

Hell yes. Thanks to freelanceastro and to TheWhelk for an excellent visualization and an introduction to an excellent musical artist, respectively.
posted by Sleeper at 10:23 PM on September 27, 2013