The tiniest star system

January 11, 2012 3:49 PM

Astronomers using data from NASA's Kepler mission have discovered the three smallest planets yet detected orbiting a star beyond our sun. The planets orbit a single star, called KOI-961, and are 0.78, 0.73 and 0.57 times the radius of Earth. The smallest is about the size of Mars.
posted by IvoShandor (29 comments total)

My God it's full of monoliths!
posted by localroger at 3:58 PM on January 11

I very much enjoy NASA's unrestrained use of such highly technical terms as "itsy-bitsy planetary system".
posted by elizardbits at 4:01 PM on January 11 [5 favorites]

IvoShandor: "Astronomers using data from NASA's Kepler mission have discovered the three smallest planets yet detected orbiting a star beyond our sun."

And you noticed this while looking for... dead pulsars, perhaps? In deep space, by any chance?
posted by Joakim Ziegler at 4:02 PM on January 11 [2 favorites]

Barnard's Star
MAJOR IMPORTS: Grain, Fruit and Veg., Animat Meat, Minerals
MAJOR EXPORTS: Synthetic Meat, Fertilizer, Heavy Plastics, Metal Alloys, Industrial Parts, Computers, Farm Machinery, Robots
ILLEGAL GOODS: Narcotics, Animal Skins, Live Animals, Slaves, Hand Weapons, Battle Weapons, Nerve Gas
posted by Artw at 4:02 PM on January 11 [11 favorites]

That clicking noise you hear is hundreds of SF writers trying to come up with ways life could evolve on planets like this. The challenges are formidable, what with the lack of visible light and the tidally locked orbits. But if most red dwarfs have planets, then some of them have to be just right.
posted by Kevin Street at 4:15 PM on January 11

All three planets are thought to be rocky like Earth but orbit close to their star, making them too hot to be in the habitable zone, which is-

NEXT!

Man, where's our pre-terraformed jungle-and-beaches planet of gorgeous aliens already? These days it's all "gas giant" this, "surface temperatures upwards of 400°C" that, and "pummeled by frequent asteroid showers" or "prone to release jets of liquid nitrogen with tremendous force from random locations" and so forth. It's like space doesn't even want us to move out there or something.
posted by Marisa Stole the Precious Thing at 4:20 PM on January 11 [12 favorites]

Red dwarf planets are probably the fixer-upper retirement homes of the stellar community. It takes some work to terraform them, but once you get them comfy they'll stay that way for billions of years. Perfect for an elderly species.
posted by Kevin Street at 4:24 PM on January 11 [9 favorites]

Nice steady energy input, ideal for server farms.
posted by Artw at 4:28 PM on January 11 [4 favorites]

So someday we develop the technology to see exoplanets as easily as we see those of our own Solar System, in real time, and maybe we find intelligent life on some world many light years away but we have no way to communicate or traverse the unthinkably vast distances between us. And maybe it turns out they've also developed these powerful telescopes and can see us too but they haven't licked the problem of space travel either. How unspeakably frustrating would that be?

I've got to stop going so long without eating.
posted by JaredSeth at 4:30 PM on January 11 [7 favorites]

I don't know about your eating habits, but that sounds like a possible idea behind the most romantic (capital R and lower case r) poem ever.
posted by MCMikeNamara at 4:36 PM on January 11 [2 favorites]

Marisa Stole the Precious Thing: "It's like space doesn't even want us to move out there or something."

Would you?
posted by brundlefly at 4:48 PM on January 11

Our mission: find them and pollute them
posted by not_on_display at 4:48 PM on January 11 [4 favorites]

Our mission: find them and pollute them

previously
posted by Trurl at 4:56 PM on January 11 [1 favorite]

But if most red dwarfs have planets, then some of them have to be just right.

That is one of the key ideas in Karl Schroeder's novel Permanence.
posted by Mars Saxman at 5:06 PM on January 11 [1 favorite]

Warp Factor Five, Mr. Sulu.
posted by Gelatin at 5:25 PM on January 11

"How unspeakably frustrating would that be?"
Would it be? A sense of mutual acknowledgment unconfirmed but with the known shared awareness of what it took to get there? And what other implications it has?

I'm not sure frustrating is the phrase I would use.
posted by edd at 5:26 PM on January 11 [3 favorites]

Would you?

I wanted to give your question careful consideration, and I think that given the chance, it would really depend on who was coming along and who I could take with me.
posted by Marisa Stole the Precious Thing at 6:20 PM on January 11

Awwww soo cuute!
posted by goodnewsfortheinsane at 6:44 PM on January 11

"It's like space doesn't even want us to move out there or something."

No, this is a function of the search method.

An Ethan Siegel blog post (hosted on the excellent Science Blogs site) on December 20th titled "First Exoplanet Smaller Than Earth: Why I'm Not Surprised" speaks to this:

The method by which the first exoplanets were ever detected was through a phenomenon known as stellar wobble. [...] So what sort of exoplanets are you most likely to detect using this method? The ones that are most massive and closest to their star, because the closer they are, the more quickly they orbit!

In other words, we didn't find these "Hot Jupiters" because they're so common and we're so rare, we found them because those are the easiest things to see! In fact, the idea that we see more of the things that are easier to see has been around in astronomy since 1922, and is known as Malmquist bias. [...]

So fast forward to today, where we've got a much better, more successful way to find exoplanets than by this "primitive" wobble method.

Using the transit method, our most sophisticated planet-finding spacecraft, Kepler, has found thousands of planets, compared to the dozens that were found with the wobble method. When an exoplanet passes in between our line-of-sight and its parent star, it blocks some portion of the star's light. This temporary "dip" in the brightness of a distant star is how we can detect a planetary transit, and hence infer the existence of an exoplanet.

So, think about it for a minute: what types of planets will we be most likely to see? Which ones will be the easiest to see and verify? Well, that would be

→  the biggest ones, because they'll block the most light and be the most noticeable,
→  the innermost ones, because they'll be most likely to transit in our line-of-sight to the star, and
→  the ones that orbit the fastest, because it takes multiple transits to confirm that this is, in fact, an exoplanet rather than just a rogue object or stellar fluctuation.

In other words, the types of planets its most likely to find are large inner planets: super-Earths!

[...] Any guesses, mind you, as to what the theoretical limit of how small a planet Kepler could possibly detect, at the very limit of its power?

Did you guess something just barely smaller than Earth, and only then if it's mind-bogglingly close to a star that's significantly smaller than our Sun? [...]

So don't be surprised at all the super-Earths so far, the smaller planets are just harder to see, and we're only starting to get there. By time the next generation of planet-finding telescope comes along, we're going to be rolling in Earths and mini-Earths, just you wait!

So we'll likely be seeing more planets discovered which are somewhat smaller than Earth, but orbiting stars which are much smaller than the Sun and orbiting much more closely to their stars—these things in combination make for planets which are not going to be habitable. Ironically, one or two of the super-Earths discovered before are more likely to be habitable.

Over time, as our equipment improves, we'll find more and more exoplanets that are more like Earth. One fundamental assumption of science, especially physics, that has long been ignored in this kind of astronomy, is that the local universe is not fundamentally different from the non-local universe. Unless we have good reasons to think otherwise, we should assume that other solar systems are more likely to be like our own than unlike. However, in the past, the assumption has been the opposite. In my lifetime, I've watched conventional wisdom move from assuming that exoplanets are very rare, to that they are almost exclusively gas giants, to what we have today.
posted by Ivan Fyodorovich at 8:38 PM on January 11 [5 favorites]

So someday we develop the technology to see exoplanets as easily as we see those of our own Solar System, in real time, and maybe we find intelligent life on some world many light years away but we have no way to communicate or traverse the unthinkably vast distances between us. And maybe it turns out they've also developed these powerful telescopes and can see us too but they haven't licked the problem of space travel either. How unspeakably frustrating would that be?

Maybe it would give both the hopeful and fearful among us something to unify around, and we would be less interested in killing/imposing our will on each other. That would be one (of many) good outcomes.

That is, until we build that tachyon transmitter to try and get their attention.

"Again, let me sincerely apologize about that. See, the Swiss used metric, and NASA used Imperial, and Bob Jones University used the Book of Exodus, and well everything just kind of got out of control after that..."
posted by lon_star at 10:05 PM on January 11 [1 favorite]

I always cringe at the assumption that other life-bearing planets must be exactly like our own. We know so little about what types of chemistry might be possible in say, a gas giant under high pressure, a cold liquid methane sea, or a molten sulfur ocean. Life really only requires four things:

1) Some type of information encoding polymer, preferably one-dimensional
2) Replication of said polymer
3) Heritable changes in the polymer's information (mutation)
4) The ability to accelerate some sort of energy gradient to harness energy

If you have a few billion years and a planet's worth of varied molecules with some sort of thermal cycling, I'd be surprised if something didn't evolve. Having no atmosphere or oceans might be a dealbreaker, however.

Intelligent radio-transmitting life may be rare, but life must have arisen multiple times. The likelihood of encountering any trace of such life is limited by the incredible vastness of empty space and the short time a technological society may survive.

I'd bet that self-replicating chemistries have arisen in the other bodies of the solar system already, but we don't really know how to look for them.
posted by benzenedream at 11:02 PM on January 11 [2 favorites]

"I'd bet that self-replicating chemistries have arisen in the other bodies of the solar system already, but we don't really know how to look for them."

I think you're probably right about that. To your larger point—I mostly agree, but I also think that it's extremely likely that there are more and less friendly environments for life and that, someday, if we encounter numerous examples of extraterrestrial, we'll find that life is more likely and frequently found in some environments and rarely found in others.
posted by Ivan Fyodorovich at 11:36 PM on January 11

Benzene, you forgot one critical factor, and that is an environment sufficiently stable for the chemistry to establish what characteristics replicate the best. This is one of the most critical deal-breaking parts of the package deal called life.
posted by Goofyy at 12:44 AM on January 12

I always cringe at the assumption that other life-bearing planets must be exactly like our own.

I think it is logical to search for planets like our own. We know of one case of a life-bearing planet, so we search for more like it.
posted by Pendragon at 3:07 AM on January 12 [1 favorite]

I don't know about your eating habits, but that sounds like a possible idea behind the most romantic (capital R and lower case r) poem ever.

Not quite what was described, but in the same ballpark.
posted by ymgve at 4:35 AM on January 12

While it's interesting to speculate about alternate chemistries for life, focusing on liquid water does make quite a bit of sense; even considering alternate temperature ranges hydrogen oxide has properties that aren't quite matched by any other molecule -- and this is something that can be declared in a pretty absolute manner, since any competing solvent would have to be fairly simple and ubiquitous in order to have similar properties, and the chemistry of such simple inorganic molecules is pretty fully understood.
posted by localroger at 5:40 AM on January 12

Based on what we now know, it seems probable that planets outnumber stars in our galaxy.

This boggles the mind.

So, if we look for evidence of liquid water (probably a requirement to find 'compatible" life forms), what are the chances we find a nearly Earth-like planet in the next 5 years? (Say, to within one or two percent of size/mass/orbital distance?)

As out technology has improved since the first extrasolar planet was discovered (in 1995!), we have discovered a little over 700 such planets. Literally, almost everywhere we have seriously looked. Since we seem to discover most such planets by occultation, there are undoubtedly many that we have simply missed because they haven't passed near enough to our line-of-sight to be discovered. Yet.

This is exciting stuff. I can only wish that I might live long enough to see some evidence of life elsewhere. It seems to be increasingly possible that this might be so.
posted by pjern at 7:40 AM on January 12

"...what are the chances we find a nearly Earth-like planet in the next 5 years? (Say, to within one or two percent of size/mass/orbital distance?)"

I don't know, but it would be wonderful if that happened! It could serve the same purpose for us that Mars served for the 19th and early 20th centuries - a repository of our hopes and dreams, urging us forward, always enticing us with the hope that someday we might get there and find that we're not alone.
posted by Kevin Street at 9:34 AM on January 12 [2 favorites]

> the first extrasolar planet was discovered (in 1995!)

The earliest extrasolar planet discoveries were the planets around the pulsar B1257+12, as reported in 1992. (And the wikipedia link above correctly credits that discovery, too.) In fact, at 0.02 Earth masses, the third planet around that pulsar is by far the smallest planet yet to be discovered.

The radiation environment for those planets would be ... unfortunate, I guess, but they are real planets measured with truly exquisite precision.

But those weren't discovered by optical astronomers, so whatever... :)
posted by RedOrGreen at 1:46 PM on January 12 [1 favorite]