Kepler-36's 'Odd Couple' Defy Planet Formation Theories 70
astroengine writes "The two planets circling Kepler-36, a sun-like star in its senior years, are as different as Earth and Neptune. But unlike the hundreds of millions of miles that separate our solar system's rocky worlds from its gas giants, Kepler-36's brood come as close as 1.2 million miles (1.9 million kilometers, or 0.01 AU) from one another — about five times the distance between Earth and the moon. This is yet another weird exoplanetary star system that defies conventional wisdom when it comes to planetary formation theories. 'The weirder they are, the more scientifically interesting they are,' Steve Howell, deputy project scientist with NASA's Kepler space telescope, told Discovery News."
Another theory proven wrong and improved (Score:5, Insightful)
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Very interesting.
I wonder if these two planets are in their death throws in terms of meeting one another in their orbital dance around their host start. Is it possible that we will be lucky enough to detect these two planets colliding in the "nearish" future?
Is it possible that these two planets have somehow found an equilibrium in their orbits, even when they get so close to one another? Time will tell.
Re:Another theory proven wrong and improved (Score:4, Interesting)
I so wish there were a big Eros-class asteroid in that kind of orbit with us.
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I wonder if these two planets are in their death throws in terms of meeting one another
Great pun, I loved it!
Obligatory xkcd (Score:3)
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that looks like one of those color blindness tests
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i'm not color blind, but i am planet blind, so that explains it
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It is pretty awesome what we're learning from Kepler, isn't it?
A field in its infancy (Score:5, Insightful)
The number of solar systems we are familiar with is approximately 1. Therefore, it stands to reason that whatever theories we've come up with regarding planet formation are bound to have flaws in them.
This is a very interesting discovery, and it highlights just how little we know about the mechanics of the universe.
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It seems like a lot of these systems we are discovering are "abnormal" (e.g.; Jupiter sized planets orbiting where mercury is in our system, this recent example, etc). Is our solar system the weird one or are there characteristics about these 'abnormal' systems that simply make them easier for us to detect (thus explaining why we seem to find alot of them!)
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Yeah, because they're larger they block more light, so they cause a more noticable dip in brightness, and because they're closer the orbit faster, which means that there's more chances to see them cross their star. Kepler's only been up there a couple of years now, and they need 3 passes to get a preliminary confirmation, so they're just now starting to have had enough time to see and confirm Earth if we'd been hunting for it.
Re:A field in its infancy (Score:5, Informative)
Big planets near the star are the easiest to detect.
Near the star means short orbital period and so the thing we are observing is happening more often (planet moving between us and the star, the star moving due to the gravity of the planet, phases of the planet changing the observed brightness of the star, etc). Bigger means the effect itself is larger.
If you are observing the planet directly, then bigger means easier to see. And closer to the start means brighter (though also more drowned our by the star itself) and thus also easier to see.
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Not to mention "easy."
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Which is a word I didn't use.
easiest and easier, sure, but those are relative terms which say nothing about any sort of absolute difficulty.
For example:
It is easier to put a man on the moon and return him safely to earth than to put a man on mercury and return him safely to earth. That does not say either is easy.
Question 7 was the easiest question in the exam. That says nothing about whether the exam (or even just question 7) would be called easy or not.
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The normal interpretation of seen: http://www.eso.org/public/images/eso0842b/ [eso.org]
You know directly observing the object rather than observing an effect caused by it.
Though I was wrong - further away is better for that - the star washing out effect is as big as you would expect so close is bad. of course indirect observation is how we find most of them and closer is better for that.
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Well, all our detection methods have a biases (for various reasons) toward large planets in small orbits, so we could blame that for how "common" hot jupiters seem. However, it's at best a partial explanation for this system (depending on the assumption that the gas giant migrated inward), inasmuch as we wouldn't have detected the gas giant if it remained where it formed.
Re:A field in its infancy (Score:5, Interesting)
I remember hearing years back that we were trying to generate models that would accrete solar systems out of dust clouds - "from first principles". At the time I read about it, none of those models would generate a solar system like ours.
Many have suggested that our oversized moon (oversized relative to Earth) is responsible for higher life, intelligent life, technological life, etc. The Earth-moon system also seems to have required a "just-right" collision between two bodies of just-right size at the just-right aiming, angle, and velocity.
What if all of these conditions really are necessary - what if there isn't another more probable way to have intelligent life? (This presumes that we qualify as "intelligent" - most of the time I think we don't qualify as "wise". (as in "sapiens"))
What if in the "meaningful" universe, by some definition of meaningful, say the range of a Star Trek warp drive in a human lifetime, we really are alone?
At the very least, it makes laying waste to a functioning biosphere an even bigger crime.
One could also go nuts with religious implications.
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What if in the "meaningful" universe, by some definition of meaningful, say the range of a Star Trek warp drive in a human lifetime, we really are alone?
Then the entire thing is ours.
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I think it was Carl Sagan in his book Cosmos, who wrote something like, "It is possible that we may someday have to face the fact that we are all alone." (I hope I remembered that right).
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One (simple) dust-cloud accretion program is located here:
http://sourceforge.net/projects/accrete/ [sourceforge.net]
Accrete is a physical simulation of solar system planet formation,
originally published to Usenet-- probably comp.sources.unix-- in 1991
by Joe Nowakowski. This software is in the public domain.
This simulation works by modelling a dust cloud around a Sun-like star,
injecting a series of masses which collect dust, and form planets.
The simulation then determines what the planetary environments will be
like in terms
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Many have suggested that our oversized moon (oversized relative to Earth) is responsible for higher life, intelligent life, technological life, etc.
At least one biochemist put that as a premise in some fiction -- Dr. Isaac Asimov, in the later Foundation books. In the Foundation universe, nothing more advanced than moss developed on any other planet but Earth.
One could also go nuts with religious implications.
Asimov was an athiest.
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Read that, it's not the only place I've seen the suggestion. Obviously Asimov's science fiction doesn't constitute either fact or rigorous theory, but he also was generally not way out in left field, unless necessary for a major plot device like hyper drive or positronic brains.
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What if all of these conditions really are necessary - what if there isn't another more probable way to have intelligent life? (This presumes that we qualify as "intelligent" - most of the time I think we don't qualify as "wise". (as in "sapiens"))
"Space is big. Really big. You just won't believe how vastly, hugely, mindbogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space, listen..."
That is from Douglas Adams, and it seems to apply very well here. People generally underestimate the enormousness of the universe, because it is so hard to comprehend its vastness. The universe is so mindbogglingly big, that even if all those conditions need to be met, not only will there be many plac
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Why do you think I added the, "meaningful, say the range of a Star Trek warp drive in a human lifetime," clause to that line? There's "So rare that it will take a long time to discover or communicate with the Other," and there's "So rare that we are physically incapable of discovering or communicating with the Other." Since it was a hypothetical question, that clause was to dump us into the second category from the first.
Offhand, and the moment I'll guess that sophisticated life may be more likely to emer
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Everybody generalizes from a single example. At least, I do....
Migration? (Score:2)
Short of a planetary migration after formation, I don't see how this is possible. The characteristics of a planet would have a lot to do with how far the interstellar material is from the central sun. Even if there were differences between planetary systems initial interstellar material, I would still expect to see similar planetary characteristics for planets in similar orbits.
If I had to bet, I'd go with planetary migration.
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There seems to be a standard assumption that everything we see, unless there's solid proof of it otherwise, is in a steady-state. I see no reason to assume that. I think our universe is a lot more dynamic than we often give it credit for, and think that we're lucky that our planet has remained more or less intact since its collision with Theia.
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Yes, migration seems to be thrown around a lot as an explanation for otherwise unexplainable planetary configurations. However, I am not sure what you mean by out "universe is a lot more dynamic". If you mean that there is a lot we don't understand, I will agree. But ultimately science works by creating a hypothesis, testing against observed data and then either throwing out the hypothesis and starting over or refining original hypothesis. I am not an expert, but I am not aware of any other hypothesis that
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Dynamic. Aka, not static, aka, steady-state. That is, assuming everything in the universe is as it has been since it's particular neighborhood formed. And I'm, not just talking about migration within a system, but everything from collisions to wandering planet capture to the burned out husks of "supercomets" to recondensed planets from boiled-away hot-jupiter matter to things we haven't even envisioned yet. I expect craziness, not predictability, of the bodies in the universe. I think our own solar sys
Re:Migration? (Score:5, Insightful)
There's a general axiom of science that the observer isn't specially priveleged. In other words, when it comes to astronomy, what we see looking out is similar to what everyone else would see. The trouble with that idea is that, because of statistical laws, it has to break down at some level - if you look for, say, 20 different things, each with a very high, say, 95% chance of occuring, there will probably be at least one that looks seriously atypical from your viewpoint (assuming those things can be treated independently, of course). Scientists tend to argue that on some scale the universe looks uniform to all observers, but that's not actually as useful a starting assumption as it sounds, because no one is sure just what that scale's boundrys are, the minimum sample needed is, or just what things are or aren't 'unifomitarian'.
For example, some 19th and early 20th century astronomers observing our own solar system, thought that Earth's having such a large moon was very unusual, and if there were extra-solar, earth-like worlds, they would usually have much smaller moons, if any. But until we can image objects the size of our moon across interstellar distances, for all we know, Venus and Mars are unusual in not having larger moons (or any moon at all in the case of Venus). The common idea, that Earth-Moon like 'double planets' are rare, is based on damned near no data.
For another, the Sun and the Moon have almost exactly the same apparent diameter as seen from Earth - surely that's just a statistically unusual coincidence, but technically, we don't really know but that it might be anomalously common, and in complete contrast to the random ratios we might expect, for the same situation to occur elsewhere.
Maybe it will turn out that gas giants in a system typically range from a largest one in the closer orbit, outward to a smallest gas giant in the largest of a series of orbits, (and our solar system mostly fits a standard rule) or maybe our solar system has it bass ackwards, or maybe gas giant size and orbit distribution is completely random.
One minor point: There are no stars 10 times older than our sun. At 4.75 billion years old, the sun is about 1/3 the age of the entire universe, so even the earliest stars formed are only about 2 1/2 times as old. So i'll predict that, if there's more 'odd configurations' in older star systems, it will have to manefest itself over a smaller range of ages.
Re:Migration? (Score:5, Insightful)
That assumption has not only messed up astronomy, but pretty much every field of applied science man is involved in. Look at all the resistance to accepting continental drift. Or evolution for that matter (nowadays at least the scientific community accepted it, but in the early days it was often a hard pill to swallow even for those who didn't feel the need to tag everything to a Bible passage - nowadays "everything is constantly changing and nothing is as it used to be" is a critical tenet of biology). It can hit multiple fields at once, like the assumption that any sizeable crater on Earth had to be volcanic, not from a large meteor, because that'd mean our planet and our solar system were still radically evolving. It gets some really smart people - for example, that assumption made it hard for Einstein to accept the Big Bang, that the universe was once some radically different place (in fact, no place whatsoever!) and is destined to become a radically different place still.
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From parent: "For another, the Sun and the Moon have almost exactly the same apparent diameter as seen from Earth - surely that's just a statistically unusual coincidence..."
This *is* actually a coincidence, and it's also a coincidence that you live in this particular time to perceive the pair as the same objective size.
As far as we can tell, the Moon has been 'receding' for hundreds of millions of years.
From Wikipedia "...some of the Earth's rotational momentum is gradually being transferred to the Moon's
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For another, the Sun and the Moon have almost exactly the same apparent diameter as seen from Earth - surely that's just a statistically unusual coincidence, but technically, we don't really know but that it might be anomalously common, and in complete contrast to the random ratios we might expect, for the same situation to occur elsewhere.
Our moon is moving away from Earth at a consistently measured speed of almost 4 cm per year. This is from directly observed evidence.
This means that on tiny galactic time scales such as hundreds of millions to a billion years, we can accurately predict the moons distance from earth at any particular point of time within that time scale.
The Suns diameter is about 400 times greater than the moons, however *right now* the Sun is also about 400 times further away, thus the apparent diameter is the same.
Further
As soon as they think they have it figured out... (Score:2)
The universe is suddenly replaced with something more inexplicable.
Just goes to show, we're not half clever enough to figure out how everything happens and what really is possible when you are talking about billyuns and billyuns of stars.
On the other hand, this keeps astrophysicists theorising and arguing for years! Like having to explain what '42' could mean by a couple of philosophers who went on to futures beyond their wildest dreams.
Sure does beat predictable, doesn't it? (c:
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Misread inexplicable as intoxicated. Somehow, that made more sense.
I expect the reality of exoplanets to often be (Score:5, Interesting)
weirder and more fascinating than even the most far-out science-fiction authors have envisioned.
Try to picture the implications, for example, of a tidally-locked hot super-earth. You can readily have a habitable-temperature cold side while the other side is hot enough to boil the surface off to plasma. What happens on such a planet? Obviously it would take detailed physics simulations to find out, but I would expect things like tremendous winds transporting matter in the upper atmosphere from the hot side to the cool side, where it'd condense and rain out. Condensation at the surface would be like chemical vapor deposition, glazing the surfaces in metals or crystals (depending largely on the oxygen availability). Condensation in the atmosphere would lead to rain of solid particles - depending on various factors affecting the formation, it could be anything from sand to beads of glass to gemstones. Will all the liberated oxygen from the hot side (oxygen makes up a large portion of planetary crusts) rain back out or could there literally be a substantial oxygen-based atmosphere on the cool side? And hey, you've got a large mass of conductive material moving plasma and metallic gasses overhead - sounds like a recipe for uneven, irregular magnetic field generation and lots of "weird" stuff like localized field pinching, flares, and other phenomena that you normally only get in stars. Perhaps even localized bouts of fusion at the pinches. Just from the rapid and extreme differentiation in the atmosphere as solid matter precipitates, combined with the high conductivity, you should get crazy lightning. And of course losing your crust to boil-off has to have some huge effects on tectonics.
Such a shame that it's so hard to get probes to these alien worlds; I'm sure some of them would be truly incredible to see. Of course, we hardly even know what's in our own solar system (for example, the subsurface oceans of several large moons), so I guess better to start there first. Even our own solar system probably has some really weird stuff that we've never imaged before, like the hypothesized metallic frosts on Venus.
Re:I expect the reality of exoplanets to often be (Score:5, Funny)
Try to picture the implications, for example, of a tidally-locked hot super-earth. You can readily have a habitable-temperature cold side while the other side is hot enough to boil the surface off to plasma.
It was a dark and stormy night. The lead sulfide rain fell in torrents — except at occasional intervals, when it was checked by a violent gust of ammonia wind which swept up the alien canals. In other words, a typical day on the dark side of Omicron 1.
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Don't quit your day job just yet....
Re:I expect the reality of exoplanets to often be (Score:5, Funny)
Re:I expect the reality of exoplanets to often be (Score:5)
It was a dark and stormy night. The lead sulfide rain fell in torrents — except at occasional intervals, when it was checked by a violent gust of ammonia wind which swept up the alien canals. In other words, a typical day on the dark side of Omicron 1.
It was a dark and stormy night; the lead sulfide rain fell in torrents — except at occasional intervals, when it was checked by a violent gust of ammonia wind which swept up the crystaline streets (for it is on Omicron 1 that our scene lies), rattling along the gemstone-encrusted housetops, and fiercely agitating the scanty flame of the spontaneous bouts of atmospheric fusion that struggled against the darkness, when Edward George Bulwer-Lytton decided that science fiction really wasn't his genre.
Kepler may tell us what is "normal" (Score:3)
Its not a ring but... (Score:3)
Klemeper Rosette ? (Score:3)
Kepler/Klemeper/Kemplerer Rosette
Truth may be stranger than fiction (See Larry Niven's pupetters)
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Kepler/Klemeper/Kemplerer Rosette
Truth may be stranger than fiction (See Larry Niven's pupetters)
A Klemperer rosette [wikipedia.org], although Niven actually called it a Kemplerer rosette. Cool idea, but you'd probably need a "reactionless, inertialess drive from the Outsiders" or four to make it stable.
Just think of the view (Score:1)
Two (slightly) larger than Earth planets that close to eachother would have a sky I'm jealous of.
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You are right. Can you imagine having Mars flit by us only 2 Million kilometers away? If my mental math is right, we'd see Mars at its closest about every 25 years or so, and it would appear to be huge, almost as big as our moon would appear.
How can they get that close without being a system (Score:1)
Netpune is 17 times more massive than Earth, if these two planets are of a similar mass ration, then shouldn't the smaller world be captured by the gravity of the larger and become a moon? Maybe we are seeing an unstable system in the process of changing. Perhaps this is the theorised "gas giant migration" actually t in progress...
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A very interesting thought. I don't know about being "captured", but I would expect some type of disturbance, possible the smaller getting flung out into space or at least into a futher out orbit.
Do we know if these two planets are in the same orbital plane? Do we know if we are dealing with roughly circular orbits?
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While I share your notion about systems not necessarily being in steady-state, it's not true that just because a large body and small body pass each other that they must be destined to have the smaller body form a moon, collide, be ejected, or some sort of non-steady-state scenario. There are all sorts of crazy but stable orbital resonances. One of my favorite occurs in Saturn's rings [nasa.gov]. Awesome, eh? Here's a couple cool plots [orbitsimulator.com] of their orbits; it's like a spirograph.
The question the researchers have to fa
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Who says they formed together that way? (Score:2)
Who says the planets formed together in their current orbit?
It is pretty well theorized that there are planets / stars / blackholes are floating around space that aren't in orbit of stars / solar systems / galaxies. As there are cosmic events that can kick / move all of these celestial objects out of their original place of formation.
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Right, my first thought, too. In fact TFA discusses the turmoil of this discovery on current hypotheses about planetary formation and migration.
My next thought, related, was "who says this planetary arrangement is stable?" Perhaps in a few million years, that system will be very different. Will the planets "capture" one another? Will one planet eject the other from the system, or perturb its orbit into a very eccentric (and perhaps more or less stable) one? Will one planet migrate inward and the other
What I Love About Science (Score:2)
This is why I refuse to accept when people speak in absolutes. We'll never know as much as we like to think we do, partially because some of us think we know more than we do. Try to keep this in mind the next time you're tempted to call someone 'tin-foil hat crazy' when espousing a theory you don't necessarily agree with, but lack the evidence to disprove.
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The gaseous one is the sloppy one, of course.
The rocky one that keeps its gases internalized is obviously the retentive one.