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13-Billion-Year-Old Alien Worlds Discovered
astroengine writes "Two exoplanets have been discovered by scientists at the Max-Planck Institute for Astronomy orbiting the star HIP 11952. But according to conventional thinking, these worlds shouldn't exist. You see, HIP 11952 is a 'metal-poor star and planetary formation is hindered around stars with low metallicity (PDF). This isn't the only thing; as metal-poor stars were the first stars to form when the Universe was very young, these two worlds also formed around the same time. They are therefore the most ancient exoplanets discovered to date."
"Planets form around sun" certainly was news 13 billion years ago, it just took this long to reach Slashdot's front page.
Blank until
Except when the ladies ask you that, you say "My love for you".
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Well, they're only 375 light-years away, so I'd say that if they had managed to exist for 13 000 000 000 years, they likelihood of them disappearing in the last 375 is pretty low. My bet is on "are".
And the worms ate into his brain.
time is not an illusion at all, it is the increase in entropy of the structures of the visible universe, it is a non-conserved state function
It doesn't matter.
Point is that we now know that planets were formed at a very early stage of the universe.
As for the planets being metal poor, it isn't a surprise really, considering the age of the planets.
Let's put aside that for astronomers everything beyond helium is a "metal", we are talking about iron (Fe) and heavier elements.
Suns can only create elements up to iron in a fusion process, everything else is created in a (super) nova, and those were only starting at the beginning of the universe.
The real surprise here is that planets were formed without (or with few) heavy elements.
There are fewer illiterates than people who can't read.
I am astounded by the amount of rhetoric and vitriol that surrounds astronomical discoveries. Whether or not they are correct, the truth boils down to: we don't have shit for current time observations of anything in the universe. I truly believe that we are on the right path, and models fit observation, but why get so skeptical about everything? By the time we all die, the universe will basically be in the same state. Let's enjoy the limits of our observation, explore and expand them, and then maybe one of our lineage will be able to explore it.
Koalas. They're telepathic. Plus, they control the weather. -Margaret
http://en.wikipedia.org/wiki/Red_dwarf#Description_and_characteristics
It's possible to have stars that can fuse material for as long as 10 trillion years. Yes, T-T-T-Trillion.
The articles I looked at regarding this planet though make no mention to what class of star they're orbiting, so YMMV.
Can a star really last for 13-billion year and not running out of fuel?
Yes. Our own star is about 5 billion years, and probably only halfway through its life cycle.
Just like with dogs, the smaller ones live longer. Red dwarfs are expected to live for thousands of times the current age of the universe, and simply peter out as they exhaust their fuel, burning it slower and slower, but never having the gravity to cause helium fusion.
Actually, it's unknown what it was like before the big bang.
Like the parent said, time itself did not exist until the big bang, therefor, there is no "before" the big bang. There is no such thing as before time, just as there is no such thing as negative mass or negative distance.
There is no "I disagree" mod for a reason. Flamebait, Troll, and Overrated are not substitutes.
They're only 375 light years away.
Not to snark at you, but Sol is estimated to be 4-5 billion years old and it's only 8 light-minutes away.
But you've raised a really good question...
Off to read up on it.
I don't know the meaning of the word 'don't' - J
http://en.wikipedia.org/wiki/Main_sequence
They can guesstimate the age of a star based on its light characteristics. Our current understanding is that stars tend to follow a set progression through their evolution, and by looking at the current characteristics of a star (mass, heat, spectral composition), they can guess roughly how old it is.
It's all guesswork, mind you, and it doesn't necessarily tell us that the planets themselves are as old as the star. They could be trapped planets from other solar systems that the stars came into contact with over the years, or even trapped proto-stars that never had enough mass to start fusion... current thinking is that the interstellar medium may have a lot of this type of planet.
Didn't get one thing: the article says the star is 13 billions yo, but it's 375 ly from our solar system.
I always have thought that distance meant age. Which other technique there is to tell a star's age?
Distance is... well, distance. The number of light years something is away means that we are looking at what happened that many years ago. In this case, what we see happened 375 years ago. It has nothing to do with the age of the object. However, if we see a galaxy 13 billion light years away, we know that the galaxy is 13 billion years old since nothing is that much older, provided it still exists. We don't really know as we would be seeing it as it existed 13 billion years ago. To see how it looks today, we'll have to wait another 13+ billion years and look at it again.
As for judging the age of a star, I'll take a stab at it, although IANAA. If I recall correctly, there are several methods used to judge the age of a star. We know by looking at what the star is composed of which developmental stage it is currently at. We know by its size and energy output how fast it is burning its fuel. So, if we see a large, bright, hydrogen star, we know that it is fairly young since large hydrogen stars don't last long. We can be more accurate by figuring out how fast it burns its fuel and how much it has left (helium to hydrogen ratio). If we see that it is composed mostly of helium, we know that it is in its second stage. We can judge by its size how long it was in its hydrogen stage before it fused it all to helium.
I have not RTFA, but I believe they are judging that this star was one of the first out of gate judging by how much metal it has in its core, meaning that it is very, very old.
Take with salt. Like I said, I'm no astrophysicist.
What I don't understand is how do the scientist know that these were not rogue planets, formed much later and then became trapped by the star's gravity. Just because a star has planets orbiting it, doesn't mean that those planets formed along with the star.
There is no "I disagree" mod for a reason. Flamebait, Troll, and Overrated are not substitutes.
13.75 +/- 0.11 billion years
(The same age as the universe)
Is position an illusion? No. Time is just position on an axis you can't understand.
-Clio
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time has a very concise and hard definition, much more so than this word "mind" you invoke with your vague and nebulous words. Reality is not an illusion; jump from the roof of a skyscraper to the street, and even though you convince yourself some other event is happening, you will die when from the sudden stop regardless. Reality trumps all, and time is a very real component of reality.
Early supernovae wouldn't help - the star is formed from the same material as the planets would, and the star demonstrably has almost no metals. Early supernovae would just mean that this star didn't exist (in its current chemistry), or that it is even younger than currently estimated, so as to form before the supernovae.
Interstellar captures are very difficult. Generally speaking, you need three gravitationally interacting bodies to allow a capture, as you need one to carry away some energy. Basically this requires the wanderer planet to turn up just when the star is passing close to another one, and even then to get really lucky. (Most often it is the lowest mass object of the three which gains energy, but we need the planet to lose energy.) Another possibility is you could lose that energy through tidal losses, but this requires the wanderer has very small positive energy initially, and passes very close to the star. Either way, the odds of such a capture are very low.
In addition, we have the fact that this star has two planets, which makes the odds against capture polynomially* smaller. Finally, if two planets were captured, we'd expect them to have different orbital planes. Given that they were detected by the 'wobble' method, I'd expect this could be measured, and would be mentioned if it had been so. However I can't promise that there aren't gravitational interactions which would bring the orbital planes into alignment over 13Gyr. Captures would also initially have highly elliptical orbits, which again the wobble method should notice, and again I don't know if 13Gyr is long enough to circularize the orbits by tidal effects or planet-planet interactions.
* This word brought to you by the Committee Against The Misuse Of The Word 'Exponentially'
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Lifetime=1/Mass^2.5.
Note that lifetime here is as a ratio of solar lifetime (so a Lifetime of 1=10 billion years) and mass is in solar masses. The paper gives the mass of HIP 11952 as about 0.83 solar masses, so an estimated main sequence lifetime would be 1/0.83^2.5= 15.9 billion years, after which it would become a red giant. Not liking the odds for its planets at that time, especially the one with a 7 day orbital period. So, it probably has a long while left, though there are wide bounds listed for mass and age, so if it is actually older and heavier, it might be living on borrowed time.
"FDA staff reviewers expressed concern about the number of patients who were left out of the study because they died."
It's possible to have stars that can fuse material for as long as 10 trillion years. Yes, T-T-T-Trillion.
10-100 short scale (U.S.) trillion, or 10-100 long scale (Euro) billion. A pretty long time, yes, considering that the universe is considered[*] to be less than 14 billion (short scale) / 14 milliard (long scale) / 14 thousand million (UK) years old.
[*]: It's hard to say with any certainty, because once you get really close to the Big Bang, time will have acted very strange from our perceptive, and what might have been a millisecond in one part of the small budding universe might have been a millions of years in another part.
time is not an illusion at all, it is the increase in entropy of the structures of the visible universe, it is a non-conserved state function
So, does time run backward in your freezer, and faster than normal around it?
Sheesh, evil *and* a jerk. -- Jade
They're only 375 light years away.
Maybe the light took the scenic route.
Sheesh, evil *and* a jerk. -- Jade
So do we say that these planets "are" orbiting HIP 11952, or that they "were" orbiting HIP 11952?
Never mind that this star is in our neighborhood, but you make the mistake of thinking of time as a universal (no pun intended) thing. When the light from a distant star hits us, the star does exist, whether the star is billions of light years away or not. It is meaningless to think that the time that the light traveled has passed, because it hasn't. If you were riding the photons from that star, only a moment would have passed for you.
If we were to go backto the faraway star at the speed of light, we would find it 2*distance older.
Yes, it's difficult to wrap one's head around, so we make up the comfortable lie of considering distant stars being older proportionally to the distance light and radio waves travel as seen from a fixed point. But that point doesn't exist. Time is always subjective, as long as the speed of light in vacuum is considered constant.
And if you thought that makes your head hurt, consider that space itself is expanding, so the distance to a far away star is longer than the distance the light has traveled...
Time is an illusion. Lunchtime, doubly so.
The probability is exponential in n, but for two planets, it is polynomial in p. I'd fixated on the second fact and missed the first. Given the context that we'd just changed n rather than p, I agree that 'exponentially' is more appropriate here.
I shall submit myself to the Committee for disciplinary action.
Quattuor res in hoc mundo sanctae sunt: libri, liberi, libertas et liberalitas.
Being stoned doesn't make you more insightful than anyone else. It just makes you stoned.
http://alternatives.rzero.com/
Nothing is "ageless".
How old is time itself?
I don't think that's a well-formed question. It's like asking "how long is distance?".
Sheesh, evil *and* a jerk. -- Jade
another idiom busted
While this discovery is very cool, it may be a very bad sign. One of the most plausible explanations for the Fermi paradox is that intelligent life almost always wipes itself out before it is able to engage in largescale space travel (as so-called Great Filter http://en.wikipedia.org/wiki/Great_filter. One of the other more satisfying explanations is that the sun is one of the first stars to have enough metal to plausibly form planets. That now seems to be less likely. There are other explanations, such as the low metal systems not having enough carbon for life to form and prosper, or that complex life is very rare. However, this discovery potentially removes one of the more plausible possible explanations, and thus makes the possibility of a Great Filter in our future to seem more likely. This is disturbing.
Well said about the capture. It's very interesting to run an N-body gravitational simulation where the initial state is a bunch of things with random masses and velocity vectors. A whole lot of stuff will be ejected as things settle down. Gravitational capture appears to be hard. That's what I learned, to my initial amazement, when I started playing with N-body simulations. I thought the code had bugs. And then I'd input some solar system ephemeris for the planets and a couple other large objects, and voila, it didn't blow up, things were nicely orbiting :)
A successful API design takes a mixture of software design and pedagogy.
Orbital dynamics and mr. Occam must be at odds today. Play with an N-body simulator and see how it goes. I don't think most people can claim any sort of common sense here unless they've been playing with one. It usually doesn't work the way one would expect. For example, one could naively think that gravity, as an attractive force, will cause eventual collapse if you start simulation with a random bunch of bodies having 0 relative velocity. To one's surprise, then, not only there will be no collapse, but a bunch of objects will get permanently ejected from such a system. Getting things cleanly orbiting one another in low-eccentricity orbits can be considered a lucky occurrence as well. That's what I remember from when I was in high school -- that's the first and last time I felt like coding up N-body (it's a pain -- naive algorithms don't work if you've not got a couple centuries to wait for the results), so feel free to correct me if I'm wrong.
A successful API design takes a mixture of software design and pedagogy.
It is difficult for a body not already in orbit around a star to be captured by it unless there is a third body or something else (dust cloud, etc.) nearby to take away some of the kinetic/potential energy involved. If there is no third body then by a conservation of energy argument -- the small body falls toward the star, faster as it gets closer then slingshots around and back into interstellar space. Even if there are "third bodies" around it is just as likely they will transfer energy to the interstellar visitor and send it out with more speed than it came in with. Similar thing happens with the solar system comets -- they are technically in orbit around the sun way, way out there but occasionally one gets perturbed and comes in close -- unless it gets further perturbed by a planet it will fly a practically parabolic trajectory and go right back out to the far edges of the solar system.
http://en.wikipedia.org/wiki/Shape_of_the_universe :
The Wilkinson Microwave Anisotropy Probe (WMAP) has confirmed that the universe is flat with only a 0.5% margin of error.[1] Within the Friedmann-Lemaître-Robertson-Walker (FLRW) model, the presently most popular shape of the Universe found to fit observational data according to cosmologists is the infinite flat model,[2] while other FLRW models that fit the data include the Poincaré dodecahedral space[3][4] and the Picard horn.[5]
We can test for changing fundamental constant. IIRC, we have observed the decay of a shortlived (in the order of days) isotope in a distant supernova. We have confirmed that the half-life is the same as is observed now. Half-lifes are quite complex, being affected by most of the fundamental constants. Either the constants are nearly unchanged since these supernova exploded, or they have changed in a way to exactly cancel out the effects of each of them on the half-life. Furthermore, the Okla natural nuclear reactor has a distribution of daughter nuclei we would expect to find today. Again, either the fundamental constants are unchanged, or their change is fine-tuned to give the correct answer. Applying Occams razor, the fine-tuning explanation is out until we find evidence that supports it and not the unchanging natural constants hypothesis.
Probably a red dwarf. They can fuse hydrogen for ages ... many billions of years. If I recall correctly the luminosity, and hence the lifetime, of a star is proportional to roughly M^3.5 (M is mass) so small mass stars will glow with much greater reduced luminosity and correspondingly much greater lifetime. Just so long as it is hot and dense enough in the core to keep fusion ticking over. This is pretty cool, wonder where the metals came for the planets to form? Is it a freak that picked up stuff from a nearby supernova during formation or what? Wonder if any life arose in that system, would have had a long time to advance by now. Just thinking.
Bitter and proud of it.
I always tell them "life without you is like a broken pencil!". If she's a Blackadder Fan she will understand :)
no, the refrigerator does work moving heat to the outside in time with some of that energy thereafter unavailable to do work, increasing the overall entropy of the universe even though causing a local decrease of entropy inside
And that folks, is the definition of a refrigerator here on Slashdot! Still wonder why you don't have any gfs? Seriously though, this is why I love /.
No. Pointless.