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New Object Found at Edge of Solar System
Rei writes to tell us NewScientist is reporting that a new object has been found beyond Pluto. The new object, nicknamed "Buffy", has an almost circular orbit which is tilted some 47 degrees off of most other bodies in our solar system. From the article: "Neptune has been blamed for scattering many other [Kuiper Belt Objects] into tilted paths. But these tend to show other signs of a past interaction with the giant planet, such as moving in elliptical paths and having one part of their orbit pass near Neptune's at 30 astronomical units from the Sun. [Buffy], however, follows a nearly circular path. And it is too distant to have come into direct contact with Neptune, traveling between 52 and 62 AU from the Sun. Its orbit is also too circular - and too small - to have been tilted by a passing star."
Just to point out that while few if any of these nicknames are going to stick once the IAU has a whack at it, we now have:
:)
Xena (and moon Gabrielle)
Easterbunny
Santa (and moon Rudolph, plus one unnamed)
Buffy
Am I missing any of the new wacky-named bodies?
Man on crucifix terrorizes church, demands they eat his flesh and blood. Details at 11.
Have you not read about New Horizons?
Man on crucifix terrorizes church, demands they eat his flesh and blood. Details at 11.
Thor is from Norse mythology.
I do not know why you think that twin stars mean they are remarkably identical. There are, in fact, many examples that we know of where a star and neutron star orbit eachother, or a star and a black hole, or a neutron star and a black hole. These all came from a star orbiting star scenario and the two were not remarkably identical. Secondly it is still possible that the sun has a twin that it orbits which we have not properly characterized. A brown dwarf would be a reasonable example of a possible twin. It does not put out much light and we might have thought it was further away than it actually is or it has yet to be seen.
While we would all like it if we could tell exactly how far away things are to within a high degree of accuracy it is simply not the case for all objects we see in the sky.
I know you're no doubt being facetious, but on the off chance you're not, they'll probably use some other names from the Greek or Roman pantheon, just to keep things consistent, while the "official name" will be something exciting like "Planetoid # 459204765.9"
This sig has absolutely no significance and serves only to take up screen space and waste the time of the reader.
Then I hate to break this to you, but the oort cloud, which is part of our solar system, is between 50,000 and 100,000 Astronomical Units away:
http://en.wikipedia.org/wiki/Oort_cloud
I don't get it.
1) Stars do disappear, in fact all low mass stars, stars with a solar mass of less than 8, will disappear eventually. It just so happens that it takes an inordinate amount of time for them to do so, on the order of 50 billion years for stars with a post supergiant solar mass of less than 1.4. (See Chandrasekhar Limit for more information.) Such stars would have long since stopped burning hydrogen and helium, the only two elements such stars would be able to use as an intenral energy source. Additionally, such stars are known as white dwarves (WD). Since they no longer have internal energy sources, and because there is not enough gravitational potential energy to overcome electron degeneracy pressure, these proverbial hot bricks will simply radiate thermal energy until they reach the ambient temperature of space, about three degrees kelvin. (That is to say nothing of black holes, which become singularities, which will also eventually disappear. However that's much more difficult to explain than WD.)
2) Only stars with a solar mass of greater than 8 will burn elements like carbon, silicon and oxygen, all the way down the nuclear potential energy well until it reaches iron, which is, at least from a nuclear standpoint, inert. Stars of less mass do not have enough gravitation potential energy to burn fuse carbon, which takes a temperature of approximately 500 million K to fuse.
3) Binary stars are not remarkably identical. In fact, if I recall correctly, all binary systems must have in common to be classified as binary are a gravitational proximity. Roughly fifty percent of stars are binary or multiple star systems.
4) Circular orbits are not impossible, they are just unlikely given the way gravity works. A circle is just an ellipse with an eccentricity equal to zero or, in otherwords, an elipse with a single focal point. In fact, there are many objects in circular orbit around the earth:
"The circular orbit is a special case since orbits are generally ellipses, or hyperbolas in the case of objects which are merely deflected by the planet's gravity but not captured. Setting the gravity force from the univeral law of gravity equal to the required centripetal force yields the description of the orbit. The orbit can be expressed in terms of the acceleration of gravity at the orbit. (1)
Obviously that's Rupert they're talking about. It's been Rupert since 1992. See Mostly Harmless for details.
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More than ten by now. Hundreds of Kuiper belt objects are known. The ones that make the news are ones that are interesting for some reason: larger than usual (Quaoar, Sedna, Xena/Gabrielle 2003 UB313, etc.) or in unusual orbits (this one).
A brown dwarf companion of the sun would probably have been discovered by now. The closest known brown dwarves are Epsilon Indi Ba and Epsilon Indi Bb, located 11.8 light years (3.63 parsecs) away. While they have very low visual luminosities (I haven't seen any published figures), they are relatively bright in the infrared (11.9 in the J band). Now, let's say a conjectured companion of the sun is 10,000 AU away. That's 0.05 parsecs, or 72.6 times closer than the Epsilon Indi brown dwarves. Since brightness is proportional to the square of the distance, that makes it 5271 times brighter or about 9.3 magnitudes brighter, giving a magnitude of 2.6 in the J band. There just aren't that many stars that bright in the infrared. It would have been noticed by now by the 2 Micron All-Sky Survey.
Similarly, nearby stars are usually discovered by proper motion surveys since nearby stars will appear to move faster against the background than far stars. Any companions of the sun would have been noticed. So there, in a nutshell, is a nail in the coffin of the Nemesis theory.
I dunno about the average Slahxpert (say it out loud, it has a nice Futurama ring to it hehe) or "scientific media whore" but I'd define the edge of the solar system to be the heliosphere.
o yager_agu.html so I guess I'm wrong... at least on Slashdot ;)
NASA seems to agree http://www.nasa.gov/vision/universe/solarsystem/v
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Actually, they've discovered several hundred objects beyond the orbit of Neptune. They're called Kuiper Belt objects. The ones that get the press are big ones, oddly shaped ones, or in this case, ones with weird orbits.
http://en.wikipedia.org/wiki/Kuiper_belt
If the orbits are correct then you can hide the companion from our view. Very unlikily but stranger things are seen in the galaxy.
No, you really can't. You see, everything in the universe that's made of matter has its own gravity, and this gravity tends to affect things in its vicinity. In fact, it could be said that everything in the universe affects everything else; luckily, most of these interactions are so tiny that they can be safely thrown out of the equations and the margin of error is on an order of magnitude so small that even an angel would have to pick up his robes and tread carefully to dance on it.
In a closer vicinity, such as the solar system, things affect each other with real-world measureable results. Distant suns wobble distinctly when they have planets orbiting them. The Earth's orbit is changed slightly by the presence of the other planets, and the planets' motions are changed slightly by the presence of ours, all in ways that people can predict, if they put enough variables in their equations (for the mathematically inclined: the orbit is no longer a single conic section at that point-- it becomes a very complex set of joined conic sections). If another sun, or even a planet, existed in our same orbit on the other side of the sun (actually in the L3 libration point, which is the only place it could orbit the sun and not allow us to see it, ever) we might not be able to directly observe it from Earth, but we would certainly be able to notice the effect it has on the other planets in the solar system. Jupiter would wobble just the wrong way, and Mars would not be quite where we thought it would be after factoring in the gravity of every known object in the solar system.
Come to think of it, perhaps the Mars Polar Lander was expecting the ground to be a few kilometers farther away than it really was...
But I digress. My point is that a mathematically closed two-body orbital system is a pipe dream. There is no such thing as a closed system in the universe when it comes to orbits, and we have become quite good at predicting the presence of objects just by watching how they affect the orbits of known objects.
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It would be possible (not likely, but possible) for a star to have formed in a position and at a time such that Alpha Centauri prevented it from building to the same mass as the sun. Nothing impossible about that.
Furthermore, several of the known star nursaries that are known are being fed by a massive blast of hydrogen and radiation from a violently dying star. It is probable that some (or all) of these stars will be ripped to shreds, as the forces are simply too great. Again, it is unlikely but not totally impossible the star nursary from which Sol and Alpha Centauri emerged was fed by such a destructive force and that not all of the stars that emerged survived.
There are other oddities - a star was recently seen catapulted from the central core of the galaxy, for example. Stars sometimes steal planets (or even companion stars) from other systems. There are "rogue" supermassive gas giant planets that have left their solar system of origin and are wandering - the sun is big, but it probably wouldn't take kindly to a planet a hundred times the mass of Jupiter doing a belly-flop into it at many times the escape velocity of the solar system.
In short, there's plenty of ways to destroy or otherwise dispose of a star of a paltry one solar mass. Do I think it happened? No. I don't believe Sol ever had a companion star, unless it was Alpha Centauri, but even there, there's a lot of surrounding rock around Alpha Centauri - too much, IMHO, for it to have been a companion to Sol.
Do I think the orbits of the planets are strange? Yes - doubly so because they mostly fit predicted models that are largely based on Keplar's motions modified for Einstein's relativistic laws. Three-body problems are bloody hard, chaotic systems. In our solar system, you really have to solve a four-body or even five-body problem to get useful results for a single planet over any decent timeframe. If you want to model over a five billion year timeframe - necessary to understand how the system reached its current state, you really want to solve a fourteen-body or fifteen-body problem, where not all of those bodies still exist and so we cannot know their mass, initial position or initial velocity.
Short of possibly one of the top 5 supercomputers, I do not believe that there is a computer out there capable of a fifteen-body relativistic simulation with enough granularity to prevent the chaotic variables swamping the results over a five billion year simulation. In consequence, I do not believe that any theory - however "proper" - is meaningful at this point. The quality of the computer models isn't there.
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