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Pluto's 3 Moons and a Probe to Study Them
It doesn't come easy writes "For those of you keeping score, Pluto now officially has three moons, with more possibly to follow. The newfound moons orbit about 27,000 miles (44,000 kilometers) from Pluto, more than twice as far as Charon, Pluto's other satellite. They are 5,000 times dimmer than Charon. The moons were found using the Hubble Space Telescope. For now, Pluto is the only Kuiper Belt object known to have satellites. Some nice images of Pluto and its moons are included in links. Enjoy!" Relatedly IZ Reloaded writes "NASA says the Atlas 5 rocket that will carry the New Horizons Pluto probe has suffered slight damage thanks to Hurricane Wilma. New Scientist reports: "The Atlas 5 rocket stands within a construction hangar at Cape Canaveral Air Force Station on Florida's east coast. As Wilma rolled though the region on 24 October, fierce 122-kilometer-per-hour winds tore holes in the hangar's 83-meter-tall door and caused minor damage to the rocket inside.""
Now that Pluto's been confirmed to have more than one moon, what will than mean for the old debate over whether Pluto or Charon's the actual planet? Ought to be fun to watch...
Creative misinterpretation is your friend.
There will be no moon probing while I'm around!
So not official. RTFA. That's no moon....that's a canditate.
Nice? The photographs are a bunch of small white dots! Does anyone else see real photographs? I guess he is referring to the "artistic conceptual drawings"
For now, Pluto is the only Kuiper Belt object known to have satellites.
My good friend UB313 would have to disagree.
There are actually several known KBOs with moons. Or was the submitter being overly litteral and meant multiple moons?
Unlike what the poster said, Pluto is not the only one with a moon.. html
Various other KBOs do, including Xena :
http://www.planetary.org/news/2005/xena_moon_1003
I hope we have our XK-PLUTO nuclear-powered bombers ready for the Old Ones. Me? I'm going to take a little trip to XK-Masada.
Pluto now officially has three moons
More like "four big asteroids are gravitating around each other beyond the orbit of Neptune".
"A door is what a dog is perpetually on the wrong side of" - Ogden Nash
Does that mean we can call them "Cerebus" collectively?
"In the game of life, someone always has to lose. To me, if life were fair, that someone would always be Oklahoma." -DKR
Okay then: "two big asteroids are known to be orbiting around each other beyond Neptune, but two more are presumed to have joined the party, which incidentally pisses Neptune off to high heavens".
"A door is what a dog is perpetually on the wrong side of" - Ogden Nash
Is it really a big deal when we name something a moon? Its just a matter of relativity. A planet, a moon, an asteroid, a rock... they're all the same thing, that varies by degrees. I suppose the things orbital path is of interest, but how much can we really learn just by applying labels? We didn't learn anything about the true scientific nature of those bodies, we just named them. I think I'll name them Susanna, Melinda and Jim.
-Da3vid-
Dubya: we need to kill Hubble. We have more, erhm.., pressing needs for money
Hubble astronomers: No wait! We found another Pluto moon !
NASA: come on, we can't kill the thing, it's useful
Dubya: hmm, I dunno...
Astronomers: Wait! wait! anOTHER moon!!
NASA: Wow
Dubya: stop that...
Astronomers: Hold on... HOLY CRAP, TEN MORE MOONS! and a black hole inside Jupiter too!!!
Dubya: We're closing guys, you need to go home now...
Astronomers: NO REALLY! LOOK! ALL THESE MOONS!!!
"A door is what a dog is perpetually on the wrong side of" - Ogden Nash
You are way out of the ballpark, I'm afraid. These two new moon are larger than Phobos (diameter approx. 22Km) and Deimos (diameter approx. 12Km). The Earth (and its moon) Mars, Venus, Mercury, the Galilean Moons and Titan are thousands of kilometers across, but everything else is much smaller. Ceres (the largest asteriod) is only 914Km across.
has really caused us a lot of grief in classifying heavenly bodies and discovering them. Not only does it interfere with scientific terminology, it hampers understanding of average people. We should just kick Pluto out and accept that we have 8 planets, not 9. Everyone would be happier (except Pluto).
Even if you rolled all the rockets we have ever launched, and all the fuel we packed into them, I doubt it they would form a sphere even a single kilometer in diameter.
A Saturn V was about 20 meters in diameter, and about 100 meters tall, more or less. Volume of a cylinder is pi r^2 * length. That would make the volume of a Saturn V about pi * 2500 meters^3.
The volume of a sphere is 3/4 * pi r^3. The volume of a sphere one kilometer in diameter would be pi * 93,750,000 meters^3. That would be volumne of something like the prelaunch volume of 37,000 Saturn Vs. The payload of a rocket is a fraction of the mass of the entire thing. Let's say 1%. Most rockets are much smaller than a Saturn V. Payloads launched into low earth orbits decay within decades, like Mir, or Spacelab.
It wouldn't surprise me if the volume of all the working satellites, and space detritus, that remain in orbit would be less than the prelaunch volume of a single Saturn V.
Would this help us any? Probably, yes. Because planets are of mixed composition, they must have formed in the very early accretion disc from the sun. Because asteroids and comets are relatively uniform, they must have formed AFTER centrifugal forces had separated out the elements - lighter elements to the outside (which is why comets contain a lot of hydrogen) and heavier elements towards the center (asteroids are based on iron and nickel, depending on location).
The label, by this scheme, would then indicate composition, structure and time of formation, as these three properties are inter-related. On the other hand, we can go by mass or diameter and learn relatively little - which I suspect is the way the IAU will go, because that's something astronomers can measure easily. Easy != (interesing || useful). In this case, easy is pretty useless and will be subject to future argument.
I'm sure there are better methods of classifying, but I firmly believe the only useful method of classification is one that will allow predictions to be made and tested. The periodic table of the elements, for example, as a way of depicting valence theory is exceptionally useful. You can make useful predictions about groups of elements or even individual elements, based on the position in the table. Astronomical classifications should be no less useful and (given that we've far more powerful ways of obtaining, classifying and representing data today than early chemists) really should be a far MORE (Moore?) powerful tool.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
How does the moon's distinct lack of heavier elements fall in line with the moon being created at the same time?
Well, there are usually two aspects to the impact ejection theory. The idea is that the earth was struck and:
1) ejected dust that formed the moon and
2) knocked the earth's axis so that it we have the tilt that generates the seasons.
Now, there are two issues that I have with this theory:
First, it presumes that the earth's equator was very close to the ecliptic. This is not something I can take for granted given that the tilts of other axes are:
Neptune: 30 degrees
Uranus: 98 degrees
Saturn: 25 degrees
Jupiter: 3.1 degrees
Mars: 25.2 degrees
Venus: 177.36 degrees
Mercury: 0 degrees
Of the eight major plants, axis tilts are sufficiently low to allow for this sort of idea only on Jupiter and Mercury. It seems unreasonale to me to think that planets such as Saturn were somehow knocked off axis by impacts. Also Venus has no moon and it seems unreasonable to indicate that it was knocked off its axis. Instead the axis of rotation seems to have been decided on a local variation.
Even if one imagines that the earth had a very low axis tilt originally, the ability to simultaniously eject enough dust to cause the moon to form witnin six degrees of the ecliptic seems a bit of a stretch to me, especially since such an impack would *also* have had to occur nearly exactly on the equator and still managed knock the earth off its axis.
The reason why these objections have generally been disregarded by the astronomical community is a theory which posits that a type of asteroid called "carbonaceous chondrites" formed the original planetessimals from which all rocky planets originated. While mercury never fit this model, it was generally assumed that these formed the basis for Venus, the Earth, Mars, etc. It was therefore believed that one would be able to form models of the interior structure of Mars consistant with the projections of this theory. As the moon clearly didn't fit, the impact theory nicely solved this problem.
However, it now appears that the idea that carbonaceous chondrites form the basic building block from which rocky planets were formed has now had some very large holes torn in it in that no model which fits the existing data on Mars can support this theory of the formation of Mars. Absent this theory, I can think of no good reason to subscribe to impact-emission theory of lunar origins, as it seems simpler to think that the moon may have formed as a smaller dustball forming from lighter particles which ended up further from the early earth in the same way that the structure of the gas giant systems (the outer planets and their moons) mirrors structurally the Sun and inner planets.
I could be wrong as I have no astronomy degree, but at least it is informed inaccuracy....
LedgerSMB: Open source Accounting/ERP
The best thing Earth has after Luna in terms of a moon is probably Cruithne, and that doesn't even count as a satellite anyway.
1) The impactor, known alternately as Orpheus or Theia, has been modeled to have been about the size of Mars, and to have hit Earth at a very oblique angle. 2) The absolute best evidence we have for the theory is that the moon has essentially no iron core. All the other terrestrial planets do. As it turns out, the comosition of the moon is remarkably similar to that of Earth's mantle (oxygen/silicon). It is theorized that most of Theia's core merged with our own. Earth's mean density is, if I recall, something on the order of 5500 kg/m^3. The moon has a mean density of something like 3300 kg/m^3. If you were to take out the Earth's iron/nickle core and replace it with mantle material, it would have a mean density similar to that of the moon. 3) As an astronomy minor and having taken planetary formation courses, I've never heard anything about carbonaceous chondrite cores forming the basic building blocks of planets. Carbon, counterintuitively, isn't even too abundant on Earth. Or anywhere else for that matter. Or rather, there certainly is a lot of it, but not compared to oxygen, silicon, iron, aluminum, etc. 4) You can't compare the models of planetary formation in the inner solar system to the outer. Not on a 1:1 basis. The outer planets are significantly larger than the inner because they formed past the frost line (about halfway through the asteroid belt). After this line, ice stays in crystalline form, allowing the rocky starts of the other planets to aggregate much more mass, both planetary and gaseous (the rocky core of Jupiter, at least, is probably about 20 times the size of Earth). With this much more mass, they can more easily capture smaller planetismals, which become moons. It would be far, far easier for a Jupiter to capture Luna than for Earth. 5) As alluded to in the beignning of this post, computer simulations have been done on both the capture and impact theories (including many variations of). The impact theory works. The capture does not. 6) That we have plate tectonics, significant ocean basins, etc, could also be construed as evidence for the giant impact theory. Venus has no moons, and there is little evidence that it ever underwent plate tectonics. The same goes for Mars, and I assume Mercury, though I am not sure on the latter. But the most important thing here is #2. That's the smoking gun.