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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.
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"
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.
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.