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NASA Science

Hubble Discovers 5th Moon of Pluto 137

Stirling Newberry writes "This image shows 'P5,' the placeholder name for a fifth natural moon of Pluto, a tiny sliver that orbits ~29,000 miles from its primary in a circular orbit. Other than Charon, Hubble has been the means by which astronomers have found all of the known moons of Pluto. 'The new detection will help scientists navigate NASA’s New Horizons spacecraft through the Pluto system in 2015, when it makes an historic and long-awaited high-speed flyby of the distant world. The team is using Hubble’s powerful vision to scour the Pluto system to uncover potential hazards to the New Horizons spacecraft. Moving past the dwarf planet at a speed of 30,000 miles per hour, New Horizons could be destroyed in a collision with even a BB-shot-size piece of orbital debris.'"
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Hubble Discovers 5th Moon of Pluto

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  • Re:Not a planet (Score:4, Informative)

    by Anonymous Coward on Wednesday July 11, 2012 @03:07PM (#40618305) []

    Lots of asteroids have moons.

  • by MarioMax ( 907837 ) on Wednesday July 11, 2012 @03:13PM (#40618395)

    According to Wikipedia:

    A natural satellite or moon is a celestial body that orbits a planet or smaller body, which is called its primary.

    Technically, Pluto fits the definition of "planet or smaller body". A moon doesn't necessarily need to orbit a planet; it can orbit a very, very dense hunk of rock that doesn't fit the definition of planet, but has a sufficiently strong gravitational pull to keep it in orbit.

  • Re:BB sized debris (Score:4, Informative)

    by jnaujok ( 804613 ) on Wednesday July 11, 2012 @04:00PM (#40619193) Homepage Journal
    Because space is big...

    Imagine there were only 19,000 people on Earth, roughly evenly distributed. What's the chance you'd ever run into another person? Now, instead of just the land area, make sure that 3/4ths of those people are on the ocean. What are the odds of running into one of them now?

    Now, imagine that, instead of just the surface of the Earth, you stack up about 500 layers, each one of them the surface of a sphere wrapping the entire Earth, each one a mile higher than the last and starting about 160 miles up. Now instead of just the surface of the Earth, spread those 19,000 people across those 500 spheres evenly and evenly spread them around the surface of the sphere they're on. And all of those spheres have more area than the surface of the Earth.

    Now, would you consider that area "dangerously heavily populated?" On top of that, you need to shrink the people down for most of the debris.

    Now, to be fair, the real test is that many of these "people" are moving really, really fast, although most of them are moving in roughly the same direction. But a few of them are going in different directions. And some of those are jumping between spheres. But it's still areas larger than the whole surface of the Earth. There have been only a tiny number of collisions between these objects. (I think the number is actually -- one.)

    Like I said, space is big. Really big. Bigger than the biggest thing you can imagine. You may think it's a long way down to the pharmacy, but that's peanuts compared to space. (With apologies to Douglas Adams)
  • by tlhIngan ( 30335 ) <> on Wednesday July 11, 2012 @04:39PM (#40619811)

    Kilobit and kilobyte and Kb (and kb) and KB are correct, and mean 1024 bits (or bytes).
    Kibibit and kibibyte and Kib and (kib) and KiB are incorrect, and mean you're a fucking dipshit.

    FYI,, a 64kbps telecommunications channel is 64,000bits/sec, not 65536bits/sec (it derives from 8kHz (8000, not 8192) sampling at 8 bits/sample). Just like 10/100/1000Mbps Ethernet is 10,000,000, 100,000,000 and 1,000,000,000 bits/sec, respectively.

    Same as your 2.6GHz CPU - it's 2,600,000,000 Hz.

    Not using the right prefix is the same as not using the right units - you're going to screw up something somewhere.

    You're a technical person, use precise language. If there's a chance of confusion, drop the prefix and use scientific notation, or define something across the board so places where the meanings can get messed up, are resolved and be consistent.

    E.g., globally declare in your source code that "Kilo means 1024 throughout" so 1km in your program is 1024m, and if you use 64,000b/s channel, it's a 62.5kbps link.

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