I'm surprised that nobody has mentioned this yet. Its kinda... uh... big, for Astronomy nuts like me anyways.
Pluto gets the boot
Yeah, this is news from a few weeks ago, but since it was virtually ignored around here I think its worth mentioning.
Pluto is no longer a planet. And its about freakin' time. For ages now I've been on the side arguing against its planetary-hood, so while I do feel a bit sad to be saying farewell to our 9th planet I'm also happy that they finally re-defined the definition of what makes a planet "a planet".
And here it is:
Pluto didn't make the grade, and neither would Ceres now or the controversial UB313, aka. "Xena".
But Pluto isn't just being tossed away to the abyss. A brand new class for celestial bodies has been created called "dwarf planets". As quoted from an article on the International Astronomical Union (IAU) website:
According to wikipedia, the defintion of a dwarf planet is a celestial body that "(a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape. (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite."
Also not to be ignored is that a second new category was created to define certain objects that can not be classed as planets or dwarf planets: "All other objects orbiting the Sun shall be referred to collectively as "Small Solar System Bodies" ... These currently include most of the Solar System asteroids, most Trans-Neptunian Objects (TNOs), comets, and other small bodies."
I personally find all of this really cool. Text books world 'round need to be changed, astronomy courses will need to be tweaked, and it'll lead to even more interesting debates. But best of all... Teachers will need to start teaching their students new rhymes to remember all the planets
Pluto gets the boot
Yeah, this is news from a few weeks ago, but since it was virtually ignored around here I think its worth mentioning.
Pluto is no longer a planet. And its about freakin' time. For ages now I've been on the side arguing against its planetary-hood, so while I do feel a bit sad to be saying farewell to our 9th planet I'm also happy that they finally re-defined the definition of what makes a planet "a planet".
And here it is:
"a celestial body that is in orbit around the sun, has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a ... nearly round shape, and has cleared the neighborhood around its orbit."
Pluto didn't make the grade, and neither would Ceres now or the controversial UB313, aka. "Xena".
But Pluto isn't just being tossed away to the abyss. A brand new class for celestial bodies has been created called "dwarf planets". As quoted from an article on the International Astronomical Union (IAU) website:
It was agreed that "planets" and "dwarf planets" are two distinct classes of objects. The first members of the "dwarf planet" category are Ceres, Pluto and 2003 UB313 (temporary name). More "dwarf planets" are expected to be announced by the IAU in the coming months and years. Currently a dozen candidate "dwarf planets" are listed on IAU's "dwarf planet" watchlist, which keeps changing as new objects are found and the physics of the existing candidates becomes better known.
According to wikipedia, the defintion of a dwarf planet is a celestial body that "(a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape. (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite."
Also not to be ignored is that a second new category was created to define certain objects that can not be classed as planets or dwarf planets: "All other objects orbiting the Sun shall be referred to collectively as "Small Solar System Bodies" ... These currently include most of the Solar System asteroids, most Trans-Neptunian Objects (TNOs), comets, and other small bodies."
I personally find all of this really cool. Text books world 'round need to be changed, astronomy courses will need to be tweaked, and it'll lead to even more interesting debates. But best of all... Teachers will need to start teaching their students new rhymes to remember all the planets