The International Astronomical Union approved new guidelines Thursday that downsize the solar system from nine planets to eight.
The leading astronomers, meeting in Prague, Czech Republic, stripped Pluto of the planetary status it has held since 1930, when it was discovered.
In doing so, the group provided a new definition of what is and what isn't a planet.
Pluto failed to make the new cut because its oblong orbit overlaps with Neptune's. It will now be a founding member of the new class of "dwarf planets."
The guidelines also require planets to have enough mass that they are close to round.
Astronomers have been trying to draw a distinction between the eight "classical planets" -- Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune -- and Pluto, which is smaller than Earth's moon and has an eccentric orbit.
Pluto has a large moon named Charon, and two small moons named Nix and Hydra were discovered in 2005.
In January, NASA sent a probe known as New Horizons on the way to Pluto. It is expected to reach the object in 2015.
2 comments:
ahhhh that's sad...someone should write a good bye pluto song ..
I remember all my life
peering into the sky cold as ice.
Shadows & clouds in the way,
a face through a telescope cryin' in the night,the night goes into
Morning just another day;
looking through my lens.
Looking into the skys,
I see a memory I never realized , how happy you made me.
Oh Pluto well,
you came and you gave without taking,
but I sent you away.
Oh, Pluto well,
you orbited uranus and stopped me from shaking,
and I need you today. Oh, Pluto!
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