[cosmos] how many planets are there in our solar system
8, 9, 10, 11, 12 or 53?
According to Hubble:
Our solar system officially has nine planets and one star: the Sun. In order from the Sun out, the planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto. The discovery of an object larger than Pluto in 2005 rekindled the debate over whether such objects, belonging to the "Kuiper Belt" - a collection of icy bodies located beyond Neptune-- should be called planets. Pluto itself belongs to the Kuiper Belt.
On Sunday, July 31st, 2005, CNN’s Sara Weisfeldt and Kate Tobin ran an item which questioned the 9:
Astronomers announced Friday that an object they discovered is large enough to be the 10th planet - 96 times as far from the Earth as the Earth is from the sun, or nearly 9 billion miles away and first photographed in October 2003 by astronomers at the California Institute of Technology's Palomar Observatory, north of San Diego.
"If Pluto is a planet, it seems reasonable that something that's bigger than Pluto, and further away than Pluto, should be called a planet, too," said Mike Brown, a Cal Tech planetary scientist.
However, a number of astronomers dispute whether Pluto, discovered in 1930, should really be classified as a planet, because it is so dissimilar from the other eight. Instead, they believe it should be classified only as a Kuiper Belt object, part of an array of icy debris in the outer reaches of the solar system.
Thousands of Kuiper objects have been discovered, and more are being found all the time. Brown concedes that both Pluto and his new planet are Kuiper objects - but argues they are also both big enough to be classified as planets.
The International Astronomical Union, the official arbiter of such disputes, has classified Pluto as a planet and recently declined to demote it. Brown said resolving the argument over whether the object his team found is a planet will take years.
Brown said:
"All of the planets are in a disc around the sun, and this object is 45 degrees out of that disc."
Today, in the Globe and Mail [Toronto], Tenille Bonoguore says:
After two years of debate, the IAU's official proposal on planets will be put to its convention in Prague today. Pluto is in. So are Charon, an object caught in a continuing dance with Pluto to create what is now considered a “double planet”; the small “dwarf planet” of Ceres that sits between Mars and Jupiter; and the so-called “10th planet,” 2003 UB313, currently nicknamed Xena.
The scientists behind the proposal say they let physics do the talking. If an orbiting object has a gravitational pull strong enough to drag its shape into a rough sphere, then it's powerful enough to be called a planet. But the man who discovered the “10th planet” says the new definition is lengthy, muddled and unscientific, and will only make things more confusing.
Mike Brown says that if the definition is applied equally, 53 round objects are already known to be circling the sun.
Under the IAU proposal, orbiting objects would be divided into two categories: planet (from the Greek word for wanderer) and the newly created pluton.
A planet orbits around a star, but cannot actually be a star, and must be massive enough for its own gravity to pull it into a nearly spherical shape. The new plutons are small planets that have orbits of more than 200 years, meaning they orbit beyond Neptune.
An IAU review committee will make the final decisions on classification. If the new definitions are approved, it means the solar system would consist of Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Uranus, Neptune, Pluto, Charon and 2003 UB313.
How many do you say there are?
Our solar system officially has nine planets and one star: the Sun. In order from the Sun out, the planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto. The discovery of an object larger than Pluto in 2005 rekindled the debate over whether such objects, belonging to the "Kuiper Belt" - a collection of icy bodies located beyond Neptune-- should be called planets. Pluto itself belongs to the Kuiper Belt.
On Sunday, July 31st, 2005, CNN’s Sara Weisfeldt and Kate Tobin ran an item which questioned the 9:
Astronomers announced Friday that an object they discovered is large enough to be the 10th planet - 96 times as far from the Earth as the Earth is from the sun, or nearly 9 billion miles away and first photographed in October 2003 by astronomers at the California Institute of Technology's Palomar Observatory, north of San Diego.
"If Pluto is a planet, it seems reasonable that something that's bigger than Pluto, and further away than Pluto, should be called a planet, too," said Mike Brown, a Cal Tech planetary scientist.
However, a number of astronomers dispute whether Pluto, discovered in 1930, should really be classified as a planet, because it is so dissimilar from the other eight. Instead, they believe it should be classified only as a Kuiper Belt object, part of an array of icy debris in the outer reaches of the solar system.
Thousands of Kuiper objects have been discovered, and more are being found all the time. Brown concedes that both Pluto and his new planet are Kuiper objects - but argues they are also both big enough to be classified as planets.
The International Astronomical Union, the official arbiter of such disputes, has classified Pluto as a planet and recently declined to demote it. Brown said resolving the argument over whether the object his team found is a planet will take years.
Brown said:
"All of the planets are in a disc around the sun, and this object is 45 degrees out of that disc."
Today, in the Globe and Mail [Toronto], Tenille Bonoguore says:
After two years of debate, the IAU's official proposal on planets will be put to its convention in Prague today. Pluto is in. So are Charon, an object caught in a continuing dance with Pluto to create what is now considered a “double planet”; the small “dwarf planet” of Ceres that sits between Mars and Jupiter; and the so-called “10th planet,” 2003 UB313, currently nicknamed Xena.
The scientists behind the proposal say they let physics do the talking. If an orbiting object has a gravitational pull strong enough to drag its shape into a rough sphere, then it's powerful enough to be called a planet. But the man who discovered the “10th planet” says the new definition is lengthy, muddled and unscientific, and will only make things more confusing.
Mike Brown says that if the definition is applied equally, 53 round objects are already known to be circling the sun.
Under the IAU proposal, orbiting objects would be divided into two categories: planet (from the Greek word for wanderer) and the newly created pluton.
A planet orbits around a star, but cannot actually be a star, and must be massive enough for its own gravity to pull it into a nearly spherical shape. The new plutons are small planets that have orbits of more than 200 years, meaning they orbit beyond Neptune.
An IAU review committee will make the final decisions on classification. If the new definitions are approved, it means the solar system would consist of Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Uranus, Neptune, Pluto, Charon and 2003 UB313.
How many do you say there are?
posted by James Higham @ 13:32
<< Home