Philosophy
September 17th, 2012
SPACEDAILY
Astronomers meeting in Beijing say they've agreed on a new definition of the fundamental unit of distance between objects in the solar system.
The "astronomical unit," defined as the distance between the sun and the Earth, is now set at exactly 149,597,870,700 meters (163,602,220,800.53 yards or 92,955,807.27 miles), the meeting of the International Astronomical Union declared.
That's 9 meters, or about 30 feet, more than the previously agreed distance, which was based on the average distance between Earth and the sun and was also tied to the mass of the sun.
But the sun is constantly losing mass as it radiates energy, which technically changes the value of the AU over time, astronomers said.
"The old definition was good when we were not able to measure distance precisely in the solar system," Sergei Klioner of the Technical University of Dresden, Germany, who has been calling for the change since 2005, told NewScientist.com.
But scientists can now make precise measurements of astronomical distances using lasers and space probes.
"I've been teaching celestial mechanics for 20 years and it was always a pain to explain the old definition," Klioner said. "It was clear that it was unnecessarily complicated."
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It has been rather quiet on the "Pluto/planet" debate and the role and significance of the The International Astronomical Union [IAU]. As readers may know that there is one Ms. Laurel Kornfeld who is an ardent supporter of Pluto's status as a planet...
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- Pluto's Day
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Philosophy
IAU made a change to the "Astronomical Unit"...now 149,597,870,700 meters
"Basic solar system measure redefined"
September 17th, 2012
SPACEDAILY
Astronomers meeting in Beijing say they've agreed on a new definition of the fundamental unit of distance between objects in the solar system.
The "astronomical unit," defined as the distance between the sun and the Earth, is now set at exactly 149,597,870,700 meters (163,602,220,800.53 yards or 92,955,807.27 miles), the meeting of the International Astronomical Union declared.
That's 9 meters, or about 30 feet, more than the previously agreed distance, which was based on the average distance between Earth and the sun and was also tied to the mass of the sun.
But the sun is constantly losing mass as it radiates energy, which technically changes the value of the AU over time, astronomers said.
"The old definition was good when we were not able to measure distance precisely in the solar system," Sergei Klioner of the Technical University of Dresden, Germany, who has been calling for the change since 2005, told NewScientist.com.
But scientists can now make precise measurements of astronomical distances using lasers and space probes.
"I've been teaching celestial mechanics for 20 years and it was always a pain to explain the old definition," Klioner said. "It was clear that it was unnecessarily complicated."
- A Fuzzy Charon Visible
Scientific American's Christopher Crockett wrote... NASA’s New Horizons spacecraft, now en route to Pluto, got its first glimpse of the dwarf planet’s largest moon, Charon, in this image released July 10. Pluto is the bright spot in the center...
- The International Astronomical Union
It has been rather quiet on the "Pluto/planet" debate and the role and significance of the The International Astronomical Union [IAU]. As readers may know that there is one Ms. Laurel Kornfeld who is an ardent supporter of Pluto's status as a planet...
- Alas Poor Pluto, I Knew Him Well
"Poor Pluto: Number Of Dwarf Planets Increases" April 26th, 2010 SPACE DAILY New research from the Australian National University has further reduced the status of Pluto by suggesting there are many more dwarf planets in the Solar System than previously...
- Pluto's Day
Not the pup but the planet[?] Pluto popped into the planet ensemble on March 13th. "Happy Pluto Discovery Day" by Doug Cornelius March 10th, 2010 Wired The discovery of Pluto was announced on March 13. Pluto was labeled a planet when it was first...
- Pluto="plutoid"
Pluto Does this satisfy everyone now? ""Plutoids": the new name for Pluto-like dwarf planets" by Jon Cartwright June 12th, 2008 physicsworld.com Pluto sub-classification The International Astronomical Union (IAU) has decided that Pluto — and other...