Thursday, August 24, 2006
Pluto demoted!
Leading astronomers declared today that Pluto is no longer a planet under historic new guidelines that downsize the solar system from nine planets to eight.
After a tumultuous week of clashing over the essence of the cosmos, the International Astronomical Union stripped Pluto of the planetary status it has held since its discovery in 1930. The new definition of what is - and isn't - a planet fills a centuries-old black hole for scientists who have labored since Copernicus without one.
After a tumultuous week of clashing over the essence of the cosmos, the International Astronomical Union stripped Pluto of the planetary status it has held since its discovery in 1930. The new definition of what is - and isn't - a planet fills a centuries-old black hole for scientists who have labored since Copernicus without one.
Thursday, August 17, 2006
Atomic force weaker than thought
A fundamental force that holds electrons inside atoms and governs how charged particles and light interact is a little weaker than previously thought, scientists reported yesterday.
The strength of electromagnetic force, one of the four fundamental forces of nature, is specified through a value known as the fine structure constant. Through studying an individual electron in isolation, scientists were able to calculate a new value for this number that is six times more precise than previous estimates.
"Little did we know that the binding energies of all the atoms in the universe were smaller by a millionth of a percent — a lot of energy given the huge number of atoms in the universe," said Gerald Gabrielse, a researcher at Harvard University.
Gabrielse and his colleagues developed a giant atom by isolating an electron in a bottle devoid of almost all particles and chilled to temperatures colder than the surface of Pluto.
Similar to a real atom, they kept the lone electron in circular motion through electric and magnetic forces. The electron also wobbled down in the direction of the magnetic field, a setup similar to a merry-go-round, with an electromagnetic trap as the carousel and the electron as the lone horse.
The setup was sensitive enough to sense when the electron is moving upwards and when the motion is restricted, allowing the electron's energy to be precisely measured. This helped refine measurements of the fine structure constant.
The strength of electromagnetic force, one of the four fundamental forces of nature, is specified through a value known as the fine structure constant. Through studying an individual electron in isolation, scientists were able to calculate a new value for this number that is six times more precise than previous estimates.
"Little did we know that the binding energies of all the atoms in the universe were smaller by a millionth of a percent — a lot of energy given the huge number of atoms in the universe," said Gerald Gabrielse, a researcher at Harvard University.
Gabrielse and his colleagues developed a giant atom by isolating an electron in a bottle devoid of almost all particles and chilled to temperatures colder than the surface of Pluto.
Similar to a real atom, they kept the lone electron in circular motion through electric and magnetic forces. The electron also wobbled down in the direction of the magnetic field, a setup similar to a merry-go-round, with an electromagnetic trap as the carousel and the electron as the lone horse.
The setup was sensitive enough to sense when the electron is moving upwards and when the motion is restricted, allowing the electron's energy to be precisely measured. This helped refine measurements of the fine structure constant.
