By Lisa Grossman August 23, 2010 | 6:43 pm | Categories: Space
The rotating corpses of massive stars can help scientists weigh the planets in the solar system. By carefully timing radio blips from spinning stellar leftovers called pulsars, astronomers have measured the masses of all the planets from Mercury to Saturn, plus all their moons and rings.
Until now, the only way to figure out the mass of a planet was to send a spacecraft past it. The spacecraft’s orbit is determined by the gravitational oomph of the planet (plus whatever moons lay within the spacecraft’s orbit), which in turn depends on the planet’s mass. The new method is the first to let astronomers weigh planets from the comfort of Earthbound observatories.
“That’s what’s remarkable about this technique,” said space technologist William Folkner of NASA’s Jet Propulsion Laboratory, a co-author of a study in the upcoming issue of Astrophysical Journal. “I can’t think of any other way to measure masses of planets from the Earth.”
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