Spinning Stars Help Scientists ‘Weigh’ Our Sun’s Planets

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Spinning Stars Help Scientists ‘Weigh’ Our Sun’s Planets

A new method for “weighing” the planets in our solar system – one that relies on the radio signals delivered from highly magnetized spinning stars – has been developed by an international research team.

Observations of a set of four of these peculiar spinning stars, called pulsars, were used to calculate the masses of Mercury, Venus, Mars, Jupiter and Saturn, including — for the first time — their moons or rings.

The researchers reported that the masses calculated using pulsar data were consistent with the most-accurate previous measurements.

Previously, astronomers determined a planet’s mass by relying on the readings of spacecraft that zoomed past — such measurements are still considered the most accurate — or by measuring the orbits of the planet’s moons. Both the size of the orbit and the length of time needed to complete one are indicators of how massive a planet is, since orbits are determined by gravitational pull, and that pull is largely a product of the planet’s mass.

In the future, the researchers said, combining pulsar timing with existing data sets will lead to even greater precision.

“This is first time anyone has weighed entire planetary systems – planets with their moons and rings,” said research team leader David Champion of the Max Planck Institute for Radio Astronomy in Bonn, Germany. “In addition, we can provide an independent check on previous results, which is great for planetary science.”

The new technique is quite precise — sensitive to about 0.003 percent of Earth’s mass, and a tenth of a millionth of Jupiter’s mass. [Gallery: Planets of the Solar System] Read more at www.space.com

 

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