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Astronomers from Australia, Germany, the United Kingdom, Canada, and the United States have come up with a new way to weigh the planets in our solar system, using radio signals from pulsars.

Measurements of planet masses made this new way could feed into data needed for future space missions. Until now, astronomers have weighed planets by measuring the orbits of their moons or of spacecraft flying past them, but this new method is based on corrections astronomers make to signals from pulsars — small spinning stars that deliver regular "blips" of radio waves.

Data from a set of four pulsars have already been used to weigh Mercury, Venus, Mars, Jupiter, and Saturn with their moons and rings. The masses were consistent with those measured by spacecraft. The mass of the Jovian system, 0.0009547921(2) times the mass of the Sun, is significantly more accurate than the mass determined from the Pioneer and Voyager spacecraft, and consistent with, but less accurate than, the value from the Galileo spacecraft.

"In the short term, spacecraft will continue to make the most accurate measurements for individual planets, but the pulsar technique will be the best for planets not being visited by spacecraft, and for measuring the combined masses of planets and their moons," said George Hobbs from the Commonwealth Scientific and Industrial Research Organization (CSIRO).”

To read the full news story please visit the Astronomy website.