Weighing the Planets - from Mercury to Saturn Pulsar timing observations allow a new way to estimate planet masses
An international research team led by David Champion, now at Max Planck Institute for Radio Astronomy in Bonn, with researchers from Australia, Germany, the U.S., UK and Canada has come up with a new way to weigh the planets in our Solar System, using radio signals from pulsars. Data from a set of four pulsars have been used to weigh Mercury, Venus, Mars, Jupiter and Saturn with their moons and rings. The new measurement technique is sensitive to just 0.003% of the mass of the Earth, and one ten-millionth of Jupiter's mass (corresponding to a mass difference of two hundred thousand million million tonnes). The results are described in an article for the "Astrophysical Journal", which is publicly accessible via preprint-server.
Astronomers from Australia, Germany, the UK, Canada and the USA 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 the trajectories of spacecraft flying past them. That's because mass produces gravity, and a planet's gravitational pull determines the orbit of anything that goes around it - both the size of the orbit and how long it takes to complete. The new method is based on adjustments astronomers have to make to signals from pulsars...small spinning stars that deliver regular 'blips' of radio waves. Read more