In the News: A New Way to Weigh Planets

[CraigS]

In the news today ...

"An international CSIRO-led team of astronomers has developed a new way to weigh the planets in our Solar System - using radio signals from the small spinning stars called pulsars."

http://www.physorg.com/news201881579.html

..."astronomers calculate when the pulses would have arrived at the Solar System’s centre of mass, or barycentre, around which all the planets orbit."

By using the difference between the actual measurements and the calculated value, they correct the values of the Solar System's planets' masses and the discrepancy goes away.

What is this leading to ? They need the planet mass value to be more accurate in order to detect gravitational waves predicted by General Relativity.

Interesting ...

Cheers

[renormalised (Carl)]

Good way of measuring mass....it's a wonder they didn't come up with this idea earlier on. Given how precise pulsar timings are, they should get very accurate measurements.

[CraigS]

Seems to be a collaborative, International effort. That probably just never happened before on this topic (?)

Also, the measurement method has some pretty ground-breaking precision:

"The new measurement technique is sensitive to a mass difference of two hundred thousand million million tonnes - just 0.003 per cent of the mass of the Earth, and one ten-millionth of Jupiter’s mass."

Cheers

[renormalised (Carl)]

That still might not be enough sensitivity to be able to predict gravitational waves. Who knows....just have to wait until they do all the experiments.