Chinese scientists propose using Earth and Jupiter to detect gravitational waves
Scientists say planets in our solar system, such as Earth and Jupiter, could be used to detect gravitational waves and better understand cosmic mysteries – from the very early universe to dark matter.
The researchers from the Institute of High Energy Physics in Beijing and the Hong Kong University of Science and Technology said the magnetospheres of these planets would act like a gigantic observatory.
That is because they would help convert elusive gravitational waves into light particles which could be picked up by specially designed probes in orbit, the team wrote in the peer-reviewed journal Physics Review Letters last month.
They said this innovative approach might lead to the observation of high-frequency gravitational waves, which were potentially produced right after the Big Bang and are impossible to detect with existing ground-based facilities.
“We demonstrate that the nearby planets, such as Earth and Jupiter, can be utilised as a laboratory for detecting the high-frequency gravitational waves,” the researchers wrote.
Gravitational waves are ripples of space-time caused by the most violent processes in the universe. For instance, the collision of two orbiting black holes can release a huge amount of gravitational energy, which propagates in all directions away from the source.
Travelling at the speed of light, these cosmic ripples carry basic information about their origins and the nature of gravity itself.
Scientists have explored ways to observe high-frequency gravitational waves indirectly, including one based on the so-called inverse Gertsenshtein effect. That describes the conversion between gravitational waves and electromagnetic waves in the presence of an external magnetic field.
When light passes through a strong magnetic field, it will produce a gravitational wave – and vice versa, according to Russian physicist Mikhail Gertsenshtein.
For a long time, this idea was considered experimentally impractical because the magnetic field needs to be astronomically large.
In their study, the Chinese team proposed Earth and Jupiter as enormous magnets for the inverse Gertsenshtein effect.
The researchers calculated the potential amount and frequencies of light particles to be produced with high-frequency gravitational waves passing through the magnetospheres of Earth and Jupiter. They said the results were very encouraging.
They said the orbit and direction of the probe should be carefully designed to optimise the detection results.
“[Our study] should be considered as a starting point for more systematic exploration of the opportunities presented by such a natural laboratory,” they wrote in Science and Technology Daily.