Scientists Use Radars To Observe Space Dust In Novel Method

Radar can now be used to make observations that previously only optical telescopes could make.
Fabienne Lang
The Kiso-Schmidt Telescope2020 The University of Tokyo

"Faint meteors, discarded remnants of asteroids, and comets" come falling down to Earth every day in the form of dust. This is called interplanetary dust, and roughly 1 million pounds (453592.37 kg) of it flutters onto our planet daily, per researchers at the University of Tokyo, Japan.

Until this month, scientists could observe this space dust in two ways: optical telescopes or radars. Thanks to the University of Tokyo's researchers, a new way of combining both methods using radar observations now works. 

Their findings have been published in the journal Planetary and Space Science on November 11. 


Radars to weigh space dust

The new research helps further investigations of the size and composition of interplanetary dust — or space dust — which in turn helps astronomers look into the activity and makeup of comets, asteroids, and meteors. 

"When in space, interplanetary dust is practically invisible. However, around 1,000 kilograms falls to Earth every day in the form of tiny meteors which appear as bright streaks in the night sky," said astronomer Ryou Ohsawa from the Institute of Astronomy at the University of Tokyo.

"We can observe these with ground-based radar and optical instruments. Radar is useful as it can cover wide areas and gather vast readings, but optical telescopes can give more detailed information useful for our studies. So we set out to bridge this gap to boost our observational capacity," he continued.

Ohsawa and his team managed to meld radar observatories with the power of optical ones and succeeded. 

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"We recorded hundreds of events over several years and have now gained the ability to read information about meteor mass from subtle signals in radar data," explained Ohsawa.

Scientists Use Radars To Observe Space Dust In Novel Method
The observatories sit 107 miles apart, allowing more accurate readings. Source: Ohsawa et al./2020 The University of Tokyo

How the team managed its radar feat

The team used the Middle and Upper Atmosphere (MU) Radar facility, and the Kiso Observatory, which are 107 miles (173 km) apart. The closeness of these facilities is paramount, as the team explained, "the closer the facilities, the more accurately the data from them can be correlated," in its paper.

The team then developed software to sift through the huge amount of data gathered and recognize faint meteors. 

This project "could help astronomers explore comets and aspects of solar system evolution like never before," stated Ohsawa's team.

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