Home Science Asteroid comes 'exceptionally close' to Earth as it passes closer than satellites

Asteroid comes 'exceptionally close' to Earth as it passes closer than satellites


An asteroid known as 2021 GW4 came within just five percent of the distance between the Earth and the Moon yesterday, allowing astronomers to snap an image of the passing space rock. According to the Virtual Telescope Project, 2021 GW4 shot by at a distance of just 20,000 kilometres.

This puts it much closer than geostationary satellites, which are situated roughly 36,000km above Earth’s equator.

Geostationary satellites are mainly used for meteorology, helping to track changes in Earth’s atmosphere, weather observations and oceanography.

A satellite which provides signal for your phone orbits the planet much closer, hovering around 500 kilometres above Earth.

The asteroid 2021 GW4 reached its closest point to Earth on April 12, with the Virtual Telescope Project imaging it a matter of hours before its nearest point to Earth.

The image shows the asteroid when it was 300,000km away against a backdrop of stars which fill up the Milky Way.

What makes the feat even more impressive is that the asteroid is just a maximum of seven metres in size.

The Virtual Telescope Project said: “The image above comes from a single, 180-second exposure, remotely taken with the ‘Elena’ (PlaneWave 17″+Paramount ME+SBIG STL-6303E) robotic unit available at Virtual Telescope.

“The telescope tracked the fast apparent motion of the asteroid, this is why stars show as long trails, while the asteroid looks like a bright and sharp dot of light in the centre of the image, marked by an arrow.

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However, small fragments of rock and dust may have reached the surface, according to the Virtual Telescope Project.

The astronomy group said: “In the recent past, objects of this size impacted with our planet, too: 2008 TC3, 2014 AA, 2018 LA and 2019 MO.

“They can produce an air burst and occasionally, fragments can reach soil (as in the case of 2008 TC3 above Sudan).

“Of course, we also had the Chelyabinsk event in 2013, which was much larger (20 metres) than 2021 GW4.”


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