A newly discovered asteroid passed by Earth on Wednesday, April 15, and for a brief time, it was closer to us than the Moon.
Asteroid 2020 GH2 was first spotted on Saturday, April 11, and has been tracked and logged by more than a half-dozen different sky surveys in the days since.
Estimated at around 13 to 30 metres wide, 2020 GH2 was identified as an Apollo asteroid - one that crosses Earth's path, but which spends most of its journey around the Sun outside of Earth's orbit. Based on observations, this particular Apollo asteroid originates from the asteroid belt beyond Mars.
This graphic from NASA's Center for Near-Earth Object Studies shows the path asteroid 2020 GH2 takes as it orbits the Sun. Credit: NASA CNEOS/Scott Sutherland
Apollo asteroids are named after the very first asteroid discovered with this type of orbit, 1862 Apollo, which was found by German astronomer Karl Reinmuth on April 24, 1932.
Depending on how fast it is travelling, a space rock of this size could do some significant damage if it were to strike Earth. The Chelyabinsk asteroid, which exploded over Russia in February of 2013, was estimated at being roughly 20 metres wide when it struck the atmosphere.
Fortunately, 2020 GH2 poses no threat to us.
The closest this interplanetary traveller came to Earth on April 15 was around 360,000 kilometres, or around 90 per cent of the distance to the Moon. That makes this a close, but safe flyby, and based on the asteroid's orbit, this will be the last time we see it for the forseeable future!
The flyby of 2020 GH2 as seen during its closest approach, from 'above' the Earth and Moon. Credit: NASA CNEOS/Scott Sutherland
Two other asteroids passed by on April 15, as well.
The first, named 2020 FX3, is a roughly 50 m wide rock that zoomed by at a distance of over 5 million kilometres (14.1 lunar distances). The second, named 2020 FZ6, is nearly 190 metres wide, and swings past us at a distance of over 8 million kilometres (21.7 lunar distances).
As with 2020 GH3, these two are no threat to us.
ASTEROID THREATS? NOT SO MUCH
In recent weeks, as if we didn't have enough to worry about, there has been a lot of hype about possible asteroid threats.
One particular target for this hype is asteroid 52768 (1998 OR2), which is passing by Earth on April 29, 2020.
The orbit of 52768 (1998 OR2), as of April 29, 2020. The inset view shows the asteroid safely positioned far beyond the orbit of the Moon during its closest pass. Credit: NASA CNEOS/Scott Sutherland
These stories have originated from various 'tabloid' news sources around the world. With flashy headlines proclaiming "NASA Warns" and using phrases like "Approaching Earth", they heavily imply that the space agency is issuing alerts about impending impacts with Earth.
Nothing could be farther from the truth, however.
Asteroid 52768 (1998 OR2) was discovered in 1998, and astronomers have logged over 3,500 observations of it, some going back as far as 1987. With that much information at their fingertips, scientists have locked down the orbit of this object.
The main reason these stories seem to be hyping this fly, apparently, is due to the asteroid's size. 52768 (1998 OR2) is estimated at being around 2.5 kilometres wide. Admittedly, that is significant, and it would be very dangerous if anything like that struck the planet.
As it passes Earth on April 29, however, 52768 (1998 OR2) will be very far away - over 6.3 million kilometres at its closest distance. For reference, that is 16.4 times farther away than the Moon.
Watch below: NASA scientist Kelly Fast, with the Planetary Defense Coordination Office shows us just how big space is!
We now know, with 100 per cent certainty, that 52768 (1998 OR2) is no threat to Earth, either now or at any time in the future.
In fact, the asteroid does not even appear on NASA's list of 'potentially hazardous asteroids' that have any chance of striking us. Some asteroids have earned a place on that list even for having an impact chance that ranks as one chance in ten billion, for a date over 100 years from now. 52768 (1998 OR2) is not on that list now, nor has it ever been (some asteroids live on the list for awhile, and then are removed when further observations demonstrate it is no threat).
Now, as always, NASA states that there are no known asteroid threats for the next 100 years (or more).