An ‘airplane-sized’ asteroid came closer to Earth than the Moon
Two potentially hazardous asteroids (PHA) swung by our little corner of the universe this week. Because, you know, this is 2020 after all and the universe is conspiring against us.
As reported by NASA, the asteroid is about the size of a small plane of bus, roughly the same size as the bolide that exploded over Russia seven years ago. Here’s what we know.
Two asteroids passing Earth
Asteroid 2011 ES4
Asteroid 2011 ES4 does not pose a threat to Earth, according to NASA, and will pass by Earth at a distance of approximately 115 873 kilometres. Yes, that’s closer than the Moon is to Earth (384 400 km).
The asteroid is 30 metres in diameter. However, there is no danger of a collision, according to astronomer Dr Tony Phillips from SpaceWeather.com. Nevertheless, it’s still important to study the asteroid.
Scientists’ observation could help to rule out the risk of a future collision with 2011 ES4. Still, the asteroid gets the trophy for the closest PHA-pass by an asteroid for the next decade.
Previous close encounter
Back in July, Asteroid 2020ND measuring 170 metres in diameter came within 0.034 astronomical units (AU) of Earth. Even an Asteroid 1 metre in diameter could cause significant damage on impact.
That said, NASA believes that there is still a one in 300 000 chance each year that Earth could cross paths with a potentially hazardous asteroid or other space rock.
Being classified as a PHA does not mean that an asteroid will impact the Earth. […] By continuing to observe and track asteroids, their orbits can be refined and more precise predictions made of their future close approaches and impact probabilities.
NASA, Jet Propulsion Laboratory
What is a PHA?
According to NASA, a PHA is defined based on “parameters that measure the asteroid’s potential to make threatening close approaches to Earth”. That means that an asteroid will be classified as a PHA if it comes within 0.05 AU.
“Specifically, all asteroids with a minimum orbit intersection distance (MOID) of 0.05 au or less are considered PHAs.”
Asteroids that could potentially impact Earth in future
Asteroid 2009 JF1 was discovered more than a decade ago. It measures only 12 metres in diameter. It is expected to fly by or hit Earth in 2022.
Another tiny asteroid, known as 2018 VP1, is expected to arrive at some point between 2020 and 2025. The largest asteroid on NASA’s doomsday list isn’t actually expected to come into contact with Earth until the year 2880.
That mister of a space rock is called 29075 (1950 DA), and it is almost three times as big as the Empire State Building; roughly 1.3 kilometres in diameter. It could cause significant damage if it impacts Earth.
Also read — Astronaut takes incredible images of Johannesburg, Cape Town and Pretoria [photos]