A large asteroid will safely pass close by Earth at 8:21 this morning, Broken Hill time (21:51 UTC).
Some asteroids are named Tomhanks and Megryan but this asteroid is simply (7482) 1994 PC1 and it has a diameter of approximately one km.
NASA’s close approach object table shows that 27 more close approach objects will swing by Earth in the next few months but more than half of them have a diameter of less than 20 metres.
(7482) 1994 PC1 would nearly cover South Broken Hill up to Bonanza Street if it did hit. Which it won’t.
The asteroid will be approximately 1.93 million kms from Earth today, which is about five times the distance to the Moon.
Because the asteroid is closer than eight million kms from Earth’s orbit and its diameter is bigger than 30 to 50 metres, it is classified as a Potentially Hazardous Object by the Planetary Defense Coordination Office (PDCO), which NASA formed in 2016, and a great deal is known about it.
The ‘1994’ in (7482) 1994 PC1 refers to the year it was discovered by Robert McNaught at the Siding Spring Observatory on August 9.
Astronomers then used the asteroid’s known trajectory to find it in images from as far back as September 1974. The asteroid takes approximately 1.5 Earth years to orbit the Sun so its orbit has been confirmed many times over in its 47 years of data.
There are three types of asteroid and this one is an S-type, which is stony and comprises silicate materials and nickel-iron.
1994 PC1 is whooshing by at 19.555 km per second, which is over 70, 000 km per hour. It will be a little further out in July and won’t be this close again for at least 200 years.
The asteroid which wiped out the dinosaurs 160 million years ago was from the Baptistina family in the asteroid belt, when a 170 km diameter asteroid was hit by a 60 km diameter one.
If there is a greater than one per cent chance of an object impacting Earth over the next 50 years, NASA will notify the Executive Office of the President, Congress and other agencies.
This one is passing through.