Question: Could you tell me about the asteroid which passed in April?

Helena Bates answered on 4 May 2020:

Yes definitely! So the asteroid was called 1998 OR2, which means it was first spotted in 1998. Its about 2 km in diameter, so quite big, but it flew past about 3.9 million miles away, which is 16 times further than the earth to the moon! We classify asteroids by looking at the light reflected off it from the sun, but not the visible light which we see with our eyes, but infrared light, which is the same thing as heat! That reflected infrared light has some characteristics which can let us work out what rocks and minerals the asteroid is mostly made up of, and assign the asteroid a classification based on its composition. 1998 OR2 is made of up silicate minerals, which are amongst the most common types of minerals in the solar system, and we give it the classification of an S-type asteroid. We’ve actually been able to track this asteroid really well, and we know what orbit its going to be doing up until 2197!!

I also want to say that lots of asteroids fly past earth all the time, 1998 OR2 was just quite big. There is actually an asteroid which is going to be going past earth tonight, at a distance only half way to the moon! so really quite close! but its very small, about the size of a bus (its about 15 metres), and if it does hit earth it will burn up in the atmosphere, so nothing to worry about!