Asteroids

Small asteroids burn up in the Earth's atmosphere and they give a wonderful fireball like this. They often also break up and people near the front will be able to see that there are some blobs because this is already begun to break up. And maybe nothing from that will land on Earth. Maybe it will all burn up or maybe something the size of your fist may land on the Earth and it could go through the roof of your car which is not good for the car or it could go through the roof of your house which is not good for the house but it's not going to kill 100s of people or wipe out life on Earth. These are a couple of images of the one that came in over Siberia in the middle of February. This bottom one isn't a good photo but I have included it because you can see it is beginning to break up into bits. Turns out this asteroid had a collision with another one and so was already quite stressed at the point it came into Earth's atmosphere. As it comes into the atmosphere it gets very hot, it starts burning, it releases gas and the gas can make the thing explode and that's what happened in this case.