The strangest thing is something that is strange or unusual in some way. The strangest thing that you have ever seen is probably going to be different from the strangest thing that someone else has ever seen.
When something is hurtling, it is moving very quickly. This can be a dangerous thing, because it is easy to lose control of something that is hurtling.
When something is clumps, it is lumpy and has a lot of small pieces. Clumps of dirt, mud, or snow can be very messy.
To guess is to make a guess about something. You might guess what the answer to a question is, or you might guess what someone else is going to say.
The subatomic level is the smallest level of the universe that we can see or measure. At the subatomic level, particles like atoms are still moving around.
The smallest is the least of something. The smallest size of pasta is called a minestrone. The smallest amount of sugar is called a teaspoon.
To orbit is to go around a planet or a star. The Earth orbits around the sun.