Your immune system is often able to fend off pathogens it’s never seen before. But defending your body against all of them all at once is a tough challenge.

There are so many fish in the ocean that if you took them out, important habitats and food sources for many creatures would be lost.

Pictures of black holes have a white outline around them when photographed, due to one of black holes’ unique and key features.

Two dental experts explain that these furthest-back molars may be a not-so-necessary leftover from early human evolution.

Sound needs matter to propagate, so the vast vacuum of space is not just empty − it’s silent.

No matter your age, if you’re being bullied − there’s help out there.

There are a lot of myths about crystals − for example, that they are magical rocks with healing powers. An earth scientist explains some of their amazing true science.

Scientists are trying to figure out if time travel is even theoretically possible. If it is, it looks like it would take a whole lot more knowledge and resources than humans have now to do it.

Slimy snot is an important part of how your immune system wards off germs and fights back from infection.

Ghosts can be spooky fun, but there’s no evidence they exist.