Question: What is a dark matter

Kathryn Boast answered on 5 Mar 2019: last edited 5 Mar 2019 2:03 pm

Short answer: Nobody knows!
Long answer:
⭐There’s something in space that is distorting the light coming from stars.
💫 There’s also something in space that makes stars move much faster than we think they should.
🌌And there seems to be something sticking galaxies together in clusters of galaxies which should just fly apart.
We *think* it’s the same stuff doing all three of these things. If you put extra invisible stuff (physicists like to use the word matter, but really it just means stuff) into space, it can solve these problems and explain the strange things we see in space. This invisible stuff we usually call “dark matter”, because we don’t know exactly what it is. It must have some mass (i.e. be heavy) to have the right effect, but really that’s all we know about it.
We think dark matter is probably all around us all the time – the highest estimates say that a dark matter particle passes through you every few seconds! But they don’t seem to have any effect on us, or on our machines. This means we have found it really hard to actually detect and measure dark matter – if it is there, it’s just going straight through our machines without changing anything. It’s also difficult to know what we should look for, because no-one about any of the properties of dark matter, except that it must weigh something.
The question of what dark matter is is one of the biggest unanswered questions in science – particularly because we think there’s about six times as much dark matter as everything else put together! ⚪➕⚫⚫⚫⚫⚫⚫