Ask An Astronomer Anything At All About Astronomy (XXXIX)

Finally ending the dry spell of questions.

1) Is there a way to tell the difference between stars and planets with the unaided eye ?
Only by ritual sacrifice to invoke a demon from the netherworld who can tell you the answer.

2) What's the difference between dark matter and anti-matter ?
Dark matter thinks the dress is blue and black whereas anti-matter thinks it's white and gold.

3) Could modifying gravity explain dark matter ?
Well it definitely can't explain why baseball is popular.

4) Why are black holes so bad at eating stuff ?
Seriously ? If you weighed a trillion tonnes and people were chucking bagels at you at a hundred thousand miles a second you think you'd do a better job ?

5) Do galaxies and galaxy clusters move ?
No. They are fixed, absolute, immutable constants, timeless and eternal immortals in the starry firmament.

6) Should we all turn our lights off to look at the stars ?
YES ! That's a brilliant idea ! Pay special attention to turning off all the lights in hospitals and police stations, make sure no-one is allowed to drive anywhere, and make sure this even happens without telling anyone ahead of time.

7) Could we all be aliens ?
No, not all of us. Just your mum.

8) Can we send some bacteria to Mars just for the lolz ?
Only if they promise to take lots of photos and tell us how they're getting on.