Follow the reluctant adventures in the life of a Welsh astrophysicist sent around the world for some reason, wherein I photograph potatoes and destroy galaxies in the name of science. And don't forget about my website,

Sunday 23 April 2017

Ask An Astronomer Anything At All About Astronomy (XXXVIII)

The torrent of questions, some clever, some worrying, some worryingly clever, continues like the rising tide of entropy.

1) When will get get these pictures of the Sag A* black hole ?
Not until Tuesday.

2) Why is the Earth still rotating ?
It got a little drunk last night.

3) Could an asteroid make the Sun implode ?
What ? No.

4) Radio bursts in space aren't at all surprising, right ?

5) If the Universe is expanding then how come the constellations haven't changed in thousands of years ?
Don't be hasty.


  1. Is there an easy way to tell the difference between stars, planets, and satellites when looking at the night sky unaided (especially in urban areas)?

    1. Satellites are easy because they move rapidly. Jupiter, Saturn and Venus are easy because they're relatively bright. Mars is harder because it's often faint. Mercury is probably the hardest because you can only see it just before and after sunset.

      It's often said that planets don't twinkle, but I have absolutely no idea why people say this, because I've never noticed any difference between the twinkling of planets and stars.

      By far the easiest and most reliable way is to consult a chart of the positions of the planets beforehand, or with an app on a phone or tablet while observing. Not very clever, but it works !


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