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Quote: Originally posted by jenchris40 on 18/7/2020

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Quote: Originally posted by Bob61 on 18/7/2020

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Quote: Originally posted by jenchris40 on 18/7/2020

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Quote: Originally posted by Bob61 on 17/7/2020

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The asteroid I don't want to see is the one without a tail because then it will be heading straight for us - lol

Post last edited on 18/07/2020 00:01:28

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Not quite Bob - the tail points away from the sun whichever way the comet is travelling.

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I thought the tail was all the debris coming off the back of the comet as it belts along at thousands of miles an hour.

Incidentally, I am sure I saw the International Space Station whizzing across the sky last night...either that or a UFO!

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No, in near enough a vacuum there's nothing to pull debris off along the path of the comet. While it's on the more distant part of its orbit a comet just travels along like any asteroid. As it gets nearer to the sun the radiation/solar wind starts to vaporize the comet and puhes the resulting gas directly away from the sun. There's a good little animation here:

https://astronomy.swin.edu.au/cosmos/C/Cometary+Tails

And the ISS has certainly been above us recently - another good link here:

https://www.heavens-above.com

If you enter your own location you can get very accurate predictions of when and where you will see the station.

Cheers

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