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, www.rhysy.net



Sunday, 26 February 2017

Ask An Astronomer Anything At All About Astronomy (XXXIII)

An extremely busy week for the now quite enormous Q&A page, running at 295 questions ! Don't forget to click the links for the actual answers.

So, here's a question for you : am I crazy to think about trying some sort of hard copy publication, dare I say the word... book ? Obviously with proper editing and expanding some answers so everything would be better self-contained, and due diligence to check for accuracy. Is this a delusion of grandeur or something you'd be prepared to torture your pets just to get a glimpse of a copy ? Or, more usefully, where between those two extremes would you rate this idea and why ?


1) What do you think of this article about generational starships being unworkable ?
It's daft.

2) Why would we bother investing huge resources in generational starships ?
Dude, have you seen how much time we spend making cat memes ?

3) What's your take on this press release about a new law of nature ?
Oh please no not again !

4) Is gravity caused by protons and electrons spinning through space ?
Err, no.

5) Time doesn't exist.
Neither does your face.

6) Is gravity caused by protons and electrons spinning through space and creating a magnetic field which could explain dark matter and dark energy ?
No, dude, let it go.

7) Is there any chance the IAU will adopt a new definition of planet ?
Dunno, but I wish they'd get rid of the current one.

8) Which place in the Solar System do you think is most likely to harbour some form of life ?
Your mum.

9) Extraterrestrials are definitely visiting Earth, you know.
No they're not.

Then we get to a special bonus section. The root question was, "White dwarfs take a very long time to cool to form black dwarfs, but is there a way to speed this up ?". And the final answer is no. But since this involved a very long discussion, I think it's worthwhile to dissect this in some detail.
10) If we increase the density of gas around a white dwarf, could we help cool it down by convection ?
No, this will make it hotter.

11) If we could increase convection inside a white dwarf, could we make it cool down faster to create a black dwarf ?
No, this will make it hotter.

12) Okay, okay ! So why can't we use convection inside a white dwarf to cool it down ?
Because it won't work.

13) Well, what if we shot a black hole through the white dwarf that could force material to mix from the hot core to the cold surface ? Would that help ?
Certainly not, but it would be bloody spectacular and I encourage reader to try this for themselves.

14) What about getting a black hole in orbit of the white dwarf to cancel out its surface gravity so we can build stuff on it ?
No.

15) What about... using lots of black holes to cancel out the surface gravity ?!
No !

16)  What if we filled a white dwarf with teeny-tiny wormholes...
NO !

17) Perhaps some sort of -
I said NO ! STOP IT !

18) But what if -
NO !!!!!


There, that's better.


19) Could we start nuclear fusion on a giant ball of iron ?
Yeah but why bother ? Your mum's so fat she has a higher accretion efficiency...

20) OK, I give up. Is there at least any sort of object that will be like a black dwarf in that it's difficult to detect unless something impacts it ?
Yes there is.

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