Evidence that white dwarf stars form crystal cores of metallic oxygen and carbon

[gary]

In a press release from the University of Warwick (https://warwick.ac.uk/newsandevents/pressreleases/thousands_of_stars/)a short time ago,
it has been announced that astronomers have discovered "the
first direct evidence of white dwarf stars solidifying into crystals"
and that "our skies are filled with them".





Press Release here :-
https://warwick.ac.uk/newsandevents/pressreleases/thousands_of_stars/

Paper in Nature :-
"Core crystallization and pile-up in the cooling sequence of evolving white dwarfs" by Tremblay et. al. (subscription required) :-
https://www.nature.com/articles/s41586-018-0791-x

[multiweb]

That's pretty cool. So does this mean all those stars out there that have already crystallised and are cold we can't see? Could that account for some of all the missing mass they're looking for still?

[gary]

Hi Marc,

It is pretty cool. :)

These are good questions that I also pondered when I read the press release.

I think what might be unknown is how many years does it take for a white
dwarf to reach a state where it ceases emitting light and heat altogether?

I would imagine a very, very, very long time.

Is the universe old enough yet for any stars to have reached a state of
emitting no detectable radiation? My guess - which isn't worth anything - is probably not.

I certainly don't think De Beers will be in a panic for quite a while. :lol:

[multiweb]

Do we know with a good dose of certainty how old the universe is or is it just an estimate and it possibly could be a lot older than we think?

[gary]

It has been independently pegged by several measurements including
by the temperature of the cosmic background radiation and by reverse
extrapolation of the rate of expansion from measuring lots of galaxy
red shifts, so the uncertainty is down around 20 million years at the
moment which is an impressive achievement.

Plus when you go back and consider the distances to the original Milky
Way Cepheid standard candles was done by parallax measurements,
I don't think the fact that lots of white dwarfs may turn out to be older
than originally thought will impact the estimates of the age of the universe.

When you consider that the Universe is only 13.799 billion years old,
I find it remarkable that it is such a finite and "small" number.

For example, when you consider the news today that Jeff Bezos and his
wife are getting divorced, that Jeff Bezos has a reported net worth of
USD137 billion and that his wife is likely to receive USD68.5 billion,
then the lawyers, accountants and bankers will have no difficulty in
processing numbers of that magnitude.

Most of us I am sure would be happy to have earned nearly 10 US Dollars
for every year since the universe was formed and for it to be waiting in
a trust account. :lol:

Anyway, whatever happened only 13.799 billion days ago must have been
one helluva day.