Ask Ethan #98: When Will The Stars Go Dark? (Synopsis)

“As the blackness of the night recedes so does the nadir of yesterday. The child I am forgets so quickly.” -Sylvia Ashton-Warner

While the night sky is littered with thousands of points of light -- the stars visible to the naked eye -- we know that beyond what human perception can see, there are hundreds of billions of stars in our galaxy alone, and hundreds of billions of galaxies in the observable Universe. Yet every star that ever has shone or will shine will someday run out of fuel and die.

Image credit: NASA/ESA and The Hubble Heritage Team (AURA/STScI), via https://www.spacetelescope.org/images/opo9935e/. Image credit: NASA/ESA and The Hubble Heritage Team (AURA/STScI), via https://www.spacetelescope.org/images/opo9935e/.

When that happens, the inner core of the star contracts down to form a tiny, degenerate but very hot object. But even so, no object with a finite amount of energy can shine forever. At some point, even those stellar remnants will cool down out of the visible portion of the spectrum. But how long will that take, how will that happen, and has the Universe been around long enough (yet) so that such an object exists?

Image credit: White Dwarf, Earth, and Black Dwarf, via BBC / GCSE (L) and SunflowerCosmos (R). Image credit: White Dwarf, Earth, and Black Dwarf, via BBC / GCSE (L) and SunflowerCosmos (R).

Find out on this week's Ask Ethan!

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Sounds like the low temperature neutrino emissions rate is not well known. How else could there be such a large variation in estimated cooling time?

Can neutrinos really pass through neutron stars, even with a tinyl cross-section the column density of a NS is phenomenally high. But I think neutrino cross sections are heavily energy dependent, so maybe a NS is "optically" thin in the low energies that would presumably dominate cooling times?

By Omega Centauri (not verified) on 24 Jul 2015 #permalink

WHY DOES THIS BLOG LOOK SO TERRIBLE COMPARED TO THE MEDIUM.COM SITE AND WHAT DO THOSE MATH WIZZES AT VANDERBILT THINK ABOUT 10 TO THE 22ND YEARS FOR OBJECTS SURVIVING THEIR FIERSOME BIG RIP

By THOMAS BARTON JD (not verified) on 24 Jul 2015 #permalink

OF COURSE VANDERBILT IS A BETTER BASKETBALL SCHOOL THAN A PHYSICS VERSION OF UCLA AND JOHN WOODEN IN THE 1960'S.

By THOMAS BARTON JD (not verified) on 24 Jul 2015 #permalink

WRONG! When the Tibetan monks finish their project on listing all the words used to name "God", the universe will go dark. I am told they are about 90% finished now they are using computers.

By Paul Blanchard (not verified) on 24 Jul 2015 #permalink

"How else could there be such a large variation in estimated cooling time?"

In this case you are right that there are large error bars for neutrinos, but the above quote is UTTERLY wrong.

Cooling depends on the diffusion of heat through a fluid, which requires nonlinear equations to be solved, and that can EASILY cause huge error bars.

You leapt with great abandon from "I haven't thought of" to "there CANNOT BE".

DO
NOT
DO
THAT.

THANK YOU THOMAS BARTON FOR YOUR VERY LOUD WORDS! THEY WERE DEFINITELY WORDS THAT APPEARED AND THEIR APPEARANCE WAS LIKE THAT OF WORDS AND WHY DON'T YOU GO PLAY BASKETBALL FOR A GREAT TEAM INSTEAD OF TYPING MANY WORDS ON A BLOG THAT DOESN'T FIT YOUR AESTHETICS BECAUSE YOU LIKE BASKETBALL A LOT AND WISH TO LIKE BASKETBALL BUT NOT SCIENCEBLOGS.

"When the Tibetan monks finish their project on listing all the words used to name “God”"

And his name is "Wow".

Thank you.

Yours in benevolence (PBUM),

God

“When the Tibetan monks finish their project on listing all the words used to name “God””

We have known that since 1953.

en.wikipedia.org/wiki/The_Nine_Billion_Names_of_God

Yup, it's me.

I decided not to end the universe. I was enjoying it.

.

Noun

God botherer (plural God botherers)

(UK, slang, pejorative) A person who persistently promotes religious beliefs to others, even when unwelcome.
(Australia, New Zealand, slang, pejorative) A religious preacher who visits homes to promote his or her beliefs.
(UK, slang, pejorative) An excessively pious person.
(UK, military slang) A military chaplain.

Where did you get YOUR definition, raggie?