Posted
on August 6, 2014
It
was one of the biggest kinds of ka-booms in the universe: a
supernova.
A
gigantic star dying in an enormous explosion – almost all of the
star's material shooting outwards at 30 thousand kilometers per
second – driving a shock wave into the mostly-empty spaces between
stars – leaving behind a super-dense pulsar (or neutron star) that
whips around its axis at the incredible speed of 15 revolutions PER
SECOND!
Of
course, the ancient Chinese and Japanese astronomers who spotted the
supernova didn't know all that. They just thought it was a new star
(which is what nova basically means).
The
year was 1181. A new glint of light appeared in the night skies where
no other star had appeared before – and stayed there for six
months! Chinese and Japanese astronomers not only noticed the “new
star,” they also kept records good enough so that modern
astronomers could find what they had been looking at – even though
the star / pulsar / shock wave faded to invisibility almost a
thousand years ago.
And
what they found is that 3C58 is cooling down a lot faster than
expected.
How
cool is it?
The
surface of the neutron star is apparently just less than a million
degrees Celsius. Seems pretty hot, right? But apparently scientists
expect a neutron star as young as this one to be even hotter.
Wait
– did you call 3C58 young? But...this pulsar was born in 1181!
More
than 800 years old may seem pretty old...but some neutron stars are
more than ten BILLION years old.
800
years – 10,000,000,000 years – that's a pretty huge range!
Most
neutron stars that we can detect as pulsars are from 100,000 to
300,000,000 years old. And there may be a lot of older “silent”
neutron stars, way older than ten billion years old, that we cannot
detect, because we cannot measure their period of rotation and their
period derivative.
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