Locked
in a spiraling orbital embrace, the super-dense remains of two dead
stars are giving astronomers the evidence needed to confirm one of
Einstein’s predictions about the Universe.
A binary system located about 3,000 light-years away, SDSS
J065133.338+284423.37 (J0651 for short) contains two white dwarfs
orbiting each other rapidly — once every 12.75 minutes. The system was
discovered in April 2011, and since then astronomers have had their eyes
— and four separate telescopes in locations around the world — on it to
see if gravitational effects first predicted by Einstein could be seen.
According to Einstein, space-time is a structure in itself, in which
all cosmic objects — planets, stars, galaxies — reside. Every object
with mass puts a “dent” in this structure in all dimensions; the more
massive an object, the “deeper” the dent. Light energy travels in a
straight line, but when it encounters these dents it can dip in and veer
off-course, an effect we see from Earth as gravitational lensing.
Einstein also predicted that exceptionally massive, rapidly rotating
objects — such as a white dwarf binary pair — would create
outwardly-expanding ripples in space-time that would ultimately “steal”
kinetic energy from the objects themselves. These gravitational waves
would be very subtle, yet in theory, observable.
According to Einstein, space-time is a structure in itself, in which all cosmic objects — planets, stars, galaxies — reside. Every object with mass puts a “dent” in this structure in all dimensions; the more massive an object, the “deeper” the dent. Light energy travels in a straight line, but when it encounters these dents it can dip in and veer off-course, an effect we see from Earth as gravitational lensing.
Einstein also predicted that exceptionally massive, rapidly rotating objects — such as a white dwarf binary pair — would create outwardly-expanding ripples in space-time that would ultimately “steal” kinetic energy from the objects themselves. These gravitational waves would be very subtle, yet in theory, observable.
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