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In 1962, 3C 273 was occulted, or
covered, several times by the moon.
By watching for the reappearance
of the radio source from behind the
lunar disk, astronomers were able
to get a very precise location of
the source. Maarten Schmidt used
those measurements to take a look
at it through the Hale Telescope,
then the largest optical telescope
in the world. He found 3C 273 to
be the brightest object yet known.
He published his findings in Nature
in March 1963, and in the same
issue, two other astronomers,
Jesse Greenstein and Thomas
Matthews, presented data on the
redshift of 3C 48, which showed
that the object was moving away
at one third of the speed of light,
making it the fastest-moving
object yet discovered.
By the early 1970s, hundreds
of quasars had been identified.
Many were even more distant than
3C 48 and 3C 273; today, most of
the quasars that have been found
are located about 12 billion light-
years away. In addition, quasars
are mostly brighter than the first
observations suggested, with
luminosities up to 100 times
that of the Milky Way.White holes?
The debate now began as to what
these things actually were. One
suggestion was that the enormous
redshifts seen in quasars were not
the result of the expansion of space,
but were the result of the light
crawling out of a large gravity
well. Such a well would be created
by a truly monstrous star, with a
gravitational field close to that of
a black hole. However, calculations
showed that such a star could
never be stable.
Another proposal was that a
quasar was the opening of a white
hole. A white hole is the opposite
of a black hole. This idea was
proposed in 1964, and white holes
remain entirely hypothetical. They
are generally ignored as a theory
today, but in the 1960s and ’70s,
black holes were also unobserved
phenomena, so the concept ofQUASARS AND BLACK HOLES
white holes carried more weight.
The idea is based on a complex
interpretation of the Einstein field
equations of general relativity,
which proposes that a black hole
that exists in the future would link
to a white hole that exists in the
past. A white hole is, therefore,
a region of space where light
and matter can leave but cannot
enter. This would match the
focused streams of radiation and
matter that were being observed
firing out of quasars. The question
remained over where all that energy
came from. The answer offered
was that it has come through
a wormhole, or Einstein–Rosen
bridge, a theoretical feature of
spacetime that connects the
future to the past.Small bangs
Currently, the only event that
is accepted as anything like a
white hole is the Big Bang itself,
and some theories suggest that
the material entering black holesAn artist’s impression shows the
possible structure of quasar 3C 279. A
disk of material rotates around a black
hole a billion times as massive as the sun.Twinkle, twinkle, quasi-star
Biggest puzzle from afar
How unlike the other ones
Brighter than a billion suns
Twinkle, twinkle, quasi-star
How I wonder what you are.
George Gamow