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American astronomers have stumbled across one of the farthest quasars
ever seen. The light from the quasar, which has a red shift of 4.21, was
emitted when the Universe was less than a fifth of its current size.

Donald Schneider of the Institute for Advanced Study in Princeton, New
Jersey, Maarten Schmidt of the California Institute of Technology in Pasadena,
and James Gunn of Princeton University discovered the object while searching
for distant quasars with the 200-inch telescope on Palomar Mountain in California.
On an image of the constellation of Pisces, they found an object they thought
might be a distant quasar.

But when they obtained better spectra, they found that the suspicious
object was only a star in our Galaxy. Beside the star, however, was another
object whose spectrum had been recorded by chance. This second object turned
out to be a quasar with an extremely large red shift.

The new quasar is one of the most distant known. In the time its light
has been travelling to the Earth, the Universe has become 5.21 times larger,
stretching the wavelength of the quasar’s light by the same factor.

To date, astronomers have published reports of only 15 other quasars
with a red shift greater than 4. The farthest-known quasar, discovered by
Schneider’s team in 1991, has a red shift of 4.897. But of all known quasars
with red shifts greater than 4, the new one is the faintest. It is 2.5 million
times dimmer than any object visible to the naked eye.

In 1987, another group of astronomers also accidentally discovered a
quasar with a red shift greater than 4. Schneider con-siders it amazing
that more than 10 per cent of the 16 known quasars with red shifts greater
than 4 have been found by accident as astronomers have mounted intense searches
for such objects.

Schneider and his colleagues will report their discovery in the March
issue of The Astronomical Journal.