(This caption from May
25, 1994, is reproduced courtesy of the Space Telescope Science Institute.)
A NASA Hubble Space Telescope image of a spiral-shaped disk of hot gas
in the core of active galaxy M87. HST measurements show the disk is
rotating so rapidly it contains a massive black hole at its hub.
A black hole is an object that is so massive yet compact nothing can
escape its gravitational pull, not even light. The object at the
center of M87 fits that description. It weights as much as three
billion suns, but is concentrated into a space no larger than our
Now that astronomers have seen the signature of the tremendous
gravitational field at the center of M87, it is clear that the region
contains only a fraction of the number of stars that would be
necessary to create such a powerful attraction.
The giant elliptical galaxy M87 is located 50 million light-years away
in the constellation Virgo. Earlier observations suggested the black
hole was present, but were not decisive. A brilliant jet of high-
speed electrons that emits from the nucleus (diagonal line across
image) is believed to be produced by the black hole engine.
The image was taken with HSTs Wide Field Planetary Camera 2
Credit: Holland Ford, Space Telescope Science Institute/Johns
Hopkins University; Richard Harms, Applied Research Corp.;
Zlatan Tsvetanov, Arthur Davidsen, and Gerard Kriss at
Johns Hopkins; Ralph Bohlin and George Hartig at Space
Telescope Science Institute; Linda Dressel and Ajay K.
Kochhar at Applied Research Corp. in Landover, Md.; and
Bruce Margon from the University of Washington in Seattle.