Window-curtain structure of the Orion Nebula revealed: Recent images made with the Wide Field Camera on NASA/ESA Hubble Space Telescope have revealed the structure of a thin sheet of gas located at the edge of the famous "Great Nebula" in Orion, an estimated 1500 light years from Earth. Astronomers, who compare the appearance of this sheet of gas with that of a rippled window curtain, report that this emission traces the boundary between the hot, diffuse interior of the nebula and an adjacent dense cool cloud. The sheet is seen in light emitted by atoms of gaseous sulfur (shown in red in the photograph). This emission is strongest under conditions which are intermediate between those in the interior of nebula and those in the dense cloud. The sulfur emission is seen to break into filamentary and clumpy structures with sizes down to the limit of what the telescope can show. In contrast, emission from gaseous oxygen and hydrogen (shown as blue and green, respectively) is favored in the interior of the nebula itself, and is distributed much more smoothly in the image. The Orion Nebula is a "stellar nursery" - a region where new stars are forming out of interstellar gas. The emission from the nebula is powered by the intense ultraviolet light from a cluster of particularly hot and luminous stars. The sulfur emission seen in the photograph is coming from the region where the light from these stars is "boiling off" material from the face of the dense cloud. This is the very cloud from which the hot stars formed, and is known to harbor additional ongoing star formation. Astronomers say that this is a good example of a case where, despite the spherical aberration that has hobbled many of the scientific programs which the Hubble Space Telescope was expected to carry out, the telescope can still be used to obtain scientifically interesting data with clarity far exceeding that normally possible from the ground. The Wide Field/Planetary Camera was designed and built by the Jet Propulsion Laboratory, which is operated by the California Institute of Technology.

Name: M 42, Messier 42, NGC 1976, Orion Nebula
Type: Milky Way : Nebula : Type : Star Formation
Category: Nebulae
Distance: 1400 light years
Release date: 4 October 1990, 05:00
Credit: NASA/ESA

Galactic black hole with optical jet (artist's impression): The energy source needed to create and maintain the galactic let in galaxy PKS 0521-36 is generated deep within the core of the galaxy, and is far too small to resolved. The favored mechanism behind these cosmic fireworks is a spinning, massive black hole. The hole is fueled by a continual in-fall of nearby gas and stars. This gravitational accretion process is far more efficient at converting mass to energy than thermonuclear fusion processes which power individual stars. The extraordinary high pressure and temperature generated near the hole would cause some of the in-falling gas to be ejected along the direction of the black hole's spinning axis to create the galactic let.

Name: PKS 0521-36, QSO B0521-365
Type: Early Universe : Galaxy : Component : Central Black Hole
Category: Quasars and Black Holes
Distance: z=0.056 (redshift)
Release date: 4 October 1990, 05:00
Credit: Dana Berry (STScI)

Braided galactic jet: This is a ten thousand light-year long jet of plasma observed by the European Space Agency's Faint Object Camera, aboard NASA/ESA Hubble Space Telescope. The image, which is much sharper than previous pictures taken with ground based telescopes. reveals unprecedented detail in the jet. The most remarkable feature is a distinctive twisted ladder structure produced by two spiral filaments of plasma. The pair of strands are separated by about 500 light-years. Other details reveal unusual knots and kinks in the outflowing material. The jet is produced by energetic activity at the core of the galaxy perhaps due to gravitational accretion of material onto a super massive black hole. In this ultraviolet light picture the image of the host galaxy, 3C 668, has been subtracted to allow details in the jet to be traced all the way in to the galaxy's nucleus (center). Image reconstruction techniques have been applied to minimize the effects of spherical aberration produced by the HST's 2.4 meter primary mirror.

Name: 3C 668
Type: Local Universe : Galaxy : Component : Central Black Hole
Category: GalaxiesMiscellaneous
Release date: 15 January 1991, 06:00
Credit: NASA and ESA

Starburst galaxy: An infrared image of the nearby starburst galaxy NGC 1569. Starburst galaxies undergo periods of intense star formation. The starburst activity in NGC 1569 is concentrated into three giant regions which are clearly visible as three red knots in the false colour image. These same starburst regions likely contain the massive X-ray binary stars which may be responsible for part of the mysterious X-ray background that permeates the universe.

Name: IRAS 0426+647P01, NGC 1569
Type: Local Universe : Galaxy : Activity : Starburst
Category: Galaxies
Distance: 7 million light years
Release date: 15 January 1991, 06:00
Credit: Antonelia Fruscione, Richard Grifliths and John MacKenty (STScI)

SN1987A: A NASA/ESA Hubble Space Telescope image of a gaseous ring surrounding the supernova 1987A, which exploded on February 23, 1987 in the Large Magellanic Cloud, an irregular satellite galaxy of the Milky Way. In this image, taken with the European Space Agency’s Faint Object Camera (FOC), HST’s 0.07 are second resolution reveals clumpy structure in the ring which indicates that the material is not uniformly distributed.

Name: SN 1987A
Type: Local Universe : Star : Evolutionary Stage : Supernova
Category: Stars
Constellation: Dorado
Distance: 170000 light years
Release date: 16 January 1991, 06:00
Credit: NASA and ESA

Artist's illustration of Beta Pictoris gas disk: This is an artist's concept of the near stellar environment of the star Beta Pictoris. This illustration is based upon recent observations made with the Goddard High Resolution Spectrograph aboard the Hubble Space Telescope. This illustration shows three major components of the near stellar region, which is roughly the size of our inner Solar System. The reddish center ring (C) is a diffuse gas disk, which has a stable orbit around the star. This ring surrounds an inner disk (D) of gas which is slowly drifting toward the star. The white "comet-like" features in this bluish disk are dense streams of gas spiraling down the star gravitational potential "well." The outer filamentary structures (A&B;), first detected by the Space Telescope, may be an expanding gas halo, or foreground features seen in the local interstellar medium.

Name: Beta Pictoris
Type: Milky Way : Star : Circumstellar Material : Disk
Category: Stars
Distance: 70 light years
Release date: 17 May 1991, 06:00
Credit: Dana Berry (STScI)

Eta Carinae: A Hubble Space Telescope observation of the star Eta Carinae, made with the Wide Field and Planetary Camera (WF/PC). An eruptive variable star, Eta Carinae has expelled a large amount of gas into the surrounding interstellar medium. The HST resolves individual clumps as small as only about ten times the size of our Solar System. Because it is clumpy on such small scales, and has such a well defined edge, the nebula is probably a thin and well defined shell of material, rather than a filled volume. Radiation pressure and stellar wind from Eta Carinae have fragmented the shell. Ejecta from the star slams into slower moving gas to create a ridge of emission to the lower right. This ridge is in fact part of a "cap" of material located to the southwest and behind the star. Small knots and filaments trace the locations of other shock fronts within the nebula.

Name: Eta Carinae
Type: Milky Way : Star : Type : Wolf-Rayet
Category: Stars
Constellation: Carina
Distance: 7500 light years
Release date: 17 May 1991, 06:00
Credit: J. Hester/Caltech & NASA/ESA