Hickson Compact Group 40

1999-02-17

Galaxies, like stars, frequently form groups. A group of galaxies is a system containing more than two galaxies but less than the tens or hundreds typically found in a cluster of galaxies. A most notable example is the Local Group of Galaxies, ...

La Ni?a Earth

1999-02-15

La Ni?a is a temporary climate change caused by unusually cold water in the central Pacific Ocean. Cold water topping an unusually low sea level is shown as purple in the above false-color picture taken by the orbiting TOPEX/Poseidon satellite ...

Dark Sky, Bright Sun

1999-02-14

In low Earth orbit there is not enough atmosphere to diffuse and scatter sunlight, so shadows are black and the sky is dark - even when the Sun shines. The harsh lighting produced this dramatic effect as mission specialist Gregory Harbaugh ...

Pluto: The Frozen Planet

1999-02-13

This portrait of Pluto and its companion Charon was taken by the Hubble Space Telescope in 1994. Pluto is usually the most distant planet from the Sun but because of its eccentric orbit Pluto crossed inside of Neptune's orbit in 1979. On ...

Lunar Close-Up

1999-02-12

Late last month, NASA's Lunar Prospector spacecraft moved in for a closer look at the Moon. Now entering an extended mission phase, controllers have reduced the altitude of this polar lunar orbiter from 100 kilometers to about 30 kilometers (18 ...

A Disk and Jet in Haro 6-5B

1999-02-11

Planets condense from disks. Several new Hubble Space Telescope pictures of stars surrounded by disks were released earlier this week. Since the glare of the central star usually makes a surrounding disk hard to see, prior observations in radio ...

GRB 990123 Host Galaxy Imaged

1999-02-10

Do the powerful explosions known as gamma-ray bursts (GRBs) originate in galaxies? This subject took on new light yesterday with the release of a Hubble Space Telescope image of the sky surrounding GRB 990123. This burst was first detected only ...

A Supernova Star-Field

1999-02-09

Bright stars don't last forever. A bright star similar to others in this field exploded in a spectacular supernova that was witnessed on Earth in 1987. The result is visible even today as unusual rings and glowing gas. The above picture is a ...

The Solar Wind Emerges

1999-02-08

Winds of fast particles blow out from the Sun, but why? Astronomers came a step closer to answering this question recently by making detailed observations of the high-speed wind source with the space-borne Solar and Heliospheric Observatory ...

Titan: Saturn's Smog Moon

1999-02-07

The largest moon of Saturn is a rare wonder. Titan is the only one of Saturn's moons with an atmosphere, and one of only two moons in the Solar System with this distinction (Neptune's Triton is the other). Titan's thick cloudy atmosphere is ...