Uranus' Moon Ariel: Valley World
2.03.1996

What formed Ariel's valleys? This question presented itself when Voyager 2 passed this satellite of Uranus in January 1986. Speculation includes that heating caused by the ancient tides of Uranus caused moonquakes and massive shifting of the moon's surface.

Astro 1 In Orbit
4.05.1996

In December of 1990, the Space Shuttle Columbia carried an array of astronomical telescopes high above the Earth's obscuring atmosphere to observe the Universe at ultraviolet and x-ray wavelengths. The telescopes, known...

Black Holes and Galactic Centers
13.01.1997

Do all galaxies have black holes at their centers? Although not even a single galaxy has yet been proven to have a central black hole, the list of candidates has increased yet again. Recent...

Jupiter: At The Belt-Zone Boundary
9.03.1997

Jupiter's thick atmosphere is striped by wind-driven cloud bands that remain fixed in latitude - dark colored bands are known as belts while light colored bands are zones. At Jupiter's belt-zone boundaries the shearing wind velocities can reach nearly 300 miles per hour.

Mars: Ridges Near the South Pole
19.03.1998

No, it's not breakfast ... but looking down from an orbiting spacecraft, the odd intersecting ridges covering this area of Mars do present a waffle-like appearance. The cause of the ridge pattern is unknown but it suggests that more complex layered deposits lie below.

A Martian Sunset
1.08.1997

You've had a hard day rolling past Martian rocks, so now just relax your APXS and enjoy the Martian sunset. The above pictures taken by Mars Pathfinder highlight how clouds vary during the end of a Martian day.

Comet Halley and the Milky Way
3.10.1997

Comet Halley was photographed superposed in front of the disk of our Milky Way Galaxy in 1986 by the Kuiper Airborne Observatory. Comet Halley is the bright white streak near this photograph's center. Comet Halley is the most famous comet in history, and returns to the inner Solar System every 76 years.

Solar Magnetic Bananas
29.06.1998

Is that our Sun? The unusual banana-shaped loops shown above are actually part of a computer-generated snap-shot of our Sun's magnetic field. This animated frame was constructed using data from the ground-based U.S. Solar Vector Magnetograph and the space-based Japanese X-Ray Telescope Yohkoh.

In the Center of the Trapezium
10.07.2005

Start with the constellation of Orion. Near Orion's belt is a fuzzy area known as the Great Nebula of Orion or M42. In this nebula is a bright star cluster known as the Trapezium, shown above. New stellar systems are forming there in gigantic globs of gas and dust known as Proplyds.

Venus on the Horizon
19.06.1999

Venus can appear as a brilliant evening star. Besides the sun and moon, Venus is the brightest object visible in Earth's sky. Because it is closer to the sun than Earth, Venus never...