Astronomy Picture Of the Day (APOD)
NGC 4414: A Telling Spiral9.06.1999
How far away is this galaxy? Cosmologists the world over have been working hard to find out. Spiral galaxy NGC 4414 contains many Cepheid variable stars that oscillate in a way that allows astronomers to estimate their distance.
Trifid Pillars and Jets
8.06.1999
Dust pillars are like interstellar mountains. They survive because they are more dense than their surroundings, but they are being slowly eroded away by a hostile environment. Visible in the above picture...
Starbirth in the Trifid Nebula
7.06.1999
Tremendous pillars of gas and dust are being boiled away in the Trifid Nebula. In the center of the picturesque Trifid lies a young hot star, located above and to the right of this picture. As soon as it was born, the massive star scorched its surroundings with bright and
Kepler Discovers How Planets Move
6.06.1999
Johannes Kepler used simple mathematics to describe how planets move. Kepler was an assistant to the most accurate astronomical observer of the time, Tycho Brahe. Kepler was able to use Brahe's data...
Betelgeuse, Betelgeuse, Betelgeuse
5.06.1999
Betelgeuse (sounds a lot like "beetle juice"), a red supergiant star about 600 light years distant, is seen in this Hubble Space Telescope image - the first direct picture of the surface of a star other than the Sun. While Betelgeuse is cooler than the Sun, it is more massive and over 1000 times larger.
NGC 3603: From Beginning To End
4.06.1999
From beginning to end, different stages of a star's life appear in this exciting Hubble Space Telescope picture of the environs of galactic emission nebula NGC 3603. For the beginning, eye-catching "pillars" of glowing hydrogen at the right signal newborn stars emerging from their dense, gaseous, nurseries.
Methane Dwarf
3.06.1999
While hunting through Sloan Sky Survey data in search of distant quasars, Princeton astronomers Xiaohui Fan and Michael Strauss came upon an undiscovered type of object very nearby - now dubbed a methane dwarf. Marked...
Thermal Mars
2.06.1999
It's 2 AM on Mars and surface temperatures range from -65C to -120C, as measured by the Thermal Emission Spectrometer (TES) onboard the Mars Global Surveyor spacecraft. TES data used...
A Gallery of Gravitational Mirages
1.06.1999
The deeper you peer into the universe, the harder it is to see straight. The reason is that distant galaxies act as gravitational lenses, deflecting light that passes nearby. These deflections result in the distortion of background sources, and in some cases the creation of multiple images.
Uranus Moon 18
31.05.1999
The discovery was there for the taking. An image of Uranus taken by Voyager 2 as it passed the giant planet 13 years ago apparently recorded a moon that had since gone unnoticed. The image on which Uranus' 18th moon was discovered was freely available from NASA. Erich Karkoschka (U.
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