Astronomy Picture Of the Day (APOD)Unusual Plates on Mars
What are those unusual plates on Mars? A leading current interpretation holds that they are blocks of ice floating on a recently frozen sea covered by dust. The unusual plates were photographed recently by the European Space Agency's Mars Express spacecraft currently orbiting Mars.
The Solar Spectrum
It is still not known why the Sun's light is missing some colors. Shown above are all the visible colors of the Sun, produced by passing the Sun's light through a prism-like device.
Scientific images of cosmic dust clouds or even frozen water can be esthetic too. In fact, this picture of thin layers of forming ice crystals uses a scientific understanding of light's wave properties solely for artistic purposes. Titled "Illume", the picture was created by astrophysicist Peter Wasilewski.
Saturn s Dragon Storm
Dubbed the "Dragon Storm", convoluted, swirling cloud features are tinted orange in this false-color, near-infrared image of Saturn's southern hemisphere. In one of a series of discoveries announced by Cassini researchers, the Dragon...
Small, icy, inner moon of Saturn, Enceladus is only about 500 kilometers in diameter. But the distant world does reflect over 90 percent of the sunlight it receives, giving its surface about the same reflectivity as fresh snow.
Voyage of an Antarctic Iceberg
What if part of New York broke off and slammed into New Jersey? Both being anchored land masses, that is unlikely to happen, but an event of that size scale did occur off the Antarctic coast over the last three months.
Persistent Saturnian Auroras
Are Saturn's auroras like Earth's? To help answer this question, the Hubble Space Telescope and the Cassini spacecraft monitored Saturn's South Pole simultaneously as Cassini closed in on the gas giant in January 2004. Hubble snapped images in ultraviolet light, while Cassini recorded radio emissions and monitored the solar wind.
Galactic Magnetar Throws Giant Flare
Was the brightest Galactic blast yet recorded a key to connecting two types of celestial explosions? Last December, a dense sheet of gamma rays only a few times wider than the Earth plowed through our Solar System, saturating satellites and noticeably reflecting off the Moon.
Oklo: Ancient African Nuclear Reactors
The remnants of nuclear reactors nearly two billion years old were found in the 1970s in Africa. These reactors are thought to have occurred naturally. No natural reactors exist today, as the relative density of fissile uranium has now decayed below that needed for a sustainable reaction.
Big Dipper Castle
The stars of the big dipper, a well known asterism in the constellation Ursa Major, are easy to recognize in this dramatic skyscape. In fact, northern hemisphere skygazers often follow along the line indicated by the two stars at the far right.