Astronomy Picture Of the Day (APOD)Phoebe: Comet Moon of Saturn
Was Saturn's moon Phoebe once a comet? Images from the robotic Cassini spacecraft taken two weeks ago when entering the neighborhood of Saturn indicate that Phoebe may have originated in the outer Solar System.
In the Center of NGC 6559
Bright gas and dark dust permeate the space between stars in the center of a nebula known as NGC 6559. The gas, primarily hydrogen, is responsible for the diffuse red glow of the emission nebula.
Spirit Rover Reaches the Columbia Hills on Mars
The Spirit robotic rover on Mars has now reached the Columbia Hills on Mars. Two of the hills are shown on approach near the beginning of June. The above true-color picture shows very nearly what a human would see from Spirit's vantage point.
Galaxy Cluster Abell 1689 Warps Space
Two billion light-years away, galaxy cluster Abell 1689 is one of the most massive objects in the Universe. In this view from the Hubble Space Telescope's Advanced Camera for Surveys, Abell 1689...
Neptune: Still Springtime After All These Years
In the 1960s spring came to the southern hemisphere of Neptune, the Solar System's outermost gas giant planet. Of course, since Neptune orbits the Sun once every 165 earth-years, it's still springtime for southern Neptune, where each season lasts over four decades.
Planet Earth from SpaceShipOne
On June 21st, pilot Mike Melvill made a historic flight in the winged craft dubbed SpaceShipOne -- the first private manned mission to space. The spaceship reached an altitude of just over 62 miles (100 kilometers) on a suborbital trajectory, similar to the early spaceflights in NASA's Mercury Program. So, how was the view?
The Galaxy Within Centaurus A
Peering deep inside Centaurus A, the closest active galaxy to Earth, the Spitzer Space Telescope's penetrating infrared cameras recorded this startling vista. About 1,000 light-years across, the twisted cosmic dust cloud apparently shaped like a parallelogram is likely the result of a smaller spiral galaxy falling into the giant Centaurus A.
A Picturesque Venus Transit
The rare transit of Venus across the face of the Sun earlier this month was one of the better-photographed events in sky history. Both scientific and artistic images have been flooding in from the areas that could see the transit: Europe and much of Asia, Africa, and North America.
Unusual Spires Found on Comet Wild 2
How did unusual spires form on comet Wild 2? Close inspection of images taken of Comet Wild 2 by the passing Stardust spacecraft in January show numerous strange pinnacles as long as 100 meters long jutting off the surface. The pinnacles were unexpected - close-ups of other comets and asteroids show no such features.
Analemma Over Ancient Nemea
An anelemma is that figure-8 curve that you get when you mark the position of the Sun at the same time each day throughout planet Earth's year. Above, 44 separate exposures (plus...