Astronomy Picture Of the Day (APOD)An Unusual Mountain on Asteroid Ceres
What created this large mountain on asteroid Ceres? No one is yet sure. As if in anticipation of today being Asteroid Day on Earth, the robotic spacecraft Dawn in orbit around Ceres took the best yet image of an unusually tall mountain on the Asteroid Belt's largest asteroid.
Sunspot Group AR 2339 Crosses the Sun
How do sunspots evolve? Large dark sunspots -- and the active regions that contain them -- may last for weeks, but all during that time they are constantly changing. Such variations were particularly apparent...
All the Colors of the Sun
It is still not known why the Sun's light is missing some colors. Here are all the visible colors of the Sun, produced by passing the Sun's light through a prism-like device.
Stars of a Summer Triangle
Rising at the start of a northern summer's night, these three bright stars form the familiar asterism known as the Summer Triangle. Altair, Deneb, and Vega are the alpha stars of their respective constellations, Aquila, Cygnus, and Lyra, nestled near the Milky Way.
What bizarre alien planet is this ? It's planet Earth of course, seen through the shimmering glow of aurorae from the International Space Station. About 400 kilometers (250 miles) above, the orbiting station is itself within the upper realm of the auroral displays, also watched from the planet's surface on June 23rd.
Star Trails Above Table Mountain
Stars trail above and urban lights sprawl below in this moonlit nightscape from Cape Town, South Africa, planet Earth. The looming form of Table Mountain almost seems to hold terrestrial lights at bay while the stars circle the planet's South Celestial Pole.
Triple Conjunction Over Galician National Park
What are those bright objects hovering over the horizon? Planets -- and the Moon. First out, the horizon featured is a shoreline of the Atlantic Ocean that occurs at the Galicia National Park in northern Spain. Next furthest out, on the left, is the Moon.
Sharpless 308: Star Bubble
Blown by fast winds from a hot, massive star, this cosmic bubble is huge. Cataloged as Sharpless 2-308 it lies some 5,200 light-years away toward the constellation of the Big Dog (Canis Major) and covers slightly more of the sky than a Full Moon.
In three weeks, the robotic New Horizons spacecraft will reach Pluto. As the featured video makes clear, though, humanity has been on an unprecedented epoch of robotic exploration of our Solar System's planets for the past half century.
Rings and Seasons of Saturn
On Saturn, the rings tell you the season. On Earth, today marks a solstice, the time when the Earth's spin axis tilts directly toward the Sun. On Earth's northern hemisphere, today is the Summer Solstice, the day of maximum daylight.