Astronomy Picture Of the Day (APOD)Eris: More Massive than Pluto
Eris, a dwarf planet currently orbiting the Sun at about twice Pluto's distance, has been measured to have about 27 percent more mass than Pluto. The mass was calculated by timing the orbit of Eris' moon Dysnomia.
Exploring the myriad shapes found in the cosmic zoo of planetary nebulae, some astronomers have focused on the intriguing example of M2-9. About 2,100 light-years away and over one light-year across, M2-9 is known as a twin jet or butterfly nebula in reference to its striking bipolar symmetry.
Analemma over the Ukraine
If you took a picture of the Sun at the same time each day, would it remain in the same position? The answer is no, and the shape traced out by the Sun over the course of a year is called an analemma.
Lunar Orbiter Views Crater Copernicus
To prepare for the Apollo landings, five Lunar Orbiter spacecraft were launched during 1966 and 1967 to gather detailed images of our fair planet's large, natural satellite. Dramatic views returned by the spacecraft cameras included this stark moonscape.
Dust lanes seem to swirl around the core of Messier 96 in this colorful, detailed portrait of the beautiful island universe. Of course M96 is a spiral galaxy, and counting the faint arms extending beyond the brighter central region it spans 100 thousand light-years or so, about the size of our own Milky Way.
vdB 152: Reflection Nebula in Cepheus
Described as a "dusty curtain" or "ghostly apparition", mysterious reflection nebula vdB 152 really is very faint. It lies about 1400 light-years away, along the northern Milky Way in the royal constellation Cepheus. Near...
Warped Sky: Star Trails Panorama
What's happened to the sky? A time warp, of sorts, and a digital space warp too. The time warp occurs because the above image captured in a single frame a four hour exposure of the night sky. Prominent and picturesque star trails are visible.
What kind of cloud is that? Not a naturally occurring one. Pictured above is the drifting smoke plume left over from last Friday's launch of the Space Shuttle Atlantis. The twisted plume was captured shortly after launch high above NASA's massive Vehicle Assembly Building, the largest single story building in the world.
The Merope Reflection Nebula
Reflection nebulas reflect light from a nearby star. Many small carbon grains in the nebula reflect the light. The blue color typical of reflection nebula is caused by blue light being more efficiently scattered by the carbon dust than red light.
Looking Back at an Eclipsed Earth
Here is what the Earth looks like during a solar eclipse. The shadow of the Moon can be seen darkening part of Earth. This shadow moved across the Earth at nearly 2000 kilometers per hour.