Astronomy Picture Of the Day (APOD)The Scale of the Universe: Interactive
What does the universe look like on small scales? On large scales? Humanity is discovering that the universe is a very different place on every proportion that has been explored. For example, so far as we know, every tiny proton is exactly the same, but every huge galaxy is different.
The Seagull Nebula
A broad expanse of glowing gas and dust presents a bird-like visage to astronomers from planet Earth, suggesting its popular moniker - The Seagull Nebula. This portrait of the cosmic bird covers a 1.6 degree wide swath across the plane of the Milky Way, near the direction of Sirius, alpha star of the constellation Canis Major.
NGC 7293: The Helix Nebula
A mere seven hundred light years from Earth, in the constellation Aquarius, a sun-like star is dying. Its last few thousand years have produced the Helix Nebula (NGC 7293), a well studied and nearby example of a Planetary Nebula, typical of this final phase of stellar evolution.
The Tadpoles of IC 410
This telescopic close-up shows off the otherwise faint emission nebula IC 410 in striking false-colors. It also features two remarkable inhabitants of the cosmic pond of gas and dust below and right of center, the tadpoles of IC 410. The picture is a composite of images taken through narrow band filters.
Sunspot at Sunset
Sunsets may be the most watched celestial event, but lately sunsets have even offered something extra. A sunspot so large it was visible to the naked eye is captured in Swiss skies in this...
M7: Open Star Cluster in Scorpius
M7 is one of the most prominent open clusters of stars on the sky. The cluster, dominated by bright blue stars, can be seen with the naked eye in a dark sky in the tail of the constellation of the Scorpion (Scorpius).
Three CubeSats Released
Cubes are orbiting the Earth. Measuring ten-centimeters on a side, CubeSats -- each roughly the size of a large coffee mug -- are designed to be inexpensive both to build and to launch. Pictured above, three CubeSats were released from the International Space Station (ISS) last November by the arm of the Japanese Kibo Laboratory module.
Galaxy NGC 474: Shells and Star Streams
What's happening to galaxy NGC 474? The multiple layers of emission appear strangely complex and unexpected given the relatively featureless appearance of the elliptical galaxy in less deep images. The cause...
Clouds and Crescents
A crescent Venus shines along the western horizon at dusk in this clearing sky. The Earth's sister planet is smiling between the low clouds near the bottom of the frame during its January 2nd conjunction with the slender, young crescent Moon above.
Lovejoy in the New Year
A rival to vanquished Comet ISON in 2013, Comet Lovejoy (C/2013 R1) still sweeps through early morning skies, captured in this starry scene on New Year's day. The frame stretches some 3.5 degrees across a background of faint stars in the constellation Hercules.