Astronomy Picture of the Day

2017-04-26 Dario Giannobile

Mt. Etna has been erupting for hundreds of thousands of years. Located in Sicily, Italy, the volcano produces lava fountains over one kilometer high. Mt. Etna is not only one of the most active volcanoes on Earth, it is one of the largest, ...

2017-04-25 Fritz Helmut Hemmerich

What's happened to Comet Lovejoy? In the pictured image, a processed composite, the comet was captured early this month after brightening unexpectedly and sporting a long and intricate ion tail. Remarkably, the typically complex effect of the ...

2017-04-24

Trillions have died in the Earth's seas. Calcified shields of the dead already make up the white cliffs of Dover. The battle between ball-shaped light-colored single-celled plants -- phytoplankton called coccolithophores -- and even smaller, ...

2017-04-23

Is this picture worth a thousand words? According to the Holographic Principle, the most information you can get from this image is about 3 x 1065 bits for a normal sized computer monitor. The Holographic Principle, yet unproven, states that ...

2017-04-22

On April 12, as the Sun was blocked by the disk of Saturn the Cassini spacecraft camera looked toward the inner Solar System and the gas giant's backlit rings. At the top of the mosaicked view is the A ring with its broader Encke and narrower ...

2017-04-21

Seen edge-on, spiral galaxy NGC 4302 (left) lies about 55 million light-years away in the well-groomed constellation Coma Berenices. A member of the large Virgo Galaxy Cluster, it spans some 87,000 light-years, a little smaller than our own Milky ...

2017-04-20

A day before its closest approach, asteroid 2014 JO25 was imaged by radar with the 70-meter antenna of NASA's Goldstone Deep Space Communications Complex in California. This grid of 30 radar images, top left to lower right, reveals the two-lobed ...

2017-04-19 Jesús M.Vargas & Maritxu Poyal

Oh what a tangled web a planetary nebula can weave. The Red Spider Planetary Nebula shows the complex structure that can result when a normal star ejects its outer gases and becomes a white dwarf star. Officially tagged NGC 6537, this two-lobed ...

2017-04-18 Taha Ghouchkanlu

What glows in the night? This night, several unusual glows were evident -- some near, but some far. The foreground surf glimmers blue with the light of bioluminescent plankton. Next out, Earth's atmosphere dims the horizon and provides a few ...

2017-04-17

If you could watch the night sky for one million years -- how would it change? Besides local effects caused by the Earth's spin and the reorientation of the Earth's spin axis, the stars themselves will move. Combining positional data of ...