Astronomy Picture of the Day

photo Millions of Stars in Omega Centauri

Millions of Stars in Omega Centauri

Globular star cluster Omega Centauri, also known as NGC 5139, is some 15,000 light-years away. The cluster is packed with about 10 million stars much older than the Sun within a volume about 150 light-years in diameter. It's the largest and ...

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photo NGC 1499: The California Nebula

NGC 1499: The California Nebula

Drifting through the Orion Arm of the spiral Milky Way Galaxy, this cosmic cloud by chance echoes the outline of California on the west coast of the United States. Our own Sun also lies within the Milky Way's Orion Arm, only about 1,500 ...

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photo Nearby Spiral Galaxy NGC 4945

Nearby Spiral Galaxy NGC 4945

Large spiral galaxy NGC 4945 is seen edge-on near the center of this cosmic galaxy portrait. In fact, it's almost the size of our Milky Way Galaxy. NGC 4945's own dusty disk, young blue star clusters, and pink star forming regions standout in the ...

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photo The Orion You Can Almost See

The Orion You Can Almost See

Do you recognize this constellation? Although it is one of the most recognizable star groupings on the sky, this is a more full Orion than you can see -- an Orion only revealed with long exposure digital camera imaging and post-processing. Here ...

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photo Animation: Spiral Disk around a Black Hole

Animation: Spiral Disk around a Black Hole

What would it look like to orbit a black hole? Many black holes are surrounded by swirling pools of gas known as accretion disks. These disks can be extremely hot, and much of the orbiting gas will eventually fall through the black hole's event ...

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photo Lenticular Clouds over Mount Etna

Lenticular Clouds over Mount Etna

What's happening above that volcano? Although Mount Etna is seen erupting, the clouds are not related to the eruption. They are lenticular clouds formed when moist air is forced upwards near a mountain or volcano. The surreal scene was captured ...

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photo Human as Spaceship

Human as Spaceship

You are a spaceship soaring through the universe. So is your dog. We all carry with us trillions of microorganisms as we go through life. These multitudes of bacteria, fungi, and archaea have different DNA than you. Collectively called your ...

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photo 1901 Photograph: The Orion Nebula

1901 Photograph: The Orion Nebula

By the turn of the 20th century advances in photography contributed an important tool for astronomers. Improving photographic materials, long exposures, and new telescope designs produced astronomical images with details not visible at the ...

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photo The Elephant's Trunk Nebula in Cepheus

The Elephant's Trunk Nebula in Cepheus

Like an illustration in a galactic Just So Story, the Elephant's Trunk Nebula winds through the emission nebula and young star cluster complex IC 1396, in the high and far off constellation of Cepheus. Also known as vdB 142, the cosmic elephant's ...

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photo The Perseids and the Plough

The Perseids and the Plough

Despite interfering moonlight, many denizens of planet Earth were able to watch this year's Perseid meteor shower. This pastoral scene includes local skygazers admiring the shower's brief, heavenly flashes in predawn hours near peak activity on ...

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