Astronomy Picture of the Day

photo Rumors of a Dark Universe

Rumors of a Dark Universe

Twenty-one years ago results were first presented indicating that most of the energy in our universe is not in stars or galaxies but is tied to space itself. In the language of cosmologists, a large cosmological constant -- dark energy -- was ...

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photo Mimas in Saturnlight

Mimas in Saturnlight

Peering from the shadows, the Saturn-facing hemisphere of Mimas lies in near darkness alongside a dramatic sunlit crescent. The mosaic was captured near the Cassini spacecraft's final close approach on January 30, 2017. Cassini's camera was ...

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photo Chamaeleon II Dark Cloud

Chamaeleon II Dark Cloud

A small constellation hiding near the south celestial pole, The Chamaeleon boasts no bright stars. Stars are forming within its constellation boundaries though, in a complex of dark, dusty molecular clouds. Some 500 light-years distant, the ...

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photo Elements in the Aftermath

Elements in the Aftermath

Massive stars spend their brief lives furiously burning nuclear fuel. Through fusion at extreme temperatures and densities surrounding the stellar core, nuclei of light elements ike Hydrogen and Helium are combined to heavier elements like ...

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photo IC 1795: The Fishhead Nebula

IC 1795: The Fishhead Nebula

To some, this nebula looks like the head of a fish. However, this colorful cosmic portrait really features glowing gas and obscuring dust clouds in IC 1795, a star forming region in the northern constellation Cassiopeia. The nebula's colors were ...

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photo Star Forming Region NGC 3582 without Stars

Star Forming Region NGC 3582 without Stars

What's happening in the Statue of Liberty nebula? Bright stars and interesting molecules are forming and being liberated. The complex nebula resides in the star forming region called RCW 57, and besides the iconic monument, to some looks like a ...

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photo Lightning over the Volcano of Water

Lightning over the Volcano of Water

Have you ever watched a lightning storm in awe? Join the crowd. Details of what causes lightning are still being researched, but it is known that inside some clouds, internal updrafts cause collisions between ice and snow that slowly separate ...

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photo The North America Nebula in Infrared

The North America Nebula in Infrared

The North America Nebula can do what most North Americans cannot -- form stars. Precisely where in the nebula these stars are forming has been mostly obscured by some of the nebula's thick dust that is opaque to visible light. However, a view of ...

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photo Chandrayaan 2 Launch

Chandrayaan 2 Launch

On July 22nd this GSLV (Geosynchronous Satellite Launch Vehicle) MkIII rocket vanished from sight into a cloud bank an instant after this dramatic snapshot was taken. Launched from India's Satish Dhawan Space Centre it carried the Chandrayaan 2 ...

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photo The Veins of Heaven

The Veins of Heaven

Transfusing sunlight through a still dark sky, this exceptional display of noctilucent clouds was captured earlier this month, reflected in the calm waters of Vallentuna Lake near Stockholm, Sweden. From the edge of space, about 80 kilometers ...

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