Browse NASA Astronomy Picture of the Day archive by date and media: Archive Discoveries
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The Brightest Spot on Ceres
Dwarf planet Ceres is the largest object in the Solar System's main asteroid belt with a diameter of about 950 kilometers. Exploring Ceres from orbit since March, the Dawn…
Daytime Moon Meets Morning Star
Venus now appears as Earth's brilliant morning star, standing in a line-up of planets above the southeastern horizon before dawn. For most, the silvery celestial beacon rose…
Arp 87: Merging Galaxies from Hubble
This dance is to the death. Along the way, as these two large galaxies duel, a cosmic bridge of stars, gas, and dust currently stretches over 75,000 light-years and joins them.…
Icelandic Legends and Aurora
Legends collide in this dramatic vista of land, sea, and sky. The land is Iceland, specifically Vk Mrdal , a southern village known for its beautiful black sand beaches . The sea,…
Comet Catalina Emerges
Comet Catalina is ready for its close-up. The giant snowball from the outer Solar System, known formally as C/2013 US10 (Catalina) , rounded the Sun last month and is now headed…
A Force from Empty Space: The Casimir Effect
This tiny ball provides evidence that the universe will expand forever. Measuring slightly over one tenth of a millimeter, the ball moves toward a smooth plate in response to…
Kepler Orrery IV
The exoplanet hunting Kepler mission's total for candidate and confirmed multiple planet systems stands at 1,705 worlds in orbit around 685 distant stars. Put all of those…
Cygnus: Bubble and Crescent
These clouds of gas and dust drift through rich star fields along the plane of our Milky Way Galaxy toward the high flying constellation Cygnus. Caught within the telescopic field…
Enceladus: Ringside Water World
Saturn's icy moon Enceladus poses above the gas giant's icy rings in this Cassini spacecraft image. The dramatic scene was captured on July 29, while Cassini cruised just below…
Golden Gate Sunset: Green Flash
The setting is San Francisco Bay, the time is sunset, and the bridge is the Golden Gate. What you are about to see is an unexpected double sunset ending with a rare green flash.…
Nebulae in Auriga
Rich in star clusters and nebulae, the ancient constellation of the Charioteer ( Auriga ) rides high in northern winter night skies. Composed from narrow and broadband filter data…
In the Center of Spiral Galaxy NGC 3521
This huge swirling mass of stars, gas, and dust occurs near the center of a nearby spiral galaxy. Gorgeous spiral NGC 3521 is a mere 35 million light-years distant, toward the…
Dark Sand Cascades on Mars
They might look like trees on Mars, but they're not. Groups of dark brown streaks have been photographed by the Mars Reconnaissance Orbiter on melting pinkish sand dunes covered…
Rosetta and Comet Outbound
Not a bright comet , 67P/Churyumov-Gerasimenko now sweeps slowly through planet Earth's predawn skies near the line-up of planets along the ecliptic . Still, this composite of…
Gravity's Grin
Albert Einstein's general theory of relativity, published 100 years ago this month, predicted the phenomenon of gravitational lensing. And that's what gives these distant galaxies…
Planets of the Morning
Planet Earth's horizon stretches across this recent Solar System group portrait, seen from the southern hemisphere's Las Campanas Observatory. Taken before dawn it traces the…
Unusual Pits Discovered on Pluto
Why are there unusual pits on Pluto? The indentations were discovered during the New Horizons spacecraft's flyby of the dwarf planet in July. The largest pits span a kilometer…
Aurora over Clouds
Auroras usually occur high above the clouds. The auroral glow is created when fast-moving particles ejected from the Sun impact the Earth's magnetosphere , from which charged…
A 212-Hour Exposure of Orion
The constellation of Orion is much more than three stars in a row. It is a direction in space that is rich with impressive nebulas. To better appreciate this well-known swath of…
Phobos: Doomed Moon of Mars
This moon is doomed. Mars , the red planet named for the Roman god of war , has two tiny moons, Phobos and Deimos , whose names are derived from the Greek for Fear and Panic .…
Recycling NGC 5291
Following an ancient galaxy-galaxy collision 200 million light-years from Earth, debris from a gas-rich galaxy, NGC 5291, was flung far into intergalactic space. NGC 5291 and the…
Leonids and Friends
Leonid meteors rained down on planet Earth this week, the annual shower of dusty debris from the orbit of Comet 55P/Tempel-Tuttle . Leonids streak through this composite night…
Centaurus A
What's the closest active galaxy to planet Earth? That would be Centaurus A, only 11 million light-years distant. Spanning over 60,000 light-years, the peculiar elliptical galaxy…
A Sudden Jet on Comet 67P
There she blows ! A dramatic demonstration of how short-lived some comet jets can be was documented in late July by the robotic Rosetta spacecraft orbiting the nucleus of Comet…
Viewing discoveries from 11 December 2015 through 18 November 2015.