Browse NASA Astronomy Picture of the Day archive by date and media: Archive Discoveries
Browse the NASA APOD archive without needing the exact date first. Filter by media type and keep moving deeper into older images and videos.
A Halo for NGC 6164
Beautiful emission nebula NGC 6164 was created by a rare, hot, luminous O-type star, some 40 times as massive as the Sun. Seen at the center of the cosmic cloud, the star is a…
A Spring Sky Over Hirsau Abbey
What's in the sky tonight? When strolling outside just after sunset, even if just going out to your car, a casual glance upwards can reveal a beautiful night sky also seen by many…
Titan Beyond the Rings
When orbiting Saturn, be sure to watch for breathtaking superpositions of moons and rings. One such picturesque vista was visible recently to the robot Cassini spacecraft now…
Rembrandt Impact Basin on Mercury
Why do portions of this huge crater on Mercury have so much iron? The unusual Rembrandt impact basin was discovered recently in images taken during the robotic MESSENGER…
NGC 2392 Nebula from Hubble
In 1787, astronomer William Herschel discovered NGC 2392 . From the ground, NGC 2392 resembles a person's head surrounded by a parka hood. In 2000, the Hubble Space Telescope…
The Whale Galaxy
NGC 4631 is a big beautiful spiral galaxy. Seen edge-on , it lies only 25 million light-years away in the well-trained northern constellation Canes Venatici . The galaxy's…
Lyrid Meteor and Milky Way
On April 22nd, the Lyrid Meteor Shower visited planet Earth's sky, an annual shower produced as the Earth plows through dust from the tail of comet Thatcher . Usually Lyrid meteor…
Framed by Clouds
Last Sunday's fading evening twilight featured a young crescent Moon along the western horizon. The young Moon also shared the sky with the lovely Pleiades star cluster and…
GRB 090423: The Farthest Explosion Yet Measured
An explosion so powerful it was seen clear across the visible universe was recorded in gamma-radiation last week by NASA's orbiting Swift Observatory . Farther than any known…
NGC 4565: Galaxy on the Edge
Is our Galaxy this thin? We believe so. Magnificent spiral galaxy NGC 4565 is likely similar to our own spiral galaxy, but viewed edge-on from far away. Also known as the Needle…
Prometheus Creating Saturn Ring Streamers
What's causing those strange dark streaks in the rings of Saturn? Prometheus . Specifically, an orbital dance involving Saturn's moon Prometheus keeps creating unusual light and…
NGC 4676: When Mice Collide
These two mighty galaxies are pulling each other apart. Known as “ The Mice ” because they have such long tails, each spiral galaxy has likely already passed through the other.…
Dark Markings of the Sky
Based on wide field photographs, American astronomer Edward Emerson Barnard cataloged the dark markings of the sky in the early 20th century. Barnard's markings are dark nebulae,…
Moon and Morning Star
Wednesday, the Moon and Venus rose together in early morning skies. Even through clouds, both show off a lovely crescent in this well-composed skyscape from Rutherford College,…
Sharpless 308
Blown by fast winds from a hot, massive star, this cosmic bubble is huge. Cataloged as Sharpless 308 it lies some 5,200 light-years away in the constellation Canis Major and…
Sky Panorama Over Lake Salda
As midnight approached, a spectacular sky appeared. Such was the case last month from the shore of Lake Salda in southwestern Turkey . In the above night sky panorama , rocky sand…
Global Warming Predictions
How much will the Earth's surface warm up over the lives of our children? No one is sure. Compared to the past 100 million years, the Earth is currently enduring a relative cold…
Flowing Barchan Sand Dunes on Mars
When does Mars act like a liquid? Although liquids freeze and evaporate quickly into the thin atmosphere of Mars, persistent winds may make large sand dunes appear to flow and…
The View Near a Black Hole
In the center of a swirling whirlpool of hot gas is likely a beast that has never been seen directly: a black hole . Studies of the bright light emitted by the swirling gas…
NGC 1333 Stardust
NGC 1333 is seen in visible light as a reflection nebula , dominated by bluish hues characteristic of starlight reflected by dust. A mere 1,000 light-years distant toward the…
Medieval Astronomy from Melk Abbey
Discovered by accident, this manuscript page provides graphical insight to astronomy in medieval times, before the Renaissance and the influence of Nicolaus Copernicus , Tycho de…
Castle and Full Moon
Clouds couldn't hide this bright Full Moon as it rose last week over the medieval castle of Tourrette-Levens near Nice, France. Exactly full on April 9 at 1456 UT, it followed the…
Jagged Shadows May Indicate Saturn Ring Particles
What's causing unusual jagged shadows on Saturn's rings? No one is yet sure. As Saturn nears equinox , its rings increasingly show only their thin edge to the Earth and Sun. As a…
M101: The Pinwheel Galaxy
Why do many galaxies appear as spirals ? A striking example is M101 , shown above , whose relatively close distance of about 27 million light years allows it to be studied in some…
Viewing discoveries from 7 May 2009 through 14 April 2009.