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.
Uranian Moons, Rings, And Clouds
The giant planet Uranus is faint and featureless when viewed in visible light . But this pair of near-infrared mosaics from the Hubble Space Telescope's NICMOS camera reveals…
The Comet and the Galaxy
The Moon almost ruined this photograph. During late March and early April, Comet Hale-Bopp passed nearly in front of the Andromeda Galaxy . Here the Great Comet of 1997 and the…
Jet Near Light Speed
Einstein 's Special Theory of Relativity says that nothing can travel faster than the speed of light. Jets of protons and electrons that shoot away from objects such as quasars…
Triton: Neptune's Largest Moon
On October 10th, 1846, William Lassell was observing the newly discovered planet Neptune . He was attempting to confirm his observation, made just the previous week, that Neptune…
Surveyor Hops
This panorama of the cratered lunar surface was constructed from images returned by the US Surveyor 6 lander. Surveyor 6 was not the first spacecraft to accomplish a soft landing…
Jupiter: Moon, Ring, and Clouds
An inner moon, an edge-on, planet-girdling ring, and high altitude cloud bands are visible in this mosaic of infrared images of gas giant Jupiter . The moon Metis , 25 miles wide…
Escape From The Sun
Twisted magnetic fields arching from the solar surface can trap ionized gas, suspending it in huge looping structures. These majestic plasma arches are seen as prominences above…
Diffraction Spikes: When Stars Look Like Crosses
Unusual appendages around bright stars are commonplace, but never seem to be mentioned. What are they? First, a telescope brings starlight falling over a large area to a small…
In the Center of the Trapezium
Start with the constellation of Orion. Below Orion 's belt is a fuzzy area known as the Great Nebula of Orion or M42. In this nebula is a bright star cluster known as the…
Barringer Crater on Earth
What happens when a meteor hits the ground? Usually nothing much, as most meteors are small, and indentations they make are soon eroded away. 49,000 years ago, however, a large…
The Leonid Meteor Shower
The Leonid Meteor Shower will likely reach its peak in the early hours this Monday morning. Though the Moon will be bright, Leo , the shower's radiant point , will be well above…
Uranus: The Tilted Planet
Uranus is the third largest planet after Jupiter and Saturn . This picture was snapped by the Voyager 2 spacecraft in 1986 - the only spacecraft ever to visit Uranus . Uranus has…
Irregular Galaxy Sextans A
Grand spiral galaxies often seem to get all the glory. Their newly formed, bright, blue star clusters found along beautiful, symmetric spiral arms are guaranteed to attract…
Mars: A Sheer Close-up
As the Mars Global Surveyor spacecraft maneuvers toward its final mapping orbit , its cameras have been producing some sharp views of Mars. At a resolution of better than 30 feet…
El Niño Earth
El Niño is a temporary global climate change resulting from unusually warm water in the central Pacific Ocean. El Niño can cause unusual or severe weather for some locations over…
The Annotated Galactic Center
The sky toward the center of our Galaxy is filled with a wide variety of celestial wonders . Most are visible with only binoculars. Constellations of nearby stars include…
Dark Volcano Active on Io
The surface of Io is changing even as we watch. The inset frame of Jupiter 's most active moon was taken by the robot spacecraft Galileo in April. Just last month the larger image…
Surveyor Slides
“Safe!” In September 1967 ( during regular season play ), the Surveyor 5 lander actually slid several feet while making a successful soft landing on the Moon's Mare…
Aristarchus' Unbelievable Discoveries
Here lived one of the greatest thinkers in human history. Aristarchus lived on the Greek island of Samos, a small island in the center of the above picture that can be identified…
Evidence for Frame Dragging Black Holes
Gravity can do more than floor you. According to recent measurements of a star system thought to contain a black hole , it can spin you too. This effect, called frame-dragging ,…
The Magnetic Carpet Of The Sun
The Sun has a magnetic carpet . Its visible surface appears to be carpeted with tens of thousands of magnetic north and south poles joined by looping field lines which extend…
The Milky Way's Gamma-Ray Halo
Our Milky Way galaxy appears to be surrounded by a halo of gamma rays . Gamma rays are the most energetic form of electromagnetic radiation , with more than a hundred thousand…
Blue Stragglers in Globular Clusters
This old dog is doing new tricks. On the left is ancient globular cluster 47 Tucanae which formed many billions of years ago. On the right is a closeup of its dense stellar center…
Irregular Moons Discovered Around Uranus
Where did these two irregular moons of Uranus originate? Last week two previously undiscovered moons of the distant gas planet were confirmed , the first in irregular orbits. All…
Viewing discoveries from 26 November 1997 through 3 November 1997.