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.
Comet Hyakutake Passes the Sun
On May 1, Comet Hyakutake made its closest approach to the Sun . During this time it was not possible to view the comet with most astronomical instruments because of the…
The Milky Way Near the Northern Cross
This beautiful image of the sky near the bright star Deneb (just above center) reveals the stars, nebulae, and dark clouds along the plane of our Milky Way Galaxy as seen from the…
Hubble's Constant and The Expanding Universe (II)
In this century, the discovery that the Universe is expanding has produced a revolution in human thought about the Cosmos. American astronomer Edwin Hubble played a major role in…
Hubble's Constant and The Expanding Universe (I)
Our Universe is expanding. Distant galaxies appear to recede from us at ever-increasing speeds. What is the rate of expansion? How long has it been expanding? What will be its…
Tracking Saturn's Moons
These five pairs of Hubble Space Telescope images track some of Saturn's moons as they orbit the ringed planet . A pair of images was taken every 97 minutes on November 21, 1995…
Sunlight Through Saturn's Rings
Normally, Earth based astronomers view Saturn's spectacular ring system fully illuminated by reflected sunlight. However, this November 1995 Hubble Space Telescope composite image…
Henize 70: A SuperBubble In The LMC
Massive stars (tens of times the mass of the Sun) profoundly affect their galactic environment. Churning and mixing the clouds of gas and dust between the stars, they leave their…
Supernova Remnant: Cooking Elements In The LMC
Massive stars cook elements in their cores through nuclear fusion . Starting with the light elements of hydrogen and helium, their central temperatures and pressures produce…
Neptune's Great Dark Spot: Gone But Not Forgotten
When NASA's Voyager 2 spacecraft flew by distant Neptune in August of 1989, astronomers were shocked . Since Neptune receives only 3 percent the sunlight Jupiter does, they…
The Clouds of Neptune
These Hubble Space Telescope (HST) images reveal glimpses of the dynamic atmosphere of Neptune , the Solar System's most distant gas giant planet . The first close-up of Neptune's…
Southern Lights and Shuttle Glow
A background of distant stars, sinuous and spiky bands of Southern Lights (Aurora Australis) , and the faint glow of charged plasma (ionized atomic gas) surrounding the Space…
Planet Near a Galaxy Core
What would the night sky look like if you lived on a planet near the center of a galaxy? Now imagine that this galaxy houses a black hole billions of times more massive than a…
Astro 1 In Orbit
In December of 1990, the Space Shuttle Columbia carried an array of astronomical telescopes high above the Earth's obscuring atmosphere to observe the Universe at ultraviolet and…
The Milky Way Near the Southern Cross
This breathtaking patch of sky would be above you were you to stand at the south pole of the Earth . Just above and to the right of the photograph's center are the four stars that…
The Tails of Comet Hyakutake
What makes comet tails so colorful? This photograph of Comet Hyakutake was taken the night of April 18th and highlights different components of the tail. The gold and red tail…
Comet Hyakutake and a Cactus
Comet Hyakutake is shown photographed the night of March 27 in Arizona, USA, with a cactus in the foreground. Polaris, the north star, is the bright star seen just to the upper…
Uranus' Ring System
The rings of Uranus are thin, narrow, and dark compared to other planetary ring systems. Brightened artificially by computer, the ring particles reflect as little light as…
Saturn's Rings Seen Sideways
Saturn's rings are actually very thin. This picture from the Hubble Space Telescope was taken on August 6, 1995 when the rings lined up sideways as seen from Earth . Saturn 's…
The Sun Sets on Comet Hyakutake
Comet Hyakutake is seen here just as the Sun sets on April 22. As April draws to a close, Comet Hyakutake will be visible only just after sunset and will be hard to discern…
Apollo 14: Rickshaw Tracks Across the Moon
Brilliant sunlight glints off tracks gently winding across the the Moon's Frau Maro highlands . The tracks were made by the Apollo 14 crew's two-wheeled Modularized Equipment…
A Giant Globular Cluster in M31
G1, pictured above, is the brightest known globular cluster in the whole Local Group of galaxies. Also called Mayall II, it orbits the center of the largest nearby galaxy: M31 .…
In the Center of the Whirlpool
In the center of M51 , a spiral galaxy 23 million light-years away, astronomers have identified a dense region of young stars. The graceful swirling arcs of this galaxy's spiral…
Giant Cluster Bends, Breaks Galaxy Images
What are those strange blue objects? Many are images of a single, unusual, beaded, blue, ring-like galaxy which just happens to line-up behind a giant cluster of galaxies. Cluster…
Comet Hyakutake on a Starry Night
It was a starry night in April (April 9th, 1996, 9:32 pm CDT to be exact) near Lone Jack, Missouri when Comet Hyakutake graced this astronomically rich field . Making an…
Viewing discoveries from 16 May 1996 through 23 April 1996.