Astronomy Picture Of the Day (APOD)21st Century M101
One of the last entries in Charles Messier's famous catalog, big, beautiful spiral galaxy M101 is definitely not one of the least. About 170,000 light-years across, this galaxy is enormous, almost twice the size of our own Milky Way Galaxy.
Teimareh Petroglyphs and Star Trails
Engraved in rock, these ancient petroglyphs are abundant in the Teimareh valley, located in the Zagros Mountains of central Iran. They likely tell a tale of hunters and animals found in the middle eastern valley 6,000 years ago or more, etched by artists in a prehistoric age.
A Morning Line of Stars and Planets
Early morning dog walkers got a visual treat last week as bright stars and planets appeared to line up. Pictured above, easily visible from left to right, were the Pleiades open star cluster, Jupiter, Venus, and the "Follower" star Aldebaran, all seen before a starry background.
Happy People Dancing on Planet Earth
What are these humans doing? Dancing. Many humans on Earth exhibit periods of happiness, and one method of displaying happiness is dancing. Happiness and dancing transcend political boundaries and occur in practically every human society. Above, Matt Harding traveled through many nations on Earth, planned on dancing, and filmed the result.
Greeley Panorama on Mars
What did you do over your winter vacation? If you were the Opportunity rover on Mars, you spent four months of it stationary and perched on the northern slope of Greeley Haven -- and tilted so that your solar panels could absorb as much sunlight as possible.
Volcano and Aurora in Iceland
Sometimes both heaven and Earth erupt. In Iceland in 1991, the volcano Hekla erupted at the same time that auroras were visible overhead. Hekla, one of the most famous volcanoes in the world, has erupted at least 20 times over the past millennium, sometimes causing great destruction.
How would you change the course of an Earth-threatening asteroid? One idea - a massive spacecraft that uses gravity as a towline - is illustrated in this dramatic artist's view of a gravitational tractor in action.
The Tidal Tail of NGC 3628
A mere 30 million light-years away, large spiral galaxy NGC 3628 (center left) shares its neighborhood in the local Universe with two other large spirals, in a magnificent grouping otherwise known as the Leo Triplet.
NGC 4565: Galaxy on Edge
Magnificent spiral galaxy NGC 4565 is viewed edge-on from planet Earth. Also known as the Needle Galaxy for its narrow profile, bright NGC 4565 is a stop on many telescopic tours of the northern sky, in the faint but well-groomed constellation Coma Berenices.
Sunspots and Silhouettes
What stands between you and the Sun? Apparently, as viewed from Paris last week, one visible thing after another. First, in the foreground, is the Basilica of the Sacred Heart, built in the late 1800s and located on the highest hill in Paris, France.