Astronomy Picture Of the Day (APOD)Julius Caesar and Leap Days
Even as leap days go, today is a remarkable one. In 46 BC, Julius Caesar, pictured above in a self-decreed minted coin, created a calendar system that added one leap day every four years.
The Sombrero Galaxy from VLT
Why does the Sombrero Galaxy look like a hat? Reasons include the Sombrero's unusually large and extended central bulge of stars, and dark prominent dust lanes that appear in a disk that we see nearly edge-on. Billions of old stars cause the diffuse glow of the extended central bulge.
The Pleiades Star Cluster
It is the most famous star cluster on the sky. The Pleiades can be seen without binoculars from even the depths of a light-polluted city. Also known as the Seven Sisters and M45, the Pleiades is one of the brightest and closest open clusters.
Impact: 65 Million Years Ago
What killed the dinosaurs? Their sudden disappearance 65 million years ago, along with about 70 percent of all species then living on Earth, is known as the K-T event (Cretaceous-Tertiary Mass Extinction event). Geologists and paleontologists often entertain the idea that a large asteroid
The Comets Of SOHO
After four years of successful sun-gazing, the space-based SOlar and Heliospheric Observatory (SOHO) has also become the most successful comet-hunter in history, racking up 102 new comets. Above are examples of SOHO's comet discoveries imaged by LASCO, an on-board coronagraph.
Get out your red/blue glasses and float next to asteroid 433 Eros, 260 million kilometers away! Orbiting the Sun once every 1.8 earth-years, asteroid Eros is a diminutive 40 x 14 x 14 kilometer world of undulating horizons, craters, boulders and valleys.
Our Sun's surface is continually changing. This time-lapse movie shows in five seconds what happens in 20 minutes on the Sun's surface near a sunspot. Visible is boiling granulation outside the sunspot...
Neighboring Galaxy: The Large Magellanic Cloud
The brightest galaxy visible from our own Milky Way Galaxy is the Large Magellanic Cloud (LMC). Visible predominantly from Earth's Southern Hemisphere, the LMC is the second closest galaxy, neighbor to the Small Magellanic Cloud, and one of eleven known dwarf galaxies that orbit our Milky Way Galaxy.
A Giant Gouge on Asteroid Eros
Asteroid 433 Eros is posing several riddles. NASA's robot spacecraft NEAR began orbiting the 30-kilometer space rock last week, and new pictures are now being beamed back to Earth regularly. As usual in science, when you arrive at a place you've never been before, you see things you don't immediately understand.
The Virgo Cluster of Galaxies
Pictured are several galaxies of the Virgo Cluster, the closest cluster of galaxies to our Milky Way Galaxy. The Virgo Cluster spans more than 5 degrees on the sky - about 10 times the angle made by a full Moon. It contains over 100 galaxies of many types - including spirals, ellipticals, and irregular galaxies.