The Cloudy Cores of Active Galaxies
24.02.2014

What would it look like to travel to the center of an active galaxy? Most galactic centers are thought to house black holes millions of times more massive than our Sun. The spaces surrounding...

Open Star Clusters M35 and NGC 2158
15.12.2003

Open clusters of stars can be near or far, young or old, and diffuse or compact. Open clusters may contain from 100 to 10,000 stars, all of which formed at nearly the same time. Bright blue stars frequently distinguish younger open clusters.

Equinox on a Spinning Earth
22.09.2021

When does the line between night and day become vertical? Today. Today is an equinox on planet Earth, a time of year when day and night are most nearly equal. At an equinox, the Earth's terminator -- the dividing line between day and night -- becomes vertical and connects the north and south poles.

Earth, Moon, Hubble
5.01.2000

The Space Shuttle Discovery Crew was fortunate enough to witness one of the brighter full moon's from orbit two weeks ago during their mission to fix the Hubble Space Telescope. Pictured...

Space Station, Venus, Sun
20.07.2004

On June 8, Venus was not the only celestial object to pass in front of the Sun. A few well-situated photographers caught the International Space Station also crossing the Sun simultaneously. Pictured above...

Olympus Mons Volcano on Mars
29.05.2000

Scroll right to virtually climb the largest volcano in the Solar System. Olympus Mons on Mars measures three times higher than Earth's highest mountain, and has a volume over fifty times greater than Earth's largest volcano. The caldera at the top is over 70 kilometers wide.

Star Trails Over Vienna
14.07.2005

As the Earth spins on its axis, the sky seems to rotate around us. This motion, called diurnal motion, produces the beautiful concentric trails traced by stars during time exposures. In the middle...

Help Map The Moon
11.09.1998

You can help map the Moon. Early tomorrow morning (Saturday, September 12) the Moon will occult, or pass in front of, the bright star Aldebaran as viewed from some Southern and Eastern areas of the U.S. as well as regions in the Caribbean Sea, Nova Scotia, Newfoundland, Mexico, and Central America.

Supernova Sonata
26.05.2011

To create a sonata from supernovae, first you have to find the supernovae. To do that composers Alex Parker and Melissa Graham relied on the Canada France Hawaii Telescope (CFHT) Legacy Survey data of four deep fields on the sky monitored from April 2003 through August 2006, adopting 241 Type Ia supernovae.

Sunspot Group AR 2339 Crosses the Sun
29.06.2015

How do sunspots evolve? Large dark sunspots -- and the active regions that contain them -- may last for weeks, but all during that time they are constantly changing. Such variations were particularly apparent...