Planet Earth at Twilight
27.12.2024

No sudden, sharp boundary marks the passage of day into night in this gorgeous view of ocean and clouds over our fair planet Earth. Instead, the shadow line or terminator is diffuse and shows the gradual transition to darkness we experience as twilight.

Sudbury Indicates Nonstandard Particle Model
10.07.2001

The Sudbury Neutrino Observatory (SNO) has been detecting so few neutrinos from the Sun that the Standard Model of fundamental particles in the universe may have to be revised. Pictured above is the SNO as it was being built.

Europa s Freckles
1.11.2002

Europa, one of Jupiter's large Galilean moons, may well posses an ocean of liquid water hidden beneath its icy surface -- and so holds the tantalizing possibility of life. In this image, constructed with...

The Perseus Cluster of Galaxies
26.04.1997

Here is one of the largest objects that anyone will ever see on the sky. Each of the fuzzy blobs in the above picture is a galaxy, together making up the Perseus Cluster, one of the closest clusters of galaxies.

7,000 Stars and the Milky Way
17.05.1997

This panorama view of the sky is really a drawing. It was made in the 1940s under the supervision of astronomer Knut Lundmark at the Lund Observatory in Sweden. To create the picture, draftsmen...

Sunset Moonlight
21.11.2003

November's lunar eclipse was one of the shortest in recent years and also one of the brightest -- demonstrating that the Earth's shadow is not completely dark. The eclipsed Moon remained easily visible...

Raining Perseids
6.08.2005

Comet dust rained down on planet Earth last August, streaking through dark skies in the annual Perseid meteor shower. So, while enjoying the anticipated space weather, astronomer Fred Bruenjes recorded a series of many 30 second long exposures spanning about six hours on the night of August 11/12 using a wide angle lens.

11 Hour Star Trails
15.09.2006

Fix your camera to a tripod, lock the shutter open, and you can make an image of star trails - graceful concentric arcs traced by the stars as planet Earth rotates on its axis. Of course, the length of the star trails will depend on the exposure time.

Sun Block
18.08.1999

During a total solar eclipse, Earth's moon blocks the sun - almost exactly. While the sun is about 400 times wider than the moon, it is also about 400 times farther away and each appears to be half a degree or so in diameter.

Sunset: Planet Earth
20.03.2008

Today, the Sun crosses the celestial equator heading north at 0548 UT. Known as the equinox, the geocentric astronomical event marks the first day of spring in the northern hemisphere and autumn in the south.