A Retreating Thunderstorm at Sunset
28.08.2013

What type of cloud is that? This retreating cumulonimbus cloud, more commonly called a thundercloud, is somewhat unusual as it contains the unusual bumpiness of a mammatus cloud on the near end, while simultaneously producing falling rain on the far end.

A Retreating Thunderstorm at Sunset
16.01.2022

What type of cloud is that? This retreating cumulonimbus cloud, more commonly called a thundercloud, is somewhat unusual as it contains the unusual bumpiness of a mammatus cloud on the near end, while simultaneously producing falling rain on the far end.

Io's Sodium Cloud
28.04.1997

Io has its own cloud. Jupiter's most active moon is visible on the left of the above false-color photograph, with its left side illuminated by sunlight. But what is happening on Io's right side? Here a plume of gas from the active volcano Prometheus also reflects sunlight.

NGC 2440: Cocoon of a New White Dwarf
26.04.1998

Like a butterfly, a white dwarf star begins its life by casting off a cocoon that enclosed its former self. In this analogy, however, the Sun would be a caterpillar and the ejected shell of gas would become the prettiest of all!

A Cluster Too Far
8.09.1998

Why is this galaxy cluster so red? Nearby clusters have galaxies with colors that are much more yellow and blue. A leading explanation is that this cluster of galaxies lies so far across our universe (z~1) that cosmological time dilation significantly reddens the light.

In the Center of the Dumbbell Nebula
13.10.1998

Here's part of the Dumbbell Nebula that you can't see through binoculars. To see this, we suggest a sophisticated spectrograph attached to a telescope with an 8-meter aperture. Pictured above is the central part of the Dumbbell Nebula, also known as M27 and NGC 6853.

NGC 2440: Cocoon of a New White Dwarf
23.01.2005

Like a butterfly, a white dwarf star begins its life by casting off a cocoon that enclosed its former self. In this analogy, however, the Sun would be a caterpillar and the ejected shell of gas would become the prettiest of all!

The Dark River to Antares
3.06.2008

Connecting the Pipe Nebula to the bright star Antares is a flowing dark cloud nicknamed the Dark River. The murkiness of the Dark River is caused by absorption of background starlight by dust, although the nebula contains mostly hydrogen and molecular gas.

ISS: Reflections of Earth
16.01.2009

Remarkable details are visible in this view of the orbiting International Space Station (ISS), recorded with a small telescope on planet Earth through a clear twilight sky. Seen on December 27th at about...

Harvest Moon Eclipse
23.09.2016

A Harvest Moon rises over Sesimbra Castle south of Lisbon in this impressive series of telephoto exposures. Captured at its full phase, the golden Moon was also gliding through the Earth's more diffuse outer shadow during September's penumbral lunar eclipse. The eclipse shading is subtle compared to a total lunar eclipse.