Equinox and the Iron Sun
23.09.2010

Today, the Sun crosses the celestial equator heading south at 03:09 Universal Time. Known as an equinox, this astronomical event marks the first day of autumn in the northern hemisphere and spring in the south. Equinox means equal night.

Active Prominences on a Quiet Sun
20.08.2018

Why is the Sun so quiet? As the Sun enters into a period of time known as a Solar Minimum, it is, as expected, showing fewer sunspots and active regions than usual. The quietness is somewhat unsettling, though, as so far this year, most days show no sunspots at all.

AR1520: Islands in the Photosphere
14.07.2012

Awash in a sea of plasma and anchored in magnetic fields, sunspots are planet-sized, dark islands in the solar photosphere, the bright surface of the Sun. Dark because they are slightly cooler than the surrounding surface, this group of sunspots is captured in a close-up telescopic snapshot from July 11.

Islands in the Photosphere
25.10.2003

Awash in a sea of plasma and anchored in magnetic fields, sunspots are planet-sized, dark islands in the solar photosphere, the bright surface of the Sun. Before the enlightened(!) age of cameras, solar observers created detailed drawings of sunspots as they changed and progressed across the visible solar disk.

Sun Storm: A Coronal Mass Ejection
9.03.2000

Late last month another erupting filament lifted off the active solar surface and blasted this enormous bubble of magnetic plasma into space. Direct light from the sun is blocked in this picture of the event with the sun's relative position and size indicated by a white half circle at bottom center.

Solstice Celebration
21.06.2000

Season's greetings! At 01:48 Universal Time on June 21 the Sun reaches its northernmost point in planet Earth's sky marking a season change and the first solstice of the year 2000. In celebration, consider this delightfully detailed, brightly colored image of the active Sun.

A Halo for Andromeda
3.09.2020

M31, the Andromeda Galaxy, is the closest large spiral galaxy to our Milky Way. Some 2.5 million light-years distant it shines in Earth's night sky as a small, faint, elongated cloud just visible to the unaided eye.

Under A Sunspot
8.11.2001

At the Sun's surface, sunspots are known to be dark, planet-sized regions of intense magnetic fields. But what lies below? Using observations from the Michelson Doppler Imager (MDI) instrument aboard the space-based SOHO observatory, astronomers have derived this premier picture of the flow of material just beneath a visible sunspot.

Sun Dance
10.10.2018

Sometimes, the surface of our Sun seems to dance. In the middle of 2012, for example, NASA's Sun-orbiting Solar Dynamic Observatory spacecraft imaged an impressive prominence that seemed to perform a running dive roll like an acrobatic dancer.

BOOMERANG Images The Early Universe
3.05.2000

Drifting through the stratosphere above Antarctica in late 1998, the balloon-borne BOOMERANG telescope peered into the cosmos at millimeter wavelengths. The blotchy structures it detected are seen above in the sharpest yet picture of the universe at an early age, perhaps a mere 300,000 years old.