Aurora over Icelandic Fault
30.08.2016

Admire the beauty but fear the beast. The beauty is the aurora overhead, here taking the form of great green spiral, seen between picturesque clouds with the bright Moon to the side and stars in the background. The beast is the wave of charged particles that creates the aurora but might, one day, impair civilization.

Sparkling Star May Indicate Galactic Composition
24.06.1998

If a star in this photograph twinkled slightly, would anyone notice? Would anyone care? Astronomers with the MACHO Collaboration noticed one such twinkle just last week, and many members of the astronomical community now care.

Curious Cometary Knots in the Helix Nebula
13.04.2008

What causes unusual knots of gas and dust in planetary nebulas? Seen also in the Ring Nebula, the Dumbbell Nebula and the Eskimo Nebula, the knots' existence was not initially predicted and their origins are still not well understood.

APOD: 2025 March 12 Б NGC 772: The Fiddlehead Galaxy
12.03.2025

Why does this galaxy look like a curly vegetable? The Fiddlehead spiral galaxy likely gets its distorted spiral appearance from a gravitational interaction with its close-by elliptical companion NGC 770, seen just below. Cataloged...

Galaxy Cluster Abell 370 and Beyond
6.05.2017

Some 4 billion light-years away, massive galaxy cluster Abell 370 only appears to be dominated by two giant elliptical galaxies and infested with faint arcs in this sharp Hubble Space Telescope snapshot. The fainter...

Pleiades, Planets, And Hot Plasma
24.05.2000

Bright stars of the Pleiades, four planets, and erupting solar plasma are all captured in this spectacular image from the space-based SOlar and Heliospheric Observatory (SOHO). In the foreground of the 15 degree wide field of view, a bubble of hot plasma, called a Coronal Mass Ejection (CME)

GRO J1655 40: Evidence for a Spinning Black Hole
1.06.2003

In the center of a swirling whirlpool of hot gas is likely a beast that has never been seen directly: a black hole. Studies of the bright light emitted by the swirling gas frequently indicate not only that a black hole is present, but also likely attributes.

The View Near a Black Hole
19.04.2009

In the center of a swirling whirlpool of hot gas is likely a beast that has never been seen directly: a black hole. Studies of the bright light emitted by the swirling gas frequently indicate not only that a black hole is present, but also likely attributes.

GRO J1655 40: Evidence for a Spinning Black Hole
28.05.2006

In the center of a swirling whirlpool of hot gas is likely a beast that has never been seen directly: a black hole. Studies of the bright light emitted by the swirling gas frequently indicate not only that a black hole is present, but also likely attributes.

GRO J1655 40: Evidence for a Spinning Black Hole
5.09.2010

In the center of a swirling whirlpool of hot gas is likely a beast that has never been seen directly: a black hole. Studies of the bright light emitted by the swirling gas frequently indicate not only that a black hole is present, but also likely attributes.