The Umbra of Earth
25.01.2019

The dark, inner shadow of planet Earth is called the umbra. Shaped like a cone extending into space, it has a circular cross section most easily seen during a lunar eclipse. For example...

Launch of the Solar Orbiter
10.02.2020

How does weather on the Sun affect humanity? To help find out, the European Space Agency (ESA) and NASA have just launched the Solar Orbiter. This Sun-circling robotic spaceship will monitor...

APOD: 2020 August 25 Б Visualization: A Black Hole Accretion Disk
24.08.2020

What would it look like to circle a black hole? If the black hole was surrounded by a swirling disk of glowing and accreting gas, then the great gravity of the black hole would deflect light emitted by the disk to make it look very unusual. The featured animated video gives a visualization.

Explosions from White Dwarf Star RS Oph
21.08.2021

Spectacular explosions keep occurring in the binary star system named RS Ophiuchi. Every 20 years or so, the red giant star dumps enough hydrogen gas onto its companion white dwarf star to set off a brilliant thermonuclear explosion on the white dwarf's surface.

The Dumbbell Nebula in Hydrogen and Oxygen
12.01.2003

The first hint of what will become of our Sun was discovered inadvertently in 1764. At that time, Charles Messier was compiling a list of "annoying" diffuse objects not to be confused with "interesting" comets.

Structure in N63A
31.12.2003

Shells and arcs abound in this false-color, multiwavelength view of supernova remnant N63A, the debris of a massive stellar explosion. The x-ray emission (blue), is from gas heated to 10 million degrees C as knots of fast moving material from the cosmic blast sweep up surrounding interstellar matter.

Composite Crab
25.03.2005

(xxxre linkxxx) The Crab Pulsar, a city-sized, magnetized neutron star spinning 30 times a second, lies at the center of this composite image of the inner region of the well-known Crab Nebula. The spectacular...

Alnitak, Alnilam, Mintaka
13.10.2005

Alnitak, Alnilam, and Mintaka, are the bright bluish stars from east to west (left to right) along the diagonal in this gorgeous cosmic vista. Otherwise known as the Belt of Orion, these three blue supergiant stars are hotter and much more massive than the Sun.

Alnitak, Alnilam, Mintaka
28.12.2006

Alnitak, Alnilam, and Mintaka, are the bright bluish stars from east to west (left to right) along the diagonal in this gorgeous cosmic vista. Otherwise known as the Belt of Orion, these three blue supergiant stars are hotter and much more massive than the Sun.

Shell Galaxy NGC 7600
23.12.2011

Similar in size to the Milky Way, elliptical galaxy NGC 7600 is about 150 thousand light-years distant. In this deep image, spanning about 1/2 degree on the sky toward the constellation Aquarius, NGC 7600 sports a remarkable outer halo of nested shells and broad circumgalactic structures.