APOD: 2024 July 31 Б Leopard Spots on Martian Rocks
31.07.2024

What is creating these unusual spots? Light-colored spots on Martian rocks, each surrounded by a dark border, were discovered earlier this month by NASA's Perseverance Rover currently exploring Mars. Dubbed leopard spots because...

Columbia Dawn
8.03.2002

Trailing a thick column of exhaust, the Space Shuttle Columbia blasted into the twilight morning sky on March 1, its thundering rockets briefly flooding a cloud bank with the light of a false dawn. The event marked the start of the ongoing eleven day mission to upgrade the Hubble Space Telescope.

The Compton Gamma Ray Observatory
11.08.1995

The Compton Gamma Ray Observatory (CGRO) was the most massive instrument ever launched by a NASA Space Shuttle and continues to revolutionize gamma-ray astronomy. This orbiting observatory sees the sky in gamma-ray photons - light so blue humans can't see it.

Simulating the Universe
8.11.1995

The above cube represents a chunk of our universe as simulated by the Grand Challenge Cosmology Consortium (GC3). The cube is huge - it would take light 500 million years to cross it. Low density gas is shown as blue, and high density gas as red.

Uranus's Moon Umbriel: A Mysterious Dark World
7.04.1996

Why is Umbriel so dark? This dark moon reflects only half the light of other Uranus' moons such as Ariel. And what is that bright ring at the top? Unfortunately, nobody yet knows. These questions presented themselves when Voyager 2 passed this satellite of Uranus in January 1986.

M101: The Pinwheel Galaxy
10.03.2003

Why do many galaxies appear as spirals? A striking example is M101, shown above, whose relatively close distance of about 22 million light years allow it to be studied in some detail. Recent evidence...

Night Lightning on Jupiter
16.12.1997

Why is there lightning on Jupiter? Lightning is a sudden rush of electrically charged particles from one location to another. To create lightning, charges must first separate inside a cloud. On Earth, drafts of colliding ice and water droplets usually create this charge separation, but what happens on Jupiter?

Betelgeuse
19.04.1998

Here is the first direct picture of the surface of a star other than our Sun. Taken by the Hubble Space Telescope in 1995, the atmosphere of Betelgeuse reveals some unexpected features, including a large bright hotspot visible below the center.

A Solar Prominence from SOHO
16.04.2006

How can gas float above the Sun? Twisted magnetic fields arching from the solar surface can trap ionized gas, suspending it in huge looping structures. These majestic plasma arches are seen as prominences above the solar limb.

Comet Between Fireworks and Lightning
5.07.2008

Sometimes the sky itself is the best show in town. Last January, people from Perth, Australia gathered on a local beach to watch a sky light up with delights near and far. Nearby, fireworks exploded as part of Australia Day celebrations. On the far right, lightning from a thunderstorm flashed in the distance.