APOD: 2023 April 24 Б The Medulla Nebula Supernova Remnant
24.04.2023

What powers this unusual nebula? CTB-1 is the expanding gas shell that was left when a massive star toward the constellation of Cassiopeia exploded about 10,000 years ago. The star likely detonated when it ran out of elements near its core that could create stabilizing pressure with nuclear fusion.

APOD: 2024 January 24 Б Earth and Moon from Beyond
24.01.2024

What do the Earth and Moon look like from beyond the Moon? Although frequently photographed together, the familiar duo was captured with this unusual perspective in late 2022 by the robotic Orion spacecraft of NASA's Artemis I mission as it looped around Earth's most massive satellite and looked back toward its home world.

Diffraction Spikes: When Stars Look Like Crosses
15.04.2001

Unusual appendages around bright stars are commonplace, but never seem to be mentioned. What are they? First, a telescope brings starlight falling over a large area to a small area. To get at this...

Zodiacal Light and the False Dawn
12.09.2001

An unusual triangle of light will be particularly bright near the eastern horizon before sunrise during the next two months for observers in Earth's northern hemisphere. Once considered a false dawn, this triangle of light is actually Zodiacal Light, light reflected from interplanetary dust particles.

Giant Cluster Bends, Breaks Images
7.08.2004

What are those strange blue objects? Many are images of a single, unusual, beaded, blue, ring-like galaxy which just happens to line-up behind a giant cluster of galaxies. Cluster galaxies here appear yellow and -- together with the cluster's dark matter -- act as a gravitational lens.

Titan s Odd Spot
27.05.2005

Titan's odd spot could be a cloud, but if so, it's a persistent one. Peering into the thick, hazy atmosphere of Saturn's largest moon, cameras on board the Cassini spacecraft found a bright spot at the same location during Titan encounters in 2005 and 2004.

Animation of Asteroids Passing Near Earth
28.03.2006

How often does an asteroid whiz by the Earth? The above time-lapse animation follows the orbit of the Earth around the Sun for two months in 2002 as numerous asteroids, also known as minor planets, approach and pass by. Some asteroids appear out of nowhere as they are plotted only when they were discovered.

NGC 6791: An Old, Large Open Cluster
12.01.2000

NGC 6791 is one of the oldest and largest open clusters of stars known. But how did it get so dirty? Open star clusters usually contain a few hundred stars each less than a billion years old.

Huge Gamma Ray Bubbles Found Around Milky Way
10.11.2010

Did you know that our Milky Way Galaxy has huge bubbles emitting gamma rays from the direction of the galactic center? Neither did anybody. As the data from the Earth-orbiting Fermi satellite began acuminating over the past two years, however, a large and unusual feature toward our Galaxy's center became increasingly evident.

A Hole in Mars
18.07.2012

What created this unusual hole in Mars? The hole was discovered by chance on images of the dusty slopes of Mars' Pavonis Mons volcano taken by the HiRISE instrument aboard the robotic Mars Reconnaissance Orbiter currently circling Mars. The hole appears to be an opening to an underground cavern, partly illuminated on the image right.