A Galactic Cloud of Antimatter
1.05.1997

The center of our Milky Way Galaxy is full of surprises. Its latest spectacular is a mysterious cloud glowing in gamma rays produced by annihilating antimatter particles! Star Trek fans are all too familiar...

Forty Thousand Meteor Origins Across the Sky
11.05.2009

Where do meteors come from? Visible meteors are typically sand-sized grains of ice and rock that once fragmented from comets. Many a meteor shower has been associated with a known comet, although some intriguing orphan showers do remain.

Fermi s Gamma-ray Moon
29.04.2016

If you could only see gamma-rays, photons with up to a billion or more times the energy of visible light, the Moon would be brighter than the Sun! That startling notion underlies this novel...

The Very Large Array at Moonset
9.10.2020

An inspirational sight, these giant dish antennas of the Karl G. Jansky Very Large Array (VLA) rise above the New Mexico desert at moonset. Mounted on piers but transportable on railroad tracks to change...

Two Tails of Comet Lulin
25.02.2009

Go outside tonight and see Comet Lulin. From a dark location, you should need only a good star map and admirable perseverance -- although wide-field binoculars might help. Yesterday, Comet Lulin passed its closest to Earth, so that the comet will remain near its brightest over the next few days.

Unusual Mountain Ahuna Mons on Asteroid Ceres
16.06.2019

What created this unusual mountain? There is a new theory. Ahuna Mons is the largest mountain on the largest known asteroid in our Solar System, Ceres, which orbits our Sun in the main asteroid belt between Mars and Jupiter. Ahuna Mons, though, is like nothing that humanity has ever seen before.

Animation: Odd Radio Circles
30.03.2022

What do you call a cosmic puzzle that no one expected to see? In this case, Odd Radio Circles, aka ORCs. ORC-1 typifies the enigmatic five objects, only visible at radio frequencies, that were serendipitously discovered in 2019 using the new Australian SKA Pathfinder radio array.

At the Center of the Milky Way
11.12.2008

At the center of our Milky Way Galaxy lies a supermassive black hole. Once a controversial claim, this conclusion is now solidly based on 16 years of observations that map the orbits of 28 stars very near the galactic center.

APOD: 2024 December 22 Б The Local Fluff
22.12.2024

The stars are not alone. In the disk of our Milky Way Galaxy, about 10 percent of visible matter is in the form of gas called the interstellar medium (ISM). The ISM is not uniform and shows patchiness even near our Sun.

Galaxy Cluster Gas Creates Hole in Microwave Background
10.04.2017

Why would this cluster of galaxy punch a hole in the cosmic microwave background (CMB)? First, the famous CMB was created by cooling gas in the early universe and flies right through most gas and dust in the universe. It is all around us.