APOD: 2024 April 8 Б The Changing Ion Tail of Comet Pons Brooks
7.04.2024

How does a comet tail change? It depends on the comet. The ion tail of Comet 12P/PonsБBrooks has been changing markedly, as detailed in the featured image sequenced over nine days from March 6 to 14 (top to bottom).

Xuyi Station and the Fireball
5.12.2024

Colorful and bright, this streaking fireball meteor was captured in a single exposure taken at Purple Mountain (Tsuchinshan) ObservatoryБs Xuyi Station in 2020, during planet Earth's annual Perseid meteor shower. The dome in the foreground houses the China Near Earth Object Survey Telescope (CNEOST), the largest multi-purpose Schmidt telescope in China.

Roses are Red
13.02.2026

Roses are red, nebulas are too, and this Valentine's gift is a stunning view! Pictured is a loving look at the Rosette Nebula (NGC 2237): a cosmic bloom of bright young stars sitting atop a stem of glowing hot gas.

APOD: 2026 March 26 Б
25.03.2026

What is the sound of two black holes merging in deep space? Sound waves don't propagate in vacuum, but gravitational waves do. In 2015 we were able to "hear" them for the first time and confirm one of Albert Einstein's theoretical predictions.

BATSE's Biggest Gamma Ray Burst (Yet)
1.10.1996

Something big exploded but astronomers have no idea what. On September 24^th, the Burst and Transient Source Experiment (BATSE) onboard the orbiting Compton Gamma Ray Observatory recorded the most intense gamma ray burst in its five year history.

Comet-like Clouds in the Cartwheel Galaxy
27.11.1996

In a cartwheel-shaped galaxy far, far away, huge comet-shaped clouds of gas have been discovered racing through the nucleus at about 700,000 miles per hour. The aptly named Cartwheel Galaxy is actually about 500 million light years distant, its suggestive shape created by a head-on collision with a smaller galaxy.

Black Hole Signature From Advective Disks
14.01.1997

What does a black hole look like? If alone, a black hole would indeed appear quite black, but many black hole candidates are part of binary star systems. So how does a black hole binary system look different from a neutron star binary system? The above drawings indicate it is difficult to tell!

Moon Shadow
11.03.1998

When the Moon's shadow reached out and touched the Earth last month, the result was a Solar Eclipse. Such an eclipse is total only for observers located along a narrow path corresponding to the ground track of the shadow's dark central portion or "umbra".

The Andromeda Galaxy in Infrared
20.10.2005

What is the Andromeda galaxy really like? To find out, astronomers looked at our largest galactic neighbor in a different light: infrared. Astronomers trained the orbiting Spitzer Space Telescope at the Messier monster (M31) for over 18 hours, creating a mosaic that incorporated 11,000 separate exposures.

A Year at Saturn
30.12.2005

Arriving at Saturn in July of 2004, the Cassini spacecraft has now spent a year and a half exploring the magnificent rings and moons of the distant gas giant. The year 2005 began with Cassini's Huygens probe landing on Saturn's large moon Titan.