The Colors of Comet Hyakutake
29.03.1996

The colors of Comet Hyakutake are caused by the action of sunlight on the dust and gas produced by the warming nucleus. The microscopic dust particles reflect sunlight while the sun's ultraviolet radiation excites and ionizes the gas molecules causing them to glow or fluoresce in a range of visible colors.

Galaxy Cluster in the Early Universe
26.02.2004

Long before medieval alchemists dreamed of transmuting base metals to gold, stellar furnaces in this massive cluster of galaxies - cataloged as RDCS 1252.9-2927 - had transformed light elements into heavy ones. In the false-color composite image individual cluster galaxies can be seen at optical and near-infrared wavelengths, shown in red, yellow, and green colors.

Lunokhod: Reflections on a Moon Robot
6.06.2010

It may look like some sort of cute alien robot, but it was created here on Earth, launched to the Moon in 1970, and now reflects laser light in a scientifically useful way. On November 17, 1970 the Soviet Luna 17 spacecraft landed the first roving remote-controlled robot on the Moon.

Heavy Black Hole Jets in 4U1630 47
20.11.2013

What are black hole jets made of? Many black holes in stellar systems are surely surrounded by disks of gas and plasma gravitationally pulled from a close binary star companion. Some of this material...

A Halo for NGC 6164
22.05.2014

Beautiful emission nebula NGC 6164 was created by a rare, hot, luminous O-type star, some 40 times as massive as the Sun. Seen at the center of the cosmic cloud, the star is a mere 3 to 4 million years old.

The Supermassive Black Holes of NGC 6240
28.11.2002

The Hubble optical image on the left shows NGC 6240 in the throes of a titanic galaxy - galaxy collision 400 million light-years away. As the cosmic catastrophe plays out, the merging galaxies spew forth distorted tidal tails of stars, gas, and dust and undergo frantic bursts of star formation.

Phaethon s Brood
12.12.2024

Based on its well-measured orbit, 3200 Phaethon (sounds like FAY-eh-thon) is recognized as the source of the meteoroid stream responsible for the annual Geminid meteor shower. Even though most meteor shower parents are comets, 3200 Phaethon is a known and closely tracked near-Earth asteroid with a 1.4 year orbital period.

APOD: 2026 March 6 Б The Astrosphere of HD 61005
6.03.2026

Do young stars blow bubbles? The larger view shows a stellar field observed with the Cerro Tololo Inter-American Observatory in Chile, and the inset highlights HD 61005, a star like our Sun, only 120 light-years away.

Quadrantid Meteors and Aurora from the Air
7.01.2008

Where do meteor showers originate? To help answer this question, astronomers studied in some detail the Quadrantid meteor shower that occurred over this past weekend. In particular, astronomers with specialized cameras flew as part...

The Rise and Fall of Supernova 2015F
9.02.2016

Sit back and watch a star explode. The actual supernova occurred back when dinosaurs roamed the Earth, but images of the spectacular event began arriving last year. Supernova 2015F was discovered in nearby spiral...