Supernova 1987a Aftermath
21.06.1995

In 1987 a star in one of the Milky Way's satellite galaxies exploded. In 1994 the Hubble Space Telescope, in orbit around the earth, took a very detailed picture of the remnants of this explosion. This picture, above, showed unusual and unexpected rings, and astronomers are not sure how they formed.

Giant Cluster Bends, Breaks Images
14.06.1998

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.

Giant Cluster Bends, Breaks Galaxy Images
3.05.1997

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.

Rumors of a Strange Universe
2.12.2001

Three years ago results were first presented indicating that most of the energy in our universe is not in stars or galaxies but is tied to space itself. In the language of cosmologists, a large cosmological constant is directly implied by new distant supernovae observations.

APOD: 2025 September 23 Б NGC 6357: Cathedral to Massive Stars
23.09.2025

How massive can a normal star be? Estimates made from distance, brightness and standard solar models had given one star in the open cluster Pismis 24 over 200 times the mass of our Sun, making it one of the most massive stars known.

Around The Arches Cluster
14.06.2001

The most compact cluster of stars known in our galaxy, the Arches cluster, boasts 100 or so massive, young stars contained within a diameter of one light-year. Seen toward the constellation Sagittarius, the Arches...

Hubble's Constant And The Expanding Universe (II)
14.05.1996

In this century, the discovery that the Universe is expanding has produced a revolution in human thought about the Cosmos. American astronomer Edwin Hubble played a major role in this profound discovery, coining the "Hubble constant".

Asteroids in the Distance
23.06.2002

Rocks from space hit Earth every day. The larger the rock, though, the less often Earth is struck. Many kilograms of space dust pitter to Earth daily. Larger bits appear initially as a bright meteor. Baseball-sized rocks and ice-balls streak through our atmosphere daily, most evaporating quickly to nothing.

Asteroids in the Distance
17.04.2005

Rocks from space hit Earth every day. The larger the rock, though, the less often Earth is struck. Many kilograms of space dust pitter to Earth daily. Larger bits appear initially as a bright meteor. Baseball-sized rocks and ice-balls streak through our atmosphere daily, most evaporating quickly to nothing.

A GRB 000301C Symphony
3.06.2001

Last March, telescopic instruments in Earth and space tracked a tremendous explosion that occurred across the universe. A nearly unprecedented symphony of international observations began abruptly on 2000 March 1 when Earth-orbiting RXTE, Sun-orbiting Ulysses, and asteroid-orbiting NEAR all detected a 10-second burst of high-frequency gamma radiation. Within 48 hours astronomers