UHZ1: Distant Galaxy and Black Hole
10.11.2023

Dominated by dark matter, massive cluster of galaxies Abell 2744 is known to some as Pandora's Cluster. It lies 3.5 billion light-years away toward the constellation Sculptor. Using the galaxy cluster's enormous...

Julius Caesar and Leap Days
29.02.2004

Today, February 29th, is a leap day - a relatively rare occurrence. In 46 BC, Julius Caesar, pictured above in a self-decreed minted coin, created a calendar system that added one leap day every four years.

X-Ray Ring Around SN1987A
12.05.2000

This false-color image from the Chandra X-ray Observatory reveals a one light-year diameter ring of hot, ten million degree plasma. It is one of the most detailed X-ray images of the expanding blast wave from supernova 1987A (SN1987A).

A Historic Brazilian Constellation
12.01.2021

The night sky is filled with stories. Cultures throughout history have projected some of their most enduring legends onto the stars above. Generations of people see these stellar constellations, hear the associated stories, and pass them down.

Saturn-Sized Worlds Discovered
30.03.2000

The last decade saw the profound discovery of many worlds beyond our solar system, but none analogs of our home planet Earth. Exploiting precise observational techniques, astronomers inferred the presence of well over two dozen extrasolar planets, most nearly as massive as gas giant Jupiter or more, in close orbits around sun-like stars.

Messier 106
9.04.2021

Close to the Great Bear (Ursa Major) and surrounded by the stars of the Hunting Dogs (Canes Venatici), this celestial wonder was discovered in 1781 by the metric French astronomer Pierre Mechain. Later, it was added to the catalog of his friend and colleague Charles Messier as M106.

Moon Struck
8.12.1999

Craters produced by ancient impacts on the airless Moon have long been a familiar sight. But now observers have seen elusive optical flashes on the lunar surface - likely the fleeting result of impacting meteoroids. Orchestrated by David Dunham, president of the International Occultation

Ultra Fast Pulsar
11.02.1998

Pulsars are rotating neutron stars, born in the violent crucibles of supernova explosions. Like cosmic lighthouses, beams of radiation from surface hotspots sweep past our viewpoint creating pulses which reveal the rotation rates of these incredibly dense stellar corpses. The most famous pulsar of all is found in the nearby supernova remnant, the Crab Nebula.

A Powerful Gamma Ray Burst
7.05.1998

Gamma-ray bursts are thought to be the most powerful explosions in the Universe, yet the cause of these high-energy flashes remains a mystery. Blindingly bright for space-based gamma-ray detectors the burst sources are so faint at visible wavelengths that large telescopes and sensitive cameras are required to search for them.

APOD: 2006 September 28- RCW 86: Historical Supernova Remnant
28.09.2006

In 185 AD, Chinese astronomers recorded the appearance of a new star in the Nanmen asterism - a part of the sky identified with Alpha and Beta Centauri on modern star charts. The new star was visible for months and is thought to be the earliest recorded supernova.