GL 229B: An Elusive Brown Dwarf?
3.12.1995

What type of matter makes up most of the universe? This question is arguably the most perplexing astronomical mystery of our time. A leading candidate is a type of dim, low mass star called a "brown dwarf" star.

Grey Sun Seething
7.01.1997

The Sun's surface is not smooth. It has thousands of bumps called granules and usually a few dark depressions called sunspots. Each of the numerous granules is the size of an Earth continent, but much shorter lived.

Ice Fishing for Cosmic Neutrinos
16.03.1999

In 1996, scientists melted a hole in the bottom of the world. In fact, several holes have been melted near the South Pole, and they are now being used as astronomical observatories. Astronomers with the Antarctic Muon and Neutrino Detector Array (AMANDA) lower into each vertical lake a string knotted with basketball-sized light detectors.

Galaxy Wars: M81 versus M82
15.04.2006

In this stunning cosmic vista, galaxy M81 is on the left surrounded by blue spiral arms. On the right marked by massive gas and dust clouds, is M82. These two mammoth galaxies have been locked in gravitational combat for the past billion years.

A Huge Solar Filament Erupts
30.07.2016

Filaments sometimes explode off the Sun. Featured, a huge filament had been seen hovering over the Sun's surface for over a week before it erupted late in 2010. The image sequence was taken by the Earth-orbiting Solar Dynamics Observatory (SDO) in one color of ultraviolet light.

Dark Filament of the Sun
22.05.2010

Suspended by magnetic fields above a solar active region this dark filament stretches over 40 earth-diameters. The ominous structure appears to be frozen in time near the Sun's edge, but solar filaments are unstable and often erupt.

Direct Projection: The Moon in My Hands
27.02.2022

You don't have to look through a telescope to know where it's pointing. Allowing the telescope to project its image onto a large surface can be useful because it dilutes the intense brightness of very bright sources. Such dilution is useful for looking at the Sun, for example during a solar eclipse.

APOD: 2023 April 3 Б The Galactic Center Radio Arc
2.04.2023

What causes this unusual curving structure near the center of our Galaxy? The long parallel rays slanting across the top of the featured radio image are known collectively as the Galactic Center Radio Arc and point out from the Galactic plane.

Ice Fishing for Cosmic Neutrinos
29.04.2001

Scientists are melting holes in the bottom of the world. In fact, several holes have been melted near the South Pole, and they are now being used as astronomical observatories. Astronomers with the Antarctic Muon and Neutrino Detector Array (AMANDA) lower into each vertical lake a string knotted with basketball-sized light detectors.

A Solar Prominence from SOHO
16.04.2006

How can gas float above the Sun? Twisted magnetic fields arching from the solar surface can trap ionized gas, suspending it in huge looping structures. These majestic plasma arches are seen as prominences above the solar limb.