Canis Major Dwarf: A New Closest Galaxy
17.11.2003

What is the closest galaxy to the Milky Way? The new answer to this old question is the Canis Major dwarf galaxy. For many years astronomers thought the Large Magellan Cloud (LMC) was closest, but its title was supplanted in 1994 by the Sagittarius dwarf galaxy.

The VLT Interferometric Array
9.03.1999

The Very Large Telescope (VLT) Interferometric Array will be able to act as individual telescopes or as one huge telescope. Of the four planned VLTs in Chile, two have now reached completion. The first VLT to operate is visible on the left of the above photograph and was recently given the name Antu.

When Roses Aren t Red
24.03.2006

Not all roses are red of course, but they can still be very pretty. Likewise, the beautiful Rosette Nebula and other star forming regions are often shown in astronomical images with a predominately red hue - in part because the dominant emission in the nebula is from hydrogen atoms.

APOD: 2025 January 26 Б The Many Tails of Comet G3 ATLAS
26.01.2025

Why does this comet have so many tails? C/2024 G3 (ATLAS) has developed several long and intricate tails visible from Earth's southern hemisphere over the past two weeks. Many observers reported seeing the impressive comet without any optical aid above the western horizon just after sunset.

Moon Struck
8.12.2001

Craters produced by ancient impacts on the airless Moon have long been a familiar sight. But only since 1999 have observers seen elusive optical flashes on the lunar surface - likely explosions resulting from impacting meteoroids. These startling observations were made with modest telescopes and video equipment during the 1999 and 2001 Leonid meteor showers.

Solar System Portrait
14.02.2002

On another Valentine's Day (February 14, 1990), cruising four billion miles from the Sun, the Voyager 1 spacecraft looked back to make this first ever family portrait of our Solar System. The complete portrait is a 60 frame mosaic made from a vantage point 32 degrees above the ecliptic plane.

Vintage Gamma Rays
6.04.2002

Gamma-rays are the most energetic form of electromagnetic radiation. But these high energy photons penetrate and interact in normal materials and cannot be focused by lenses and mirrors like those in optical telescopes. So how do you make an image in gamma-ray light?

A Triple Sunrise Over Gdansk Bay
4.08.2009

How can the same Sun rise three times? Last month on Friday, 2009 July 10, a spectacular triple sunrise was photographed at about 4:30 am over Gdansk Bay in Gdansk, Poland. Clearly, our Sun rises only once. Some optical effect is creating at least two mirages of the Sun -- but which effect?

NGC 6357: Stellar Wonderland
26.12.2016

For reasons unknown, NGC 6357 is forming some of the most massive stars ever discovered. This complex wonderland of star formation consists of numerous filaments of dust and gas surrounding huge cavities of massive star clusters. The intricate patterns are caused by complex interactions between interstellar winds, radiation pressures, magnetic fields, and gravity.

The Flame Nebula in Visible and Infrared
8.12.2014

What lights up the Flame Nebula? Fifteen hundred light years away towards the constellation of Orion lies a nebula which, from its glow and dark dust lanes, appears, on the left, like a billowing fire. But fire, the rapid acquisition of oxygen, is not what makes this Flame glow.