The Vela Pulsar s Dynamic Jet
3.07.2003

The Vela pulsar is a neutron star born over 10,000 years ago in a massive supernova explosion. Above, false-color x-ray images from the Chandra Observatory reveal details of this remnant pulsar's x-ray bright nebula along with emission from a spectacular jet of high-energy particles.

Comet Meets Ring Nebula: Part I
11.05.2006

As dawn approached on May 8, astronomer Stefan Seip carefully watched Fragment C of broken comet 73P/Schwassmann-Wachmann 3 approach M57 - the Ring Nebula, and faint spiral galaxy IC 1296. Of course, even though...

Cosmic Rays at Voyager 1
8.09.2012

Launched on a grand tour of the outer planets in 1977, by good fortune the twin Voyager spacecraft were also headed in the general direction of the Sun's motion relative to nearby stars. Thirty five years later, Voyager 1 appears to be nearing the boundary of the Sun's heliosphere and interstellar space.

Orion over El Castillo
21.12.2012

Welcome to the December solstice, a day the world does not end ... even according to the Mayan Calendar. To celebrate, consider this dramatic picture of Orion rising over El Castillo, the central pyramid at Chichén Itzá, one of the great Mayan centers on the Yucatán peninsula.

APOD: 2023 September 13 Б NGC 4632: Galaxy with a Hidden Polar Ring
13.09.2023

Galaxy NGC 4632 hides a secret from optical telescopes. It is surrounded by a ring of cool hydrogen gas orbiting at 90 degrees to its spiral disk. Such polar ring galaxies have previously been discovered using starlight. However, NGC 4632 is among the first in which a radio telescope survey revealed a polar ring.

The Local Void in the Nearby Universe
6.08.2019

What does our region of the Universe look like? Since galaxies are so spread out over the sky, and since our Milky Way Galaxy blocks part of the distant sky, it has been hard to tell.

Big Dipper Above and Below Chilean Volcanoes
9.05.2017

Do you see it? This common question frequently precedes the rediscovery of one of the most commonly recognized configurations of stars on the northern sky: the Big Dipper. This grouping of stars is one of the few things that has likely been seen, and will be seen, by every generation.

APOD: 2024 January 1 Б NGC 1232: A Grand Design Spiral Galaxy
1.01.2024

Galaxies are fascinating not only for what is visible, but for what is invisible. Grand spiral galaxy NGC 1232, captured in detail by one of the Very Large Telescopes, is a good example.

APOD: 2025 February 3 Б Wolf Rayet Star 124: Stellar Wind Machine
3.02.2025

Some stars explode in slow motion. Rare, massive Wolf-Rayet stars are so tumultuous and hot that they are slowly disintegrating right before our telescopes. Glowing gas globs each typically over 30 times more massive than the Earth are being expelled by violent stellar winds.

Ikeya Zhang: Comet Over Colorado
4.04.2002

Comet Ikeya-Zhang ("ee-KAY-uh JONG") has become a most photogenic comet. This lovely early evening view of the comet in Rocky Mountain skies looks northwest over ridges and low clouds. The time exposure was recorded on March 31st from an 8,000 foot elevation near Yampa, Colorado, USA.