Comet 13P Olbers
28.06.2024

Not a paradox, Comet 13P/Olbers is returning to the inner Solar System after 68 years. The periodic, Halley-type comet will reach its next perihelion or closest approach to the Sun on June 30 and has become a target for binocular viewing low in planet Earth's northern hemisphere night skies.

Simulated Transit of Mercury
8.11.2006

Mercury, the solar system's innermost planet, will spend about five hours crossing in front of the Sun today - beginning at 1912 UT (2:12pm EST), November 8. Specially equipped telescopes are highly recommended...

APOD: 2026 May 8 Б Comet R3 PanSTARRS Before Rigel
8.05.2026

Which way is Comet R3 PanSTARRS going? Not towards the star at the top of the image, because that is Rigel, which, being far in the background, is unrelated to the comet. Not through...

Galaxies in the River
8.01.2020

Large galaxies grow by eating small ones. Even our own galaxy engages in a sort of galactic cannibalism, absorbing small galaxies that are too close and are captured by the Milky Way's gravity.

A Superior Conjunction Of Mercury
8.09.1999

In astronomical parlance, an interior planet is at superior conjunction when it is located on the opposite side of the Sun from Earth. Mercury, the solar system's innermost planet, zips past this point in its orbit today.

A Message from Earth
17.07.1997

What are these Earthlings trying to tell us? The above message was broadcast from Earth towards the globular star cluster M13 in 1974. During the dedication of the Arecibo Observatory - still the largest radio telescope in the world - a string of 1's and 0's representing the above diagram was sent.

Comet Hale Bopp Over Val Parola Pass
23.12.2012

Comet Hale-Bopp, the Great Comet of 1997, became much brighter than any surrounding stars. It was seen even over bright city lights. Away from city lights, however, it put on quite a spectacular show. Here Comet Hale-Bopp was photographed above Val Parola Pass in the Dolomite mountains surrounding Cortina d'Ampezzo, Italy.

APOD: 2026 March 29 Б A Message from Earth
29.03.2026

What are these Earthlings trying to tell us? The featured message was broadcast from Earth towards the globular star cluster M13 in 1974. During the dedication of an upgrade to the Arecibo Observatory - then the largest single radio telescope in the world - a string of 1's and 0's representing the diagram was sent.

NGC 5101 and Friends
8.02.2014

This sharp telescopic field of view holds two bright galaxies. Barred spiral NGC 5101 (top right) and nearly edge-on system NGC 5078 are separated on the sky by about 0.5 degrees or about the apparent width of a full moon.

Stargate Milky Way
17.08.2022

There is a huge gate of stars in the sky, and you pass through it twice a day. The stargate is actually our Milky Way Galaxy, and it is the spin of the Earth that appears to propel you through it.