APOD: 2026 April 12 Б Comet R3 PanSTARRS Brightens
11.04.2026

Comet R3 is brightening rapidly -- will it survive? C/2025 R3 (PanSTARRS) has been slowly brightening and extending an ion tail since its discovery last year. This shedding mountain of dirty ice puts...

Comet 2022 E3 ZTF
23.12.2022

Comet C/2022 E3 (ZTF) was discovered by astronomers using the wide-field survey camera at the Zwicky Transient Facility this year in early March. Since then the new long-period comet has brightened substantially and is now sweeping across the northern constellation Corona Borealis in predawn skies.

APOD: 2023 February 13 Б Comet ZTF and Mars
12.02.2023

No, Comet ZTF is not going to hit Mars. Nicknamed the Green Comet for its bright green coma, C/2022 E3 (ZTF) did, however, pass almost in front of the much-more distant planet a few days ago, very near in time to when the featured picture was taken.

Comet ISON Rising
27.11.2013

Will Comet ISON survive tomorrow's close encounter with the Sun? Approaching to within a solar diameter of the Sun's surface, the fate of one of the most unusual comets of modern times will finally be determined.

Jets from Comet Churyumov Gerasimenko
2.02.2015

Where do comet tails come from? Although it is common knowledge that comet tails and comas originate from comet nuclei, exactly how that happens is an active topic of research. One of the best...

The Rotating Jets of Comet Hyakutake
14.04.1996

Comet Hyakutake will reach its closest point to the Sun on May 1, passing well inside the orbit of Mercury. At this time, the comet's dust and ion tail will be at their greatest physical length.

Solar Sail
7.03.2003

Nearly 400 years ago astronomer Johannes Kepler observed comet tails blown by a solar breeze and suggested that vessels might likewise navigate through space using appropriately fashioned sails. It is now widely recognized that...

Comet Hale Bopp Over Val Parola Pass
7.12.2021

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.

Hickson 91 in Piscis Austrinus
23.03.2016

Scanning the skies for galaxies, Canadian astronomer Paul Hickson and colleagues identified some 100 compact groups of galaxies, now appropriately called Hickson Compact Groups (HCGs). This sharp telescopic image captures one such galaxy group, HCG 91, in beautiful detail.

Water Found Around Nearby Star CW Leonis
16.07.2001

Do worlds outside our Solar System have oceans of water like Earth? An indication that such worlds might exist was bolstered recently by new evidence that nearby star system CW Leonis harbors water. Recent observations with the Submillimeter Wave Astronomy Satellite (SWAS) found significant detections of light at specific colors emitted by water.