Primordial Contact Binary 2014 MU69
22.05.2019

Primordial contact binary 2014 MU69, also known as Ultima Thule, really is very red. In fact, it's the reddest outer solar system object ever visited by a spacecraft from Earth. Its reddish hue is believed to be due to organic materials on its surface.

APOD: 2024 March 26 Б Comet Pons Brooks Ion Tail
26.03.2024

Comet Pons-Brooks has quite a tail to tell. First discovered in 1385, this erupting dirty snowball loops back into our inner Solar System every 71 years and, this time, is starting to put on a show for deep camera exposures.

Hale-Bopp and Andromeda
1.04.1997

Which is closer: the comet or the galaxy? Answer: the comet. In its trek through the inner Solar System, Comet Hale-Bopp has passed nearly in front of the Andromeda Galaxy (M31), seen on the lower left.

Comet Stonehouse
14.05.1998

Comets move against a field of background stars. Their apparent motion is slow but carefull tracking reveals their orbits, allowing these visitors to the inner solar system to be identified as old or new acquaintances. Recently a new comet, designated 1998 H1, was discovered by observer Patrick L.

Venus and Jupiter are Far
3.07.2015

On June 30 Venus and Jupiter were actually far apart, but both appeared close in western skies at dusk. Near the culmination of this year's gorgeous conjunction, the two bright evening planets...

Between the Rings
22.04.2017

On April 12, as the Sun was blocked by the disk of Saturn the Cassini spacecraft camera looked toward the inner Solar System and the gas giant's backlit rings. At the top of the mosaicked view is the A ring with its broader Encke and narrower Keeler gaps visible.

Orionids in Taurus
26.10.2023

History's first known periodic comet, Comet Halley (1P/Halley), returns to the inner Solar System every 76 years or so. The famous comet made its last appearance to the naked-eye in 1986. But dusty...

APOD: 2024 June 4 Б Comet Pons Brooks Develops Opposing Tails
4.06.2024

Why does Comet Pons-Brooks now have tails pointing in opposite directions? The most spectacular tail is the blue-glowing ion tail that is visible flowing down the image. The ion tail is pushed directly out from the Sun by the solar wind. On the upper right is the glowing central coma of Comet 12P/PonsБBrooks.

APOD: 2026 January 25 Б Phobos: Doomed Moon of Mars
25.01.2026

This moon is doomed. Mars, the red planet named for the Roman god of war, has two tiny moons, Phobos and Deimos, whose names are derived from the Greek for Fear and Panic. These...

Galileo, Cassini, and the Great Red Spot
2.08.1996

Imagine a hurricane that lasted for 300 years! Jupiter's Great Red Spot indeed seems to be a giant hurricane-like storm system rotating with the Jovian clouds. Observed in 1655 by Italian-French astronomer Jean-Dominique Cassini it is seen here over 300 years later - still going strong - in a mosaic of recent Galileo spacecraft images.