The Unusual Boulder at Tychos Peak
7.05.2018

Why is there a large boulder near the center of Tycho's peak? Tycho crater on the Moon is one of the easiest features to see, visible even to the unaided eye (inset, lower right). But at the center of Tycho (inset, upper left) is a something unusual -- a 120-meter boulder.

Falcon 9 Boostback
12.03.2020

Short star trails appear in this single 84 second long exposure, taken on March 6 from a rotating planet. The remarkable scene also captures the flight of a Falcon 9 rocket and Dragon cargo spacecraft over Cape Canaveral Air Force Station shortly after launch, on a resupply mission bound for the International Space Station.

APOD: 2020 August 25 Б Visualization: A Black Hole Accretion Disk
25.08.2020

What would it look like to circle a black hole? If the black hole was surrounded by a swirling disk of glowing and accreting gas, then the great gravity of the black hole would deflect light emitted by the disk to make it look very unusual. The featured animated video gives a visualization.

Three Tails of Comet NEOWISE
8.03.2021

What created the unusual red tail in Comet NEOWISE? Sodium. A spectacular sight back in the summer of 2020, Comet NEOWISE, at times, displayed something more than just a surprisingly striated white dust tail and a pleasingly patchy blue ion tail.

Explosions from White Dwarf Star RS Oph
22.08.2021

Spectacular explosions keep occurring in the binary star system named RS Ophiuchi. Every 20 years or so, the red giant star dumps enough hydrogen gas onto its companion white dwarf star to set off a brilliant thermonuclear explosion on the white dwarf's surface.

The Snows of Churyumov Gerasimenko
6.01.2024

You couldn't really be caught in this blizzard while standing by a cliff on periodic comet 67P/Churyumov-Gerasimenko. Orbiting the comet in June of 2016, the Rosetta spacecraft's narrow angle camera did record...

APOD: 2025 June 29 Б Dark Sand Cascades on Mars
29.06.2025

Are these trees growing on Mars? No. Groups of dark brown streaks have been photographed by the Mars Reconnaissance Orbiter on melting pinkish sand dunes covered with light frost. The featured image was taken in 2008 April near the North Pole of Mars.

Apollo 17 s Lunar Rover
9.06.2001

In December of 1972, Apollo 17 astronauts Eugene Cernan and Harrison Schmitt spent about 75 hours exploring the Moon's Taurus-Littrow valley while colleague Ronald Evans orbited overhead. Cernan and Schmitt were the last humans to walk or ride on the Moon - aided in their explorations by a Lunar Roving Vehicle.

Structure in N63A
1.01.2004

Shells and arcs abound in this false-color, multiwavelength view of supernova remnant N63A, the debris of a massive stellar explosion. The x-ray emission (blue), is from gas heated to 10 million degrees C as knots of fast moving material from the cosmic blast sweep up surrounding interstellar matter.

Phobos: Doomed Moon of Mars
19.11.2004

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...