The Sun Unleashed: Monster Filament in Ultraviolet
9.04.2018

One of the most spectacular solar sights is an explosive flare. In 2011 June, the Sun unleashed somewhat impressive, medium-sized solar flare as rotation carried active regions of sunpots toward the solar limb. That...

In Motion: Uranus and Moons
30.11.2021

What's that moving across the sky? A planet just a bit too faint to see with the unaided eye: Uranus. The gas giant out past Saturn was tracked earlier this month near opposition -- when it was closest to Earth and at its brightest.

The Far Side of the Moon
25.02.2007

Does this moon look familiar? Possibly not, even though it is Earth's Moon. Locked in synchronous rotation, the Moon always presents its well-known near side to Earth. But from lunar orbit, Apollo astronauts also grew to know the Moon's far side.

APOD: 2023 January 11 Б Spiral Aurora over Iceland
11.01.2023

The scene may look like a fantasy, but it's really Iceland. The rock arch is named Gatklettur and located on the island's northwest coast. Some of the larger rocks in the foreground span a meter across. The fog over the rocks is really moving waves averaged over long exposures.

AR9077: Solar Magnetic Arcade
20.07.2000

On July 14th, solar active region 9077 (AR9077) produced a massive flare. The event also blasted an enormous cloud of energetic charged particles toward planet Earth, triggering magnetic storms and dramatic auroral displays. This striking close-up of AR9077 was made by the orbiting TRACE satellite shortly after the flare erupted.

A Twisted Meteor Trail Over Tenerife
2.06.2010

Did this meteor take a twisting path? No one is sure. Considered opinions are solicited. Meteors, usually sand sized grains that originate in comets, will typically disintegrate as they enter the Earth's atmosphere. A fast moving meteor ionizes molecules in the Earth's atmosphere that subsequently glow when they reacquire electrons.

Framed by Trees: A Window to the Galaxy
19.07.2021

The photographer had this shot in mind for some time. He knew that objects overhead are the brightest -- since their light is scattered the least by atmospheric air. He also that knew the core of our Milky Way Galaxy was just about straight up near midnight around this time of year in South Australia.

Earth Flyby of BepiColombo
4.05.2020

What it would look like to approach planet Earth? Such an event was recorded visually in great detail by ESA's and JAXA's robotic BepiColombo spacecraft last month as it swung back past Earth on its journey in to the planet Mercury.

Earth, Clouds, Sky, Comet
3.04.1997

Does a comet's dust tail always orbit behind it? Since comets rotate, they shed gas and dust in all directions equally. Small ice and dust particles expelled by the comet, however, are literally pushed around by sunlight. The smaller the particle, the greater the effect.

Titan: Moon over Saturn
26.05.2018

Like Earth's moon, Saturn's largest moon Titan is locked in synchronous rotation. This mosiac of images recorded by the Cassini spacecraft in May of 2012 show's its anti-Saturn side, the side always facing away from the ringed gas giant.