APOD: 2024 April 23 Б Contrail Shadow X
23.04.2024

What created this giant X in the clouds? It was the shadow of contrails illuminated from below. When airplanes fly, humid engine exhaust may form water droplets that might freeze in Earth's cold upper atmosphere. These persistent streams of water and ice scatter light from the Sun above and so appear bright from below.

The North Pole of Venus
14.05.2003

If you could look down on the North Pole of Venus what would you see? The Magellan probe that orbited Venus from 1990 to 1994 was able to peer through the thick Venusian clouds and build up the above image by emitting and re-detecting cloud-penetrating radar.

Jupiter Swallows Comet Shoemaker Levy 9
4.08.1998

What happens when a comet encounters a planet? If the planet has a rocky surface, a huge impact feature will form. A giant planet like Jupiter, however, is mostly gas. When Comet Shoemaker-Levy 9 struck Jupiter in 1994, each piece was swallowed into the vast Jovian atmosphere.

Nozomi: Earth and Moon
4.09.1998

Japan launched its first mission to orbit Mars, Nozomi (Hope), on July 3rd from the Kagoshima Space Center on the island of Kyushu. Nozomi's goal is to explore the Martian atmosphere and magnetic field as well as regions of the planet's surface and moons.

Triton: Neptunes Largest Moon
4.03.2007

In October of 1846, William Lassell was observing the newly discovered planet Neptune. He was attempting to confirm his observation, made just the previous week, that Neptune had a ring. But this time he discovered that Neptune had a satellite as well.

Millennium Annular Solar Eclipse
22.01.2010

The Moon's shadow raced across planet Earth on January 15. Observers within the central shadow track were able to witness an annular solar eclipse as the Moon's apparent size was too small to completely cover the Sun.

Juno Rockets Toward Jupiter
9.08.2011

Next stop: Jupiter. Last week included one of the few times in history that humanity launched something completely off the Earth, moving away so fast that it will never return. Well, almost -- Juno...

Golden Gate Sunset: Green Flash
2.12.2015

The setting is San Francisco Bay, the time is sunset, and the bridge is the Golden Gate. What you are about to see is an unexpected double sunset ending with a rare green flash.

Ripples Through a Dark Sky
30.07.2016

Sunlight ripples through a dark sky on this Swedish summer midnight as noctilucent or night shining clouds seem to imitate the river below. In fact, the seasonal clouds often appear at high latitudes in corresponding summer months. Also known as polar mesospheric clouds, they form as water vapor is driven into the cold upper atmosphere.

APOD: 2023 October 22 Б Ghost Aurora over Canada
22.10.2023

What does this aurora look like to you? While braving the cold to watch the skies above northern Canada early one morning in 2013, a most unusual aurora appeared. The aurora definitely appeared to be shaped like something, but what?