APOD: 2024 December 8 Б Aurora around Saturns North Pole
8.12.2024

Are Saturn's auroras like Earth's? To help answer this question, the Hubble Space Telescope and the Cassini spacecraft monitored Saturn's North Pole simultaneously during Cassini's final orbits around the gas giant in September 2017. During this time, Saturn's tilt caused its North Pole to be clearly visible from Earth.

Retrograde Mars
16.12.2003

Why would Mars appear to move backwards? Most of the time, the apparent motion of Mars in Earth's sky is in one direction, slow but steady in front of the far distant stars. About every two years, however, the Earth passes Mars as they orbit around the Sun.

Sunset, Shadowrise
29.07.2010

From central Australia, this serene 360 degree panorama follows a clear horizon as twilight began on May 28. At left, a bright western sky is still illuminated by the setting Sun. But sweeping right...

Lunar Eclipse over a Skyscraper
22.11.2021

Why is the Moon on top of this building? Planning. It took the astrophotographer careful planning -- including figuring out exactly where to place the camera and exactly when to take the shot -- to create this striking superposition.

Rocket Streak and Star Trails
30.01.2014

Fixed to a tripod and looking east across the Kennedy Space Center's Turn Basin, a camera captured these star trails as a series of short exposures over a three hour period on the evening of January 23rd.

Asteroids in the Distance
17.04.2005

Rocks from space hit Earth every day. The larger the rock, though, the less often Earth is struck. Many kilograms of space dust pitter to Earth daily. Larger bits appear initially as a bright meteor. Baseball-sized rocks and ice-balls streak through our atmosphere daily, most evaporating quickly to nothing.

Islands of Four Mountains from Above
22.06.2010

Our Earth is covered by volcanoes. Volcanoes are breaks in the Earth's cool surface where hot liquid rock from the interior comes out -- sometimes suddenly. In the above image from the ASTER camera...

APOD: 2023 April 19 Б Auroral Storm over Lapland
19.04.2023

On some nights the sky is the best show in town. On this night, auroras ruled the sky, and the geomagnetic storm that created this colorful sky show originated from an increasingly active Sun.

Solar Storm Causes X-Ray Aurora
18.04.1997

On April 7, the SOHO spacecraft spotted a Solar Storm ejecting a cloud of energetic particles toward planet Earth. The plasma cloud's center missed Earth, but high energy particles swept up by Earth's magnetosphere still created a geomagnetic storm!

A Near Record Ozone Hole in 2003
6.10.2003

As expected, the ozone hole near Earth's South Pole is back again this year. This year's hole, being slightly larger than North America, is larger than last year but short of the record set on 2000 September 10. Ozone is important because it shields us from damaging ultraviolet sunlight.