Volcanos on Mars: Elysium Region
30.07.1998

This "synthetic color" image swath of the Elysium Volcanic Region of Mars was recorded by Mars Global Surveyor's wide angle camera on July 2. North is up and the sun illuminates the scene from the lower right. Bright clouds hover near the northern most dome-shaped volcano Hecates Tholus.

Working in Space
23.05.2004

High above planet Earth, a human helps an ailing machine. The machine, in this potentially touching story, is the Hubble Space Telescope, which is not in the picture. The human is Astronaut Steven L.

Autumn and the Active Sun
23.09.1998

As the Sun heads South, crossing the celestial equator today at 1:37 a.m. Eastern Time, Autumn begins for Earth's Northern Hemisphere. This Autumnal Equinox finds an increasingly active Sun steadily approaching a solar cycle maximum expected around the year 2003.

Kepler Discovers How Planets Move
6.06.1999

Johannes Kepler used simple mathematics to describe how planets move. Kepler was an assistant to the most accurate astronomical observer of the time, Tycho Brahe. Kepler was able to use Brahe's data...

To Fly Free in Space
16.09.2007

At about 100 meters from the cargo bay of the space shuttle Challenger, Bruce McCandless II was further out than anyone had ever been before. Guided by a Manned Maneuvering Unit (MMU), astronaut McCandless, pictured above, was floating free in space.

To Fly Free in Space
27.09.2009

At about 100 meters from the cargo bay of the space shuttle Challenger, Bruce McCandless II was further out than anyone had ever been before. Guided by a Manned Maneuvering Unit (MMU), astronaut McCandless, pictured above, was floating free in space.

Aurora Over Alaska
6.10.2010

Are those green clouds or aurora? Photographed above two weeks ago, puffy green aurora help the Moon illuminate the serene Willow Lake and the snowy Wrangell and Saint Elias Mountains in eastern Alaska, USA.

An Aurora Cupcake with a Milky Way Topping
9.09.2014

This sky looked delicious. Double auroral ovals were captured above the town lights of жstersund, Sweden, last week. Pictured above, the green ovals occurred lower to the ground than violet aurora rays above, making the whole display look a bit like a cupcake.

Night Sky Highlights: March to May
14.03.2018

What might you see in the night sky over the next few months? The featured graphic gives a few highlights. Viewed as a clock face centered at the bottom, sky events in March fan out toward the left, April toward the top, and May toward the right.

APOD: 2023 February 28 Б Crescent Moon Beyond Greek Temple
28.02.2023

Why is a thin crescent moon never seen far from a horizon? Because the only geometry that gives a thin crescent lunar phase occurs when the Moon appears close to the Sun in the sky.