If You Could Stand on Mars
6.02.1996

If you could stand on Mars - what would you see? Viking 1 robot landers answered this question in 1976 with pictures like the one shown above. The dark rocks, red soil, and green-tinged sky grace this rendition of a normal Martian afternoon. At the bottom corners of the picture are portions of Viking spacecraft.

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.

A Rusty Sunset on Mars
4.08.1997

On Mars, sunsets can appear salmon pink. The unusual color is partly due to rust: oxidized iron from Martian dust circulating in the Martian atmosphere. Clouds appear in the morning and evening, but usually evaporate in the midday Sun.

On a Blue Moon
1.09.2012

Rising at sunset, the gorgeous Full Moon of August 31 became the second Full Moon in a month. According to modern reckoning, that makes it a Blue Moon. In fact, parts of the Full Moon do look a little blue in this sharp lunar portrait.

Sun and Winter Solstice 1996
20.12.1996

Today is the Winter Solstice for 1996. After steadily sinking in Northern Hemisphere skies, the Sun is now at its lowest declination - marking the first day of Northern Winter (but Southern Summer!). The Earth...

A Landing at Meridiani Planum
25.01.2004

After an interplanetary journey of nearly 300 million miles, Opportunity bounced down on the martian surface at about 9:05 pm PST Saturday, its final plunge cushioned by airbags. Now the second NASA rover...

The Color of the Moon
15.02.2006

Earth's Moon is normally seen in subtle shades of grey or yellow. But small color differences have been greatly exaggerated to make this dramatic mosaic image of the Moon's gibbous phase. The familiar Sea of Tranquility (Mare Tranquillitatis) is the blue area right of center.

A Berry Bowl of Martian Spherules
5.04.2004

How were these unusual Martian spherules created? Thousands of unusual gray spherules, made of iron and rock but dubbed blueberries, were found embedded in and surrounding rocks near the landing site of the robot Opportunity rover on Mars.

Southwest Mercury
13.09.1996

The planet Mercury resembles a moon. Mercury's old surface is heavily cratered like many moons. Mercury is larger than most moons but smaller than Jupiter's moon Ganymede and Saturn's moon Titan. Mercury is much denser and more massive than any moon, though, because it is made mostly of iron.

Southwest Mercury
15.02.2003

The planet Mercury resembles a moon. Mercury's old surface is heavily cratered like many moons. Mercury is larger than most moons but smaller than Jupiter's moon Ganymede and Saturn's moon Titan. Mercury is much denser and more massive than any moon, though, because it is made mostly of iron.