Beijing Ancient Observatory
6.05.1998

Did observatories exist before telescopes? One example that still stands today is the Beijing Ancient Observatory in China. Starting in the 1400s astronomers erected large instruments here to enable them to measure star and planet positions with increasing accuracy.

Shapley 1: An Annular Planetary Nebula
9.08.1998

What happens when a star runs out of nuclear fuel? The center condenses into a white dwarf while the outer atmospheric layers are expelled into space and appear as a planetary nebula. This particular planetary nebula, designated Shapley 1 after the famous astronomer Harlow Shapley, has a very apparent annular ring like structure.

A Winter Solstice
21.12.1997

Today is the Winter Solstice, the shortest day of the year in the Northern Hemisphere. The yearly cycle of Seasons on planet Earth once again finds the Sun at its lowest point in the Northern Sky.

Water World
30.05.1998

Water (Dihydrogen Oxide, H2O) is a truly remarkable chemical compound, fundamental to life on Earth. Earth is the only planet in the Solar System where the present surface temperature and pressure allow the three forms of water, solid (ice), liquid (ocean), and gas (water vapor condensing in clouds) to exist simultaneously.

Mercury's Faults
21.01.1996

The surface of the planet Mercury is not without fault. In this case, however, "fault" refers to unusual surface features that are the topic of much speculation. The above fault line is called Santa Maria Rupes, and runs through many prominent craters.

Shapley 1: An Annular Planetary Nebula
16.08.2011

What happens when a star runs out of nuclear fuel? For stars about the mass of our Sun, the center condenses into a white dwarf while the outer atmospheric layers are expelled into space and appear as a planetary nebula.

Aurora in the Night
31.10.2002

For much of the month of October, traveling shock waves from the Sun and solar wind gusts have buffeted planet Earth's magnetosphere. As a result, skywatchers at high latitudes in the northern hemisphere were treated to many displays of the aurora borealis or northern lights.

Looking Down on Saturn
21.09.1997

This picture of Saturn could not have been taken from Earth. No Earth based picture could possibly view the night side of Saturn and the corresponding shadow cast across Saturn's rings. Since Earth is much closer to the Sun than Saturn, only the day side of the planet is visible from the Earth.

Eye Sky a Dragon
22.09.2019

What do you see when you look into this sky? In the center, in the dark, do you see a night sky filled with stars? Do you see a sunset to the left? Clouds all around? Do you see the central band of our Milky Way Galaxy running down the middle?

The Grand Canyon of Mars
20.07.1995

The Mariner Valley, also known as the Valles Marineris canyon system, appears in this mosaic of images from NASA's Viking spacecraft as a huge gouge across the red planet. This "Grand Canyon" of Mars is about 2500 miles long and up to 4 miles deep.