Diamond Ring in a Cloudy Sky
25.08.2017

As the Moon's shadow swept across the US on August 21, eclipse chasers in the narrow path of totality were treated to a diamond ring in the sky. At the beginning and end of totality, the fleeting and beautiful effect often produces audible gasps from an amazed audience.

ROSAT Explores The X-Ray Sky
19.08.2000

Launched in 1990, the orbiting ROSAT observatory explored the Universe by viewing the entire sky in x-rays -- photons with about 1,000 times more energy than visible light. This ROSAT survey produced the sharpest, most sensitive image of the x-ray sky to date.

Henrietta Leavitt Calibrates the Stars
3.09.2000

Humanity's understanding of the relative brightness and variability of stars was revolutionized by the work of Henrietta Swan Leavitt (1868-1921). Working at Harvard College Observatory, Leavitt precisely calibrated the photographic magnitudes of 47 stars to which all other stars could be compared.

An Earth Ornament
25.12.1996

The Apollo 8 astronauts spent the 1968 Christmas Season in lunar orbit, returning with striking images of the Moon and Earth from space which inspired the world. While in lunar orbit...

Water World
16.03.1997

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 surface temperature and pressure allow the three forms of water, solid (ice), liquid (ocean), and gas (water vapor condensing in clouds) to exist simultaneously on its surface.

Eta Carinae Before Explosion
12.07.1995

The star Eta Carinae, at the center of the photo, will likely destroy itself in a spectacular explosion in a few million years - or sooner! Currently it is one of the brightest, most massive, and least stable stars known. Much of the gas in this Hubble Space Telescope photograph was blown off the star itself.

The Sky Towards Sagittarius
7.09.1998

A variety of stars and nebulae can be found towards the constellation of Sagittarius. Dense fields of stars laced with dark lanes of dust crowd this region only a few degrees from the center of our Galaxy.

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.

Henrietta Leavitt Calibrates the Stars
27.10.1998

Humanity's understanding of the relative brightness and variability of stars was revolutionized by the work of Henrietta Swan Leavitt (1868-1921). Working at Harvard College Observatory, Leavitt precisely calibrated the photographic magnitudes of 47 stars to which all other stars could be compared.

A Prominent Solar Prominence
27.01.1997

One of the most spectacular solar sights is a prominence. A solar prominence is a cloud of solar gas held above the Sun's surface by the Sun's magnetic field. The Earth would easily fit under one of the loops of the prominence shown in the above picture.