Lunar Craters Langrenus and Petavius
11.11.2019

The history of the Moon is partly written in its craters. Pictured here is a lunar panorama taken from Earth featuring the large craters Langrenus, toward the left, and Petavius, toward the right. The craters formed in separate impacts.

COBE Dipole: Speeding Through the Universe
27.06.1999

Our Earth is not at rest. The Earth moves around the Sun. The Sun orbits the center of the Milky Way Galaxy. The Milky Way Galaxy orbits in the Local Group. The Local Group falls toward the Virgo Cluster of Galaxies.

Red Auroral Corona
15.01.2002

Few auroras show this level of detail. This unusual display of an auroral corona occurred on Earth three days after an unusual solar event -- the fifth most powerful explosion yet recorded on the Sun. An X14-class solar flare on April 15 sent a tremendous Coronal Mass Ejection (CME) into the Solar System.

Comet C 2001 Q4 (NEAT)
23.04.2004

Inbound from the distant solar system, comet C/2001 Q4 will soon pass just inside planet Earth's orbit and should be one of two bright, naked-eye comets visible in southern skies in May. First...

100 Steps Forward
15.09.2017

A beautiful conjunction of Venus and Moon, human, sand, and Milky Way is depicted in this night skyscape from planet Earth. The scene is a panorama of 6 photos taken in a moment near the end of a journey.

APOD: 2025 September 20 Б Gibbous vs Crescent
20.09.2025

Early risers around planet Earth have enjoyed a shining crescent Moon near brilliant Venus, close to the eastern horizon in recent morning twilight skies. And yesterday, on September 19, skygazers watching from some locations...

A Chamaeleon Sky
9.06.2002

A photogenic group of nebulae can be found toward Chamaeleon, a constellation visible predominantly in skies south of the Earth's equator. Celestial objects visible there include the blue reflection nebulas highlighted by thin dust surrounding the bright stars in the above image center.

A Cosmic Snowball
30.05.1997

Like cosmic snowballs, fluffy comet-like objects the size of houses and composed mostly of water-ice, may be pummeling planet Earth 5 to 30 times a minute. This controversial theory was originally proposed in 1986 by Dr. Louis Frank (U. Iowa) based on data from NASA's Dynamics Explorer 1.

Mars: Just The Fiction
28.05.1997

For centuries, astronomers have observed Mars, patiently compiling many facts and theories. Like a distant mirror of Earth dwellers' hopes and fears for the future, Mars, the fourth planet from the sun, has inspired profound works of fiction as well.

Circling the Sun
13.01.2024

Earth's orbit around the Sun is not a circle, it's an ellipse. The point along its elliptical orbit where our fair planet is closest to the Sun is called perihelion. This year...