PG 1115+080: A Gravitational Cloverleaf
31.03.1999

All four blue images in the above photograph are the same object. The gravitational lens effect of the red, foreground, elliptical galaxy visible near image center creates a cloverleaf image of the single distant quasar. Light from the quasar is pulled around the massive galaxy in different paths, corresponding to different images.

A Day in the Life of a Human Sundial
12.08.2017

Have you ever wanted to be a gnomon? Of course, a gnomon is the tall part of a sundial that casts a shadow. The gnomon's shadow moves as the Sun moves across the sky, indicating time by the shadow's position on the dial face.

Olympus Mons From Orbit
19.10.1998

Olympus Mons on Mars is the largest volcano in the Solar System. Although three times higher than Earth's Mount Everest, Olympus Mons would not be difficult to climb because of the volcano's great breadth.

APOD: 2025 October 9 Б The Jenga Moon
9.10.2025

That big, bright, beautiful Full Moon you watched rise on the night of October 6 was the Harvest Moon. Famed in festival, story, and song, Harvest Moon is just the traditional name of the full moon nearest the time of the northern hemisphere's autumnal equinox. According to lore the name is a fitting one.

Antares and Clouds
17.04.2012

Antares is a huge star. In a class called red supergiant, Antares is about 850 times the diameter of our own Sun, 15 times more massive, and 10,000 times brighter. Antares is the brightest star in the constellation of Scorpius and one of the brighter stars in all the night sky.

APOD: 2023 April 26 Б The Moon through the Arc de Triomphe
26.04.2023

Was this a lucky shot? Although many amazing photographs are taken by someone who just happenedбto be in the right place at the right time, this image took skill and careful planning. First...

Sunset to Sunrise over the Baltic Sea
16.06.2023

This serene view from the coast of Sweden looks across the Baltic sea and compresses time, presenting the passage of one night in a single photograph. From sunset to sunrise, moonlight illuminates the creative sea and skyscape. Fleeting clouds, fixed stars, and flowing northern lights leave their traces in planet Earth's sky.

Mercury: Closest Planet to the Sun
14.08.1995

This picture was compiled from images taken by the NASA spacecraft Mariner 10 which flew by the planet three times in 1974. Mercury is the closest planet to the Sun, the second hottest planet (Venus gets hotter), and the second smallest planet (Pluto is smaller).

Manhattan Skylines
17.02.2018

City lights shine along the upper east side of Manahattan in this dramatic urban night skyscape from February 13. Composed from a series of digital exposures, the monochrome image is reminiscent of the time when sensitive black and white film was a popular choice for dimly lit night and astro-photography.

Breaking Distant Light
19.03.2002

In the distant universe, time appears to run slow. Since time-dilated light appears shifted toward the red end of the spectrum (redshifted), astronomers are able to use cosmological time-slowing to help measure vast distances in the universe.