Analemma Over Ancient Nemea
21.06.2004

An anelemma is that figure-8 curve that you get when you mark the position of the Sun at the same time each day throughout planet Earth's year. Above, 44 separate exposures (plus...

The Analemma and the Temple of Olympian Zeus
22.12.2006

An analemma is that figure-8 curve you get when you mark the position of the Sun at the same time each day throughout planet Earth's year. Above, 47 separate exposures (plus one foreground...

Periodic Comet Swift Tuttle
7.08.2024

A Halley-type comet with an orbital period of about 133 years, Comet 109P/Swift-Tuttle is recognized as the parent of the annual Perseid Meteor Shower. The comet's last visit to the inner Solar System was in 1992.

APOD: 2024 June 30 Б Earthrise: A Video Reconstruction
29.06.2024

About 12 seconds into this video, something unusual happens. The Earth begins to rise. Never seen by humans before, the rise of the Earth over the limb of the Moon occurred about 55.5 years ago and surprised and amazed the crew of Apollo 8.

Genesis Missions Hard Impact
14.09.2004

A flying saucer from outer space crash-landed in the Utah desert last week after being tracked by radar and chased by helicopters. No space aliens were involved, however. The saucer, pictured above...

Asteroid 9969 Braille
5.08.1999

NASA probe Deep Space 1 zoomed past asteroid 9969 Braille last week as it continued to test its new ion drive in the inner Solar System. The flyby was the closest approach a spacecraft has ever made to an asteroid. Looking back afterwards, DS1 took the above picture.

Frosty Mountains on Mars
30.07.2003

What causes the unusual white color on some Martian mountains? The answer can be guessed by noticing that the bright areas disappear as springtime takes hold in the south of Mars: dry ice. Unlike water ice, dry carbon dioxide ice sublimates directly to gas from its frozen state.

Genesis Missions Hard Impact
5.07.2009

A flying saucer from outer space crash-landed in the Utah desert in 2004 after being tracked by radar and chased by helicopters. No space aliens were involved, however. The saucer, pictured above, was the Genesis sample return capsule, part of a human-made robot Genesis spaceship launched in 2001 by NASA itself to study the Sun.

SMART 1: Pythagoras Crater
2.02.2005

Stark shadows show off the central peaks and terraced walls of 120 kilometer wide Pythagoras Crater in this mosaic of images from ESA's SMART-1 spacecraft. Characteristic of large, complex impact craters on the Moon, the central uplift was produced by a rebound of the suddenly molten lunar crust during the violent impact event.

Mercurys Transit: An Unusual Spot on the Sun
24.08.2014

What's that dot on the Sun? If you look closely, it is almost perfectly round. The dot is the result of an unusual type of solar eclipse that occurred in 2006. Usually it is the Earth's Moon that eclipses the Sun. This time, the planet Mercury took a turn.