High Noon Analemma Over Azerbaijan
14.10.2013

Is the Sun always straight up at noontime? No. For example, the Sun never appears directly overhead from locations well north or south of the Earth's equator. Conversely, there is always a place on Earth where the Sun will appear at zenith at noon -- for example on the equator during an equinox.

APOD: 2023 February 21 Б Comet ZTF over Yosemite Falls
21.02.2023

They are both falling. The water in Yosemite Falls, California, USA, is falling toward the Earth. Comet ZTF is falling toward the Sun. This double cosmic cascade was captured late last month as fading Comet C/2022 E3 (ZTF) had just passed its closest to planet Earth. The orange star just over the falls is Kochab.

Three Galaxies and a Comet
21.12.2023

Distant galaxies abound in this one degree wide field of view toward the southern constellation Grus (The Crane). But the three spiral galaxies at the lower right are quite striking. In fact, all three galaxies are grouped about 70 million light years away and sometimes known as the Grus Triplet.

Searching For Solar Systems
15.11.1996

Observational astronomy has recently provided evidence of the existence of massive Jupiter-sized planets orbiting distant suns, protoplanetary disks of gas and dust surrounding newly formed stars, and planetary bodies orbiting exotic stellar corpses known as pulsars. Indeed, the formation of planets seems to be a broader and more varied phenomenon than previously imagined.

Space Laser Creates Artificial Star
25.04.2001

Some astronomers don't like stars. Bright star fluctuations can indicate how the Earth's atmosphere is changing, but many times no bright star exists in the direction where atmospheric information is needed.

Oceans Under Jupiters Callisto
31.07.2001

Why does Jupiter's moon Callisto alter the magnetic field of Jupiter in its vicinity? Callisto itself does not have a strong magnetic field. One possible answer is that Callisto harbors sub-surface oceans of electrically conducting salt-water. This hypothesis was bolstered recently by a new analysis of how Callisto creates and dissipates heat.

Mars Rising Behind Poodle Rock
13.08.2003

Have you seen Mars lately? As Earth and Mars near their closest approach in nearly 60,000 years on August 27, the red planet has begun to appear dramatically bright and show interesting details through telescopes and binoculars. Although not yet visible at sunset, Mars can be seen rising increasingly earlier in the evening.

Red Moon Triple
29.10.2004

Some thought of baseball and some thought of Halloween during October 27th's widely viewed total lunar eclipse. Sliding through Earth's shadow, the Moon turned haunting shades of red and orange during the eclipse's total phase.

Eclipsed Moon and Stars
8.03.2007

This dramatic image features a dark red Moon during a total lunar eclipse -- celestial shadow play enjoyed by many denizens of planet Earth last Saturday. Recorded near Wildon, Austria, the picture is a composite...

Vesta Rocks
10.12.2011

These colorful images are of thin slices of meteorites viewed through a polarizing microscope. Part of the group classified as HED meteorites for their mineral content (Howardite, Eucrite, Diogenite), they likely fell to Earth from 4 Vesta, the mainbelt asteroid currently being explored by NASA's Dawn spacecraft.