Cosmology Solved?
4.11.1998

At the Nature of the Universe Debate held last month at the Smithsonian, top cosmologists P. James E. Peebles (Princeton) and Michael S. Turner (Chicago) argued over whether new data is finally resolving the type of universe in which we live.

Mercury in Accentuated Color
19.03.2008

The colors of Mercury are subtle but beautiful. At first glance, our Solar System's innermost planet appears simply black and white, but images that include infrared colors normally beyond human vision accentuate a world of detail. One such image, shown above, was acquired by the robotic MESSENGER spacecraft that swung by Mercury in mid-January.

Stars Young and Old
26.03.2009

Galactic or open star clusters are relatively young. These swarms of stars are born near the plane of the Milky Way, but their numbers steadily dwindle as cluster members are strewn through the Galaxy by gravitational interactions.

Plato and the Lunar Alps
3.12.2014

The dark-floored, 95 kilometer wide crater Plato and sunlit peaks of the lunar Alps (Montes Alpes) are highlighted in this sharp digital snapshot of the Moon's surface. While the Alps of planet Earth...

AE Aurigae and the Flaming Star Nebula
26.03.2019

Is star AE Aurigae on fire? No. Even though AE Aurigae is named the flaming star, the surrounding nebula IC 405 is named the Flaming Star Nebula, and the region shape gives the appearance of fire, there is no fire.

Fifty Gravitational Wave Events Illustrated
4.11.2020

Over fifty gravitational wave events have now been detected. These events mark the distant, violent collisions of two black holes, a black hole and a neutron star, or two neutron stars. Most of the 50 events were detected in 2019 by the LIGO gravitational wave detectors in the USA and the VIRGO detector in Europe.

Ganymede from Juno
14.06.2021

What does the largest moon in the Solar System look like? Jupiter's moon Ganymede, larger than even Mercury and Pluto, has an icy surface speckled with bright young craters overlying a mixture of older, darker, more cratered terrain laced with grooves and ridges.

APOD: 2023 October 1 Б A Desert Eclipse
1.10.2023

A good place to see a ring-of-fire eclipse, it seemed, would be from a desert. In a desert, there should be relatively few obscuring clouds and trees. Therefore late December of 2019, a group...

APOD: 2025 September 11 Б The Umbra of Earth
11.09.2025

The dark, inner shadow of planet Earth is called the umbra. Shaped like a cone extending into space, it has a circular cross section most easily seen during a lunar eclipse.

APOD: 2025 October 1 Б NGC 6960: The Witchs Broom Nebula
1.10.2025

Ten thousand years ago, before the dawn of recorded human history, a new light would suddenly have appeared in the night sky and faded after a few weeks. Today we know this light was from a supernova, or exploding star, and record the expanding debris cloud as the Veil Nebula, a supernova remnant.