APOD: 2023 November 6 Б Red Aurora over Italy
6.11.2023

What was that red glow on the horizon last night? Aurora. Our unusually active Sun produced a surface explosion a few days ago that sent out a burst of electrons, protons, and more massive charged nuclei.

Apollo 11: Catching Some Sun
20.09.2003

Bright sunlight glints and long dark shadows dramatize this image of the lunar surface taken by Apollo 11 astronaut Neil Armstrong, the first to walk on the Moon. Pictured is the mission's lunar...

Auroras over Northern Canada
9.10.2022

Gusting solar winds and blasts of charged particles from the Sun resulted in several rewarding nights of auroras back in 2014 December, near the peak of the last 11-year solar cycle. The featured image captured dramatic auroras stretching across a sky near the town of Yellowknife in northern Canada.

A Molten Galaxy Einstein Ring Galaxy
5.07.2022

It is difficult to hide a galaxy behind a cluster of galaxies. The closer cluster's gravity will act like a huge lens, pulling images of the distant galaxy around the sides and greatly distorting them. This is just the case observed in the featured image recently re-processed image from the Hubble Space Telescope.

Venus Unveiled
30.03.2002

The surface of Venus is perpetually covered by a veil of thick clouds and remains hidden from even the powerful telescopic eyes of earth-bound astronomers. But in the early 1990s, using imaging radar...

Mercury in Stereo: Craters Within Craters
12.01.1997

This Stereo image pair of craters on on Mercury was produced using data from NASA's robot explorer Mariner 10 which performed three close flybys of the Sun's closest companion, two in 1974 and one in 1975. However, the spacecraft was not equipped with a Stereo camera!

The Planet and the Radio Dish
3.08.2010

What planet is this? Although seemingly something out of The Little Prince, the planet is actually Earth. More specifically, it is a small part of the Earth incorporated into a four image stereographic "Little Planet " projection.

Titan from Cassini in Infrared
6.07.2004

Could life exist under the smog of Titan? If not, what is creating all of the methane? To help answer these questions, the largest and most mysterious moon of Saturn got a quick first look from the Cassini robot spacecraft soon after entering orbit around the giant planet last week.

The Flash Spectrum of the Sun
12.03.2016

In a flash, the visible spectrum of the Sun changed from absorption to emission on March 9 during the total solar eclipse. That fleeting moment, at the beginning the total eclipse phase, is captured by telephoto lens and diffraction grating in this image from clearing skies over Ternate, Indonesia.

APOD: 2025 September 23 Б NGC 6357: Cathedral to Massive Stars
23.09.2025

How massive can a normal star be? Estimates made from distance, brightness and standard solar models had given one star in the open cluster Pismis 24 over 200 times the mass of our Sun, making it one of the most massive stars known.