To Fly Free in Space
1.01.2012

At about 100 meters from the cargo bay of the space shuttle Challenger, Bruce McCandless II was farther out than anyone had ever been before. Guided by a Manned Maneuvering Unit (MMU), astronaut McCandless, pictured above, was floating free in space.

To Fly Free in Space
31.12.2017

What would it be like to fly free in space? At about 100 meters from the cargo bay of the space shuttle Challenger, Bruce McCandless II was living the dream -- floating farther out than anyone had ever been before. Guided by a Manned Maneuvering Unit (MMU), astronaut McCandless, pictured, was floating free in space.

A Leonid Meteor Over Sweden
21.11.2006

This past weekend, small remnant bits of a distant comet lit up the skies over much of planet Earth. Incoming reports, however, have this year's Leonid meteor shower as less active than Leonid meteor showers a few years ago.

Unexpected Comet Pojmanski Now Visible
6.03.2006

Have you ever seen a comet? Comets bright enough to be visible to the unaided eye appear only every few years. Right now, however, a new comet has brightened unexpectedly and is visible as a faint streak to the unaided northern observer in the eastern morning sky just before sunrise. Binoculars may help.

In Ganymede s Shadow
7.10.2022

At opposition, opposite the Sun in Earth's sky, late last month Jupiter is also approaching perihelion, the closest point to the Sun in its elliptical orbit, early next year. That makes Jupiter exceptionally close to our fair planet, currently resulting in excellent views of the Solar System's ruling gas giant.

Unusual Gullies and Channels on Mars
5.02.2003

What could have formed these unusual channels? Inside Newton Basin on Mars, numerous narrow channels run from the top down to the floor. The above picture covers a region spanning about 1500 meters across.

APOD: 2024 February 12 Б HFG1 & Abell 6: Planetary Nebulae
12.02.2024

Planetary nebulae like Heckathorn-Fesen-Gull 1 (HFG1) and Abell 6 in the constellation Cassiopeia are remnants from the last phase of a medium sized star like our Sun. In spite of their shapes, planetary nebulae have nothing in common with actual planets.

To Scale: The Solar System
25.12.2015

Want to build a scale model Solar System? A blue marble 1.4 centimeters (about half an inch) across would be a good choice for a scale model Earth. Since the Sun is 109 times the diameter of Earth, a 1.5 meter diameter balloon could represent the Sun.

APOD: 2025 January 7 Б A New Years Aurora and SAR Arc
7.01.2025

It was a new year, and the sky was doubly red. The new year meant that the Earth had returned to its usual place in its orbit on January 1, a place a few days before its closest approach to the Sun.

X-Ray Moon
4.10.2003

This x-ray image of the Moon was made by the orbiting ROSAT (Röntgensatellit) Observatory in 1990. In this digital picture, pixel brightness corresponds to x-ray intensity. Consider the image in three parts: the bright hemisphere of the x-ray moon, the darker half of the moon, and the x-ray sky background.