Spherical Planetary Nebula Abell 39
8.10.2012

Ghostly in appearance, Abell 39 is a remarkably simple, spherical nebula about five light-years across. Well within our own Milky Way galaxy, the cosmic sphere is roughly 7,000 light-years distant toward the constellation Hercules.

The Fractured North Pole of Saturns Enceladus
21.10.2015

The north pole of Saturn's moon Enceladus is unexpectedly fascinating and complex. Previous to the latest flyby of the robotic Cassini spacecraft, the northern region was known mostly for its unusually high abundance of craters.

Blue Marble Earth
6.02.2022

Welcome to planet Earth, the third planet from a star named the Sun. The Earth is shaped like a sphere and composed mostly of rock. Over 70 percent of the Earth's surface is water. The planet has a relatively thin atmosphere composed mostly of nitrogen and oxygen.

A Daytime Fireball in 1944
28.07.2001

While stationed in central Africa in December 1944, Norman Appleton witnessed a meteor so bright he remembered it his entire life. Right before his eyes a tremendous smoking fireball streaked across the daytime sky. Years later, as an accomplished member of the Guild

NGC 6164: A Bipolar Emission Nebula
6.06.2006

How did a star form this beautiful nebula? In the middle of emission nebula NGC 6164-5 is an unusually massive star nearing the end of its life. The star, visible in the center...

Home from Above
30.12.2008

There's no place like home. Peering out of the window of the International Space Station (ISS), astronaut Greg Chamitoff takes in the planet on which we were all born. About 350 kilometers up, the ISS is high enough so that the Earth's horizon appears clearly curved.

Phoenix Lander Arrives at Mars
25.05.2008

Will Phoenix survive its landing today on Mars? Phoenix's landing sequence will ramp up starting at about 7:30 pm EDT (23:30 UTC) today and last just over an hour. If all goes well, one of Phoenix's first images from Mars will appear on APOD tomorrow.

The First Color Panorama from Mars by Curiosity
11.08.2012

You've just landed on Mars and opened your eyes -- what do you see? If you're the Curiosity rover, you see a strange gravelly place with a large mountain in the distance.

The X-ray Timing Explorer
3.01.1996

Launched Saturday on a Delta rocket, the X-ray Timing Explorer (XTE) will watch the sky for rapid changes in X-rays. XTE carries three separate X-ray telescopes. The Proportional Counter Array (PCA) and the High Energy X-ray Timing Experiment (HEXTE) will provide the best timing information in the widest X-ray energy range yet available.

Ganymede Enhanced
20.09.2009

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