Crescent Moon and Planets Over Portugal
18.08.2010

Sometimes, it's fun to share the sky. Although it might appear that the two sky enthusiasts on the ridge are sharing only a crescent moon between them, three bright planets also stand before them.

All the Water on Planet Earth
15.05.2012

How much of planet Earth is made of water? Very little, actually. Although oceans of water cover about 70 percent of Earth's surface, these oceans are shallow compared to the Earth's radius.

All the Water on Planet Earth
11.09.2016

How much of planet Earth is made of water? Very little, actually. Although oceans of water cover about 70 percent of Earth's surface, these oceans are shallow compared to the Earth's radius.

A Horizon with Blue and Red
5.12.2017

What's happening on the horizon? The horizon itself, past a spinach field in Guatemala, shows not only trees but a large volcano: the VolcАn de Fuego (Volcano of Fire). The red glow at the top of the volcano is hot lava.

Seeing Titan
18.08.2018

Shrouded in a thick atmosphere, Saturn's largest moon Titan really is hard to see. Small particles suspended in the upper atmosphere cause an almost impenetrable haze, strongly scattering light at visible wavelengths and hiding Titan's surface features from prying eyes.

Moon and Planets at Twilight
28.11.2019

This week's ongoing conjunction of Venus and Jupiter may have whetted your appetite for skygazing. Tonight is the main course though. On November 28, a young crescent Moon will join them posing next to the two bright planets above the western horizon at twilight.

An Evening Sky Full of Planets
11.01.2025

Only Mercury is missing from a Solar System parade of planets in this early evening skyscape. Rising nearly opposite the Sun, bright Mars is at the far left. The other naked-eye planets Jupiter, Saturn...

Comet Hale Bopp in the Outer Solar System
26.03.2001

Whatever became of Comet Hale-Bopp? The brightest comet in recent years has continued into the outer Solar System and is now further from the Sun than Saturn. To the surprise of many, Comet Hale-Bopp is still active, continuing to spew gas, ice and dust particles out into space.

Jumbled Galaxy Centaurus A
30.06.2007

At the center of this sharp skyscape, Centaurus A seems to be a fantastic jumble of old yellow stars, young blue star clusters, and imposing dark dust lanes. Spanning over 60,000 light-years, the peculiar elliptical galaxy is apparently the result of a collision of two otherwise normal galaxies.

Brighter Than Mars
27.08.2010

Even though you may have just read an email claiming Mars will be incredibly bright tonight, the brightest star on the horizon is not Mars. From central Iran on August 24th, the brightest star in this twilight desert skyview is Venus, aka the Evening Star.