Planetary Alignment over Italy
18.12.2021

It is not a coincidence that planets line up. That's because all of the planets orbit the Sun in (nearly) a single sheet called the plane of the ecliptic. When viewed from inside that plane -- as Earth dwellers are likely to do -- the planets all appear confined to a single band.

Southwest Mercury
12.02.2000

The planet Mercury resembles a moon. Mercury's old surface is heavily cratered like many moons. Mercury is larger than most moons but smaller than Jupiter's moon Ganymede and Saturn's moon Titan. Mercury is much denser and more massive than any moon, though, because it is made mostly of iron.

A Zodiacal Sky over Horseshoe Bend
21.05.2017

What's causing the unusual ray of white light extending upward from the central horizon? Dust orbiting the Sun. At certain times of the year, a band of sun-reflecting dust from the inner Solar System rises prominently before sunrise and is called zodiacal light.

Planets of the Solar System: Tilts and Spins
19.05.2019

How does your favorite planet spin? Does it spin rapidly around a nearly vertical axis, or horizontally, or backwards? The featured video animates NASA images of all eight planets in our Solar System to show them spinning side-by-side for an easy comparison.

Crescent Saturn
7.08.2020

From Earth, Saturn never shows a crescent phase. But when viewed from a spacecraft the majestic giant planet can show just a sunlit slice. This image of crescent Saturn in natural color was taken by the robotic Cassini spacecraft in 2007.

Three Planets and a Comet
22.12.2021

Are you still looking for that perfect holiday gift for an astronomer? If your night sky is dark and horizon clear enough, the Solar System may have done your shopping for you. Send them outside after sunset to see three planets and a comet.

Planets of the Solar System: Tilts and Spins
10.09.2022

How does your favorite planet spin? Does it spin rapidly around a nearly vertical axis, or horizontally, or backwards? The featured video animates NASA images of all eight planets in our Solar System to show them spinning side-by-side for an easy comparison.

The Colorful Moon
15.03.2002

Do you recognize the Earth's Moon when you see it? The crazy, patchwork appearance of the false-color image makes this almost full view of the Moon's familiar near side look very strange.

Natural Saturn On The Cassini Cruise
11.05.2002

What could you see approaching Saturn aboard an interplanetary cruise ship? Your view would likely resemble this subtly shaded image of the gorgeous ringed gas giant. Processed by the Hubble Heritage project, the picture...

Venus: Earths Cloudy Twin
16.05.2004

This picture by the Galileo spacecraft shows just how cloudy Venus is. Venus is very similar to Earth in size and mass - and so is sometimes referred to as Earth's sister planet - but Venus has a quite different climate.