Uranus: The Tilted Planet
26.08.2001

Uranus is the third largest planet in our Solar System after Jupiter and Saturn. Uranus is composed mostly of rock and ices, but with a thick hydrogen and helium atmosphere. The blue hue of Uranus' atmosphere arises from the small amount of methane which preferentially absorbs red light.

Beta Pictoris Revisited
27.11.1997

In the early 1980s, Beta Pictoris became one of the most important stars in the sky. Satellite and ground-based telescopic observations revealed the presence of a surrounding outer disk of material and an inner "clear" zone about the size of our solar system - strong evidence for the formation of planets.

Star Size Comparison 2
11.06.2018

How big is our Sun compared to other stars? In dramatic and popular videos featured on YouTube, the relative sizes of planets, stars, and even the universe are shown from smallest to largest. The featured video begins with Earth's Moon and progresses through increasingly larger moons and planets in our Solar System.

A Flock of Stars
5.10.2001

Only a few stars can be found within ten light-years of our lonely Sun, situated near an outer spiral arm of the Milky Way galaxy. But if our Sun were found within a star cluster, thousands of stars might occupy a similar space.

Solar System Ball Drop
24.08.2021

Does a ball drop faster on Earth, Jupiter, or Uranus? The featured animation shows a ball dropping from one kilometer high toward the surfaces of famous solar system bodies, assuming no air resistance. The force of gravity depends on the mass of the attracting object, with higher masses pulling down with greater forces.

Solar System Portrait
10.02.2017

On Valentine's Day in 1990, cruising four billion miles from the Sun, the Voyager 1 spacecraft looked back one last time to make this first ever Solar System family portrait. The complete portrait is a 60 frame mosaic made from a vantage point 32 degrees above the ecliptic plane.

Haumea of the Outer Solar System
16.10.2017

One of the strangest objects in the outer Solar System has recently been found to have a ring. The object, named Haumea, is the fifth designated dwarf planet after Pluto, Ceres, Eris, and Makemake. Haumea's oblong shape makes it quite unusual.

One Night One Telescope One Camera
27.07.2018

Taken on the same night, from the same place, with the same telescope and camera, these postcards from our Solar System are shown at the same scale to provide an interesting comparison of apparent sizes. Spanning about half a degree in planet Earth's sky, the Moon is a stitched mosaic of six images.

Solar System Family Portrait
13.02.2019

On Valentine's Day in 1990, cruising four billion miles from the Sun, the Voyager 1 spacecraft looked back one last time to make this first ever Solar System family portrait. The complete portrait is a 60 frame mosaic made from a vantage point 32 degrees above the ecliptic plane.

To Scale: The Solar System
24.12.2015

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.