Star Size Comparisons
6.06.2013

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

A Perseid Aurora
9.08.2003

Just after the Moon set but before the Sun rose in the early morning hours of 2000 August 12, meteors pelted the Earth from the direction of the constellation Perseus, while ions pelted the Earth from the Sun.

The Surface of Titan
4.08.1999

If sailing the hydrocarbon seas of Titan, beware of gasoline rain. Such might be a travel advisory issued next millennium for adventurers visiting Titan, the largest moon of Saturn. Images of Titan's surface were released last week from the Keck 10-meter telescope featuring the finest details yet resolved.

A Spiral Aurora over Iceland
12.09.2021

What's happened to the sky? Aurora! Captured in 2015, this aurora was noted by Icelanders for its great brightness and quick development. The aurora resulted from a solar storm, with high energy particles bursting out from the Sun and through a crack in Earth's protective magnetosphere a few days later.

The McMath-Pierce Solar Observatory
15.03.1996

This odd-looking structure silhouetted in the foreground houses the three largest solar telescopes in the world. Located in Kitt Peak, Arizona, the largest telescope inside the McMath-Pierce Facility is 1.6-meters in diameter and contains only mirrors. The telescope contains no windows or lenses because focusing bright sunlight would overheat them.

Uranus' Ring System
30.04.1996

The rings of Uranus are thin, narrow, and dark compared to other planetary ring systems. Brightened artificially by computer, the ring particles reflect as little light as charcoal, although they are really made of ice chucks darkened by rock.

ERAST Pathfinder Plus: Daedalus Defied
12.08.1998

Daedalus warned Icarus that if he flew too high, the Sun would melt his wings. Apparently, nobody gave the ERAST Pathfinder-Plus aircraft a similar warning. Earlier this month, not only did Pathfinder-Plus fly higher than any previous propeller-driven aircraft - its wings converted sunlight into power.

IC 1805: The Heart Nebula
4.03.2013

Sprawling across almost 200 light-years, emission nebula IC 1805 is a mix of glowing interstellar gas and dark dust clouds. Derived from its Valentine's-Day-approved shape, its nickname is the Heart Nebula. About 7,500 light-years away in the Perseus spiral arm of our galaxy, stars were born in IC 1805.

The Surface of Titan
20.08.2000

If sailing the hydrocarbon seas of Titan, beware of gasoline rain. Such might be a travel advisory issued one future day for adventurers visiting Titan, the largest moon of Saturn. New images of Titan's surface were released last week from the Canada-France Hawaii Telescope featuring the finest details yet resolved.

The Crater Chain
15.07.1995

NASA's robot spaceprobe Voyager 1, took this closeup image of the surface of Jupiter's crater scarred moon Callisto in 1979. A mysterious chain of craters is seen to extend diagonally across the image (upper left to lower right). What could cause the craters to line up in such a regular fashion?