Solargraphy Analemmas
20.03.2014

Today is the equinox. The Sun crosses the celestial equator heading north at 16:57 UT, marking the northern hemisphere's first day of spring. To celebrate, consider this remarkable image following the Sun's yearly trek through planet Earth's sky, the first analemmas exposed every day through the technique of solargraphy.

V838 Light Echo: The Movie
17.06.2014

What caused this outburst of V838 Mon? For reasons unknown, star V838 Mon suddenly became one of the brightest stars in the entire Milky Way Galaxy. Then, just a few months later, it faded.

Rainbow Airglow over the Azores
21.03.2016

Why would the sky glow like a giant repeating rainbow? Airglow. Now air glows all of the time, but it is usually hard to see. A disturbance however -- like an approaching storm -- may cause noticeable rippling in the Earth's atmosphere.

Sharpest Ultima Thule
27.02.2019

On January 1, New Horizons swooped to within 3,500 kilometers of the Kuiper Belt world known as Ultima Thule. That's about 3 times closer than its July 2015 closest approach to Pluto.

The Milky Way Over Ontario
29.07.2008

Sometimes, after your eyes adapt to the dark, a spectacular sky appears. Such was the case earlier this month over Ontario, Canada, when part of a spectacular sky also became visible in a reflection off a lake.

Massive Stars in NGC 6357
4.02.2016

Massive stars lie within NGC 6357, an expansive emission nebula complex some 6,500 light-years away toward the tail of the constellation Scorpius. In fact, positioned near center in this ground-based close-up...

Eclipse Moon Trail
13.10.2000

Tonight, Friday the 13th, October's big, bright, beautiful full Moon will be in the sky, rising as the sun sets. A time exposure of this evening's full Moon would show a brilliant circular arc or Moon trail tracing its celestial path.

Powers of Ten
31.01.2011

How different does the universe look on small, medium, and large scales? The most famous short science film of its generation gives breathtaking comparisons. That film, Powers of Ten, originally created in the 1960s, has now been officially posted to YouTube and embedded above.

Tunguska: The Largest Recent Impact Event
2.10.2011

Yes, but can your meteor do this? The most powerful natural explosion in recent Earth history occurred on 1908 June 30 when a meteor exploded above the Tunguska River in Siberia, Russia. Detonating with...

MAVEN at Mars
26.09.2014

Launched on November 18, 2013, the MAVEN (Mars Atmosphere and Volatile EvolutioN) spacecraft completed its interplanetary voyage September 21, captured into a wide, elliptical orbit around Mars. MAVEN's imaging ultraviolet spectrograph has already...