Month: August 2020

Perseids from Perseus

Where are all these meteors coming from? In terms of direction on the sky, the pointed answer is the constellation of Perseus. That is why the meteor shower that peaks tomorrow night is known as the Perseids — the meteors...

The Origin of Elements

The hydrogen in your body, present in every molecule of water, came from the Big Bang. There are no other appreciable sources of hydrogen in the universe. The carbon in your body was made by nuclear fusion in the interior...

Crescent Saturn

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...

The Pipe Nebula

East of Antares, dark markings sprawl through crowded star fields toward the center of our Milky Way Galaxy. Cataloged in the early 20th century by astronomer E. E. Barnard, the obscuring interstellar dust clouds include B59, B72, B77 and B78,...

Messier 20 and 21

The beautiful Trifid Nebula, also known as Messier 20, is easy to find with a small telescope in the nebula rich constellation Sagittarius. About 5,000 light-years away, the colorful study in cosmic contrasts shares this well-composed, nearly 1 degree wide...

Ancient sun daggers will not hurt you, but they may tell you the time.  A sun dagger is a dagger-shaped gap in a shadow created by sunlight streaming through a crevice in a nearby rock. Starting over a thousand year ago,...

Distorted galaxy NGC 2442 can be found in the southern constellation of the flying fish, (Piscis) Volans. Located about 50 million light-years away, the galaxy’s two spiral arms extending from a pronounced central bar have a hook-like appearance in wide-field...

Did the Earth part to show us this comet? Of course not, even if this image makes it seem that way. Pictured far in the background is Comet NEOWISE as it appeared about two weeks ago over northern Greece. Above...

How different does sunset appear from Mars than from Earth? For comparison, two images of our common star were taken at sunset, one from Earth and one from Mars. These images were scaled to have same angular width and featured...

The Elephant’s Trunk Nebula in Cepheus

Like an illustration in a galactic Just So Story, the Elephant’s Trunk Nebula winds through the emission nebula and young star cluster complex IC 1396, in the high and far off constellation of Cepheus. Also known as vdB 142, the...