Where is Jupiter’s ammonia? Gaseous ammonia was expected to be seen in Jupiter’s upper atmosphere by the orbiting Juno spacecraft — but in many clouds is almost absent. Recent Juno […]

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 […]

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 […]

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 […]

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 […]

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 […]

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 […]

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 […]

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 […]