Messier 6 and Comet Siding Spring
17.10.2014

This looks like a near miss but the greenish coma and tail of Comet Siding Spring (C/2013 A1) are really 2,000 light-years or so away from the stars of open cluster Messier 6. They do appear close together though, along the same line-of-sight in this gorgeous October 9th skyscape toward the constellation Scorpius.

M2 9: Wings of a Butterfly Nebula
13.09.2020

Are stars better appreciated for their art after they die? Actually, stars usually create their most artistic displays as they die. In the case of low-mass stars like our Sun and M2-9 pictured here, the stars transform themselves from normal stars to white dwarfs by casting off their outer gaseous envelopes.

Earth During a Total Solar Eclipse
29.12.2020

What does the Earth look like during a total solar eclipse? It appears dark in the region where people see the eclipse, because that's where the shadow of the Moon falls. The shadow...

Dueling Bands in the Night
1.03.2022

What are these two bands in the sky? The more commonly seen band is the one on the right and is the central band of our Milky Way galaxy. Our Sun orbits...

Full Moon Perseids
18.08.2022

The annual Perseid meteor shower was near its peak on August 13. As planet Earth crossed through streams of debris left by periodic Comet Swift-Tuttle meteors rained in northern summer night skies. But even...

APOD: 2023 January 11 Б Spiral Aurora over Iceland
11.01.2023

The scene may look like a fantasy, but it's really Iceland. The rock arch is named Gatklettur and located on the island's northwest coast. Some of the larger rocks in the foreground span a meter across. The fog over the rocks is really moving waves averaged over long exposures.

APOD: 2026 April Б Caught in the Web
3.04.2026

How can we see what is invisible? Black holes are not easy to see in the dark cosmic night, but astronomers can find them by analyzing their gravitational effects on matter, light and spacetime.

Shells in the Egg Nebula
20.05.1997

The Egg Nebula is taking a beating. Like a baby chick pecking its way out of an egg, the star in the center of the Egg Nebula is casting away shells of gas and dust as it slowly transforms itself into a white dwarf star.

Shell Game in the LMC
18.05.2006

An alluring sight in dark southern skies, the Large Magellanic Cloud (LMC) is seen here through a narrow filter that transmits only the red light of hydrogen atoms. Ionized by energetic starlight, a hydrogen atom emits the characteristic red H-alpha light as its single electron is recaptured and transitions to lower energy states.

Spicules: Jets on the Sun
2.11.2008

Imagine a pipe as wide as a state and as long as half the Earth. Now imagine that this pipe is filled with hot gas moving 50,000 kilometers per hour. Further imagine that this pipe is not made of metal but a transparent magnetic field.