Black hole Cygnus X-1 has fast, powerful dancing jets

The Cygnus X-1 black hole emits jets that are bent by stellar winds from a companion star. This has enabled astronomers to calculate the power of those jets.

Summer solstice in Mars’ southern hemisphere is April 25

The summer solstice in Mars' southern hemisphere happens on April 25, 2026. Summertime there typically kicks off dust season on the red planet.

Happy Earth Day! Why do we celebrate it on April 22?

April 22 is the date of Earth Day in part because of Arbor Day, an earlier observance. The focus for 2026 is "Our Power, Our Planet."

Earth images from space: 10 incredible photos of our planet

Happy Earth Day! As a celebration of Earth, enjoy these photos, a collection of the 10 best Earth images from space. What are your favorites?

A pileus cloud means bad weather is on the way

A pileus cloud looks like a curved, white cap on the top of a towering cumulus cloud. Pileus clouds are a sign that bad weather is on the way.

Meet M13, the Great Globular Cluster in Hercules

Many stargazers call it the finest globular cluster in the northern half of the heavens. It's M13, also known as the Great Globular Cluster in Hercules.

Small ants clean larger ants in a surprising twist of nature

Small ants clean larger ants, a researcher has discovered. It's the first known case of interspecies grooming between ants.

Can we find alien life in groups of similar planets?

A new study from Japan suggests we could search for a sign of alien life by looking for suspiciously similar planets close together.

Do Newton and Einstein’s laws of gravity hold across the cosmos?

Newton and Einstein's laws of gravity hold true across the largest structures in the universe. This new evidence strengthens the case for dark matter.

Simulating how black holes light up the dark

When black holes tear apart stars, the wreckage heats up, creating brilliant flares. New simulations are showing these flares with more detail than ever before.