This final test of NASA's SLS megarocket was needed to launch the first uncrewed mission in the Artemis program - Artemis 1 - by the end of 2021. Now the program's schedule is uncertain.

Over the next several evenings - January 19, 20 and 21, 2021 - let the moon show you the red planet Mars, and then use Mars to find the distant ice giant planet, Uranus.

The US Postal Service announced that they'll be releasing a series of stamps highlighting images of the sun captured by NASA's Solar Dynamics Observatory.

Venus has been the "morning star," shining brightly near the horizon just before sunrise. Photographers are capturing pictures in January 2021 and sharing those images with EarthSky.

The surface features of brown dwarfs - objects midway in mass between planets and stars - can't be seen. But researchers have found a way to reveal Jupiter-like stripes and bands in the atmosphere of the closest brown dwarf, Luhman 16B.

Here are some of the space missions to keep an eye out for in 2021.

A close look at the "stellar stream" known as Theia 456 finds it contains contains 468 stars born at the same time.

Our Earth and sun were born together, and their fates are tied together. As our star becomes a red giant and billows outward, our planet will become a dry, scorched, uninhabitable rock. This will happen even as our Milky Way galaxy collides with the Andromeda galaxy next door.

A new study has found that pollution from microplastics is widespread in the Arctic Ocean, and 92% of those particles are minuscule synthetic fibers from our clothes.

2020 was Earth's hottest year in the 140-year record, effectively tying 2016, the previous record-holder.