Why isn't there an endless variety of planet sizes in the universe? Why are most planets like those in our solar system: small and rocky, or big and gaseous? 

In 2020, the longest lunar month happens between the February 23 and March 24 new moons; and the shortest one between the August 19 to September 17 new moons.

New laboratory studies - simulating conditions on the planet Mars and using salt-loving microbes - suggest that similar organisms could be producing Mars' mysterious methane.

A report suggests that snakes – the Chinese krait and the Chinese cobra – might have been the original source of the coronavirus that's triggered an outbreak of deadly infectious respiratory illnesses in China this year.

After sunset on January 26, 27 and 28, 2020, watch for the young moon and planet Venus in the west at dusk and nightfall. Use the lit side of the moon to locate Mercury, the innermost planet. If you have a telescope, use Venus to locate the Neptune, the farthest planet.

Jenney Disimon captured the crescent moon and Jupiter over Sabah, N. Borneo, on January 23, 2020.

Watch the last of January's 3 International Space Station spacewalks tomorrow.

A new research study suggests that K-type dwarf stars (smaller and cooler than our sun) are the best place to search for alien life. These stars are not too hot, not too cool, and not too violent for life to evolve.

Cast your vote to help name the next Mars rover, scheduled to launch in July or August 2020. The names were drawn from 9 finalist essays written by K-12 students. The voting will remain open through January 27.

Byrd received the prize from the American Astronomical Society, the largest organization of U.S. astronomers. The prizes are given for outstanding achievements in scientific research, education, scholarly writing, and service to the astronomical community.