Polaris surrounded by star trails, in an image by Ken Christison. Polaris is the star around which the northern half of the celestial sphere appears to turn.
A new study shows that Mars has a unique water vapor cycle that occurs only once about every 2 years. The cycle might help explain how Mars lost most of its water. Read more.
Around the world on Tuesday evening, Jupiter rises first in the hours after sunset, followed by the moon and then Saturn around midnight. The waning gibbous moon shines close to Saturn on the sky's dome. If you're not a night owl, try catching Saturn before daybreak. See the chart below. Read more.
