Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2018 August 23 Explanation: The greenish coma of comet 21P/Giacobini-Zinner stands out at the left of this telephoto skyscape spanning over 10 degrees toward the northern constellations Cassiopeia an

Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2018 August 28 Explanation: Every step caused the sand to light up blue. That glow was bioluminescence -- a blue radiance that also lights the surf in this surreal scene captured last month at Meyer'

Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2018 August 27 Explanation: Where were you during the Great American Eclipse of 2017? A year ago last week, over 100 million of people in North America went outside to see a partial eclipse of the Su