Category: Image of the Day

Sharpless 308: The Dolphin Nebula

Blown by fast winds from a hot, massive star, this cosmic bubble is much larger than the dolphin it appears to be. Cataloged as Sharpless 2-308 it lies some 5,200 light-years away toward the constellation of the Big Dog (Canis...

/ March 2, 2020

A Hole in Mars

What created this unusual hole in Mars? The hole was discovered by chance in 2011 on images of the dusty slopes of Mars’ Pavonis Mons volcano taken by the HiRISE instrument aboard the robotic Mars Reconnaissance Orbiter currently circling Mars....

/ March 1, 2020

Julius Caesar and Leap Days

In 46 BC Julius Caesar reformed the calendar system. Based on advice by astronomer Sosigenes of Alexandria, the Julian calendar included one leap day every four years to account for the fact that an Earth year is slightly more than...

/ February 29, 2020

South Celestial Rocket Launch

At sunset on December 6 a Rocket Lab Electron rocket was launched from a rotating planet. With multiple small satellites on board it departed on a mission to low Earth orbit dubbed Running Out of Fingers from Mahia Peninsula on...

/ February 28, 2020

Two Hemisphere Night Sky

The Sun is hidden by a horizon that runs across the middle in this two hemisphere view of Earth’s night sky. The digitally stitched mosaics were recorded from corresponding latitudes, one 29 degrees north and one 29 degrees south of...

/ February 27, 2020

NGST 10b: Discovery of a Doomed Planet

This hot jupiter is doomed. Hot jupiters are giant planets like Jupiter that orbit much closer to their parent stars than Mercury does to our Sun. But some hot jupiters are more extreme than others. NGTS-10b, illustrated generically, is the...

/ February 26, 2020

Moon Corona, Halo, and Arcs over Manitoba

Yes, but could you get to work on time if the Moon looked like this? As the photographer was preparing to drive to work, refraction, reflection, and even diffraction of moonlight from millions of falling ice crystals turned the familiar...

/ February 25, 2020

Illustris Simulation of the Universe

How did we get here? Click play, sit back, and watch. A computer simulation of the evolution of the universe provides insight into how galaxies formed and perspectives into humanity’s place in the universe. The Illustris project exhausted 20 million...

/ February 23, 2020

Central Centaurus A

A mere 11 million light-years away, Centaurus A is the closest active galaxy to planet Earth. Also known as NGC 5128, the peculiar elliptical galaxy is over 60,000 light-years across. A region spanning about 8,500 light-years, including the galaxy’s center...

/ February 22, 2020

LDN 1622: Dark Nebula in Orion

The silhouette of an intriguing dark nebula inhabits this cosmic scene. Lynds’ Dark Nebula (LDN) 1622 appears against a faint background of glowing hydrogen gas only visible in long telescopic exposures of the region. In contrast, the brighter reflection nebula...

/ February 21, 2020