Enjoying EarthSky? Subscribe.

172,902 subscribers and counting ...


Posts by Larry Sessions

South to overhead late summer to autumn
Tonight | Aug 25, 2015

Star of the week: 61 Cygni, the Flying Star

61 Cygni isn’t bright. But it moves exceptionally rapidly against the background of more distant stars. Its motion reveals its nearness to Earth.

Rock formation in Ebihens, France
Science Wire | Aug 20, 2015

Seeing things that aren’t there

Seeing animals in clouds, or a face in the moon, are examples of pareidolia. Look here for photos and to test your own ability to see things that aren’t there.

Hertzsprung-Russel_cropped
Tonight | Aug 19, 2015

Deneb is distant and very luminous

Deneb is one of the most distant stars you will see with your eye alone. That’s because it’s one of the most luminous stars in the Milky Way galaxy.

Photo Credit:  A. Dupree, R. Gilliland, NASA
Science Wire | Aug 12, 2015

How far is Betelgeuse?

Finding star distances isn’t easy. Here’s how it’s done, and why astronomers recently modified the distance estimate to the famous star Betelgeuse.

Altair via astronomers John Monnier and Ming Zhao
Tonight | Aug 11, 2015

Altair is bright star of the Eagle

Altair needs only 10 hours to spin once on its axis, in contrast to roughly a month for our sun. This mighty star spins on its axis more rapidly than Earth!

Vega via NASA Jet Propulsion Laboratory
Tonight | Jul 21, 2015

Star of the week: Vega, the Harp Star

One of the prettiest stories in all skylore surrounds this star. “On the 7th night of the 7th moon … “

Antares and M4 image by stargazerbob@aol.com
Tonight | Jul 02, 2015

Antares is Heart of the Scorpion

The ruby Heart of Scorpius is the 16th brightest star in our sky and one of the most gigantic stars known.

clock_almost_midnight
Science Wire | Jun 29, 2015

Leap second scheduled for June 30

World timekeepers will add one extra second on June 30, 2015. Meanwhile, a proposal to dump the leap second has been deferred until October.

Telescopic view of daytime Venus (l) and moon via NASA
Science Wire | Jun 19, 2015

Venus and Jupiter dance in daylight

Most of us think only of viewing planets at night, but sometimes you can catch them in broad daylight! The next great chance to do that is Saturday, June 20.

The sun in extreme ultraviolet, false color green
Science Wire | Jun 14, 2015

10 cool things about stars

Here’s a collection of 10 unexpected, intriguing facts about the stars of our universe – including our sun – that you probably didn’t know!