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Larry Sessions

Larry Sessions

Larry Sessions has written many favorite posts in EarthSky's Tonight area. He's a former planetarium director in Little Rock, Fort Worth and Denver and an adjunct faculty member at Metropolitan State University of Denver. He's a longtime member of NASA's Solar System Ambassadors program. His articles have appeared in numerous publications including Space.com, Sky & Telescope, Astronomy and Rolling Stone. His small book on world star lore, Constellations, was published by Running Press.

Crab Nebula

The Crab Nebula was an exploding star

Posted by in Astronomy Essentials | Clusters Nebulae Galaxies | 1 week ago
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The Crab Nebula, about 6,500 light-years from Earth, is the scattered fragments of a supernova, or exploding star, observed by earthly skywatchers in the year 1054.

Use Big Dipper to find North Star

Posted by in Tonight | 4 weeks ago
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The 2 outermost stars in the bowl of the Big Dipper point to Polaris, the North Star.
A darkened skyline, with smoke from a chimney blowing sideways and a single star, Fomalhaut, above.

Fomalhaut: The loneliest star

Posted by and in Astronomy Essentials | Brightest Stars | 4 weeks ago
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It’s also sometimes called the autumn star for us in the Northern Hemisphere. In its large dark patch of sky, only Fomalhaut shines brightly. Here’s how to see it.

Altair: Bright star of the Eagle

Posted by in Astronomy Essentials | Brightest Stars | 2 months ago
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Altair is only 16.8 light-years from Earth, making it one of our closest stellar neighbors. At least 2 features of the star make it distinctive. For one thing, Altair needs only 10 hours to spin once on its axis, in contrast to roughly a month for our sun.

A celestial cloud of swirling gases.

See Messier 8, the Lagoon Nebula

Posted by in Astronomy Essentials | Clusters Nebulae Galaxies | 2 months ago
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The Lagoon – aka M8 – is the largest and brightest nebula, or cloud in space, in the vicinity of the Teapot asterism in the constellation Sagittarius.

61 Cygni is the Flying Star

Posted by in Astronomy Essentials | Brightest Stars | 2 months ago
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Although it’s not bright, 61 Cygni moves exceptionally rapidly against the background of more distant stars. Its motion reveals its nearness to Earth.

Antares is the Heart of the Scorpion

Posted by in Astronomy Essentials | Brightest Stars | Favorite Star Patterns | 3 months ago
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Bright red Antares is easy to spot now. It’s the brightest star in the constellation Scorpius and represents the Scorpion’s Heart.
Photo of blue-white star Spica.

Spica is a whirling double star

Posted by and in Astronomy Essentials | Brightest Stars | 5 months ago
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Spica’s 2 stars orbit a common center of gravity in only 4 days. Their mutual gravity distorts each star into an egg shape, with the pointed ends facing each other.
What appears to be a densely populated star field with a few galaxies visible.

The Coma Cluster of galaxies

Posted by in Clusters Nebulae Galaxies | 6 months ago
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The Coma Cluster is one of the richest galaxy clusters known. How many suns and how many worlds might be located in this direction of space?

Observatory dome in foreground, Milky Way in background, and Alpha Centauri's position marked.

Alpha Centauri, star system closest to our sun

Posted by in Astronomy Essentials | Brightest Stars | 6 months ago
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We see this nearly star system as a single star in our sky, but it’s really 3 stars. Of the 3, Proxima is closer to our sun than any other known star.