What’s a safe distance from a supernova for Earth?

What's a safe distance from a supernova? To survive a supernova, recent data says Earth would have to be at least 160 light-years away from the exploding star.

How many red dwarf stars in nearby space?

Astronomer Guy Ottewell uses 2 charts - showing 2 different volumes of space - to contemplate and question the density of red dwarf stars in our Milky Way.

Sky measurements: Degrees, arcminutes and arcseconds

What are sky measurements - or distances - in the night sky? Here's what it means for objects to be several degrees (or arcminutes or arcseconds) apart.

A deep penumbral lunar eclipse overnight tonight

A penumbral lunar eclipse happens tonight, May 5-6, 2023. It's visible from eastern Europe, Africa, Asia, Australia, New Zealand, Antarctica and Indonesia.

A penumbral eclipse of the moon is subtle

There are 3 kinds of lunar eclipses: total, partial and penumbral. A penumbral eclipse is very subtle. You can notice a shading on the moon's face.

Happy May Day! Today is an astronomy holiday

Happy May Day! This annual celebration has its roots in astronomy as one of 4 cross-quarter days. Dancing around a maypole is a traditional May Day celebration.

Coma Berenices: How Leo the Lion lost his tail

Coma Berenices is the constellation of Queen Berenice's Hair. It used to be the tail of Leo the Lion before it became its own constellation.

Look for Lunar X and Lunar V at 1st-quarter moon

Lunar X and Lunar V are optical features on the moon, visible through a telescope for several hours around the time of the 1st quarter moon.

How far is a light-year? Plus, distances in space

How can we comprehend the distances to the stars and other galaxies? Here's a way to understand a light-year in terms miles and kilometers.

Oddly shaped suns and moons on the horizon

When light from the sun or the moon travels through more atmosphere to your eyes, you see oddly shaped suns or moons in interesting and beautiful ways.