Olbers’ paradox asks ‘Why is the night sky dark?’

Olbers' paradox asks why is space dark if the universe is filled with stars. The answer has to do with traveling light and red-shifting colors.

Guy Ottewell’s Astronomical Calendar 2024 is here

The popular and information Astronomical Calendar for 2024 by Guy Ottewell is available. It comes in either electronic or printed form. Learn more here.

Observing meteors: Top 10 tips for the Perseids

The 2021 Perseid meteor shower is rising to its peak and many are observing meteors. Here are our best 10 tips for watching this shower, or any other!

How does Earth look from outer space?

How does Earth look from space? You could see it from Neptune, but it's brighter from closer locations. Spacecraft photos tell the tale.

What are gravitational waves? Ripples in spacetime

First postulated by Albert Einstein in 1916 but not observed directly until September 2015, gravitational waves are ripples in spacetime.

Geminid meteor mystery solved? It was a collision!

Data from the Parker Solar Probe helped scientists discover that the Geminid meteor shower is most likely the result of a violent event on asteroid Phaethon.

Comet C/2021 T4 Lemmon is sweeping through southern skies

Comet C/2021 T4 Lemmon was discovered at Mount Lemmon Observatory in 2021. It's currently in the southern skies and might become bright enough for binoculars.

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.

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.