Posts by 

Andy Briggs

Exoplanets are worlds orbiting other stars

Exoplanets are worlds orbiting distant stars. Watch a video with an astronomer who studies them. Learn the history of our knowledge of exoplanets, and more.

What’s a galaxy? All you need to know

What is a galaxy? We live in a galaxy called the Milky Way. But there is so much more to know about these grand and glorious star islands in space!

Dark matter, a mysterious substance … What is it?

What is dark matter? It doesn't emit light. It hasn't been directly observed. Yet it appears to exist and to exert a major influence on galaxies.

What’s a constellation? What’s an asterism?

Constellations and asterisms are patterns of stars. Some asterisms consist of stars from different constellations, and some are part of one constellation.

What is the Milky Way? It’s our home galaxy

When someone says "Milky Way," do you think of the starry pathway across our sky, or of the great pinwheel-shaped galaxy in space? Both are correct!

What’s a red dwarf? Only the most abundant Milky Way star

A red dwarf star is smallest and coolest type of star known. They're also extremely common, making up around 60 to 70% of the stars in the Milky Way.
Astronomy Essentials

What are red giants? Our sun will become one!

What are red giants? Most main-sequence stars, like our sun, will become one. Red giants swell to such a large size they can swallow their inner planets.

What was the Carrington Event, and why does it matter?

The Carrington Event of 1859 was a massive geomagnetic storm triggered by an active sun. People saw auroras at low latitudes bright enough to read by.

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.

What is a neutron star? How do they form?

A neutron star is born from a supernova explosion. They contain a couple of times the mass of our sun, squeezed into a sphere the size of a city on Earth.