TRAPPIST-1 planet illustration

M-Dwarves and the Search for Life

In recent years, astronomers have broadened their search for habitable planets to include previously ignored stars like M-dwarves.
A colorful map measures gravity anomalies around the Chicxulub crater

How We Know What Killed the Dinosaurs

How do we know that a meteor caused the extinction of the dinosaurs?
A concept illustration of three aligned planets

There May Be a Ninth Planet (And It’s Not Pluto)

Caltech astronomer Michael Brown has proposed the existence of a ninth planet, the existence of which would explain the strange orbits of six KBOs. 
Visualization of Einstein's Theory of General Relativity.

General Relativity 100 Years On

Einstein's groundbreaking theory of general relativity has remained an essential hallmark of modern physics.
Credit: NASA/JPL/University of Arizona
Caption: Alfred McEwen

The Canals of Mars

We now know there's liquid water on Mars, according to NASA. But at the turn of the 20th century, we believed something else: that Mars had canals.
Artist's concept of buckyballs and polycyclic aromatic hydrocarbons around an R Coronae Borealis star rich in hydrogen. Credit: MultiMedia Service (IAC)

What’s between the Stars? Buckyballs!

How buckyballs fit into the formation of new stars.