Latest Articles
What Is a Quasar? The Most Luminous Objects in the Universe Explained
What is a quasar? A quasar is the most luminous persistent object in the universe. The brightest known quasar outshines its entire host galaxy by a factor of more than 100. It releases energy equivalent to trillions of suns, from a region smaller than our solar system. And it does this powered by nothing more…
What Makes a Theory Scientific? Why “Just a Theory” Gets Science Completely Backward
The word “theory” means something very different in science than it does in everyday speech. In casual use, a theory is a guess, an untested hunch. In science, a theory is the highest category of explanation: a well-tested framework that accounts for a broad range of observations, makes specific predictions, and has survived repeated attempts…
Neanderthals and Denisovans: What Ancient DNA Reveals About Our Closest Relatives
For most of the twentieth century, Neanderthals and Denisovans were portrayed as brutish dead ends, a failed experiment in human evolution that was swept aside when modern humans arrived from Africa. That picture is now completely overturned. Ancient DNA analysis has revealed that Neanderthals, Denisovans, and modern humans interbred, that most people alive today carry…
The Big Bang Theory Explained: What It Actually Says About the Origin of the Universe
The Big Bang theory is the most tested and well-supported cosmological model in the history of science. It is also the most widely misunderstood. It does not describe an explosion in empty space. It does not say the universe began as a pinpoint of matter. And it does not attempt to explain what came “before”…
Life on Mars: What the Evidence Actually Shows
Mars is the most studied planet in the solar system besides Earth. We have sent more than fifty missions to it. We have driven rovers across its surface for decades. We have drilled into its rocks, sniffed its atmosphere, photographed its ancient river channels, and identified the remnants of a magnetic field that once might…
What Is Dark Energy? The Force Accelerating the Universe’s Expansion
In 1998, two independent teams of astronomers studying distant supernovae made a discovery that upended cosmology. They expected to find that the universe‘s expansion was slowing down, pulled back by the gravity of all the matter within it. Instead, they found the opposite: the expansion of the universe is accelerating. Something is pushing space apart…
