Browsing: Matthew Francis

An illustration of wave interferenceSybille Yates via Shutterstock Though we can see in remarkably low-light conditions, humans aren’t quite sensitive enough to see individual photons—the particles that make up all types of light. In our day-to-day lives, we are so awash with light that its particle nature is just as masked as the atomic nature […]

Why the Milky Way looks like it spirals.

No known object in existence has as clear a division between “inside” and “outside” as a black hole. We live and see the outside, and no probe will bring us information about the inside. We can send radio messages or robotic spacecraft, but once they cross over into a black hole’s interior, we’ll never […]

A microscopic image of a metamaterial used to test relativity in a lab.Lawrence Berkeley National Laboratory Like happy families, every free electron is alike: They all have the same mass, the same electric charge, and the same spin. But inside a solid, various interactions can make electrons behave like entirely different particles. They may act […]

“Some part of our being knows this is where we came from. We long to return. And we can. Because the cosmos is also within us. We’re made of star stuff. We are a way for the cosmos to know itself.” —Carl Sagan, Cosmos That Carl Sagan quote is among one of his most famous sayings, […]

Our Universe is vast and mostly empty. Even if many of the billions of planets we suspect are out there have life, most of the cosmos is uninhabitable, and those worlds are unreachable by any means we know. That’s just within our galaxy, which is one of about 100 billion in the part of the […]