The Expansion of the Universe Raises Unnerving Questions

Princeton Cosmologist Jo Dunkley Explains Why We Are Always Updating Our Understanding of How We Got Here

Jo Dunkley is a leading researcher into the origins and evolution of the universe and professor of physics and astrophysical sciences at Princeton University. In her work, Dunkley uses the Atacama Cosmology Telescope to probe the history of the universe and study the ancient radiation known as Cosmic Microwave Background. She has received numerous awards and honors, including the James Clerk Maxwell Medal, the Royal Society Rosalind Franklin Award, and, most recently, the New Horizons in Physics Prize. In October 2019, following the publication of her book Our Universe: An …

Before We Settle on Mars, Let’s Make Sure It’s Not Already Occupied

While the Technology Is Within Reach, We Haven't Figured out How to Minimize the Risks to Both Humans and Martians

Humanity has dreamed of going to Mars for decades. Mars appeals to us as a possible second home because of how Earthlike it is—and how much more Earthlike it might …

How the Industrial Age Fuels Our Belief in UFOs

Fears of Zeppelins, Rockets, and Drones Have Replaced the "Celestial Wonders" of Ancient Times

In 1896, newspapers throughout the United States began reporting accounts of mysterious airships flying overhead. Descriptions varied, but witnesses frequently invoked the century’s great technological achievements. Some sources reported dirigibles …

Who Should Be Our Alien Liaison?

If Extraterrestrials Make Contact, Science Fiction Has Some Advice for Selecting Humanity’s Spokesperson

On May 25, 2015, a radio telescope in Zelenchukskaya, Russia, picked up a signal coming from star HD164595 in the Hercules constellation. We don’t know much about this star located …

Even in Deep Space, There Are Shades of Black

How a Planet Hunter Finds Faint Objects in a Sea of Darkness

In my line of work, I stare at shades of black.

My work starts on dark, black nights, when there is no moon or reflection from it. The telescopes I …

What Do Raindrops Look Like in Outer Space?

How Arizona’s Monsoons Got Me Chasing Storms on Titan

Living in Tucson, Arizona—a Sonoran desert city surrounded by tall mountains—can make you obsess about rain. In 1993, I had just moved into a new office at the University of …