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 become, given a whole lot of human ingenuity and planet-scale engineering. Furthermore, Mars has the potential to be habitable by humans, though it is potentially already inhabited by microorganisms that could be DNA-based life forms.

Recently, NASA, SpaceX, Blue Origin, the Mars One Foundation and the Mars 2117 Project all have their eyes on transporting humans to the red planet. …

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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 …

Why Pluto Still Deserves Our Love

Nine Years After Its Launch, a NASA Spacecraft Is About to See What the Formerly Major Planet Can Tell Us About the Origins of the Solar System

One of my first memories as a child in the 1950s was a discussion I had with my brother in our tiny bedroom in the family house in Bethlehem, Pennsylvania. …