A big open question in 21st-century science is how life began here on Earth. The metabolism-first scenario just might be the best one.

30 years ago, we didn’t know other stars had planets orbiting them. Now, we may be on the verge of finding Earth’s Twin. Sara Seager explains.

Science has assembled an incredible story outlining our Universe's whole history. Despite its unrivaled success, 9 profound gaps remain.

“Deep down the natural endpoint of this whole goal of looking for planets is to answer the question: are we alone?”

The fear of unleashing forces beyond control has haunted science for centuries.

Our Earthbound definitions of life could leave us blind to the Universe’s strangest forms.

Somewhere, at some point in the history of our Universe, life arose. We're evidence of that here on Earth, but many big puzzles remain.

As the closest icy ocean world to Earth, Ceres may be a promising candidate in the search for signs of ancient life.

These microbes endured the unlivable. The NASA astrobiologist who studies them reveals what that means for us today

A Cambridge-based team claims to find molecules on an exoplanet that are only produced by life on Earth. Don't fall for the unfounded hype.

Life may have arisen far earlier — and more rapidly — than previously thought.

How did life on Earth begin? Is there life on other worlds? An answer to either question will reflect heavily on the other. 

It's deceptively tricky to distinguish living systems from non-living systems. Physics may be key to solving the problem.

How do scientists measure and define life in the natural world? Dr. Lee Cronin gives us a definition, in 4 minutes:

In "Life As No One Knows It," Sara Imari Walker explains why the key distinction between life and other kinds of "things" is how life uses information.

"What modern science has taught us is that life is not a property of matter."

Don’t fall into the determinism trap. Everything is, in fact, random, says chemist Lee Cronin:

“The physics of the universe doesn't predict the emergence of biology.” Glasgow chemist Lee Cronin explains how inanimate matter becomes evolutionary:

“We wouldn’t be able to talk about minerals if it weren’t for the minerals themselves.” Mineralogist Bob Hazen explains how Earth’s rocks can teach us about our planet’s technicolor history.

“I study the mineral kingdom — and its secrets could lead us to alien life.”

The Moon is the most likely place for evidence from the dawn of life on Earth to be preserved in cold storage.

Physicist Sean Carroll on entropy, complexity, and the origins of life:

In a recent paper, biologists outlined a three-part hypothesis for how all life as we know it began.

Although early Earth was a molten hellscape, once it cooled, life arose almost immediately. That original chain of life remains unbroken.

If there’s life lurking on the moons of Saturn and Jupiter, could our instruments even detect it?

Life became a possibility in the Universe as soon as the raw ingredients were present. But living, inhabited worlds required a bit more.

Earth wasn't created until more than 9 billion years after the Big Bang. In some lucky places, life could have arisen almost right away.

From how life emerged on Earth to why we dream, these unanswered questions continue to perplex scientists.

Scientists agree that eons ago, a bacterium took up residence inside another cell and became its powerhouse, the mitochondrion. But there are competing theories about the birth of other organelles such as the nucleus and endoplasmic reticulum.

We don’t need to think about what life is made of but rather what it does.