Cosmologist Urges New, More Inclusive, Definition of Life

Cosmologist Charley Lineweaver argues that the potential diversity of life in outer space requires a change in the definition of life, from biological boundaries to physical ones.

What's the Latest Development?

As NASA works to build a machine that can detect extraterrestrial life in space, cosmologist Charley Lineweaver argues that our traditional definition of life is too strict and therefore ill-suited to allow for the diversity of what life may look like on other planets. While defining life has always been tricky--scientists still disagree on whether viruses are alive--Lineweaver disagrees with the very idea that life is something that undergoes Darwinian evolution. Why? "What is the unit of Darwinian evolution?" he asks. "Is it the gene? Is it the cell? Is it a multicellular organism? Is a city evolving? How about Gaia? Is that a life form?"

What's the Big Idea?

Lineweaver offers his own definition of life: "A far-from-equilibrium dissipative system." In other words, a system which feeds on energy associated with different gradients in the environment. Here, Lineweavers moves from a biological definition to a physical definition of life. By his standard, fire or a hurricane would be considered living. While that sounds like a step backwards in the search for a suitable definition of life, Lineweaver concludes: "It makes more sense to me to increase the size of what we call 'life' than to continually search for a meaningful boundary where there is none."

Photo credit:


LinkedIn meets Tinder in this mindful networking app

Swipe right to make the connections that could change your career.

Getty Images
Swipe right. Match. Meet over coffee or set up a call.

No, we aren't talking about Tinder. Introducing Shapr, a free app that helps people with synergistic professional goals and skill sets easily meet and collaborate.

Keep reading Show less

Can the keto diet help treat depression? Here’s what the science says so far

A growing body of research shows promising signs that the keto diet might be able to improve mental health.

Public Domain
Mind & Brain
  • The keto diet is known to be an effective tool for weight loss, however its effects on mental health remain largely unclear.
  • Recent studies suggests that the keto diet might be an effective tool for treating depression, and clearing up so-called "brain fog," though scientists caution more research is necessary before it can be recommended as a treatment.
  • Any experiments with the keto diet are best done in conjunction with a doctor, considering some people face problems when transitioning to the low-carb diet.
Keep reading Show less

A world map of Virgin Mary apparitions

She met mere mortals with and without the Vatican's approval.

Strange Maps
  • For centuries, the Virgin Mary has appeared to the faithful, requesting devotion and promising comfort.
  • These maps show the geography of Marian apparitions – the handful approved by the Vatican, and many others.
  • Historically, Europe is where most apparitions have been reported, but the U.S. is pretty fertile ground too.
Keep reading Show less

Want to age gracefully? A new study says live meaningfully

Thinking your life is worthwhile is correlated with a variety of positive outcomes.

Surprising Science
  • A new study finds that adults who feel their lives are meaningful have better health and life outcomes.
  • Adults who felt their lives were worthwhile tended to be more social and had healthier habits.
  • The findings could be used to help improve the health of older adults.
Keep reading Show less