Cosmic questions, answers pending

Special section

Throughout human history, great missions of exploration have been inspired by curiosity, the desire to find out about unknown realms. Such missions have taken explorers across wide oceans and far below their surfaces, deep into jungles, high onto mountain peaks and over vast stretches of ice to the Earth’s polar extremities.

Today’s greatest exploratory mission is no longer Earthbound. It’s the scientific quest to explain the cosmos, to answer the grandest questions about the universe as a whole.

What is the identity, for example, of the “dark” ingredients in the cosmic recipe, composing 95 percent of the universe’s content? And just what, if anything, occurred more than 13.7 billion years ago, when the universe accessible to astronomical observation was born? Will physicists ever succeed in devising a theory to encompass all the forces and particles of nature in one neat mathematical package (and in so doing, perhaps, help answer some of these other questions)? Will that package include the supposedly basic notions of space and time, or will such presumed preexisting elements of reality turn out to be mere illusions emerging from ur-material of impenetrable obscurity? And finally (fittingly), what about cosmic finality? Will the universe end in a bang, a whimper or the cosmic equivalent of a Bruce Willis movie (everything getting blown apart)?

In the pages that follow, Science News writers assess the state of the evidence on these momentous issues. In none of these arenas are the results yet firm. But as string theorist Brian Greene wrote in his book The Elegant Universe, “sometimes attaining the deepest familiarity with a question is our best substitute for actually having the answer.”

Read features from this special edition of Science News:

Pre-Bang branes and bubbles

What happened before the big bang? By Ron Cowen

In the dark

What is the universe made of? By Alexandra Witze

Strung together

Is there a theory of everything? By Matt Crenson

Out of the fabric

Are space and time fundamental? By Tom Siegfried

Hanging in the balance

What is the fate of the universe? By Elizabeth Quill

More stories:

Mission: reveal the secrets of the universe

Tools for the mission

Download PDF versions of these stories here, and read additional references for the Cosmic Questions special edition here.

Tom Siegfried is a contributing correspondent. He was editor in chief of Science News from 2007 to 2012 and managing editor from 2014 to 2017.