Science explores the nature of time and space

We tend to treat time as a quantifiable commodity — something that can be managed, saved and retrieved for future use, like a stick of butter in the freezer. But our perceptions of past and present are often not so solid.

Archaeologists try to reconstruct ancient history from artifacts, and those clues often allow enough leeway to imagine alternative pasts. Take the current controversy over whether the ancient Clovis people, who lived in North America around 13,000 years ago, killed mammoths and other large mammals. Dioramas of these brave hunters felling massive beasts with stone-tipped spears have been a staple of natural history museums for decades. But new research reported by behavioral sciences writer Bruce Bower suggests that those elegant stone points lacked the oomph to inflict a lethal blow. Scientists tested that hypothesis with experiments that included reconstructing a mammoth-foot analog and attempting to inflict “wounds.” These findings could shift the long debate over how much humans are at fault for mammoth extinctions, compared with climate or other environmental changes.

I’m content to marvel at the beauty of those Clovis points, be they mammoth killers or simple butchering tools. But this issue also provides deeper questions to consider, in an essay by contributing correspondent Tom Siegfried.

In the last century, discoveries in quantum physics have challenged our understanding of space and time — and the very nature of reality. It’s as if that stick of butter in my freezer could be simultaneously baked into a croissant in Paris. Or that both butter and croissant could be mere human perceptions and not a fundamental feature of reality. Or what our brains and senses perceive on the human scale of time and space may be just one of multiple realities.

Exploration of the quantum realm promises to bring more challenges to our imaginations in the years to come, as well as dazzling realities like practical applications for quantum computing. For now, I’ll presume that both Clovis points and a fresh-baked croissant deserve to be real.

Nancy Shute is editor in chief of Science News Media Group. Previously, she was an editor at NPR and US News & World Report, and a contributor to National Geographic and Scientific American. She is a past president of the National Association of Science Writers.