To test the interpretation of quantum mechanics, look to cosmology.
Quantum physicists do love their beer. By day they build instruments, measure numbers, solve equations. By night they retire to the bar or pub and muse about the philosophical puzzles of quantum theory. By “philosophical” they mean “fun but impractical.” Maybe quantum theory betrays the existence of parallel universes, maybe it exposes causal influences coming […]
Here’s a talk I gave at the Centre for Quantum Technologies in Singapore on March 24, 2016. Note that it was the first time I’d given this particular talk and it had a couple of first-iteration glitches.
“Atoms” of space are too small to see, but betray themselves indirectly.
I’m fascinated by how the humblest observations can lead you to the profoundest conclusions, and here’s one I learned from Thanu Padmanabhan, an eminent theoretical physicist at the Inter-University Centre for Astronomy and Astrophysics in Pune, India. Suppose you cup your hands around a glass of cold water to warm it up. From this simple […]
Step one to understand the mysteries of black holes: build a big bathtub.
Don’t be alarmed, but there is a black hole in your bathtub. When you drain the tub, water converges on the plughole and speeds up, eventually flowing too fast for surface waves to propagate outwards. Those waves get swept down the drain like hapless astronauts falling into a black hole (see video at end of […]
Spacetime seems to have a granular structure, but what the heck are the grains?
Joe Polchinski, based at the Kavli Institute for Theoretical Physics in Santa Barbara, is one of the world’s leading string theorists and an avid cyclist. (Many colleagues have challenged him to a race, to their later chagrin.) He is best known for showing that string theory isn’t just about strings—it predicts a huge diversity of […]
Spacetime derives from a deeper quantum reality, suggests the U.C. Santa Barbara theoretical physicist.
One of the scientists I follow in my book is Steve Giddings, a theoretical physicist at U.C. Santa Barbara who is also a highly skilled mountain-climber. In this video, he explains how quantum mechanics, when applied to black holes, calls the principle of locality into question and suggests that spacetime is not a fundamental ingredient […]
Black holes might be explosions occuring in extremely slow motion, says theoretical physicist Carlo Rovelli.
Theoretical physicist Carlo Rovelli, one of the creators of loop quantum gravity, and his collaborator Hal Haggard have just come out with a new paper on black holes. Ever attuned to puns, Rovelli calls it the “fireworks” model, alluding to the firewall argument that has consumed black-hole theorists over the past two years. As if […]
Could time come to an end? What would that even mean? In April 2013 I gave a talk about this strange physics idea at a TEDx event in Trento, Italy, based on a Scientific American article I wrote in 2010. My conceit was that time’s end poses a paradox that might be resolved if time […]
Who’d have thought viscous fluids would act like gravitational waves caroming off a black hole?
The whole point of an explanation is to reduce something you don’t know to something you do. By that standard, you don’t gain much by explaining anything in terms of black holes. Appealing to the most mysterious objects known to science as an explanation sounds like using one mystery to explain another. Yet this is […]
Maybe not long at all, if black holes are ringed by “firewalls.”
In chatting with colleagues after a talk this week, Joe Polchinski said he’d love to fall into a black hole. Most theoretical physicists would. It’s not because they have some peculiar death wish or because science funding prospects are so dark these days. They are just insanely curious about what would happen. Black holes are […]
Standard formation models can’t account for this triplet.
Last Thursday, my colleague John Matson described a truly amazing galaxy known, somewhat unromantically, as BX442. It has a majestic spiral pattern while hundreds of its galactic contemporaries were gawky and misshapen—a peculiar and special anomaly which suggests to many astronomers that cosmic pinwheels are ephemeral art forms, like Tibetan sand mandalas. John’s piece spurs […]
Black holes are not just distant cosmic monsters. Microscopic ones may exist all around us, with potentially momentous consequences.
It may well have been the liveliest hour and a half I’ve ever spent in the company of theoretical physicists. In April, during a workshop I was attending on black holes, Bill Unruh gave a talk that challenged his colleagues on a point almost all of them thought had been settled in the mid-1980s. His […]
Out in the cosmos, “dark accelerators” slingshot particles to huge speeds and no one knows why.
At a lecture I went to some years ago, astrophysicist Trevor Weekes compared garden-variety elementary particles to mosquitoes. They are plentiful and easy to find—indeed, they find you. But ultra-high-energy gamma rays, he said, are like elephants. They are fairly rare, but among the greatest of creatures. They often roam in spectacular habitats. Their sheer […]