Scientists are testing a mind-blowing time theory in a nuclear reactor

Date:16 February 2021

Scientists are using nuclear reactors to test a quantum theory that flips our understanding of time on its head.

Physicist Joan Vaccaro first articulated the divisive “quantum theory of time”—that “dynamics may be a phenomenological consequence of a fundamental violation of time reversal symmetry,” in her words—a few years ago. But now, researchers can use neutrinos and antineutrinos to measure the passage of time within a powerful nuclear reactor.

Vaccaro has been open about the theory as a far-out educated guess rather than a sure thing, and the findings should be interesting to other scientists either way.

What’s going on when time passes? That depends on who you ask, but the passage of time is still a pretty big mystery. For people, time flows in what seems like one direction: from the past and into the future. Physicists generally explain this as time flowing from lower into higher entropy, or disorder.

Instead, Vaccaro believes entropy might result from time, not the other way around. New Atlas‘s Michael Irving reports: “[Vaccaro] uses the analogy of a tree blowing in the wind—while the leaves (entropy) may appear to be shaking the tree, they aren’t responsible for the motion themselves, but are the result of another force (wind). In this new theory, the ‘wind’ is created by time reversal symmetry violations (T violations).”

The analogy of a tree goes further, because it represents a split Vaccaro identifies in the idea of “spacetime,” as one word and one knitted-together concept, rather than space and time. A tree stands in space as a localized, specific, discrete object. But time flows around all things almost interchangeably except for in specific cases where it’s bent. If time is “localized,” it’s to huge regions of space like entire planets or systems.

To test Vaccaro’s theory, scientists are using the Open Pool Australian Lightwater (OPAL) reactor in Sydney, Australia. They’ve installed atomic clocks in different parts of the reactor. As particles react and erupt in the reactor, time could flex with those changes.

From the Australian Nuclear Science and Technology Organization: “[T]he investigators travelled to ANSTO to install two timing stations with atomic clocks in proximity to the reactor, where they will collect data for six months. Each station comprises a caesium primary clock, three secondary clocks and the measurement systems used to compare the clocks to less than a billionth of a second.”

Why is a nuclear reactor the right place for this experiment? Because one specific product of nuclear reaction, neutrinos, is believed to make time reversal symmetry violations, or T violations. As with charge parity, neutrinos are a key special case that allows scientists to shake loose evidence of complex physical phenomena.

Measuring the two atomic clocks over six months should show scientists if a very localized time change happens within the reactor. There will even be scheduled downtime, giving the scientists clear turn-on and turn-off times to compare to their atomic clocks.

The watched pot may never boil, but observing this nuclear reactor could show us a new understanding of time altogether.

This article was written by Caroline Delbert and published in Popular Mechanics on 5 February 2021.


Picture: Pixabay

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