Brazilian researchers have proposed an elegant solution to a long-standing physics debate, suggesting that in our relativistic universe, everything could theoretically be measured using just a single unit: time. This finding challenges decades of conventional thinking about how we measure the physical world.
Published in Nature Scientific Reports | Estimated reading time: 4 minutes
The research team, comprising scientists from multiple Brazilian institutions, has tackled a fundamental question that sparked debate among physicists at CERN in 1992: how many basic units are truly needed to measure everything in the observable universe?
The new study suggests that in relativistic space-time – the framework of Einstein’s theory of relativity that describes our universe – all physical quantities could theoretically be measured using only time units. This marks a significant departure from current scientific practice, which typically relies on multiple fundamental units like meters for length and kilograms for mass.
The research team includes George Matsas and Vicente Pleitez from the Institute of Theoretical Physics at São Paulo State University (IFT-UNESP), Alberto Saa from the University of Campinas (IMECC-UNICAMP), and Daniel Vanzella from the University of São Paulo (IFSC-USP). Their work builds upon and potentially resolves a famous debate initiated by physicists Michael Duff, Lev Okun, and Gabriele Veneziano in 2002.
“The goal is to find the most fundamental description of physics possible,” explains Matsas. “The question raised by Okun, Duff and Veneziano is by no means trivial. As physicists, we’re faced with the need to understand what’s the minimum number of standards we need to measure everything.”
The researchers demonstrate that while older “Galilean” space-time required both rulers and clocks for measurements, Einstein’s relativistic space-time needs only clocks. In fact, they show that high-precision clocks, like today’s atomic clocks, could theoretically handle all measurement needs.
This finding has profound implications for our understanding of physical measurements and could potentially simplify how we think about fundamental constants in physics. The research suggests that rather than needing multiple basic units like meters, kilograms, and seconds, we might only need the second as our fundamental unit of measurement.
Glossary
- Relativistic space-time
- The four-dimensional framework that combines space and time, as described by Einstein’s theory of relativity
- Galilean space-time
- The classical framework of space and time used in Newtonian physics, where space and time are treated as separate entities
- Fundamental constants
- Basic standards needed to measure everything in the observable universe
Test Your Knowledge
What is the main difference between Galilean and relativistic space-time in terms of measurement needs?
Galilean space-time requires both rulers and clocks for measurements, while relativistic space-time needs only clocks.
According to the research, what is the minimum number of fundamental units needed in relativistic space-time?
Just one unit – time (measured in seconds) – is theoretically sufficient to measure all physical quantities in relativistic space-time.
How does this research relate to the 2002 debate among physicists?
It provides a potential resolution to the debate between Duff, Okun, and Veneziano about how many fundamental constants are needed to describe the observable universe.
What key insight about space and time in relativity makes this single-unit measurement possible?
In relativity, space and time are so interrelated that a single unit is sufficient to describe all quantities, making it possible to express all measurements in terms of time.
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