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It’s a small-er world

Don’t take the atomic change in the proton’s radius lightly. Its implications can be mind-boggling.

india Updated: Jul 08, 2010 23:47 IST
Hindustan Times

The ultimate in size reduction happened this week with scientists at the Paul Scherrer Institute in Switzerland concluding that the proton, a basic subatomic building block of all matter, has a radius four per cent less than was originally believed. The amount may sound small — and it’s indeed mind-bogglingly small — but its implications may shake the foundations of nuclear physics. The proton’s dimensions were worked out by analysing its interaction with the much smaller electron, which was replaced with a larger particle called a muon. Its larger size meant muon’s interactions with the proton were greater. This allowed the latter’s dimensions to be determined with greater accuracy.

What makes this important is that the properties of the proton and its ilk have been the foundation stone for almost all contemporary physics. The so-called standard model that physicists use to explain the subatomic universe, black holes and galaxies is derived from human understanding of these particles. A four per cent size reduction is enormous in a scientific world where major measurement changes are normally several places to the right of a decimal point. If the proton weighs less, this means, for example, the universe as a whole has significantly less mass than was once assumed. This, in turn, could mean the universe will expand faster than is being presently predicted. The sun may burn differently than is now believed. And it goes on.

It could also mean that the present understanding of how electronic machinery works could be flawed. The findings are being re-tested by other scientists. And just because the theory behind them may change, it doesn’t mean the reality that one’s television, laptop or light switch works has changed. Textbooks, however, may have to be revised and some space-and-star film plots may be deemed to have more fiction and less science than once believed.

First Published: Jul 08, 2010 23:45 IST