An image taken from an animation using Kostelecky’s Standard Model Extenstion to predict how apples might fall differently. (Credit: Indiana University)
Physicists at Indiana University have developed a promising new way to identify a possible abnormality in a fundamental building block of Einstein’s theory of relativity known as “Lorentz invariance.” If confirmed, the abnormality would disprove the basic tenet that the laws of physics remain the same for any two objects traveling at a constant speed or rotated relative to one another.
… “It is surprising and delightful that comparatively large relativity violations could still be awaiting discovery despite a century of precision testing,” said Kostelecky. “Discovering them would be like finding a camel in a haystack instead of a needle.”
If the findings help reveal the first evidence of Lorentz violations, it would prove relativity is not exact. Space-time would not look the same in all directions and there would be measurable relativity violations, however minuscule.
The violations can be understood as preferred directions in empty space-time caused by a mesh-like vacuum of background fields. These would be separate from the entirety of known particles and forces, which are explained by a theory called the Standard Model that includes Einstein’s theory of relativity. …
“No dedicated experiment has yet sought a seasonal variation of the rate of an object’s fall in the Earth’s gravity,” said Kostelecky. “Since Newton’s time over 300 years ago, apples have been assumed to fall at the same rate in the summer and the winter.”
Spotting these minute variances is another matter as the differences in rate of fall would be tiny because gravity is a weak force. The new paper catalogues possible experiments that could detect the effects. Among them are ones studying gravitational properties of matter on the Earth and in space.
The Standard Model Extension predicts that a particle and an antiparticle would interact differently with the background fields, which means matter and antimatter would feel gravity differently. So, an apple and an anti-apple could fall at different rates, too.
“The gravitational properties of antimatter remain largely unexplored,” said Kostelecky. “If an apple and an anti-apple were dropped simultaneously from the leaning Tower of Pisa, nobody knows whether they would hit the ground at the same or different times.” …