Completed Physics & Astronomy Mathematics & Statistics

Copy of Precision tests of gravitation at short ranges

Funder STFC (part of UKRI)
Recipient organisation University of Birmingham
Funding £1.3M
Period Feb 2009 — Sept 2012

In plain English

AI plain-English summary

Physicists are building experiments to measure gravity at distances thinner than a human hair—around 10 micrometres—to see if the force behaves differently at that scale. The problem is a fundamental conflict in physics. Quantum theory explains the subatomic world with great success, while Einstein’s relativity describes the cosmos through the bending of space and time. The two theories are mutually exclusive, largely because gravity appears far weaker than the other fundamental forces. Some theories, such as string theory, predict that gravity is actually much stronger at very short ranges, but that strength is hidden from us at larger scales. If these experiments detect a stronger gravitational pull at micrometre distances, it would provide convincing evidence for string theory and could help resolve deep-rooted problems in unifying gravity with quantum mechanics. This is fundamental science with no immediate practical application. However, past fundamental research into forces and fields—from Faraday’s electromagnetism to quantum mechanics—eventually enabled technologies such as GPS, semiconductors, and medical imaging. A deeper understanding of gravity could, in time, reshape how we think about space, time, and the structure of the universe itself.

View original technical description
In physics progress is made by making theories more simple and more universal. This continues the tradition started by Isaac Newton and Michael Faraday where the seemingly disparate and complicated became unified and pleasingly simple. At present there is conflict between the theories that describe phenomena at the very smallest scales, probed by particle accelerators like the LHC, and the very largest scales as observed through telescopes by astronomers. Quantum theory has successfully described the forces of the sub-atomic world and Faraday's forces of electricity and magnetism. On the other hand the evolution of the Universe is described, according to Einstein's relativity, by the bending of space and time by matter. Both these theories are flawed as they are strongly mutually exclusive. The main reason for this incompatibility is the apparent weakness of gravitation compared with the other forces. Physicists have boldly postulated that, fundamentally, gravity is significantly stronger than it appears to us. In order to sense its full strength we have to design experiments that can explore space at the scale of 10 or so micrometers (which is thinner than a human hair). If gravity were found to be stronger at these distances this would be convincing evidence for a new theory of quantum gravity called String Theory and a number of deep-rooted problems associated with the unification of gravity and quantum theory could be resolved, hopefully leading to a simplified and more pleasing view of the Universe.

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Researchers

Clive Speake (Principal Investigator)

Related Research

Grants with similar aims, by meaning.

Aspects of the double copy
Constraining gravity with cosmology
Precision tests on the quantum nature of gravity
Gravity, thermodynamics and cosmology
New Frontiers in Particle Physics, Cosmology and Gravity

Original classification

Research Grant

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