Dr. Mark Edwards Participates in NSF “Ideas Lab” to Measure “Big G”

Dr. Mark Edwards

Dr. Mark Edwards was chosen by the National Science Foundation (NSF) to participate
in the “Ideas Lab: Measuring ‘Big G’ Challenge” held this past July 18-22, 2016
at the National Institute of Standards and Technology (NIST) in Gaithersburg, MD.
The purpose of this event was to bring a group of scientists together to brainstorm
new ideas for measuring Newton’s Universal Gravitational Constant also known as
“Big G”.

In the 1600s, Sir Isaac Newton discovered the “law of gravity” which states that
the gravitational force between two objects is proportional to the product of their
masses divided by the square of the distance between them. Big G is the constant
of proportionality that relates these two quantities and is a fundamental constant
of nature.

The first quantitative measurement of Big G was made in the late 1700s by Henry
Cavendish and many more measurements of Big G have been made since then.  Even after
200 years, Big G remains the mostly poorly measured fundamental constant of nature.
Some of the measurement made in the last 10-15 years have actually made the uncertainty
in the value of Big G increase.  This situation has provided the motivation for the
ideas lab.

At the ideas lab Edwards presented an idea for measuring Big G aboard the International
Space Station (ISS).  In 2017, the National Aeronautics and Space Administration (NASA)
plans to deploy a new experiment to the ISS called the Cold Atom Laboratory (CAL).
This experiment will be capable of creating ultra-cold atomic gases that have been
cooled into a state called a Bose-Einstein condensate (BEC).  When the gas is in the
BEC state, it can be split in two and separated in the microgravity environment of the
ISS.  When this is done with a large source mass present, the source mass pulls
gravitationally on the two BEC pieces differently and this difference can be measured
if the two pieces are put back together.

Dr. Edwards is working on refinements to the design of this proposed experiment.  He is
collaborating with Dr. Doga Murat Kurkcuoglu, a professor in the Physics Department at
Georgia Southern and a physics major, Ms. Elizabeth Ashwood and with Dr. Charles W.
Clark of the Joint Quantum Institute (JQI).  The JQI is run jointly by NIST and the
University of Maryland at College Park.

More information about the Ideas Lab: Measuring ‘Big G’ Challenge can be found at

Posted in Department, Faculty

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