Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Gravitons
Name: N/A
Status: N/A
Age: N/A
Location: N/A
Country: N/A
Date: 1991 

Has there been any new evidence on the existence of Gravitons? My Physics Professor told us that physicists think that they exist, but have not actually seen them yet. Why is this?

There is indirect evidence for gravitational radiation. The most recent Nobel prize in physics was given for the experiments that uncovered this evidence. The evidence comes from measuring the spin of an object called a "pulsar", which is supposed to be a spinning compact mass - a neutron star, perhaps. The pulsar orbits around a companion star that is nearby. The energy of the system was observed to decrease slightly over a time of several years. The decrease appeared to be consistent with the amount of decrease predicted by general relativity from the radiation of gravitational energy. We believe that if gravitational energy is radiated, then it must be radiated in discrete quanta. These quanta would be "gravitons". There is no direct evidence for gravitons to date.

Jack L. Uretsky

Click here to return to the Physics Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (, or at Argonne's Educational Programs

Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory