Saturday, June 5, 2021

Laser Pulses: Faster Than Speed-of-Light?

An image of our Sun, which is a natural fusion energy reactor. Research indicating faster-than-light laser pulses could help develop artificial and clean fusion energy reactors on Earth.

(Image Sources:, By NASA Goddard Laboratory for Atmospheres and Yohkoh Legacy data Archive - NASA Goddard Laboratory for Atmospheres mission of ISAS, Japan. The Yohkoh Soft X-ray telescope was prepared by the Lockheed-Martin Solar and Astrophysics Laboratory, the National Astronomical Observatory of Japan, and the University of Tokyo with the support of NASA and ISAS., Public Domain,

By Glenn A. Walsh

Reporting for SpaceWatchtower

Many people have heard that Albert Einstein, in his Special Theory of Relativity, sets-up a “cosmic speed limit” which forbids anything from traveling faster than the speed-of-light. Well, scientists now claim that a laser pulse can move slower or faster than the speed-of-light, in special circumstances.

The speed-of-light is defined, precisely, as 299,792,458 meters-per-second, which also translates to 186,282.39705 miles-per-second. And, this “cosmic speed limit” has always referred to light or anything in the electromagnetic spectrum, conventional matter, energy, or any signal carrying information, passing through a vacuum.

Now, scientists from the Lawrence Livermore National Laboratory in Livermore, California and the University of Rochester Laboratory for Laser Energetics in Rochester, New York have succeeded in both slowing-down and speeding-up the transmission of a laser pulse through hot plasma. This research was outlined in a paper titled, "Slow and Fast Light in Plasma Using Optical Wave Mixing", published in the journal Physical Review Letters on 2021 May 19.

In these hot swarms of charged particles, the researchers have been able to fine-tune the speed of a laser beam from one-tenth the speed-of-light to more than 30 per-cent faster than the speed-of-light! The scientists emphasize that, in these cases, the laser pulses can exceed the speed-of-light, without violating Dr. Einstein's “cosmic speed limit” or any other laws of physics.

Electromagnetism mandates that individual photons must stay within the “cosmic speed limit”. However, within certain frequencies, pulses of photons create regular light waves.

What is called “group velocity” describes the rate at which whole groups of light waves move through a medium. Depending on the specific electromagnetic conditions of the medium, the group velocity can be tweaked to slow-down or speed-up.

In these experiments, the researchers did this by using a laser to strip-away electrons from hydrogen (H) and helium (He) ions. They were, then, able to use a second laser to change the group velocity of light pulses from the first laser.

These experiments will not lead to “Star Trek”-type faster-than-light travel anytime in the foreseeable future. However, it could lead to breakthroughs in advanced technologies.

This could be particularly true for laser technologies. It could lead to much more powerful lasers, a research emphasis at Lawrence Livermore National Laboratory.

The problem with traditional laser technology is that as the energy increases, their solid-state components tend to get damaged. This problem could be solved by using streams of plasma to amplify or change the light characteristics.

Clean fusion energy and speeding-up research particle accelerators are just two of the applications which could benefit from these more powerful lasers.

 Internet Links to Additional Information ---

More Details on This Research: Link >>> 

Research Paper Abstract: Link >>> /PhysRevLett.126.205001 

Speed-of-Light: Link >>> 

Laser: Link >>> 

Plasma: Link >>>

Source: Glenn A. Walsh Reporting for SpaceWatchtower, a project of Friends of the Zeiss.

                 Saturday, 2021 June 5.

                             Like This Post?  Please Share!

           More Astronomy & Science News - SpaceWatchtower Twitter Feed:
            Link >>>

        Astronomy & Science Links: Link >>>

                Want to receive SpaceWatchtower blog posts in your in-box ?
                Send request to < >.


Glenn A. Walsh, Informal Science Educator & Communicator:
Link >>>
Electronic Mail: < >
Project Director, Friends of the Zeiss: Link >>>
SpaceWatchtower Editor / Author: Link >>>
Formerly Astronomical Observatory Coordinator & Planetarium Lecturer, original Buhl Planetarium & Institute of Popular Science (a.k.a. Buhl Science Center), Pittsburgh's science & technology museum from 1939 to 1991.
Formerly Trustee, Andrew Carnegie Free Library and Music Hall, Pittsburgh suburb of Carnegie, Pennsylvania.
Author of History Web Sites on the Internet --
* Buhl Planetarium, Pittsburgh: Link >>>  Buhl Observatory: Link >>>
* Adler Planetarium, Chicago: Link >>>
* Astronomer, Educator, Optician John A. Brashear: Link >>>
* Andrew Carnegie & Carnegie Libraries: Link >>>