Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Photonic booms may help illuminate astronomical secrets

12.01.2015

If you sweep a laser pointer across the Moon fast enough, you can create spots that actually move faster than light. Anyone can do it.

At a meeting of the American Astronomical Society in Seattle, Wash., today, Robert Nemiroff, a physics professor at Michigan Technological University, reported that this theoretical curiosity may turn out to be practically useful out in the cosmos. When a superluminal sweep occurs, it typically starts with a flash that may reveal previously unknown three-dimensional information about the scattering object.


This image depicts Hubble's Variable Nebula.

Credit: William Sparks (STScI), Sylvia Baggett (STScI) et al., & the Hubble Heritage Team (AURA/ STScI/ NASA)

Flashes, dubbed "photonic booms" because they are directly analogous to sonic booms, may be detectable on the Moon, on passing asteroids, on fast moving shadows cast on reflecting dust clouds near variable stars, and on objects illuminated by the rapidly rotating beam of a pulsar, said Nemiroff, author of a study accepted for publication by the Publications of the Astronomical Society of Australia, with a preliminary version available online at http://arxiv.org/abs/1412.7581. "And if detected, we could learn more about all of these objects," said Nemiroff.

"The concept, although not proven in practice, is quite intriguing," said Rosanne Di Stefano, a leading researcher at the Harvard-Smithsonian Center for Astrophysics.

To reveal the size and surface features of asteroids passing near the Earth, a laser beam might be swept across the rock's surface thousands of times a second, with each sweep forcing a harmless but telling photonic boom. The flashes could be recorded with high-speed cameras attached to large telescopes, potentially mapping out major features on the asteroid.

Photonic booms could also be seen much farther out in the universe. An example occurs in Hubble's Variable Nebula in the constellation of Monoceros. There, shadows cast by clouds moving between the bright star "R Mon" and reflecting dust move so fast that they might create photonics booms visible even for days or weeks.

The physics that creates the photonic boom is tied to the faster-than-light sweep speeds of the illuminating spots and cast shadows. Specifically, a flash is seen by an observer when the speed of the scattered spot toward the observer drops from above the speed of light to below the speed of light. The phenomenon is possible only because the spots contain no mass and so cannot only move faster than light, but decelerate past the speed of light without violating Einstein's theory of special relativity.

Details of the effect hinge on the interplay between the time it takes for a sweeping light beam to cross an object, and the time it takes for the light beam to traverse the depth of the object. Therefore, measuring photonic booms gives information about the depth of the scatterer. Were the Moon just a flat disk on the sky, for example, no photonics boom would occur.

"Photonic booms happen around us quite frequently -- but they are always too brief to notice," says Nemiroff. "Out in the cosmos they last long enough to notice -- but nobody has thought to look for them!"

The light flash from a photonic boom is quite different from well-known Cherenkov radiation, light emitted when a charged object breaks the speed of light inside transparent matter, he notes.

Michigan Technological University is a leading public research university developing new technologies and preparing students to create the future for a prosperous and sustainable world. Michigan Tech offers more than 130 undergraduate and graduate degree programs in engineering; forest resources; computing; technology; business; economics; natural, physical and environmental sciences; arts; humanities; and social sciences.

Robert Nemiroff | EurekAlert!

More articles from Physics and Astronomy:

nachricht Neutron star merger directly observed for the first time
17.10.2017 | University of Maryland

nachricht Breaking: the first light from two neutron stars merging
17.10.2017 | American Association for the Advancement of Science

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Ocean atmosphere rife with microbes

17.10.2017 | Life Sciences

Neutrons observe vitamin B6-dependent enzyme activity useful for drug development

17.10.2017 | Life Sciences

NASA finds newly formed tropical storm lan over open waters

17.10.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>