. 24/7 Space News .
TIME AND SPACE
Venerable Radio Telescope Sets Standard for Universal Constant
by Staff Writers
Columbia MA (SPX) Jan 05, 2017


illustration only

About 150 hours of observing time on the 1,000-ft radio telescope at the Arecibo Observatory in Puerto Rico over the course of the last several years have been devoted to determining whether the most fundamental constant in physics really is constant.

The target is the so-called fine structure constant, usually known as alpha, which describes the electromagnetic interaction between elementary charged particles. Its value is crucial to understanding the nature of atomic spectra, which in turn allows astronomers to measure the radial velocity of galaxies from which these spectral lines are observed.

Such observations led to the discovery that galaxies appear to be receding from one another with velocities that increase with the distance between them. This is a manifestation of the expansion of the universe following the Big Bang.

Our current model for the expansion and acceleration of the universe depends on the assumption that neither alpha nor mu, the proton-to-electron mass ratio, have changed with time. This assumption is key to our current understanding of the age of the universe. But what if alpha does change with time? Then our knowledge of the distance between galaxies or the age of the universe would have to be revised.

The Arecibo telescope has recently been used to set a new limit on how constant things are. While the latest data suggest that there may be a small change in alpha, it is still too early to be sure. With an uncertainty on the measurement of about one part in a million, it is not yet time to celebrate, nor to heave a sigh of relief.

The Arecibo observations have been carried out by Nissim Kanekar and Jayaram Chengalur of the National Center for Radio Astrophysics in India, and Tapasi Ghosh, a Universities Space Research Association (USRA) astronomer at the Arecibo Observatory. Their experiment makes use of a marvelous concordance of cosmic circumstances involving quasar PKS 1413+135, which is located about 3 billion light-years away. In front of that quasar, and probably surrounding its radio-bright nucleus, is a cloud of OH molecules (OH is also known as hydroxyl).

The atomic properties of hydroxyl are extremely well known from laboratory and theoretical studies. The OH cloud in the Arecibo experiment is observed in two spectral lines, one at 1612 MHz and the other at 1720 MHz. What is unusual is that one of the lines (1612) is seen in absorption and the other (1720) in emission. These lines are said to be conjugate, that is, they are mirror images of one another, which assures that they originate from the same gas cloud.

This is a crucial factor in reducing systematic uncertainties in the measurement of alpha. From the Arecibo spectra, we can measure the observed frequency difference between the two lines and compare that with the laboratory results. Because this quasar is seen as it was 3 billion years in the past and our laboratory is in the present, we can determine just how truly constant alpha is over time.

The 150-hour integration at Arecibo allows the two spectral lines to be compared with very high accuracy. The result implies that alpha has not changed by more than 1.3 parts in a million, in these 3 billion years.

To make the measurements even more accurate would require either more telescope time or the good fortune to find a more distant quasar with a similar OH cloud in its neighborhood. For example, to improve the accuracy by a factor of 10 would require 100 times more observing time than has already been devoted to the project. That is not a realistic possibility.

"We are hopeful that current searches for more quasar candidates showing the necessary OH lines will be successful," noted Dr. Tapasi Ghosh. "These could provide even tighter constraints on any possible variations of this atomic constant."

Until then, the Arecibo measurement is the new gold standard in defining how certain we are that a key physical constant - a constant that sets the very size and scale of the universe - is truly constant.

USRA's Dr. Tapasi Ghosh is presenting these findings at a press briefing at the American Astronomical Society's meeting in Grapevine, Texas, on January 4, 2017.


Comment on this article using your Disqus, Facebook, Google or Twitter login.


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only


.


Related Links
Universities Space Research Association
Understanding Time and Space






Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Previous Report
TIME AND SPACE
ALPHA observes light spectrum of antimatter for first time
Geneva, Switzerland (SPX) Dec 29, 2016
In a paper published in the journal Nature, the ALPHA collaboration reports the first ever measurement on the optical spectrum of an antimatter atom. This achievement features technological developments that open up a completely new era in high-precision antimatter research. It is the result of over 20 years of work by the CERN antimatter community. "Using a laser to observe a transition i ... read more


TIME AND SPACE
Space station battery replacements to begin New Year's Eve

Launch of Russia's new progress spacecraft set for February 2

Tech show looks beyond 'smart,' to new 'realities'

'Passengers' and the real-life science of deep space travel

TIME AND SPACE
SpaceX ready to launch again

Europe and Russia looking at Space Tug Project

India to develop large scale solid fuel mixer

Russia won't be leaving Baikonur anytime soon

TIME AND SPACE
Odyssey recovering from precautionary pause in activity

3-D images reveal features of Martian polar ice caps

Small Troughs Growing on Mars May Become 'Spiders'

All eyes on Trump over Mars

TIME AND SPACE
China Plans to Launch 1st Mars Probe by 2020 - State Council Information Office

China to expand int'l cooperation on space sciences

China sees rapid development of space science and technology

China Space Plan to Develop "Strength and Size"

TIME AND SPACE
Airbus DS and Energia eye new medium-class satellite platform

OneWeb announces key funding form SoftBank Group and other investors

Space as a Driver for Socio-Economic Sustainable Development

SoftBank delivers first $1 bn of Trump pledge, to space firm

TIME AND SPACE
Russian static discharge measure unit to prolong satellite equipment lifespan

'Just the first stage': unique 3D-printed Siberian satellite to orbit Earth

How to 3-D print your own sonic tractor beam

Saab, UAE sign radar support deal

TIME AND SPACE
The blob can learn and teach

Searching a sea of 'noise' to find exoplanets - using only data as a guide

Microlensing Study Suggests Most Common Outer Planets Likely Neptune-mass

Exciting new creatures discovered on ocean floor

TIME AND SPACE
Exploring Pluto and the Wild Back Yonder

Juno Captures Jupiter 'Pearl'

Juno Mission Prepares for December 11 Jupiter Flyby

Research Offers Clues About the Timing of Jupiter's Formation









The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.