Forum für Wissenschaft, Industrie und Wirtschaft

Hauptsponsoren:     3M 
Datenbankrecherche:

 

Dark Energy Alternatives to Einstein Are Running Out of Room

10.01.2013
Research by University of Arizona astronomy professor Rodger Thompson finds that a popular alternative to Albert Einstein’s theory for the acceleration of the expansion of the universe does not fit newly obtained data on a fundamental constant, the proton to electron mass ratio.
Thompson's findings, reported Jan. 9 at the American Astronomical Society meeting in Long Beach, Calif., impact our understanding of the universe and point to a new direction for the further study of its accelerating expansion.

To explain the acceleration of the expansion of the universe, astrophysicists have invoked dark energy – a hypothetical form of energy that permeates all of space. A popular theory of dark energy, however, does not fit new results on the value of the proton mass divided by the electron mass in the early universe.

Thompson computed the predicted change in the ratio by the dark energy theory (generally referred to as rolling scalar fields) and found it did not fit the new data.

UA alumnus Brian Schmidt, along with Saul Perlmutter and Adam Reiss, won the 2011 Nobel Prize in Physics for showing that the expansion of the universe is accelerating rather than slowing down as previously thought.

The acceleration can be explained by reinstating the "cosmological constant" into Einstein's theory of General Relativity. Einstein originally introduced the term to make the universe stand still. When it was later found that the universe was expanding, Einstein called the cosmological constant "his biggest blunder."

The constant was reinstated with a different value that produces the observed acceleration of the universe’s expansion. Physicists trying to calculate the value from known physics, however, get a number more than 10 to the power of 60 (one followed by 60 zeros) too large – a truly astronomical number.

That's when physicists turned to new theories of dark energy to explain the acceleration.

In his research, Thompson put the most popular of those theories to the test, targeting the value of a fundamental constant (not to be confused with the cosmological constant), the mass of the proton divided by the mass of the electron. A fundamental constant is a pure number with no units such as mass or length. The values of the fundamental constants determine the laws of physics. Change the number, and the laws of physics change. Change the fundamental constants by a large amount, and the universe becomes very different from what we observe.

The new physics model of dark energy that Thompson tested predicts that the fundamental constants will change by a small amount. Thompson identified a method of measuring the proton to electron mass ratio in the early universe several years ago, but it is only recently that astronomical instruments became powerful enough to measure the effect. More recently, he determined the exact amount of change that many of the new theories predict.

Last month, a group of European astronomers, using a massive radio telescope in Germany, made the most accurate measurement of the proton-to-electron mass ratio ever accomplished and found that there has been no change in the ratio to one part in 10 million at a time when the universe was about half its current age, around 7 billion years ago.

When Thompson put this new measurement into his calculations, he found that it excluded almost all of the dark energy models using the commonly expected values or parameters. If the parameter space or range of values is equated to a football field, then almost the whole field is out of bounds except for a single 2-inch by 2-inch patch at one corner of the field. In fact, most of the allowed values are not even on the field.

"In effect, the dark energy theories have been playing on the wrong field," Thompson said. "The 2-inch square does contain the area that corresponds to no change in the fundamental constants, and that is exactly where Einstein stands."

Thompson expects that physicists and astronomers studying cosmology will adapt to the new field of play, but for now, "Einstein is in the catbird seat, waiting for everyone else to catch up."

Jennifer Fitzenberger | University of Arizona
Further information:
http://www.arizona.edu

More articles from Physics and Astronomy:

nachricht Smooth propagation of spin waves using gold
26.06.2017 | Toyohashi University of Technology

nachricht A 100-year-old physics problem has been solved at EPFL
23.06.2017 | Ecole Polytechnique Fédérale de Lausanne

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: Hyperspektrale Bildgebung zur 100%-Inspektion von Oberflächen und Schichten

„Mehr sehen, als das Auge erlaubt“, das ist ein Anspruch, dem die Hyperspektrale Bildgebung (HSI) gerecht wird. Die neue Kameratechnologie ermöglicht, Licht nicht nur ortsaufgelöst, sondern simultan auch spektral aufgelöst aufzuzeichnen. Das bedeutet, dass zur Informationsgewinnung nicht nur herkömmlich drei spektrale Bänder (RGB), sondern bis zu eintausend genutzt werden.

Das Fraunhofer IWS Dresden entwickelt eine integrierte HSI-Lösung, die das Potenzial der HSI-Technologie in zuverlässige Hard- und Software überführt und für...

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Klima-Satellit: Mit robuster Lasertechnik Methan auf der Spur

Hitzewellen in der Arktis, längere Vegetationsperioden in Europa, schwere Überschwemmungen in Westafrika – mit Hilfe des deutsch-französischen Satelliten MERLIN wollen Wissenschaftler ab 2021 die Emissionen des Treibhausgases Methan auf der Erde erforschen. Möglich macht das ein neues robustes Lasersystem des Fraunhofer-Instituts für Lasertechnologie ILT in Aachen, das eine bisher unerreichte Messgenauigkeit erzielt.

Methan entsteht unter anderem bei Fäulnisprozessen. Es ist 25-mal wirksamer als das klimaschädliche Kohlendioxid, kommt in der Erdatmosphäre aber lange nicht...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Alle Focus-News des Innovations-reports >>>

Anzeige

Anzeige

IHR
JOB & KARRIERE
SERVICE
im innovations-report
in Kooperation mit academics
Veranstaltungen

Future Security Conference 2017 in Nürnberg - Call for Papers bis 31. Juli

26.06.2017 | Veranstaltungen

Von Batterieforschung bis Optoelektronik

23.06.2017 | Veranstaltungen

10. HDT-Tagung: Elektrische Antriebstechnologie für Hybrid- und Elektrofahrzeuge

22.06.2017 | Veranstaltungen

 
VideoLinks
B2B-VideoLinks
Weitere VideoLinks >>>
Aktuelle Beiträge

„Digital Mobility“– 48 Mio. Euro für die Entwicklung des digitalen Fahrzeuges

26.06.2017 | Förderungen Preise

Fahrerlose Transportfahrzeuge reagieren bald automatisch auf Störungen

26.06.2017 | Verkehr Logistik

Forscher sorgen mit ungewöhnlicher Studie über Edelgase international für Aufmerksamkeit

26.06.2017 | Physik Astronomie