Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Time to overhaul Newton's theory of gravitation? Galaxy cluster models cast doubt on dark matter

For almost 75 years, astronomers have believed that the Universe has a large amount of unseen or ‘dark’ matter, thought to make up about five-sixths of the matter in the cosmos.

With the conventional theory of gravitation, based on Newton’s ideas and refined by Einstein 92 years ago, dark matter helps to explain the motion of galaxies, and clusters of galaxies, on the largest scales.

Now two Canadian researchers at the Perimeter Institute for Theoretical Physics suggest that the motion of galaxies in a distant cluster is more easily explained by a Modified Gravity (MOG) theory than by the presence of dark matter. Graduate student Joel Brownstein and his supervisor Professor John Moffat of the University of Waterloo present their results in a paper in the 21 November edition of Monthly Notices of the Royal Astronomical Society.

The two scientists analysed images of the ‘Bullet Cluster’ of galaxies made using the Hubble Space Telescope, Chandra X-ray and Spitzer infrared observatories and the Magellan telescope in Chile. The Bullet Cluster consists of two merging clusters of galaxies and lies at a distance of over 3 billion light years in the direction of the southern constellation of Carina.

This arsenal of instrumentation gave them maps of the 150 million degree hot gas between the galaxies and show the effect of gravitational lensing, where the gravity of an intervening object – here the Bullet Cluster - deflects the path of light emitted by a more distant galaxy.

Previous studies suggested that the Bullet Cluster clearly demonstrates the presence of dark matter. But when Brownstein and Moffat compared the observed gravitational lensing and distribution of gas with that predicted using MOG theory, they found no evidence for this. In other words, it is more natural to explain the appearance of this cluster using a revised theory of gravitation than by including dark matter.

MOG theory emerges from a generalization of relativity that eluded even Einstein, has been developed by Moffat for nearly thirty years and is now yielding astronomical and cosmological results. The theory has been used to successfully explain the movement of stars in over 100 galaxies and the motion of galaxies in more than 100 clusters. MOG theory may also explain the apparent anomalous deceleration of the Pioneer 10 and 11 space probes, launched in the early 1970s and now more than 12000 million km from the Sun.

The two physicists are enthusiastic about their findings. Brownstein comments, ‘Using Modified Gravity (MOG) theory, the ‘normal’ matter in the Bullet Cluster is enough to account for the observed gravitational lensing effect. In time, better observations will lead to higher resolution pictures of the systems we are studying. Continuing the search for and then analysing other merging clusters of galaxies will help us decide whether dark matter or MOG theory offers the best explanation for the large scale structure of the Universe.’

Professor Moffat adds, ‘If the multi-billion dollar laboratory experiments now underway succeed in directly detecting dark matter, then I will be happy to see Einsteinian and Newtonian gravity retained. However, if dark matter is not detected and we have to conclude that it does not exist, then Einstein and Newtonian gravity must be modified to fit the extensive amount of astronomical and cosmological data, such as the bullet cluster, that cannot otherwise be explained.’

Robert Massey | alfa
Further information:

More articles from Physics and Astronomy:

nachricht First results of NSTX-U research operations
26.10.2016 | DOE/Princeton Plasma Physics Laboratory

nachricht Scientists discover particles similar to Majorana fermions
25.10.2016 | Chinese Academy of Sciences Headquarters

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: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Greater Range and Longer Lifetime

26.10.2016 | Power and Electrical Engineering

VDI presents International Bionic Award of the Schauenburg Foundation

26.10.2016 | Awards Funding

3-D-printed magnets

26.10.2016 | Power and Electrical Engineering

More VideoLinks >>>