Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The first 3-D map of the universe

06.03.2007
By analyzing the COSMOS field, the largest field of galaxies ever observed with the Hubble space telescope, an international team of scientists led by researchers from the California Institute of Technology (United States) and researchers from the associated laboratories of the CNRS and the CEA , made the first three-dimensional map of dark matter in the Universe using gravitational lensing effects. This historic first seems to confirm the standard theories on the formation of the large structures of the Universe. This study was presented in the January 7, 2007 issue of the journal "Nature."

For astronomers, mapping the distribution of the mass in the Universe from its light component is a considerable challenge. It is an exercise as complicated as determining the extent of a city solely from aerial photographs taken at night. Luminous matter (stars, galaxies, ionized gas) represents only about one sixth of the total matter of the Universe. The remainder is invisible and composed in particular of the mysterious component called dark matter.

Nonetheless, despite the complexity of the task, a three-dimensional map of all of the mass, luminous and dark matter was made for the first time in the COSMOS field. An international team of astronomers achieved this feat by using the gravitational lens effect to measure the large-scale distribution of matter. This new map brings more information comparable to what we would have by seeing a city in daylight rather than at night to be able to distinguish all of the fine details.

The map of dark matter was made by measuring the shapes of half a million distant galaxies. To reach us, their light had to cross the "fields" of dark matter and the beams of light were slightly deflected. This phenomenon is a direct consequence of Albert Einstein's theory of general relativity which predicts that the presence of a large mass locally distorts Space-Time. In consequence, the trajectory of particles passing close to this concentration of mass is diverted. Photons, particles associated with electromagnetic radiation, are not an exception. The deformation observed in the shapes of the galaxies was used to reconstruct the distribution of the mass along the line of sight.

The COSMOS field covers a region of the sky nine times the size of the Moon (1.6 square degrees). The COSMOS survey done by Hubble includes 575 images from the ACS camera (Advanced Camera for Surveys), corresponding to close to 1,000 hours of observation. Following the observations made with Hubble, many additional observations with telescopes (like the Subaru, the VLT and the CFHT) and in space (XMM-Newton) on the ground were carried out. In particular, the multi-color images from the Subaru and the Canada-France-Hawaii Telescopes, as well as the thousands of VLT spectra measured with the VIMOS instrument allowed for estimation of the distance of the various structures, thereby enabling this 3 dimensional map to be made. It shows that luminous matter concentrates along the densest regions of the dark matter and a network of filaments that intersect where clusters of galaxies are located. Furthermore, the map covers close to half of the age of the Universe and makes it possible to monitor the evolution of the distribution of dark matter, as it becomes more and more structured over time.

"Mapping the distribution of dark matter in space and time is fundamental for understanding how the galaxies developed and grouped themselves over time. The results obtained through the COSMOS survey seem to be in accordance with the standard theories of the formation of the large-scale structures of the Universe," says Jean Paul Kneib, CNRS researcher at the Marseilles Laboratory of Astrophysics.

The COSMOS survey thus brings us a three-dimensional map of the dark matter in the Universe and will allow us for the first time to monitor the relationship between the distribution of dark matter and the formation and evolution of galaxies. This type of mapping of the Universe by the weak gravitational lens effect is already orienting future space missions that are now already underway... We can thus imagine that in the decades to come the whole Universe could be mapped, in an even more detailed manner, perhaps making it possible to shed light on the existence and the nature of dark energy, the elusive force which is thought to be accelerating the expansion of the Universe.

Monica McCarthy | EurekAlert!
Further information:
http://www.cnrs.fr
http://www.cea.fr

More articles from Physics and Astronomy:

nachricht New thruster design increases efficiency for future spaceflight
16.08.2017 | American Institute of Physics

nachricht Tracking a solar eruption through the solar system
16.08.2017 | American Geophysical Union

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: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

Im Focus: Scientists improve forecast of increasing hazard on Ecuadorian volcano

Researchers from the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science, the Italian Space Agency (ASI), and the Instituto Geofisico--Escuela Politecnica Nacional (IGEPN) of Ecuador, showed an increasing volcanic danger on Cotopaxi in Ecuador using a powerful technique known as Interferometric Synthetic Aperture Radar (InSAR).

The Andes region in which Cotopaxi volcano is located is known to contain some of the world's most serious volcanic hazard. A mid- to large-size eruption has...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

New thruster design increases efficiency for future spaceflight

16.08.2017 | Physics and Astronomy

Transporting spin: A graphene and boron nitride heterostructure creates large spin signals

16.08.2017 | Materials Sciences

A new method for the 3-D printing of living tissues

16.08.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>