Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Astronomers construct largest-ever 3D map of a million galaxies

15.05.2006


An international team of astronomers released today (15 May) new results on the Cosmos, based on the largest map of the heavens ever produced.



This massive atlas emphatically confirmed recent findings that the Universe is full of ’dark energy’, a mysterious substance that makes up three-quarters of our Universe, together with ’dark matter’ which accounts for most of the remaining quarter. Understanding this composition is now one of the most important problems facing the whole of science.

"We now have a precise view of what makes up our Universe, but little idea as to why,” said Prof. Ofer Lahav, a member of the international team and the Head of the Astrophysics Group at University College London. “It is intriguing that the ordinary matter our bodies are made of and that we experience in everyday life only accounts for a few percent of the total cosmic budget."


Our Universe contains billions of galaxies of all shapes and sizes. In recent years astronomers have used increasingly large surveys to map out the positions of these galaxies, stepping their way out into the Cosmos.

The new cosmic map unveiled today is the largest to date -- a three-dimensional atlas of over a million galaxies spread over a distance of more than 5 billion light years. The findings confirm that we live in a Universe filled with mysterious dark matter and dark energy.

"We have analyzed the patterns in this map and discovered waves of structure over a billion light years across," said Dr. Chris Blake of the University of British Columbia, principal author of the study. "These waves were generated billions of years ago and have been vastly stretched in size by the expanding Universe."

Construction of the cosmic atlas was led by co-author Dr. Adrian Collister of the University of Cambridge, as part of his PhD work, using a novel Artificial Intelligence technique he developed with his supervisor Prof. Ofer Lahav.

"By using very accurate distances of just 10,000 galaxies to train the computer algorithm we have been able to estimate reasonably good distances for over a million galaxies," said Collister. "This novel technique is the way of the future."

The original 2-dimensional positions of colours of the one million galaxies were from the Sloan Digital Sky Survey.

The precise observations of the 10,000 galaxy distances were made as part of an international collaboration between U.S., U.K. and Australian teams using data from the Sloan Digital Sky Survey and the Anglo-Australian Telescope.

By measuring the positions of galaxies, astronomers can unravel the balance of forces that govern our Universe: the force of gravity which pulls everything together, and the competing effect of the expanding Universe which smoothes things out. These cosmic forces have arranged the galaxy distribution into a complex network of clusters, filaments and voids.

"The galaxy map can tell us the amount of ordinary ’baryonic’ matter relative to the amount of mysterious ’dark matter’,” said co-author Dr. Sarah Bridle of University College London. "We have confirmed that over 80% of the material in the Universe consists of an invisible dark matter whose nature is not yet understood."

The cosmic atlas of a million galaxies will shortly be made freely available on the World Wide Web for the benefit of other researchers. This free exchange of data is an important feature of modern astronomy, since many discoveries are only possible when different observations are combined.

The key problem in mapping the cosmos is determining the distance to each galaxy. Researchers can measure these distances because as the Universe expands, the colour of each galaxy changes as their emitted light waves are stretched or ‘redshifted’.

Traditionally, astronomers have needed to take a "spectrum" of each galaxy to determine this distance, splitting its light into many components to reveal sharp features with which to measure the amount of redshifting. This requires a time-consuming, individual observation of each galaxy.

The new cosmic map has been constructed using a novel technique focusing on a special class of galaxy whose intrinsic colour is very well known. For these ‘Luminous Red Galaxies’ researchers can measure the amount of colour distortion, and hence the approximate distance of the galaxy, just by looking at digital images of the sky, without the need to obtain a full spectrum.

All that is needed to exploit the technique is accurate observations of a small sample of the galaxies. In this case, precise measurements of just 10,000 galaxies were used to produce the atlas of over a million galaxies. These techniques will be very important for future large astronomical projects such as the Dark Energy Survey, scheduled to start in 2009, in which University College London and the universities of Portsmouth, Cambridge and Edinburgh are key partners.

Prof. Ofer Lahav | alfa
Further information:
http://www.ras.org.uk/

More articles from Physics and Astronomy:

nachricht APEX takes a glimpse into the heart of darkness
25.05.2018 | Max-Planck-Institut für Radioastronomie

nachricht First chip-scale broadband optical system that can sense molecules in the mid-IR
24.05.2018 | Columbia University School of Engineering and Applied 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: Powerful IT security for the car of the future – research alliance develops new approaches

The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.

Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

In focus: Climate adapted plants

25.05.2018 | Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

 
Latest News

In focus: Climate adapted plants

25.05.2018 | Event News

Flow probes from the 3D printer

25.05.2018 | Machine Engineering

Less is more? Gene switch for healthy aging found

25.05.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>