Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Astronomers put quasars in their place

04.10.2002


A team of UK astronomers, led by postgraduate student Ed Hawkins, has made a decisive step toward resolving an argument that has rumbled on in the astronomical community for decades. The scientists from the University of Nottingham have been investigating the properties of quasars and nearby galaxies. As part of this study, they have overturned previous analyses which suggested that these two classes of object are physically associated, thus confirming the alternative, more widely-held view that quasars are some of the most distant objects in the Universe.



Quasars are star-like in appearance, but seem to be flying away from Earth at velocities comparable to the speed of light. The majority of astronomers believe that this high speed is a result of the expansion of the Universe, and that the quasars are traveling so fast because they are at enormous distances. However, a vociferous minority, including such notable figures as the great astronomer Fred Hoyle, has argued forcefully that quasars are much closer by. In particular, they have pointed to apparent associations between quasars and nearby galaxies, suggesting that the quasars have somehow been ejected from these galaxies in the recent past.

One of the pieces of evidence to support this idea was the tentative discovery that quasars only seem to move away from galaxies at particular speeds: for example, a surprisingly large number of quasars seem to be moving relative to neighbouring galaxies at speeds of 59% of the speed of light. If the quasars were actually on the far side of the Universe, how would they know to move at exactly 59% of the speed of light relative to a completely unrelated foreground galaxy?


Very little progress has been made toward resolving this controversy, essentially because there just hasn`t been enough data to tell whether the apparent associations between galaxies and quasars are real or just coincidences. However, this has all changed with two newly-completed huge surveys undertaken with the Anglo-Australian Telescope, one measuring the positions and velocities of 200,000 galaxies, and the other measuring the same quantities for 25,000 quasars. "These enormous new data sets offered a great opportunity to take another look at this question," said Hawkins. "To do as fair a test as possible, we discussed with the supporters of both theories what they would expect to see before we analyzed the data."

By carefully sifting through these datasets, Hawkins and collaborators found 1647 examples of quasars that appear close to galaxies, and hence might be associated. Sadly for the nearby-quasar supporters, there was no excess of quasars moving at 59% of the speed of light, or any of the other "magic speeds" that had previously been tentatively identified. Without this evidence to support an association between quasars and galaxies, the case for quasars being flung out of nearby galaxies is much weakened.

Hawkins concluded "it`s a shame, as it would have been great to find that the conventional view of quasars is all wrong. However, it`s also something of a relief to know that most astronomers have not been barking up completely the wrong tree for the last thirty years."

Prof. Michael Merrifield | alfa

More articles from Physics and Astronomy:

nachricht Spiral arms: not just in galaxies
30.09.2016 | Max-Planck-Institut für Radioastronomie

nachricht Discovery of an Extragalactic Hot Molecular Core
29.09.2016 | National Astronomical Observatory of Japan

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: First-Ever 3D Printed Excavator Project Advances Large-Scale Additive Manufacturing R&D

Heavy construction machinery is the focus of Oak Ridge National Laboratory’s latest advance in additive manufacturing research. With industry partners and university students, ORNL researchers are designing and producing the world’s first 3D printed excavator, a prototype that will leverage large-scale AM technologies and explore the feasibility of printing with metal alloys.

Increasing the size and speed of metal-based 3D printing techniques, using low-cost alloys like steel and aluminum, could create new industrial applications...

Im Focus: New welding process joins dissimilar sheets better

Friction stir welding is a still-young and thus often unfamiliar pressure welding process for joining flat components and semi-finished components made of light metals.
Scientists at the University of Stuttgart have now developed two new process variants that will considerably expand the areas of application for friction stir welding.
Technologie-Lizenz-Büro (TLB) GmbH supports the University of Stuttgart in patenting and marketing its innovations.

Friction stir welding is a still-young and thus often unfamiliar pressure welding process for joining flat components and semi-finished components made of...

Im Focus: First quantum photonic circuit with electrically driven light source

Optical quantum computers can revolutionize computer technology. A team of researchers led by scientists from Münster University and KIT now succeeded in putting a quantum optical experimental set-up onto a chip. In doing so, they have met one of the requirements for making it possible to use photonic circuits for optical quantum computers.

Optical quantum computers are what people are pinning their hopes on for tomorrow’s computer technology – whether for tap-proof data encryption, ultrafast...

Im Focus: OLED microdisplays in data glasses for improved human-machine interaction

The Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP has been developing various applications for OLED microdisplays based on organic semiconductors. By integrating the capabilities of an image sensor directly into the microdisplay, eye movements can be recorded by the smart glasses and utilized for guidance and control functions, as one example. The new design will be debuted at Augmented World Expo Europe (AWE) in Berlin at Booth B25, October 18th – 19th.

“Augmented-reality” and “wearables” have become terms we encounter almost daily. Both can make daily life a little simpler and provide valuable assistance for...

Im Focus: Artificial Intelligence Helps in the Discovery of New Materials

With the help of artificial intelligence, chemists from the University of Basel in Switzerland have computed the characteristics of about two million crystals made up of four chemical elements. The researchers were able to identify 90 previously unknown thermodynamically stable crystals that can be regarded as new materials. They report on their findings in the scientific journal Physical Review Letters.

Elpasolite is a glassy, transparent, shiny and soft mineral with a cubic crystal structure. First discovered in El Paso County (Colorado, USA), it can also be...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Paper – Panacea Green Infrastructure?

30.09.2016 | Event News

HLF: From an experiment to an establishment

29.09.2016 | Event News

European Health Forum Gastein 2016 kicks off today

28.09.2016 | Event News

 
Latest News

First-Ever 3D Printed Excavator Project Advances Large-Scale Additive Manufacturing R&D

30.09.2016 | Materials Sciences

New Technique for Finding Weakness in Earth’s Crust

30.09.2016 | Earth Sciences

Cells migrate collectively by intermittent bursts of activity

30.09.2016 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>