Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Zooming star points to supermassive black hole at the center of the Milky Way

17.10.2002


Supermassive black holes – the name given to black holes whose mass is more than 1,000,000 times the mass of the sun – can be found at the center of many galaxies. Scientists from the Weizmann Institute of Science, the Max Planck Institute for Extraterrestrial Physics, and several institutions in France have succeeded in tracking a star racing around a dark mass at the center of our galaxy. This achievement offers more support for the widely held view that the dark mass is a supermassive black hole. The findings were published in the current issue of Nature.



The scientists tracked, for the first time, a star completing an orbit around a known unusual source of radiation (a black hole candidate) in the center of our galaxy. This discovery heralds a new epoch of high precision black hole astronomy and that might help us better understand how galaxies are born and evolve.

Supermassive black holes are thought to evolve when many smaller black holes merge at the center of a galaxy, and start swallowing everything that comes their way. Such a black hole is a remnant of an exploded sun much bigger than our own. The explosion is a rare celestial phenomenon called supernova, which happens when these developed suns use up all their nuclear fuel. Without fuel to maintain the huge pressure that is required to counter gravity, the star first implodes, and then the outer layers rebound against the sun’s core and are violently ejected into space, in a process that is one of the most powerful explosions that occur in nature. Simultaneously, the massive core continues to cave in. It rapidly collapses into itself and forms a black hole.


The pull of this dark mass is so great that even light can’t escape it, rendering it invisible. "Invisible - but not powerless," said Dr. Tal Alexander, a theoretical astrophysicist at the Weizmann Institute of Science’s Physics Faculty. "The black hole’s presence is felt by its immense gravitational pull. A star that happens to be close to a supermassive black hole will orbit very rapidly around a point of seemingly empty space." Another clue is the radiation emitted by gas that is heated up just before it is swallowed forever by the black hole.

Alexander and his colleagues at the Max Planck Institute for Astrophysics tracked the orbit of the closest known star to the black hole candidate Sagittarius A*, a dark mass 3,000,000 times the mass of the sun. Following the star for 10 years, they found that it does indeed orbit Sagittarius A*. Approaching the black hole’s maw, the star reaches its highest velocity, whizzing past it at 5,000 kilometers per second.

Some astrophysicists have suggested in the past that perhaps the dark mass in the center of the Milky Way is not a black hole, but rather a dense cluster of compact stars, or even a giant blob of mysterious sub-atomic particles. It now appears that these are not viable alternatives. The new detailed analysis of the orbit, made possible by the techniques developed by the team, is fully consistent with the view that the dark mass is a supermassive black hole.

Their technique allowed precise observation of the center of the galaxy, overcoming the problem of interstellar dust permeating space. The observations were made with the new European Very Large Telescope in Chile whose detectors were developed by scientists from the Max Planck Institute for Extraterrestrial Physics, Observatoire de Paris, Office National d’Etudes et de Recherches Aerospatiales, and Observatoire de Grenoble.

Such observations could provide information on a point we know surprisingly little about: our own place in the universe. Alexander said: "We currently do not even know the earth’s exact distance from the center of our own galaxy – understanding such stellar orbits might tell us where we are."

Jeffrey J. Sussman | EurekAlert!
Further information:
http://www.weizmann.ac.il/

More articles from Physics and Astronomy:

nachricht From rocks in Colorado, evidence of a 'chaotic solar system'
23.02.2017 | University of Wisconsin-Madison

nachricht Prediction: More gas-giants will be found orbiting Sun-like stars
22.02.2017 | Carnegie Institution for 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: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>