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 Innovative LED High Power Light Source for UV
22.06.2017 | Omicron - Laserage Laserprodukte GmbH

nachricht Spin liquids − back to the roots
22.06.2017 | Universität Augsburg

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: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

Im Focus: Optoelectronic Inline Measurement – Accurate to the Nanometer

Germany counts high-precision manufacturing processes among its advantages as a location. It’s not just the aerospace and automotive industries that require almost waste-free, high-precision manufacturing to provide an efficient way of testing the shape and orientation tolerances of products. Since current inline measurement technology not yet provides the required accuracy, the Fraunhofer Institute for Laser Technology ILT is collaborating with four renowned industry partners in the INSPIRE project to develop inline sensors with a new accuracy class. Funded by the German Federal Ministry of Education and Research (BMBF), the project is scheduled to run until the end of 2019.

New Manufacturing Technologies for New Products

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

A new technique isolates neuronal activity during memory consolidation

22.06.2017 | Life Sciences

Plant inspiration could lead to flexible electronics

22.06.2017 | Materials Sciences

A rhodium-based catalyst for making organosilicon using less precious metal

22.06.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>