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 A chip for environmental and health monitoring
15.12.2017 | Friedrich-Alexander-Universität Erlangen-Nürnberg

nachricht New type of smart windows use liquid to switch from clear to reflective
14.12.2017 | The Optical Society

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: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Plasmonic biosensors enable development of new easy-to-use health tests

14.12.2017 | Health and Medicine

New type of smart windows use liquid to switch from clear to reflective

14.12.2017 | Physics and Astronomy

BigH1 -- The key histone for male fertility

14.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>