Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New virtual telescope zooms in on Milky Way's super-massive black hole

05.09.2008
Radio dishes in 3 states create virtual telescope 2,800 miles across

An international team, led by astronomers at the MIT Haystack Observatory, has obtained the closest views ever of what is believed to be a super-massive black hole at the center of the Milky Way galaxy.

The astronomers linked together radio dishes in Hawaii, Arizona and California to create a virtual telescope more than 2,800 miles across that is capable of seeing details more than 1,000 times finer than the Hubble Space Telescope. The cosmic target of the observations was the source known as Sagittarius A* ("A-star"), long thought to mark the position of a black hole whose mass is 4 million times that of the sun.

Though Sagittarius A* was discovered three decades ago, the new observations for the first time have an angular resolution, or ability to observe small details, that is matched to the size of the black hole "event horizon" — the region inside of which nothing, including light, can ever escape.

The concept of black holes, objects so dense that their gravitational pull prevents anything including light itself from ever escaping their grasp, has long been hypothesized, but their existence has not yet been proved conclusively. Astronomers study black holes by detecting the light emitted by matter that heats up as it is pulled closer to the event horizon. By measuring the size of this glowing region at the Milky Way center, the new observations have revealed the highest density yet for the concentration of matter at the center of our galaxy, which "is important new evidence supporting the existence of black holes," said Sheperd Doeleman of MIT, lead author of the study that will be published in the Sept. 4 issue of the journal Nature.

"This technique gives us an unmatched view of the region near the Milky Way's central black hole," Doeleman said. "The new observations have a resolution equivalent to being able to see, from Earth, a baseball on the surface of the moon."

The key to making these observations is a technique called very long baseline interferometry, or VLBI, which links simultaneous observations from several radio telescopes that can be thousands of miles apart. The signals from these radio dishes are combined to create a "virtual" telescope with the same resolving power as a single telescope as large as the distance between the participating dishes. As a result, VLBI can reveal exquisitely sharp details. To create the continent-sized telescope, the team developed and installed special equipment at four observatories: the Arizona Radio Observatory's Submillimeter Telescope (ARO-SMT) of the University of Arizona, the Combined Array for Research in Millimeter-wave Astronomy (CARMA) in California, and both the James Clerk Maxwell Telescope (JCMT) and the Submillimeter Array (SMA) in Hawaii.

The new observations were done using very short radio waves of 1.3 millimeters wavelength, which can penetrate the fog of interstellar gas that blurs observations at longer wavelengths. Like a distant light seen through a dense mist, longer-wavelength views of the Galactic Center are dimmed and distorted. "The short wavelength observations combined with the large distances between the radio observatories is what makes this virtual telescope uniquely suited to study the black hole," said Lucy Ziurys, Director of the Arizona Radio Observatory and a co-author of the study.

Though it takes light more than 25,000 years to reach us from the center of the Milky Way, the team measured the size of Sagittarius A* to be only one-third the Earth-sun distance — a trip that light would make in only three minutes. The astronomers concluded that the source of the radiation likely originates in either a disk of matter swirling in toward the black hole, or a high-speed jet of matter being ejected by the black hole. "Future observations that create even larger virtual telescopes will be able to pinpoint exactly what makes Sagittarius A* light up," Doeleman said. "Most galaxies are now thought to have black holes at their centers, but because Sagittarius A* is in our own galaxy, it is our best chance to observe what's happening at an event horizon."

"This pioneering paper demonstrates that such observations are feasible," commented theorist Avi Loeb of Harvard University, who was not a member of the discovery team. "It opens up a new window for probing the structure of space and time near a black hole and testing Einstein's theory of gravity."

Teresa Herbert | EurekAlert!
Further information:
http://www.mit.edu

More articles from Physics and Astronomy:

nachricht Further Improvement of Qubit Lifetime for Quantum Computers
09.12.2016 | Forschungszentrum Jülich

nachricht Electron highway inside crystal
09.12.2016 | Julius-Maximilians-Universität Würzburg

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: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>