Featured Research

from universities, journals, and other organizations

The Star Splitter: Microlensing Technique Pioneered By NSF Researchers Finds Lone Black Holes Adrift In The Galaxy

Date:
January 17, 2000
Source:
National Science Foundation
Summary:
In a Robert Frost poem, a farmer relies on a telescope called the "Star Splitter" to satisfy his curiosity about our place in the universe. Two international teams of astronomers supported by the National Science Foundation (NSF) recently used another “star splitter,” the technique of gravitational lensing, to examine another curiosity -- isolated black holes drifting among the stars in our galaxy.

In a Robert Frost poem, a farmer relies on a telescope called the "Star Splitter" to satisfy his curiosity about our place in the universe.* Two international teams of astronomers supported by the National Science Foundation (NSF) recently used another “star splitter,” the technique of gravitational lensing, to examine another curiosity -- isolated black holes drifting among the stars in our galaxy.

David Bennett of the University of Notre Dame and his collaborators presented these results today at the 195th meeting of the American Astronomical Society in Atlanta, Ga.

Albert Einstein, in his General Theory of Relativity, first showed that the gravitational field of a star distorts space so that light passing near is deflected, much like an optical lens or magnifying glass deflects light. In 1936 Einstein predicted what an observer would see if a very faint object with a strong gravitational field such as a black hole passed in front of a faint star. The black hole's gravity would act like a powerful lens, splitting the star's image into multiple images and making the star appear brighter. In some cases, the images would blend into a perfect ring of light. This phenomenon is known as gravitational lensing; in the case of stars, it is called microlensing.

Einstein thought that because the separation between images would be so small, earth-based instruments would never be able to observe it -- and in fact, no one has observed the split images of stars (though astronomers have seen split images of galaxies). But today's powerful instruments can detect the brightening associated with the stars and pinpoint their locations.

Astronomers supported by NSF through its Science and Technology Center for Particle Astrophysics at the University of California at Berkeley are using microlensing to look at millions of stars in a search for the changing brightness predicted by Einstein. Dubbed the MACHO project, for Massive Compact Halo Objects, the search seeks to learn more about the "dark matter" that dominates the mass of our galaxy, some of which might be in the form of massive compact objects. Already, the MACHO astronomers have noted 300 instances of gravitational microlensing near the central regions of our galaxy, each marking the passage of an unseen object in front of the star.

Bennett and his collaborators examined two microlensing events, seen in 1996 and 1998, and followed up with observations by the Mount Stromlo Observatory in Australia, NSF's Cerro Tololo Inter-American Observatory in Chile, and NASA's Hubble Space Telescope. Complex calculations of the location and brightness of the stars and the mass of the objects passing in front led the teams to conclude the objects were probably black holes drifting through space -- a new find for astronomers. All previously known black holes have been found in orbit around stars, with their presence detected by their effect on the companion star.

The microlensing technique holds promise for detecting other solitary black holes, dark matter and planets. “Robert Frost's Star Splitter" didn't do a thing but split a star in two or three,’” said Morris Aizenman of NSF’s Astronomical Sciences Division. “Microlensing, which is nature’s ‘star splitter,’ is revealing much more about the unseen matter in our galaxy.”

-NSF-

Editors: Images are available on the Internet at:
http://oposite.stsci.edu/pubinfo/pr/2000/03
http://oposite.stsci.edu/pubinfo/pictures.html
http://oposite.stsci.edu/pubinfo/pr/2000/03/pr-photos.html

For more information, see:
http://www.MACHO.mcmaster.ca/
http://bustard.phys.nd.edu/MPS/

* "The Star Splitter", by Robert Frost (1874-1963)


Story Source:

The above story is based on materials provided by National Science Foundation. Note: Materials may be edited for content and length.


Cite This Page:

National Science Foundation. "The Star Splitter: Microlensing Technique Pioneered By NSF Researchers Finds Lone Black Holes Adrift In The Galaxy." ScienceDaily. ScienceDaily, 17 January 2000. <www.sciencedaily.com/releases/2000/01/000117072611.htm>.
National Science Foundation. (2000, January 17). The Star Splitter: Microlensing Technique Pioneered By NSF Researchers Finds Lone Black Holes Adrift In The Galaxy. ScienceDaily. Retrieved September 17, 2014 from www.sciencedaily.com/releases/2000/01/000117072611.htm
National Science Foundation. "The Star Splitter: Microlensing Technique Pioneered By NSF Researchers Finds Lone Black Holes Adrift In The Galaxy." ScienceDaily. www.sciencedaily.com/releases/2000/01/000117072611.htm (accessed September 17, 2014).

Share This



More Space & Time News

Wednesday, September 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Boeing, SpaceX to Send Astronauts to Space Station

Boeing, SpaceX to Send Astronauts to Space Station

AFP (Sep. 17, 2014) — NASA selected Boeing and SpaceX on Tuesday to build America's next spacecraft to carry astronauts to the International Space Station (ISS) by 2017, opening the way to a new chapter in human spaceflight. Duration: 01:13 Video provided by AFP
Powered by NewsLook.com
East Coast Treated To Rare Meteor Sighting

East Coast Treated To Rare Meteor Sighting

Newsy (Sep. 16, 2014) — Numerous residents along the East Coast reported seeing a bright meteor flash through the sky Sunday night. Video provided by Newsy
Powered by NewsLook.com
Space Race Pits Bezos Vs Musk

Space Race Pits Bezos Vs Musk

Reuters - Business Video Online (Sep. 16, 2014) — Amazon CEO Jeff Bezos' startup will team up with Boeing and Lockheed to develop rocket engines as Elon Musk races to have his rockets certified. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
NASA Picks Boeing and SpaceX to Ferry Astronauts

NASA Picks Boeing and SpaceX to Ferry Astronauts

AP (Sep. 16, 2014) — NASA is a giant step closer to launching Americans again from U.S. soil. It has announced it has picked Boeing and SpaceX to transport astronauts to the International Space Station in the next few years. (Sept. 16) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

    Technology News



    Save/Print:
    Share:  

    Free Subscriptions


    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile


    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?


    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile iPhone Android Web
    Follow Facebook Twitter Google+
    Subscribe RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins