Featured Research

from universities, journals, and other organizations

Scientists Find Black Hole's 'Point Of No Return'

Date:
January 11, 2006
Source:
Massachusetts Institute of Technology
Summary:
A team from MIT and Harvard has found that a certain type of X-ray explosion common on neutron stars is never seen around their black hole cousins, as if the gas that fuels these explosions has vanished into a void. This is strong evidence, the team said, for the existence of a theoretical border around a black hole called an event horizon, a point from beyond which nothing, not even light, can escape.

This image is an animation of a neutron star X-ray burst.
Credit: Image credit: NASA/Dana Berry

Scientists have found new evidence that black holes are performing the disappearing acts for which they are known.

A team from MIT and Harvard has found that a certain type of X-ray explosion common on neutron stars is never seen around their black hole cousins, as if the gas that fuels these explosions has vanished into a void.

This is strong evidence, the team said, for the existence of a theoretical border around a black hole called an event horizon, a point from beyond which nothing, not even light, can escape.

Ron Remillard of the Kavli Institute for Astrophysics and Space Research at MIT led the analysis and is discussing his team's result Jan. 9 at a press conference at the 207th meeting of the American Astronomical Society in Washington, D.C. His colleagues are Dacheng Lin of MIT and Randall Cooper and Ramesh Narayan of the Harvard-Smithsonian Center for Astrophysics in Cambridge.

The scientists studied a complete sample of transient X-ray sources detected with NASA's Rossi X-ray Timing Explorer during the last nine years. They detected 135 X-ray bursts from the 13 sources believed to be neutron stars, but none from the 18 suspected black holes.

Gas released by a nearby star can accumulate on the hard surface of a neutron star, and it will eventually erupt in a thermonuclear explosion. The more massive compact objects in this study suspected of being black holes appeared to have no surface. Gas falling toward the black hole seems to disappear.

"Event horizons are invisible by definition, so it seems impossible to prove their existence," said Remillard. "Yet by looking at dense objects that pull in gas, we can infer whether that gas crashes and accumulates onto a hard surface or just quietly vanishes. For the group of suspected black holes we studied, there is a complete absence of surface explosions called X-ray bursts."

A black hole forms when a very massive star runs out of fuel. Without energy to support its mass, the star implodes. If the star is more than 25 times more massive than our sun, the core will collapse to a point of infinite density with no surface. Within a boundary of about 50 miles from the black hole center, gravity is so strong that not even light can escape its pull. This boundary is the theoretical event horizon.

Stars of about 10 to 25 solar masses will collapse into compact spheres about 10 miles across, called neutron stars. These objects have a hard surface and no event horizon.

Black holes and their neutron star cousins are sometimes located in binary systems, orbiting a relatively normal star companion. Gas from these stars, lured by strong gravity, can flow toward the compact object periodically. This process, called accretion, releases large amounts of energy, predominantly in the form of X-rays.

Gas can accumulate on a neutron star surface, and when conditions are ripe, the gas will ignite in a thermonuclear explosion that is visible as a one-minute event called a Type I X-ray burst. The suspected black holes -- that is, the more massive types of compact objects in this study -- behave as if they have no surface and are located behind event horizons.

The idea of using the absence of X-ray bursts to confirm the presence of event horizons in black holes was proposed in 2002 by Harvard's Narayan and Jeremy Heyl of the University of British Columbia in Vancouver.

The Rossi Explorer, launched on Dec. 30, 1995, is operated by NASA Goddard Space Flight Center in Greenbelt, Md.

###

For more information, including images, visit http://universe.nasa.gov/press/event_horizon/event_horizon.html.


Story Source:

The above story is based on materials provided by Massachusetts Institute of Technology. Note: Materials may be edited for content and length.


Cite This Page:

Massachusetts Institute of Technology. "Scientists Find Black Hole's 'Point Of No Return'." ScienceDaily. ScienceDaily, 11 January 2006. <www.sciencedaily.com/releases/2006/01/060111074825.htm>.
Massachusetts Institute of Technology. (2006, January 11). Scientists Find Black Hole's 'Point Of No Return'. ScienceDaily. Retrieved September 19, 2014 from www.sciencedaily.com/releases/2006/01/060111074825.htm
Massachusetts Institute of Technology. "Scientists Find Black Hole's 'Point Of No Return'." ScienceDaily. www.sciencedaily.com/releases/2006/01/060111074825.htm (accessed September 19, 2014).

Share This



More Space & Time News

Friday, September 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

MIT BioSuit A New Take On Traditional Spacesuits

MIT BioSuit A New Take On Traditional Spacesuits

Newsy (Sep. 19, 2014) The MIT BioSuit could be an alternative to big, bulky traditional spacesuits, but the concept needs some work. Video provided by Newsy
Powered by NewsLook.com
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

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