Featured Research

from universities, journals, and other organizations

Using black holes to measure the universe's rate of expansion

Date:
April 22, 2013
Source:
American Friends of Tel Aviv University
Summary:
Scientists have developed a method that uses black holes to measure distances of billions of light years with a high degree of accuracy. The ability to measure these distances will allow scientists to see further into the past of the universe than ever before.

Radiation emitted in the vicinity of black holes could be used to measure distances of billions of light years, says TAU researcher

A few years ago, researchers revealed that the universe is expanding at a much faster rate than originally believed -- a discovery that earned a Nobel Prize in 2011. But measuring the rate of this acceleration over large distances is still challenging and problematic, says Prof. Hagai Netzer of Tel Aviv University's School of Physics and Astronomy.

Now, Prof. Netzer, along with Jian-Min Wang, Pu Du and Chen Hu of the Institute of High Energy Physics of the Chinese Academy of Sciences and Dr. David Valls-Gabaud of the Observatoire de Paris, has developed a method with the potential to measure distances of billions of light years with a high degree of accuracy. The method uses certain types of active black holes that lie at the center of many galaxies. The ability to measure very long distances translates into seeing further into the past of the universe -- and being able to estimate its rate of expansion at a very young age.

Published in the journal Physical Review Letters, this system of measurement takes into account the radiation emitted from the material that surrounds black holes before it is absorbed. As material is drawn into a black hole, it heats up and emits a huge amount of radiation, up to a thousand times the energy produced by a large galaxy containing 100 billion stars. For this reason, it can be seen from very far distances, explains Prof. Netzer.

Solving for unknown distances

Using radiation to measure distances is a general method in astronomy, but until now black holes have never been used to help measure these distances. By adding together measurements of the amount of energy being emitted from the vicinity of the black hole to the amount of radiation which reaches Earth, it's possible to infer the distance to the black hole itself and the time in the history of the universe when the energy was emitted.

Getting an accurate estimate of the radiation being emitted depends on the properties of the black hole. For the specific type of black holes targeted in this work, the amount of radiation emitted as the object draws matter into itself is actually proportional to its mass, say the researchers. Therefore, long-established methods to measure this mass can be used to estimate the amount of radiation involved.

The viability of this theory was proved by using the known properties of black holes in our own astronomical vicinity, "only" several hundred million light years away. Prof. Netzer believes that his system will add to the astronomer's tool kit for measuring distances much farther away, complimenting the existing method which uses the exploding stars called supernovae.

Illuminating "Dark Energy"

According to Prof. Netzer, the ability to measure far-off distances has the potential to unravel some of the greatest mysteries of the universe, which is approximately 14 billion years old. "When we are looking into a distance of billions of light years, we are looking that far into the past," he explains. "The light that I see today was first produced when the universe was much younger."

One such mystery is the nature of what astronomers call "dark energy," the most significant source of energy in the present day universe. This energy, which is manifested as some kind of "anti-gravity," is believed to contribute towards the accelerated expansion of the universe by pushing outwards. The ultimate goal is to understand dark energy on physical grounds, answering questions such as whether this energy has been consistent throughout time and if it is likely to change in the future.


Story Source:

The above story is based on materials provided by American Friends of Tel Aviv University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Jian-Min Wang, Pu Du, David Valls-Gabaud, Chen Hu, Hagai Netzer. Super-Eddington Accreting Massive Black Holes as Long-Lived Cosmological Standards. Physical Review Letters, 2013; 110 (8) DOI: 10.1103/PhysRevLett.110.081301

Cite This Page:

American Friends of Tel Aviv University. "Using black holes to measure the universe's rate of expansion." ScienceDaily. ScienceDaily, 22 April 2013. <www.sciencedaily.com/releases/2013/04/130422123040.htm>.
American Friends of Tel Aviv University. (2013, April 22). Using black holes to measure the universe's rate of expansion. ScienceDaily. Retrieved August 29, 2014 from www.sciencedaily.com/releases/2013/04/130422123040.htm
American Friends of Tel Aviv University. "Using black holes to measure the universe's rate of expansion." ScienceDaily. www.sciencedaily.com/releases/2013/04/130422123040.htm (accessed August 29, 2014).

Share This




More Space & Time News

Friday, August 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Experiment Tests Whether Universe Is Actually A Hologram

Experiment Tests Whether Universe Is Actually A Hologram

Newsy (Aug. 27, 2014) — Researchers at Fermilab are using a device called "The Holometer" to test whether our universe is actually a 2-D hologram that just seems 3-D. Video provided by Newsy
Powered by NewsLook.com
SpaceX’s Falcon 9 Rocket Explodes After Liftoff

SpaceX’s Falcon 9 Rocket Explodes After Liftoff

Newsy (Aug. 23, 2014) — The private spaceflight company says it is preparing a thorough investigation into Friday's mishap. Video provided by Newsy
Powered by NewsLook.com
Did Russia Really Find Plankton On The ISS? NASA Not So Sure

Did Russia Really Find Plankton On The ISS? NASA Not So Sure

Newsy (Aug. 21, 2014) — Russian cosmonauts say they've found evidence of sea plankton on the International Space Station's windows. NASA is a little more skeptical. Video provided by Newsy
Powered by NewsLook.com
Space to Ground: Hello Georges

Space to Ground: Hello Georges

NASA (Aug. 18, 2014) — Europe's ATV-5 delivers new science and the crew tests smart SPHERES. Questions or comments? Use #spacetoground to talk to us. Video provided by NASA
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