Featured Research

from universities, journals, and other organizations

Hubble constant: A new way to measure the expansion of the universe

Date:
July 27, 2011
Source:
International Centre for Radio Astronomy Research
Summary:
Using a measurement of the clustering of the galaxies surveyed, plus other information derived from observations of the early universe, researchers have measured the Hubble constant with an uncertainly of less than 5 percent. The new work draws on data from a survey of more than 125,000 galaxies.

The 6df Galaxy Survey data, each dot is a galaxy and Earth is at the center of the sphere.
Credit: Image courtesy of International Centre for Radio Astronomy Research

Using a measurement of the clustering of the galaxies surveyed, plus other information derived from observations of the early universe, researchers have measured the Hubble constant with an uncertainly of less than 5 percent. The new work draws on data from a survey of more than 125,000 galaxies.

Related Articles


A PhD student from The International Centre for Radio Astronomy Research (ICRAR) in Perth has produced one of the most accurate measurements ever made of how fast the Universe is expanding.

Florian Beutler, a PhD candidate with ICRAR at the University of Western Australia, has calculated how fast the Universe is growing by measuring the Hubble constant.

"The Hubble constant is a key number in astronomy because it's used to calculate the size and age of the Universe," said Mr Beutler.

As the Universe swells, it carries other galaxies away from ours. The Hubble constant links how fast galaxies are moving with how far they are from us.

By analysing light coming from a distant galaxy, the speed and direction of that galaxy can be easily measured. Determining the galaxy's distance from Earth is much more difficult. Until now, this has been done by observing the brightness of individual objects within the galaxy and using what we know about the object to calculate how far away the galaxy must be.

This approach to measuring a galaxy's distance from Earth is based on some well-established assumptions but is prone to systematic errors, leading Mr Beutler to tackle the problem using a completely different method.

Published July 26 in the Monthly Notices of the Royal Astronomical Society, Mr Beutler's work draws on data from a survey of more than 125,000 galaxies carried out with the UK Schmidt Telescope in eastern Australia. Called the 6dF Galaxy Survey, this is the biggest survey to date of relatively nearby galaxies, covering almost half the sky.

Galaxies are not spread evenly through space, but are clustered. Using a measurement of the clustering of the galaxies surveyed, plus other information derived from observations of the early Universe, Mr Beutler has measured the Hubble constant with an uncertainly of less than 5%.*

"This way of determining the Hubble constant is as direct and precise as other methods, and provides an independent verification of them," says Professor Matthew Colless, Director of the Australian Astronomical Observatory and one of Mr Beutler's co-authors. "The new measurement agrees well with previous ones, and provides a strong check on previous work."

The measurement can be refined even further by using data from larger galaxy surveys.

"Big surveys, like the one used for this work, generate numerous scientific outcomes for astronomers internationally," says Professor Lister Staveley-Smith, ICRAR's Deputy Director of Science.

* The new measurement of the Hubble constant is 67.0 3.2 km s-1 Mpc-1


Story Source:

The above story is based on materials provided by International Centre for Radio Astronomy Research. Note: Materials may be edited for content and length.


Journal Reference:

  1. Florian Beutler et al. The 6dF Galaxy Survey: Baryon Acoustic Oscillations and the Local Hubble Constant. Monthly Notices of the Royal Astronomical Society, 25 July 2011 DOI: 10.1111/j.1365-2966.2011.19250.x

Cite This Page:

International Centre for Radio Astronomy Research. "Hubble constant: A new way to measure the expansion of the universe." ScienceDaily. ScienceDaily, 27 July 2011. <www.sciencedaily.com/releases/2011/07/110726101719.htm>.
International Centre for Radio Astronomy Research. (2011, July 27). Hubble constant: A new way to measure the expansion of the universe. ScienceDaily. Retrieved January 25, 2015 from www.sciencedaily.com/releases/2011/07/110726101719.htm
International Centre for Radio Astronomy Research. "Hubble constant: A new way to measure the expansion of the universe." ScienceDaily. www.sciencedaily.com/releases/2011/07/110726101719.htm (accessed January 25, 2015).

Share This


More From ScienceDaily



More Space & Time News

Sunday, January 25, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

NASA's On Course To Take Pluto's Best Photo Ever

NASA's On Course To Take Pluto's Best Photo Ever

Newsy (Jan. 25, 2015) NASA&apos;s New Horizons probe is en route to snap a picture of Pluto this summer, but making sure it doesn&apos;t miss its one chance to do so starts now. Video provided by Newsy
Powered by NewsLook.com
Rosetta Captures Stunning Views, Diverse Data Of Comet 67P

Rosetta Captures Stunning Views, Diverse Data Of Comet 67P

Newsy (Jan. 23, 2015) The first images of the European Space Agency&apos;s Rosetta probe comet orbit could provide clues about its origin and how it got its unique shape. Video provided by Newsy
Powered by NewsLook.com
New Planets Could Be Lurking Far Beyond Neptune

New Planets Could Be Lurking Far Beyond Neptune

Newsy (Jan. 21, 2015) Scientists say planets located beyond Neptune could be altering the orbits of objects in the farthest reaches of our solar system. Video provided by Newsy
Powered by NewsLook.com
130,000 Pages Of UFO Investigation Docs Now Online

130,000 Pages Of UFO Investigation Docs Now Online

Newsy (Jan. 20, 2015) "UFO enthusiast" John Greenewald says he&apos;s spent 20 years collecting these docs, and believes there&apos;s a cover-up going on. Video provided by Newsy
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:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

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