Featured Research

from universities, journals, and other organizations

SuperNova Legacy Survey: First Results Describing The Nature Of Dark Energy

Date:
November 23, 2005
Source:
Journal Astronomy & Astrophysics
Summary:
The SuperNova Legacy Survey collaboration started the largest survey to measure the distance of far supernovae. Distant supernovae are powerful tools to measure cosmological distances. The first results of the survey, to be published in Astronomy & Astrophysics, place strong constraints on cosmological models. In the near future, this new Legacy Survey will possibly help us understand the nature of dark energy.

This supernova is as bright as 100 billion Sun-like stars. It exploded 3 billion years ago. At the maximum of its brightness, it was 25 000 times less bright than the blue star seen in the middle of the image. This central blue star is 100 times less bright than the faintest star visible with the naked eye. (Copyright CFHTLS/SNLS/Terapix)

The SuperNova Legacy Survey collaboration started the largest survey yet launched to measure the distance to far supernovae. Distant supernovae are powerful tools to measure cosmological distances. The first results of the survey, to be published in Astronomy & Astrophysics, place strong constraints on cosmological models. In the near future, this new Legacy Survey will possibly help us understand the nature of dark energy.

Related Articles


The SuperNova Legacy Survey is an international collaboration involving about 40 researchers, that aims to discover several hundred far supernovae and mesure their distance. The team's first results will be published in a coming issue of Astronomy & Astrophysics. The SuperNova Legacy Survey is the largest observational project of its kind. It started in 2003 and will last for five years. So far, the team has measured the distance to 71 supernovae that exploded between 2 and 8 billion years ago. Many of the largest telescopes worldwide are involved in this project; the imaging part of the programme is carried out at the Canada-France-Hawaii Telescope (CFHT), in the framework of the CFHT Legacy Survey. Spectroscopic observations are obtained at the ESO/Very Large Telescope , the Gemini and Keck observatories.

Measuring the distance to faraway supernovae is a key tool for cosmologists. Supernovae are exploding stars, known to have similar brightnesses whatever their location in other galaxies. Observing these exploding stars can thus make it possible to measure their distances: they are known as “standard candles” for measuring long distances in the Universe.

Measurement of these distances revealed a startling phenomenon; in the late 1990s, astronomers found that the expansion of the Universe is accelerating. This expansion was first discovered in 1929 by American astronomer Edwin Hubble. The expansion of the Universe was thought to be slowing down because of the gravitational attraction of matter. Astronomers were thus very surprised to discover this was not the case at all. Theorists then attempted to explain the acceleration of expansion through various cosmological models. These models all involved the so-called “dark energy” concept, which is a kind of repulsive force against gravitational attraction. Nobody knows what dark energy is, but we can make an attempt to understand how it behaves.

In recent years, cosmological observations have supported that the Universe is made of about 25 % of matter and 75 % of dark energy. Unlike matter, which dilutes with expansion, dark energy appears to stay roughly constant. The new results, to be published by the SuperNova Legacy Survey team, put strong constraints on the absence of dilution of dark energy. Such a kind of dark energy was already foreseen by Einstein himself when he introduced the famous “cosmological constant” into his General Relativity equations. Such a constant was needed for the equations to be consistent with a static universe, as it was believed to be at that time. When the Universe was discovered to be expanding, it seemed that the cosmological constant was no longer needed in the equations. Later, Einstein refered to it as his “greatest blunder”. The discovery of the accelerating Universe expansion suggested the need for a cosmological constant that might, among other models, explain the acceleration of the expansion. The first results of the Legacy Survey indeed show that the existence of a cosmological constant is the best way to fit their observations. Once completed, by the end of 2008, their Survey will bring even more restrictive constraints to these cosmological models. It will help us better understand the physical nature of this cosmological constant: 80 years later, “Einstein’s greatest blunder” is perhaps less of a blunder after all.


Story Source:

The above story is based on materials provided by Journal Astronomy & Astrophysics. Note: Materials may be edited for content and length.


Cite This Page:

Journal Astronomy & Astrophysics. "SuperNova Legacy Survey: First Results Describing The Nature Of Dark Energy." ScienceDaily. ScienceDaily, 23 November 2005. <www.sciencedaily.com/releases/2005/11/051123171939.htm>.
Journal Astronomy & Astrophysics. (2005, November 23). SuperNova Legacy Survey: First Results Describing The Nature Of Dark Energy. ScienceDaily. Retrieved December 23, 2014 from www.sciencedaily.com/releases/2005/11/051123171939.htm
Journal Astronomy & Astrophysics. "SuperNova Legacy Survey: First Results Describing The Nature Of Dark Energy." ScienceDaily. www.sciencedaily.com/releases/2005/11/051123171939.htm (accessed December 23, 2014).

Share This


More From ScienceDaily



More Space & Time News

Tuesday, December 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

NASA Prepares for Next Phase of Hubble Successor

NASA Prepares for Next Phase of Hubble Successor

Reuters - Innovations Video Online (Dec. 22, 2014) Scientists and engineers prepare for the next phase of the James Webb Space Telescope, the scientific successor to the Hubble. Nathan Frandino reports. Video provided by Reuters
Powered by NewsLook.com
Spokesman: 'NORAD Ready to Track Santa'

Spokesman: 'NORAD Ready to Track Santa'

AP (Dec. 19, 2014) Pentagon spokesman Rear Adm. John Kirby said that NORAD is ready to track Santa Claus as he delivers gifts next week. Speaking tongue-in-cheek, he said if Santa drops anything off his sleigh, "we've got destroyers out there to pick them up." (Dec. 19) Video provided by AP
Powered by NewsLook.com
NASA's Planet-Finding Kepler Mission Isn't Over After All

NASA's Planet-Finding Kepler Mission Isn't Over After All

Newsy (Dec. 18, 2014) More than a year after NASA declared the Kepler spacecraft broken beyond repair, scientists have figured out how to continue getting useful data. Video provided by Newsy
Powered by NewsLook.com
Rover Finds More Clues About Possible Life On Mars

Rover Finds More Clues About Possible Life On Mars

Newsy (Dec. 17, 2014) NASA's Curiosity rover detected methane on Mars and organic compounds on the surface, but it doesn't quite prove there was life ... yet. 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