Subscribe free to our newsletters via your
. 24/7 Space News .




SKY NIGHTLY
Astronomers Upgrade Their Cosmic Light Bulbs
by Staff Writers
Pasadena CA (JPL) Mar 30, 2015


A new study analyzes several sites where dead stars once exploded. Image courtesy SDSS. For a larger version of this image please go here.

The brilliant explosions of dead stars have been used for years to illuminate the far-flung reaches of our cosmos. The explosions, called Type Ia supernovae, allow astronomers to measure the distances to galaxies and measure the ever-increasing rate at which our universe is stretching apart.

But these tools aren't perfect. In the cosmic hardware store of our universe, improvements are ongoing. In a new report, appearing in the journal Science, astronomers identify the best, top-of-the-line Type Ia supernovae for measuring cosmic distances, pushing other, more clunky tools to the back of the shelf.

Using archived data from NASA's Galaxy Evolution Explorer (GALEX), scientists show that a particular class of Type Ia supernovae that occur near youthful stars can improve these measurements with a precision of more than two times that achieved before.

"We have discovered a population of Type Ia supernovae whose light output depends very precisely on how quickly they fade, making it possible to measure very exact distances to them," said Patrick Kelly of the University of California, Berkeley, lead author of the new study. "These supernovae are found close to populations of bright, hot young stars."

The findings will help light the way to understanding dark energy, one of the greatest mysteries in the field of cosmology, the study of the origin and development of the universe. Dark energy is the leading culprit behind the baffling acceleration of our cosmos, a phenomenon discovered in 1998. The acceleration was uncovered when astronomers observed that galaxies are pulling away from each other at increasing speeds.

The key to measuring this acceleration - and thus the nature of dark energy - lies with Type Ia supernovae, which work much like light bulbs strung across space. Imagine lining up 60-watt light bulbs across a field and standing at one end. The farthest light bulb wouldn't appear as bright as the closest one due to its distance. Since you know how bright the light bulb inherently is, you can use the extent of its dimming to figure out the distance.

Type Ia supernovae, also referred to as "standard candles," work in a similar way because they consistently shine with about the same amount of light. While the process that leads to these explosions is still not clear, they occur when the burnt-out core of a star, called a white dwarf, blasts apart in a regular way, briefly lighting up the host galaxy.

However, the explosions aren't always precisely uniform. They can differ considerably depending on various factors, which appear to be connected to the environments and histories of the exploding stars. It's as if our 60-watt bulbs sometimes give off 55 watts of light, skewing distance measurements.

Kelly and his team investigated the reliability of these tools by analyzing the surroundings of nearly 100 previous Type Ia explosions. They used data from GALEX, which detects ultraviolet light. Populations of hot, young stars in galaxies will shine brightly with ultraviolet light, so GALEX can distinguish between young and older star-forming communities.

The results showed that the Type Ia supernovae affiliated with the hot, young stars were significantly more reliable at indicating distances than their counterparts.

"These explosions are likely the result of youthful white dwarfs," said Kelly.

By focusing on this particular brand of Type Ia tools, astronomers will be able to, in the future, make even sharper measurements of the size and scale of our universe. According to the science team, this class of tools could work at distances up to six billion light-years away, and perhaps farther.

"GALEX surveyed the entire sky, allowing past and future eruptions of these high-quality standard candles to be identified easily," said Don Neill, a member of the GALEX team at the California Institute of Technology in Pasadena, not affiliated with the study. "Any improvement in the standard candles will have a direct impact on theories of dark energy, allowing us to home in on this mysterious force propelling the acceleration of the universe."

.


Related Links
NASA JPL
Astronomy News from Skynightly.com






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





SKY NIGHTLY
Automation offers big solution to big data in astronomy
Madison WI (SPX) Mar 26, 2015
It's almost a rite of passage in physics and astronomy. Scientists spend years scrounging up money to build a fantastic new instrument. Then, when the long-awaited device finally approaches completion, the panic begins: How will they handle the torrent of data? That's the situation now, at least, with the Square Kilometer Array (SKA), a radio telescope planned for Africa and Australia that ... read more


SKY NIGHTLY
Extent of Moon's giant volcanic eruption is revealed

Yutu Changes Everything We Thought We Knew About Our Moon

Extent of moon's giant volcanic eruption is revealed

NASA's LRO Spacecraft Finds March 17, 2013 Impact Crater and More

SKY NIGHTLY
Ancient Martian lake system records 2 water-related events

Curiosity Rover Finds Biologically Useful Nitrogen on Mars

NASA's Opportunity Mars Rover Passes Marathon Distance

NASA Reformats Memory of Longest-Running Mars Rover

SKY NIGHTLY
Feud on Earth but peace in space for US and Russia

Russia Plans to Boost Space Tourism at Orbital Outpost

50 years ago today, space welcomed its first sandwich

Small Staff has Big Impact Showing How NASA Can Engage Students

SKY NIGHTLY
China completes second test on new carrier rocket's power system

China's Yutu rover reveals Moon's "complex" geological history

China's Space Laboratory Still Cloaked

China has ability but no plan for manned lunar mission: expert

SKY NIGHTLY
Soyuz spacecraft docks at ISS for year-long mission

One-Year Crew Set for Launch to Space Station

Russia, US May Sign New Deal to Send Astronauts to ISS

Lockheed Martin reveals new method for resupplying space station

SKY NIGHTLY
Russia Launches Satan Missile With S Korean Kompsat 3A Satellite

United Launch Alliance Launches Second Mission in Less than Two Weeks

UAE Moves to Purchase Russian Spacecraft Launch Platform

DoD Works to Build Competition Into Space Launches

SKY NIGHTLY
Planets in the habitable zone around most stars, calculate researchers

Our Solar System May Have Once Harbored Super-Earths

SOFIA Finds Missing Link Between Supernovae and Planet Formation

ESA's CHEOPS Satellite: The Pharaoh of Exoplanet Hunting

SKY NIGHTLY
Cluster satellite catches up

Scuttling satellites to save space

Data structures influence speed of quantum search in unexpected ways

New optical materials break digital connectivity barriers




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.