New Results Pin Down Distance to Galaxy Next Door
This
artist's impression shows an eclipsing binary star system. As the two
stars orbit each other they pass in front of one another and their
combined brightness, seen from a distance, decreases. By studying how
the light changes, and other properties of the system, astronomers can
measure the distances to eclipsing binaries very accurately. A long
series of observations of very rare cool eclipsing binaries has now led
to the most accurate determination so far of the distance to the Large
Magellanic Cloud, a neighboring galaxy to the Milky Way and crucial step
in the determination of distances across the Universe. (Credit: ESO/L.
Calçada)
Mar. 4, 2013 — After nearly a
decade of careful observations an international team of astronomers has
measured the distance to our neighbouring galaxy, the Large Magellanic
Cloud, more accurately than ever before. This new measurement also
improves our knowledge of the rate of expansion of the Universe -- the
Hubble Constant -- and is a crucial step towards understanding the
nature of the mysterious dark energy that is causing the expansion to
accelerate. The team used telescopes at ESO's La Silla Observatory in
Chile as well as others around the globe. These results appear in the 7
March 2013 issue of the journal Nature.
Astronomers survey the scale of the Universe by first measuring the distances to close-by objects and then using them as standard candles [1] to pin down distances further and further out into the cosmos. But this chain is only as accurate as its weakest link. Up to now finding an accurate distance to the Large Magellanic Cloud (LMC), one of the nearest galaxies to the Milky Way, has proved elusive. As stars in this galaxy are used to fix the distance scale for more remote galaxies, it is crucially important.
Sources: European Southern Observatory (ESO), ScienceDaily.com .
gaw
Glenn A. Walsh, Project Director,
Friends of the Zeiss < http://friendsofthezeiss.org >
Electronic Mail - < gawalsh@planetarium.cc >
About the Author: < http://buhlplanetarium.tripod.com/#GAW >
SPACE & SCIENCE NEWS, ASTRONOMICAL CALENDAR:
< http://buhlplanetarium.tripod.
Twitter: < http://twitter.com/
Facebook: < http://www.facebook.com/pages/
Blog: < http://spacewatchtower.
Author of History Web Sites on the Internet --
* Buhl Planetarium, Pittsburgh:
< http://www.planetariu p.m. m.
* Adler Planetarium, Chicago:
< http://adlerplanetarium.
* Astronomer, Educator, Optician John A. Brashear:
< http://johnbrashear.tripod.com >
* Andrew Carnegie & Carnegie Libraries:
< http://www.andrewcarnegie.
* Civil War Museum of Andrew Carnegie Free Library:
< http://garespypost.tripod.com >
* Duquesne Incline cable-car railway, Pittsburgh:
< http://inclinedplane.tripod.
* Public Transit:
< http://andrewcarnegie2.tripod.
No comments:
Post a Comment