2013年8月8日星期四

First hundred thousand years of our universe

First hundred thousand years of our universe

"We found that the standard picture of an early universe, in which radiation domination was followed by matter domination, holds to the level we can test it with the new data, but there are hints that radiation didn't give way to matter exactly as expected," says Eric Linder, a theoretical physicist with Berkeley Lab's Physics Division and member of the Supernova Cosmology Project. "There appears to be an excess dash of radiation that is not due to CMB photons."

Our knowledge of the Big Bang and the early formation of the universe stems almost entirely from measurements of the CMB, primordial photons set free when the universe cooled enough for particles of radiation and particles of matter to separate. These measurements reveal the CMB's influence on the growth and development of the large-scale structure we see in the universe today.

Linder, working with Alireza Hojjati and Johan Samsing, who were then visiting scientists at Berkeley Lab, analyzed the latest satellite data from the European Space Agency's Planck mission and NASA's Wilkinson Microwave Anisotropy Probe (WMAP), which pushed CMB measurements to higher resolution, lower noise, and more sky coverage than ever before.

"With the Planck and WMAP data we're really pushing back the frontier and looking further back in the history of the universe, to regions of high energy physics we previously could not access," Linder says. "While our analysis shows the CMB photon relic afterglow of the Big Bang being followed mainly by dark matter as expected, there was also a deviation from the standard that hints at relativistic particles beyond CMB light."

Linder says the prime suspects behind these relativistic particles are "wild" versions of neutrinos, the phantomlike subatomic particles that are the second most populous residents (after photons) of today's universe. The term "wild" is used to distinguish these primordial neutrinos from those expected within particle physics and being observed today. Another suspect is dark energy, the anti-gravitational force that accelerates our universe's expansion. Again, however, this would be from the dark energy we observe today.

"Early dark energy is a class of explanations for the origin of cosmic acceleration that arises in some high energy physics models," Linder says. "While conventional dark energy, such as the cosmological constant, are diluted to one part in a billion of total energy density around the time of the CMB's last scattering, early dark energy theories can have 1-to-10 million times more energy density."

Linder says early dark energy could have been the driver that seven billion years later caused the present cosmic acceleration. Its actual discovery would not only provide new insight into the origin of cosmic acceleration, but perhaps also provide new evidence for string theory and other concepts in high energy physics.

"New experiments for measuring CMB polarization that are already underway, such as the POLARBEAR and SPTpol telescopes, will enable us to further explore primeval physics, Linder says.

Linder, Hojjati and Samsing are the authors of a paper describing these results in the journal Physical Review Letters titled "New Constraints on the Early Expansion History of the Universe." Hojjati is now with the Institute for the Early Universe in South Korea, and Samsing is with the DARK Cosmology Centre in Denmark.


Welcome to SUV System Ltd!

SUV System Ltd is ISO 90012008 Certified electronics distributor with 10 years of experiences.

We have built up long term business relationship with about many companies which are stockers and authorized agents. we have a steady and reliable supply to meet customer's demands to the greatest extent .Confidently, we are able to lower your cost and support your business with our years of professional service.

SUV System Ltd is Electronic Components Distributor Supplies,Find Quality Electronic Components Supplies Products IC(Integrated Circuits),Connectors,Capacitor,Resistors,Diodes,Transistors,LED at Suvsystem.com. Sourcing Other Energy, Environment, Excess Inventory Products from Manufacturers and Suppliers at Suvsystem.com

Electronic Components distributor:http://www.suvsystem.com

Connectors Distributor:http://www.suvsystem.com/l/Connectors-1.html

IC Distributor:http://www.suvsystem.com/l/IC(Integrated-Circuits)-1.html

LED Distributor:http://www.suvsystem.com/l/LED-1.html

Capacitor Distributor:http://www.suvsystem.com/l/Capacitor-1.html

Transistor Distributor:http://www.suvsystem.com/l/Transistors-1.html

Resistor Distributor:http://www.suvsystem.com/l/Resistors-1.html

Diode Distributor:http://www.suvsystem.com/l/Diodes-1.html

SUV System Ltd insists on the managing faith ofsincereness,speciality,foresight, win-win,so we build up stable-relationship customers located all over the world, including the States, Europe, Argentina, UAE, Malaysia, Australia,and India etc

we are focus on the following fields,and hope we can help you.


IR transistor LINEAR IC Thin Film Resistors Fleld Effect Transistors Infineon Technologies Transistors components IC(Integrated Circuits) PANASONIC HARRIS IC Transistors Texas Instruments(TI) IC Schottky Diodes FAIRCHILD diodes NXP Transistors LITTELFUSE Diodes Industrial IC Fast Recovery Diodes Kingbrigt LED Connectors NEC Transistors Freescale Semiconductor Diodes AVX Resistors Atmel IC MAXIM IC ELPIDA IC DIODES Transistors Other Parts ST Diodes TOSHIBA Diodes chip Filter saws ALTERA IC Chip Inductors AD IC Chip Ferrite Beads NEC Diodes YAGEO Resistors TOSHIBA Transistors Chip Fuses INFLNEON Diodes
http://www.suvsystem.com/a/4735.aspx

没有评论:

发表评论