Follow eufisica

Follow eufisica

Showing posts with label universe. Show all posts
Showing posts with label universe. Show all posts

Tuesday, March 18, 2014

First direct evidence of cosmic inflation

Credit: BICEP 2014


Researchers working on the Background Imaging of Cosmic Extragalactic Polarization (BICEP2) project at the South Pole announced yesterday the first direct evidence of cosmic inflation with the detection of primordial gravitational waves.


"What they detected is known as primordial B-mode polarization and is important for at least two reasons. It would be the first detection of gravitational waves, which are predicted to exist under Einstein’s theory of relativity but have never before been seen. But the thing that has scientists really excited is that it could provide the first direct evidence for a theorized event called inflation that caused the universe to exponentially grow just a fraction of a fraction of a second after it was born." in wired.com
"Gravitational waves from inflation are interesting for a couple of reasons. First, we know they should be there; gravitation certainly exists, and it’s a massless field. Second, there is a way to disentangle the gravitational waves from the density fluctuations, using thepolarization of the CMB. [...] Finally, how strong the gravitational waves are at different wavelengths reveals a great deal about the details of inflation — including one magic number, the energy density of the universe during the inflationary era." in Sean Carroll website
Here is the abstract of the paper submited to arXiv website:

BICEP2 I: Detection Of B-mode Polarization at Degree Angular Scales

We report results from the BICEP2 experiment, a Cosmic Microwave Background (CMB) polarimeter specifically designed to search for the signal of inflationary gravitational waves in the B-mode power spectrum around l=80. [...] BICEP2 observed from the South Pole for three seasons from 2010 to 2012. A low-foreground region of sky with an effective area of 380 square degrees was observed to a depth of 87 nK-degrees in Stokes Q and U. In this paper we describe the observations, data reduction, maps, simulations and results. We find an excess of B-mode power over the base lensed-LCDM expectation in the range 30<l<150, inconsistent with the null hypothesis at a significance of >5σ. [...] Additionally, cross-correlating BICEP2 against 100 GHz maps from the BICEP1 experiment, the excess signal is confirmed with 3σ significance and its spectral index is found to be consistent with that of the CMB, disfavoring synchrotron or dust at 2.3σ and 2.2σ, respectively. The observed B-mode power spectrum is well-fit by a lensed-LCDM + tensor theoretical model with tensor/scalar ratio r=0.20+0.070.05, with r=0 disfavored at 7.0σ. Subtracting the best available estimate for foreground dust modifies the likelihood slightly so that r=0 is disfavored at 5.9σ.
Paper available here: http://arxiv.org/abs/1403.3985

Minute Physics video:

Sunday, October 6, 2013

Astro Watch: 'Higgsogenesis'

The Globe - CERN
(C) Photo by José Gonçalves (eufisica)
"Two physicists suggest that the Higgs had a key role in the early Universe, producing the observed difference between the number of matter and antimatter particles and determining the density of the mysterious dark matter that makes up five-sixths of the matter in the Universe.
- AstroWatch
Astronomy and Space News - Astro Watch: 'Higgsogenesis' Proposed to Explain Dark Matter: A key riddle in cosmology may be answered by the 2012 discovery of the Higgs boson — now a leading contender for the 2013 Nobel Prize in...

Friday, August 16, 2013

Hubble time sequence

Credit: NASA, ESA, M. Kornmesser
Credit: NASA, ESA, M. Kornmesser
This image shows us the Universo in different time moments (present, 4 and 11 billion years ago). Each diagram shows us the form of the galaxies.

Tuesday, August 13, 2013

How Do We Measure the Distance to Stars?

Distances in the Universe
Credit: www.ualberta.ca



Concept map about this topic:


Crie os seus próprios mapas mentais no MindMeister

Thursday, March 28, 2013

Universe by Planck's satellite


ESA's Planck satellite has delivered its first all-sky image of the Cosmic Microwave Background (CMB), bringing with it new challenges about our understanding of the origin and evolution of the cosmos. The image has provided the most precise picture of the early Universe so far. Read more.

Monday, February 25, 2013

How Big is the Universe?


"No one knows if the universe is infinitely large, or even if ours is the only universe there is."
Read the document from Harvard website.


Throughout history, humans have used a variety of techniques and methods to help them answer the questions 'How far?' and 'How big?' Generations of explorers have looked deeper and deeper into the vast expanse of the universe. And the journey continues today, as new methods are used, and new discoveries are made.
It was knowing this fundamental distance from the Earth to the Sun that helped us find the true scale of the entire Solar system for the first time.
When we leave the solar system, we find our star and its planets are just one small part of the Milky Way galaxy. The Milky Way is a huge city of stars, so big that even at the speed of light, it would take 100,000 years to travel across it.
The further away a star is, the fainter it looks. Astronomers use this as a clue to figure out the distance to stars that are very far away. 
Beyond our own galaxy lies a vast expanse of galaxies. The deeper we see into space, the more galaxies we discover. We see them not as they are today, but as they looked long before there was any life on Earth. 
Finding the distance to these very distant galaxies is challenging, but astronomers can do so by watching for incredibly bright exploding stars called supernovae. Some types of exploding stars have a known brightness so we can figure out how far they are by measuring how bright they appear to us, and therefore how far away it is to their home galaxy. 


Adapted from NASA website

Sunday, December 30, 2012

Monday, May 7, 2012

Magnifying the Universe

Magnifying the Universe is an interactive infographic that illustrates the scale of over 100 items. From galaxies to insects, nebulae and stars to molecules and atoms. And more...
Click to view in full screen and start using it:

Wednesday, March 28, 2012

How large is the Universe

This pan sequence shows some highlights from the widest deep view of the sky ever taken using infrared light. It was created by combining more than 6000 individual images from the VISTA survey telescope at ESO's Paranal Observatory in Chile. (Credit: ESA Observatory)





The mind-blowing answer comes from a theory describing the birth of the universe in the first instant of time.

The universe has long captivated us with its immense scales of distance and time. 

How far does it stretch? Where does it end... and what lies beyond its star fields... and streams of galaxies extending as far as telescopes can see?

These questions are beginning to yield to a series of extraordinary new lines of investigation... and technologies that are letting us to peer into the most distant realms of the cosmos...
(credit: SpaceRip)


Friday, July 8, 2011

The Rho Ophiuchi Star Formation Region revisited by ESO

The Rho Ophiuchi Star Formation Region revisited by ESO: (follow the link for the full article and full resollution pictures)
The Rho Ophiuchi Star Formation Region revisited by ESO
Credit: ESO/S. Guisard (www.eso.org/~sguisard)

Wednesday, April 13, 2011

Anti-Gravity

Image credit: NASA
(PhysOrg.com) -- In 1998, scientists discovered that the Universe is expanding at an accelerating rate. Currently, the most widely accepted explanation for this observation is the presence of an unidentified dark energy, although several other possibilities have been proposed. One of these alternatives is that some kind of repulsive gravity – or antigravity – is pushing the Universe apart. As a new study shows, general relativity predicts that the gravitational interaction between matter and antimatter is mutually repulsive, and could potentially explain the observed expansion of the Universe without the need for dark energy.

Versão Portuguesa aqui.

Featured Post

IBSE about Light Pollution

Here is my presentation that happened in the Discover the Cosmos Conference (Volos, Greece - 2013). The presentation was an Inquiry Base...

Twitter Updates

<- widget2 ->

Popular Posts