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Posts Tagged ‘universe’

Watch Live On October 28: The Making Of Dark Universe With Neil Tyson

October 25, 2013 Leave a comment

Tyson, the narrator of Dark Universe, will discuss what goes into the Space Show with astrophysicist Mordecai-Mark Mac Low, who curated the Space Show; Carter Emmart, who oversees astrovisualization at the Museum and served as the Space Show’s director; Vivian Trakinski, who produced Dark Universe; Timothy Ferris, author of Coming of Age in the Milky Way and other acclaimed books, who wrote the Dark Universe script; and composer Robert Miller, whose previous collaborations with the Museum included the score for the Space Show Journey to the Stars.

Link To Full Story

On The Trail Of Dark Energy: Physicists Propose Higgs Boson ‘Portal’

August 12, 2013 Leave a comment

One of the biggest mysteries in contemporary particle physics and cosmology is why dark energy, which is observed to dominate energy density of the universe, has a remarkably small (but not zero) value. This value is so small, it is perhaps 120 orders of magnitude less than would be expected based on fundamental physics.

Resolving this problem, often called the cosmological constant problem, has so far eluded theorists.

Now, two physicists – Lawrence Krauss of Arizona State University and James Dent of the University of Louisiana-Lafayette – suggest that the recently discovered Higgs boson could provide a possible “portal” to physics that could help explain some of the attributes of the enigmatic dark energy, and help resolve the cosmological constant problem.

In their paper, “Higgs Seesaw Mechanism as a Source for Dark Energy,” Krauss and Dent explore how a possible small coupling between the Higgs particle, and possible new particles likely to be associated with what is conventionally called the Grand Unified Scale – a scale perhaps 16 orders of magnitude smaller than the size of a proton, at which the three known non-gravitational forces in nature might converge into a single theory – could result in the existence of another background field in nature in addition to the Higgs field, which would contribute an energy density to empty space of precisely the correct scale to correspond to the observed energy density.

Full Story: https://asunews.asu.edu/20130809-dark-energy-krauss

‘Cosmic Mirages’ Confirm Accelerated Cosmic Expansion

April 11, 2012 Leave a comment

An international team of researchers led by Masamune Oguri at Kavli IPMU and Naohisa Inada at Nara National College of Technology conduced an unprecedented survey of gravitationally lensed quasars, and used it to measure the expansion history of the universe. The result provides strong evidence that the expansion of the universe is accelerating. There were several observations that suggested the accelerated cosmic expansion, including distant supernovae for which the 2011 Nobel Prize in Physics was awarded. The team’s result confirms the accelerated cosmic expansion using a completely different approach, which strengthens the case for dark energy. This result will be published in The Astronomical Journal.

Full Story: http://www.ipmu.jp/node/1281

New SCUBA-2 Camera Reveals Wild Youth of Universe

March 27, 2012 Leave a comment

A team of astronomers from the UK, Canada and the Netherlands have commenced a revolutionary new study of cosmic star-formation history, looking back in time to when the universe was still in its lively and somewhat unruly youth! The consortium, co-led by University of Edinburgh astrophysicist Professor James Dunlop, is using a brand new camera called SCUBA-2, the most powerful camera ever developed for observing light at “sub-mm” wavelengths (light that has a wavelength 1000 times longer than we can see with our eyes). Prof. Dunlop will present the first results from the survey on Tuesday 27 March at the National Astronomy Meeting in Manchester.

SCUBA-2 is mounted on the world’s largest sub-mm telescope, the 15-metre James Clerk Maxwell Telescope (JCMT), located atop the 4,300-metre high peak of Mauna Kea in Hawaii. The new project, named the SCUBA-2 Cosmology Legacy Survey will run for 3 years and will use the camera to provide the clearest view to date of dust-enshrouded star-forming galaxies. These objects are so remote that the light we detect left them billions of years ago, so we see them as they looked in the distant past. With SCUBA-2 astronomers are able to study objects that existed as far back as 13 billion years ago, within the first billion years after the Big Bang.

Full Story: http://www.jodrellbank.manchester.ac.uk/meetings/nam2012//pressreleases/nam05.html

Scientists Release Most Accurate Simulation of the Universe to Date

October 2, 2011 Leave a comment

“Bolshoi” supercomputer simulation provides new benchmark for cosmological studies

The Bolshoi supercomputer simulation, the most accurate and detailed large cosmological simulation run to date, gives physicists and astronomers a powerful new tool for understanding such cosmic mysteries as galaxy formation, dark matter, and dark energy.

The simulation traces the evolution of the large-scale structure of the universe, including the evolution and distribution of the dark matter halos in which galaxies coalesced and grew. Initial studies show good agreement between the simulation’s predictions and astronomers’ observations.

Full Story: http://www.astronews.us/2011-09-30-1225.html

Discovery Sheds Light on Ecosystem of Young Galaxies

August 30, 2011 Leave a comment

A team of scientists, led by Michael Rauch from the Carnegie Observatories, has discovered a distant galaxy that may help elucidate two fundamental questions of galaxy formation: How galaxies take in matter and how they give off energetic radiation. Their work will be published in the Monthly Notices of the Royal Astronomical Society.

Full Story: http://carnegiescience.edu/news/new_discovery_sheds_light_ecosystem_young_galaxies

Science Magazine Honors Universe Awareness Program

August 26, 2011 Leave a comment

Universe Awareness, a program endorsed by the IAU that uses astronomy to inspire and educate very young children around the world, has been recognized for its educational value by Science Magazine.

Universe Awareness (UNAWE) is the recipient of the Science Prize for Online Resources in Education (SPORE) award, introduced by Science Magazine as a means to showcase the best educational resources that are available on the internet and bring them to a wider audience.

Full Story: http://www.iau.org/public_press/news/detail/iau1104/

Giant Space Blob Glows from Within

August 17, 2011 Leave a comment

This image shows one of the largest known single objects in the Universe, the Lyman-alpha blob LAB-1. This picture is a composite of two different images taken with the FORS instrument on the Very Large Telescope (VLT) — a wider image showing the surrounding galaxies and a much deeper observation of the blob itself at the centre made to detect its polarisation. The intense Lyman-alpha ultraviolet radiation from the blob appears green after it has been stretched by the expansion of the Universe during its long journey to Earth. These new observations show for the first time that the light from this object is polarised. This means that the giant "blob" must be powered by galaxies embedded within the cloud. Credit: ESO/M. Hayes

** Synopsis: Observations from ESO’s Very Large Telescope have shed  light on the power source of a rare vast cloud of glowing gas in the early Universe. The observations show for the first time that this
giant “Lyman-alpha blob” — one of the largest single objects known — must be powered by galaxies embedded within it. The results appear in the 18 August issue of the journal Nature. **

A team of astronomers has used ESO’s Very Large Telescope (VLT) to study an unusual object called a Lyman-alpha blob [1]. These huge and very luminous rare structures are normally seen in regions of the early Universe where matter is concentrated. The team found that the light coming from one of these blobs is polarized [2]. In everyday life, for example, polarized light is used to create 3D effects in cinemas [3]. This is the first time that polarization has ever been found in a Lyman-alpha blob, and this observation helps to unlock the mystery of how the blobs shine.

“We have shown for the first time that the glow of this enigmatic object is scattered light from brilliant galaxies hidden within, rather than the gas throughout the cloud itself shining.” Explains Matthew Hayes (University of Toulouse, France), lead author of the paper.

Lyman-alpha blobs are some of the biggest objects in the Universe: gigantic clouds of hydrogen gas that can reach diameters of a few hundred thousand light-years (a few times larger than the size of the Milky Way), and which are as powerful as the brightest galaxies. They are typically found at large distances, so we see them as they were when the Universe was only a few billion years old. They are therefore important in our understanding of how galaxies formed and evolved when the Universe was younger. But the power source for their extreme luminosity, and the precise nature of the blobs, has remained unclear.

The team studied one of the first and brightest of these blobs to be found. Known as LAB-1, it was discovered in 2000, and it is so far away that its light has taken about 11.5 billion years to reach us (redshift 3.1). With a diameter of about 300,000 light-years it is also one of the largest known, and has several primordial galaxies inside it, including an active galaxy [4].

There are several competing theories to explain Lyman-alpha blobs. One idea is that they shine when cool gas is pulled in by the blob’s powerful gravity, and heats up. Another is that they are shining because of brilliant objects inside them: galaxies undergoing vigorous star formation, or containing voracious black holes engulfing matter. The new observations show that it is embedded galaxies, and not gas being pulled in, that power LAB-1.

The team tested the two theories by measuring whether the light from the blob was polarized. By studying how light is polarized astronomers can find out about the physical processes that produced the light, or what has happened to it between its origin and its arrival at Earth. If it is reflected or scattered it becomes polarized and this subtle effect can be detected by a very sensitive instrument. To measure polarization of the light from a Lyman-alpha blob is, however, a very challenging observation, because of their great distance.

“These observations couldn’t have been done without the VLT and its FORS instrument. We clearly needed two things: a telescope with at least an eight-meter mirror to collect enough light, and a camera
capable of measuring the polarization of light. Not many observatories in the world offer this combination.” adds Claudia Scarlata (University of Minnesota, USA), co-author of the paper.

By observing their target for about 15 hours with the Very Large Telescope, the team found that the light from the Lyman-alpha blob LAB-1 was polarized in a ring around the central region, and that there was no polarization in the center. This effect is almost impossible to produce if light simply comes from the gas falling into the blob under gravity, but it is just what is expected if the light originally comes from galaxies embedded in the central region, before being scattered by the gas.

The astronomers now plan to look at more of these objects to see if the results obtained for LAB-1 are true of other blobs.

Notes

[1] The name comes from the fact that these blobs emit a characteristic wavelength of light, known as “Lyman-alpha” radiation, that is produced when electrons in hydrogen atoms drop from the second-lowest to the lowest energy level.

[2] When light waves are polarized, their component electric and magnetic fields have a specific orientation. In unpolarized light the orientation of the fields is random and has no preferred direction.

[3] The 3D effect is created by making sure the left and right eyes are seeing slightly different images. The trick used in some 3D cinemas involves polarized light: separate images made with differently polarized light are sent to our left and right eyes by polarizing filters in the glasses.

[4] Active galaxies are galaxies whose bright cores are believed to be powered by a vast black hole. Their luminosity comes from material being heated as it is pulled in by the black hole.

# # #

This research was presented in the paper “Central Powering of the Largest Lyman-alpha Nebula is Revealed by Polarized Radiation” by Hayes et al. to appear in the journal Nature on 18 August 2011:
http://www.eso.org/public/archives/releases/sciencepapers/eso1130/eso1130.pdf

The team is composed of Matthew Hayes (University of Toulouse, France and Observatory of Geneva, Switzerland), Claudia Scarlata (University of Minnesota, USA) and Brian Siana (University of California, Riverside, USA).

Photos of the VLT:
http://www.eso.org/public/images/archive/category/paranal/

ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organization in Europe and the world’s most productive astronomical observatory. It is supported by 15 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious program focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organizing cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning a 40-meter-class European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

Original Story: http://www.eso.org/public/news/eso1130/