Galaxy clusters are the largest structures in the Universe that are bound together by gravity. They form when smaller clusters or groups of galaxies collide and merge. Collisions between galaxy clusters, such as this one in Abell 1758 and its more famous cousin the Bullet Cluster, are the most energetic events in the Universe since the Big Bang. Their growth rate over the last 7 billion years is believed to have been slowed by the effects of dark energy.
Utane Sawangwit and Tom Shanks of Durham University believe that errors on the “gold standard” cosmic microwave background results from the WMAP satellite that includes dark matter, dark energy and the exponential expansion after the big bang known as inflation may be larger than previously supposed.
It is the pattern of ripples detected by microwave background telescopes such as WMAP that underpin the idea that the Universe is composed of 22% dark exotic particles and 74% dark energy with the remaining 4% being the atoms in the ordinary material that we see around us.
This model produces a largest ripple size of about 1 degree on the microwave sky and this is well matched by the ripples seen in the WMAP data. So these WMAP ripples have a size that is roughly twice the size of the Full Moon as they appear on the sky. Models that don’t have dark energy or dark matter tend to produce CMB ripples that are smaller, only about half the standard model size and so just about the size of the Full Moon.
Sawangwit and Shanks have used point-like radio sources to test how much the WMAP telescope smoothes these CMB ripples and have found evidence that this ”beam smoothing” is much larger than suggested from WMAP’s observations of the planet Jupiter.
The Herschel Space Observatory's HIFI instrument was designed to follow the water trail in the Universe over a wide range of scales, from the Solar System out to extragalactic sources. Early results, presented this week at the Herschel First Results Symposium, demonstrate how HIFI uses water to probe the physical and chemical conditions in different regions of the cosmos.
Water is crucial in the processes of star formation, because this molecule contributes to the cooling of the gas and dust mixture from which stars are born. Early results demonstrated the detection of water in various proto-stellar systems. Along with upcoming data from star-forming clouds throughout the Milky Way, these data will help astronomers understand the mechanisms of star formation in great detail. Beyond our Galaxy, water signatures have been found in nearby galaxies which are known to be undergoing intense bursts of star formation.
Water trails go all the way from vast star-forming clouds down to stars and planets on much smaller scales. In the proto-planetary discs surrounding stars in the process of forming, water vapour may in fact freeze onto dust grains; these cold grains would then condense into icy planetesimals, the seeds of planet formation.
A team of physicists, including some from MIT, has found surprising differences between the flavor-switching behavior of neutrinos and antineutrinos. If confirmed, the finding could help explain why matter, and not antimatter, dominates our universe. Neutrinos, elementary particles generated by nuclear reactions in the sun, "suffer from an identity crisis as they cross the universe, morphing between three different flavors.” Their antimatter counterparts do the same thing.
“People are very excited about it because it suggests that there are differences between neutrinos and antineutrinos,” says Georgia Karagiorgi, an MIT graduate student and one of the leaders of the analysis of experimental data produced by the Booster Neutrino Experiment (MiniBooNE) at the Fermi National Accelerator Laboratory.
The new results appear to be one of the first observed violations of CP symmetry: the theory that matter and antimatter should behave in the same way. CP symmetry violation has been seen before in quarks, but never in neutrinos or electrons. CP symmetry means in the words of Roger Penrose (The Road to Reality), "CP sends a particle's zig into its antiparticle's zag, and vice versa."
A new image from NASA's Hubble, Chandra and Spitzer space telescopes shows a giant jet of particles that has been shot out from the vicinity of a type of supermassive black hole called a quasar. The jet is enormous, stretching across more than 100,000 light-years of space - a size comparable to the entire Milky Way galaxy.
EcoAlert: "Earth Needs a Major Volcanic Eruption Every 18 Months to Reduce Temperatures and Delay Icecap Melt"
A new report from the Proceedings from the National Acadmey of Sciences of the United States of America says that repairing the damage from global warming will prove extremely difficult and non-cost-effective.
Severe treatment would mean injecting "sulphur dioxode particles equivalent to a major volcanic eruption, such as that of Mt Pinatubo, every 18 months to reduce temperatures and delay ice-cap melt and sea-level rises," The Ecologist reports. Other geoengineering options include installing mirrors in space and afforestation. Geoengineering approaches are risky and raise several questions about what effects they will have on the planet, leading many scientists and policy-makers to shy away from their use.
Via The Ecologist
Astrophysicists says that supermassive black hole – of the type that are usually found at the core of large galaxies – could release gamma ray jets that interact with surrounding dark matter that may be detectable on Earth. A new study shows that two of the “darkest” things in the Universe may in fact be combining to produce highly-energetic radiation that may open the way for developing new techniques aimed at observing dark matter.
At this point, astronomers only infer that dark matter exists, based on the gravitational effects it exerts on normal matter within galaxies. But the stuff itself has never been observed, despite all attempts according to a report in New Scientist.
Walter Wagner is at it again: but is this the last we'll hear from him? The most recent lawsuit to protest the dangers posed by the Large Hadron Collider at CERN in Geneva, Switzerland, has been dismissed. On 24 August, a Hawaiian appeals court concluded that: "The alleged injury, destruction of the Earth, is in no way attributable to the US government's failure to draft an environmental impact statement," reads the court's decision.
The appeal was brought by Walter Wagner of Hawaii and Luis Sancho of Spain. In 2008, as the LHC was nearing completion, the pair filed a lawsuit in Hawaii's US District Court against CERN and US contributors to the project demanding that they not operate the LHC until they proved it safe. According to the Telegraph, that suit was dismissed via a 24-page ruling.
Doug McCuistion, director of the NASA Mars Exploration Program
The ExoMars Mars Climate Sounder instrument on NASA's Mars Reconnaissance Orbiter on a 2016 mission will map the vertical distribution of temperatures, dust, water vapor and ice clouds in the Martian atmosphere as the orbiter flies a near-polar orbit searching for faint gaseous clues about possible life on Mars. Two of the other selected instruments are spectrometers - one each from Europe and the United States - designed to detect very low concentrations of methane and other important trace gases in the Martian atmosphere.