Image of the Week: Simulations Reveal Unusual Death for Stars
Massive primordial stars, between 55,000 and 56,000 times the mass of our Sun, may have died unusually. In death, these objects — among the universe’s first generation of stars — would have exploded as supernovae and burned completely, leaving no remnant black hole behind.
Astrophysicists at the UC Santa Cruz and the Univ. of Minnesota came to this conclusion after running a number of supercomputer simulations at the Department of Energy’s (DOE) National Energy Research Scientific Computing Center (NERSC) and Minnesota Supercomputing Institute. They relied extensively on CASTRO, a compressible astrophysics code developed at the DOE’s Lawrence Berkeley National Laboratory’s (Berkeley Lab’s) Computational Research Division (CRD). Their findings were recently published in the Astrophysical Journal (ApJ).
Higgs Boson May Explain Earliest Expansion of the Universe
Fedor Bezrukov from the RIKEN BNL Research Center and Mikhail Shaposhnikov from EPFL propose that the Higgs boson may be responsible for the mode of inflation and shape of the Universe shortly after the Big Bang.
“There is an intriguing connection between the world explored in particle accelerators today and the earliest moments of the existence of the Universe,” explained Bezrukov.
An international team of sky scholars, including a key researcher from Johns Hopkins, has produced new maps of the material located between the stars in the Milky Way. The results should move astronomers closer to cracking a stardust puzzle that has vexed them for nearly a century.
The maps and an accompanying journal article appear in today’s issue of the journal Science. The researchers say their work demonstrates a new way of uncovering the location and eventually the composition of the interstellar medium — the material found in the vast expanse between star systems within a galaxy.
Earth, Moon are Around 60 M Years Older than Thought
Work presented at the European Association of Geochemistry’s Goldschmidt Geochemistry Conference in Sacramento, California shows that the timing of the giant impact between Earth’s ancestor and a planet-sized body occurred around 40 million years after the start of solar system formation. This means that the final stage of Earth’s formation is around 60 million years older than previously thought.
Early Universe’s Radiation Key to Testing Einstein’s Theory
Astrophysicists at UC San Diego have measured the minute gravitational distortions in polarized radiation from the early universe and discovered that these ancient microwaves can provide an important cosmological test of Einstein’s theory of general relativity. These measurements have the potential to narrow down the estimates for the mass of ghostly subatomic particles known as neutrinos.
The radiation could even provide physicists with clues to another outstanding problem about our universe: how the invisible “dark matter” and “dark energy,” which has been undetectable through modern telescopes, may be distributed throughout the universe.
A massive computer simulation has produced a model of the universe’s evolution with new accuracy in some important measures — and yielded a new prediction concerning the distribution of matter in the cosmos.
The new Illustris model, constructed by researchers at several institutions, including MIT, simulates 13 billion years of cosmic evolution, and has generated a new degree of fidelity for certain observed features of the universe. These features include the frequency with which galaxies of different shapes occur in the universe, as well as the preponderance of certain elements in space.
“Wimpy” Dwarf Fossil Galaxy Sheds Light on Early Universe
Out on the edge of the universe, 75,000 light years from us, a galaxy known as Segue 1 has some unusual properties: it is the faintest galaxy ever detected. It is very small, containing only about 1,000 stars. And it has a rare chemical composition, with vanishingly small amounts of metallic elements present.
Now a team of scientists, including an MIT astronomer, has analyzed that chemical composition and come away with new insights into the evolution of galaxies in the early stages of our universe — or, in this case, into a striking lack of evolution in Segue 1. Commonly, stars form from gas clouds and then burn up as supernova explosions after about a billion years, spewing more of the elements that are the basis for a new generation of star formation.
An international team of planetary scientists determined that the Moon formed nearly 100 million years after the start of the solar system, according to a paper published today in Nature. This conclusion is based on measurements from the interior of the Earth combined with computer simulations of the protoplanetary disk from which the Earth and other terrestrial planets formed.
The team of researchers from France, Germany and the U.S. simulated the growth of the terrestrial planets (Mercury, Venus, Earth and Mars) from a disk of thousands of planetary building blocks orbiting the Sun. By analyzing the growth history of the Earth-like planets from 259 simulations, the scientists discovered a relationship between the time the Earth was impacted by a Mars-sized object to create the Moon and the amount of material added to the Earth after that impact.
'Cosmic Barometer' May Reveal Universe's Violent Past
Scientists have developed a way of reading the universe’s “cosmic barometer” to learn more about ancient violent events in space. Exploding stars, random impacts involving comets and meteorites and even near misses between two bodies can create regions of great heat and high pressure.
Researchers from Imperial College London have now developed a method for analyzing the pressure experienced by tiny samples of organic material that may have been ejected from dying stars before making a long journey through the cosmos. The researchers have investigated a type of aromatic hydrocarbon called dimethylnaphthalene, which should enable them to identify violent events in the history of the universe.
Watch a Scientist Get Told His Life’s Work Has Been Proven Right
On Monday, news hit that researchers made a major physics advance- they found evidence to support the Big Bang Theory and the explosion of growth that immediately followed.
Physicist Alan Guth formally proposed inflationary theory in 1980, when he was a postdoctoral scholar at SLAC, as a modification of conventional Big Bang theory. Instead of the universe beginning as a rapidly expanding fireball, Guth theorized that the universe inflated extremely rapidly from a tiny piece of space and became exponentially larger in a fraction of a second. This idea immediately attracted lots of attention because it could provide a unique solution to many difficult problems of the standard Big Bang theory.
A paper published in Springer’s EPJ H provides the first English translation and an analysis of one of Albert Einstein’s little-known papers, “On the cosmological problem of the general theory of relativity.” Published in 1931, it features a forgotten model of the universe, while refuting Einstein’s own earlier static model of 1917. In this paper, Einstein introduces a cosmic model in which the universe undergoes an expansion followed by a contraction. This interpretation contrasts with the monotonically expanding universe of the widely known Einstein-de Sitter model of 1932.
Every Thursday, Laboratory Equipment features a Scientist of the Week, chosen from the science industry’s latest headlines. This week’s scientist is Jens Krog from the Univ. of Southern Denmark. He and a team preformed new calculations that confirm that the universe may one day collapse – and they concluded that the risk of a collapse is even greater than previously thought.
An international team of astronomers has discovered the first Earth-mass planet that transits, or crosses in front of, its host star. KOI-314c is the lightest planet to have both its mass and physical size measured. Surprisingly, although the planet weighs the same as Earth, it is 60 percent larger in diameter, meaning that it must have a very thick, gaseous atmosphere.
"This planet might have the same mass as Earth, but it is certainly not Earth-like," says David Kipping of the Harvard-Smithsonian Center for Astrophysics (CfA), lead author of the discovery. "It proves that there is no clear dividing line between rocky worlds like Earth and fluffier planets like water worlds or gas giants."
On a clear night, the moon’s battered history comes into sharp relief: even from 240,000 miles away, its largest craters are so massive as to be visible to the naked eye.
Scientists have long thought that such lunar craters arose during a period called the Late Heavy Bombardment (LHB), about four billion years ago. During that time, a hailstorm of giant asteroids pummeled the solar system, slamming into the moon, along with young planets like Mercury, Venus, Earth and Mars. But now scientists from MIT, the Univ. of Paris and elsewhere have found that craters on the near side of the moon may not reflect the intensity of asteroid impacts from that period. Instead, much smaller asteroids likely created these craters — a finding that may redefine scientists’ picture of the LHB.