Tag Archives: gravity

Clocking an Accelerating Universe: First Results from BOSS

By Guest PostApril 4, 2012Scienceaccelerate, adam riess, apache point observatory, bao, baryon acoustic oscillation, berkeley lab, beth reid, big bang, brian schmidt, cmb, cosmic microwave background, dan long, dark energy, david schlegel, density peak, einstein, eric huff, euclidean universe, Galaxy, george smoot, gravitational attraction, gravity, high z supernova, hubble, martin white, megaparsecs, Milky Way, new mexico, nobel prize, phenomenon, redshifts, saul perlmutter, scp, sdss, sloan telescope, spectrograph, statistical analysis, universe, zosia rostomian

Berkeley Lab scientists are the leaders of BOSS, the Baryon Oscillation Spectroscopic Survey. They and their colleagues in the third Sloan Digital Sky Survey have announced the most precise measurements ever made of the era when dark energy turned on.

Some six billion light years distant, almost halfway from now back to the big bang, the universe was undergoing an elemental change. Held back until then by the mutual gravitational attraction of all the matter it contained, the universe had been expanding ever more slowly. Then, as matter spread out and its density decreased, dark energy took over and expansion began to accelerate.

Today BOSS, the Baryon Oscillation Spectroscopic Survey, the largest component of the third Sloan Digital Sky Survey (SDSS-III), announced the most accurate measurement yet of the distance scale of the universe during the era when dark energy turned on. (more…)

Astronomy Team That Includes UCLA Finance Professor Discovers Nearby Dwarf Galaxy

By Guest PostFebruary 10, 2012Scienceaaron romanowsky, astronomer, big bang, c28 telescope, centurion 28, christine black, david martinez delgado, david reitzel, dwarf galaxy, francis longstaff, frazier park, Galaxy, gravitational attraction, gravitational tug, gravity, griffith observatory, halo population, Hubble Space Telescope, hydrogen gas, james riffle, kern county, light, light years, living fossil, michael rich, Milky Way, milky way galaxy, ngc 4449, night sky, polaris observatory association, r jay gabany, sagittarius dwarf galaxy, sky, star formation, telescope, transient stage

A team led by UCLA research astronomer Michael Rich has used a unique telescope to discover a previously unknown companion to the nearby galaxy NGC 4449, which is some 12.5 million light years from Earth. The newly discovered dwarf galaxy had escaped even the prying eyes of the Hubble Space Telescope.

The research is published Feb. 9 in the journal Nature. (more…)

In The Dragonfish’s Mouth: The Next Generation of Superstars to Stir Up Our Galaxy

By Guest PostDecember 5, 2011Scienceastronomers, astronomical terms, celestial gas shell, Chile, christopher matzner, dae sik moon, deep sea creature, dragonfish, european southern observatory, Galaxy, gravity, infrared, light years, mouth, mubdi rahman, new technology telescope, peter shearer, radio waves, spitzer satellite, sun, supermassive stars, telescopes, ultraviolet, university of toronto, visible light, wmap satellite

TORONTO, ON – Three astronomers at the University of Toronto have found the most numerous batch of young, supermassive stars yet observed in our galaxy: hundreds of thousands of stars, including several hundreds of the most massive kind –blue stars dozens of times heavier than our Sun. The light these newborn stars emit is so intense it has pushed out and heated the gas that gave them birth, carving out a glowing hollow shell about a hundred light-years across.

These findings will be published in the December 20 issue of Astrophysical Journal Letters. For the researchers, the next step is already clear: “By studying these supermassive stars and the shell surrounding them, we hope to learn more about how energy is transmitted in such extreme environments,” says Mubdi Rahman, a PhD candidate in the Department of Astronomy & Astrophysics at the University of Toronto, who led the work with his supervisors, Professors Dae-Sik Moon and Christopher Matzner. (more…)

Newly Found Dwarf Galaxies Could Help Reveal the Nature of Dark Matter

By Guest PostNovember 12, 2011Scienceandromeda, andromeda xxviii and xxix, astronomers, colin slater, dwarf galaxies, dwarf galaxies around andromeda, dwarf spheroidal galaxy 200 kpc from andromeda, earth, eric bell, gemini north telescope, gravitational effects, gravity, hawaii, how matter relates to dark matter, hypothesis, invisible substance, light years, night sky, predictions, satellites of andromeda, sloan digital sky survey, spiral galaxy, star counting technique, telescopes, understanding of dark matter, universe mass, university of michigan

ANN ARBOR, Mich.— In work that could help advance astronomers’ understanding of dark matter, University of Michigan researchers have discovered two additional dwarf galaxies that appear to be satellites of Andromeda, the closest spiral galaxy to Earth.

Eric Bell, an associate professor in astronomy, and Colin Slater, an astronomy Ph.D. student, found Andromeda XXVIII and XXIX—that’s 28 and 29. They did it by using a tested star-counting technique on the newest data from the Sloan Digital Sky Survey, which has mapped more than a third of the night sky. They also used follow-up data from the Gemini North Telescope in Hawaii. (more…)

Berkeley Lab’s Saul Perlmutter wins Nobel Prize in Physics

By Guest PostOctober 4, 2011Science2011 nobel prize in physics, accelerating expansion of the universe, adam riess, anisotropy of the cosmic microwave background radiation, astrophysicist, berkeley lab, brian schmidt, Chile, dark energy, department of energy, expansion of the universe, france, george smoot iii, gravity, high z supernova search team, international supernova cosmology project, Japan, knowledge, lawrence berkeley national laboratory, mysterious force, nature of dark energy, nobel prize, nobel prize in physics, paul alivisatos, saul perlmutter, spain, supernova cosmology project, supernovae, Sweden, swedish kroner, united kingdom, united states, university of california at berkeley

BERKELEY, CA — Saul Perlmutter, an astrophysicist at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory and a professor of physics at the University of California at Berkeley, has won the 2011 Nobel Prize in Physics “for the discovery of the accelerating expansion of the universe through observations of distant supernovae.” Perlmutter heads the international Supernova Cosmology Project, which pioneered the methods used to discover the accelerating expansion of the universe, and he has been a leader in studies to determine the nature of dark energy.

Perlmutter shares the prize with Brian Schmidt and Adam Riess, leader of the High-z Supernova Search Team and first author of that team’s analysis, respectively, which led to their almost simultaneous announcement of accelerating expansion. (more…)

NASA’s WISE Mission Captures Black Hole’s Wildly Flaring Jet

By Guest PostSeptember 21, 2011Sciencea w blain, accretion disks, astronomers, black hole called gx 339 4, black holes, blazing jets, center of our galaxy, d m russell, extreme environments around black holes, flaring black hole, gamma rays, gravity, infrared observations, japan aerospace exploration agency, jaxa, jets, magnetic field, NASA, neowise, peter eisenhardt, physics of jets, poshak gandhi, radio waves, s markoff, speed of light, ultra dense collection of matter, wide field infrared survey explorer, wise, xrays

PASADENA, Calif. — Astronomers using NASA’s Wide-field Infrared Survey Explorer (WISE) have captured rare data of a flaring black hole, revealing new details about these powerful objects and their blazing jets.

Scientists study jets to learn more about the extreme environments around black holes. Much has been learned about the material feeding black holes, called accretion disks, and the jets themselves, through studies using X-rays, gamma rays and radio waves. But key measurements of the brightest part of the jets, located at their bases, have been difficult despite decades of work. WISE is offering a new window into this missing link through its infrared observations. (more…)

NASA’s Dawn Spacecraft Enters Orbit Around Asteroid Vesta

By Guest PostJuly 17, 2011Scienceasteroid, asteroid vesta, ceres, charles bolden, dawn, dawn spacecraft, dwarf planet, german aerospace center, gravitational pull, gravity, italian space agency, jet propulsion laboratory, los angeles, main asteroid belt between mars and jupiter, marshall space flight center in huntsville, max planck institute for solar system research, NASA, President Obama, spacecraft, university of california, vesta

PASADENA, Calif. — NASA’s Dawn spacecraft on Saturday became the first probe ever to enter orbit around an object in the main asteroid belt between Mars and Jupiter.

Dawn will study the asteroid, named Vesta, for a year before departing for a second destination, a dwarf planet named Ceres, in July 2012. Observations will provide unprecedented data to help scientists understand the earliest chapter of our solar system. The data also will help pave the way for future human space missions. (more…)

NASA Telescope Helps Confirm Nature of Dark Energy

By Guest PostMay 20, 2011Science3 d map, albert einstein, anglo australian telescope, australia, big bang, caltech, chris blake, christopher martin, constant force, cosmic time, dark energy, dark matter, galaxies, galaxy evolution explorer, gravitational attractions, gravity, how dark energy works, jon morse, melbourne, NASA, siding spring mountain, swinburne university of technology, universe

PASADENA, Calif. — A five-year survey of 200,000 galaxies, stretching back seven billion years in cosmic time, has led to one of the best independent confirmations that dark energy is driving our universe apart at accelerating speeds. The survey used data from NASA’s space-based Galaxy Evolution Explorer and the Anglo-Australian Telescope on Siding Spring Mountain in Australia.

The findings offer new support for the favored theory of how dark energy works — as a constant force, uniformly affecting the universe and propelling its runaway expansion. They contradict an alternate theory, where gravity, not dark energy, is the force pushing space apart. According to this alternate theory, with which the new survey results are not consistent, Albert Einstein’s concept of gravity is wrong, and gravity becomes repulsive instead of attractive when acting at great distances. (more…)