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How Galaxies Grow Up

By Guest PostOctober 20, 2012Scienceadam block, age, andromeda galaxy, astronomer, benjamin weiner, blue galaxies, california, computer program, computer simulation, deep2, emission line, galaxies, Galaxy, galaxy evolution, galaxy population, galaxy type, gas, grow up, hawaii, internal motion, keck telescopes, lick observatory, light years, m88 galaxy, massive system, Milky Way, mount lemmon, NASA, observational data, random motion, redshift survey, rotation speed, santa cruz, skycenter, spiral disk shape, star forming galaxies, susan kassin, ua, universe, university, velocity

A study of 544 star-forming galaxies shows that disk galaxies like our own Milky Way reached their current state as orderly rotating pinwheels much later than previously thought, long after much of the universe’s star formation had ceased.

Galaxies are in no hurry to grow up, a team of astronomers has discovered. A comprehensive study of hundreds of galaxies observed by the Keck telescopes in Hawaii and NASA’s Hubble Space Telescope has revealed an unexpected pattern of change that extends back 8 billion years, or more than half the age of the universe.

Researchers say the distant blue galaxies they studied are gradually transforming into rotating disk galaxies like our own Milky Way. Until now, it had not been clear how a galaxy’s organization and internal motion change over time, said Benjamin Weiner, assistant astronomer at the UA Steward Observatory and co-author of the paper describing the findings, which are published in The Astrophysical Journal. (more…)

The First Spectroscopic Measurement of an Anti-Atom

By Guest PostMarch 11, 2012Scienceafrd, alpha collaboration, anti atoms trapped, antielectrons, antihydrogen, antihydrogen atom, antimatter, astronomy, atomic spectrum, berkeley lab, CERN, charge conjugation, cosmic rays, cpt, electric interaction, electron, emission line, geneva, hydrogen, hydrogen atom, hyperfine splitting, joel fajans, jonathan wurtele, magnetic, magnetic fields, magnetic trap, microwaves, parity, positrons, proton nucleus, quantum state, resonant frequency, simone straka, spectroscopic measurements, spin, symmetrical state, time reversal, trapped hydrogen, universe

*Berkeley Lab scientists helped build and operate the ALPHA antimatter trap at CERN, which has now probed the internal structure of the antihydrogen atom for the first time, taking the first step toward possible new insights into the difference between matter and antimatter*

The ALPHA collaboration at CERN in Geneva has scored another coup on the antimatter front by performing the first-ever spectroscopic measurements of the internal state of the antihydrogen atom. Their results are reported in a forthcoming issue of Nature and are now online.

Ordinary hydrogen atoms are the most plentiful in the universe, and also the simplest – so simple, in fact, that some of the most fundamental physical constants have been discovered by measuring the tiny energy shifts resulting from the magnetic and electric interactions of hydrogen’s proton nucleus with its single orbiting electron. (more…)

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How Galaxies Grow Up

The First Spectroscopic Measurement of an Anti-Atom