MIT scientists identify a plasma plume that naturally protects the earth against solar storms.
The Earth’s magnetic field, or magnetosphere, stretches from the planet’s core out into space, where it meets the solar wind, a stream of charged particles emitted by the Sun. For the most part, the magnetosphere acts as a shield to protect the Earth from this high-energy solar activity.
But when this field comes into contact with the Sun’s magnetic field — a process called “magnetic reconnection” — powerful electrical currents from the Sun can stream into Earth’s atmosphere, whipping up geomagnetic storms and space weather phenomena that can affect high-altitude aircraft, as well as astronauts on the International Space Station.
Now scientists at MIT and NASA have identified a process in the Earth’s magnetosphere that reinforces its shielding effect, keeping incoming solar energy at bay.
Astronomers at the University of Michigan have, for the first time, directly measured the spin of a distant supermassive black hole.
A new innovative instrument called MUSE (Multi Unit Spectroscopic Explorer) has been successfully installed on ESO’s Very Large Telescope (VLT) at the Paranal Observatory in northern Chile. MUSE has observed distant galaxies, bright stars and other test targets during the first period of very successful observations.
Following testing and preliminary acceptance in Europe in September 2013, MUSE was shipped to ESO’s Paranal Observatory in Chile. It was reassembled at the base camp before being carefully transported to its new home at the VLT, where it is now installed on Unit Telescope 4. MUSE is the latest of the second generation instruments for the VLT; the first two were X-shooter (http://www.eso.org/public/news/eso0920) and KMOS (http://www.eso.org/public/news/eso1251), and the next, SPHERE (http://www.eso.org/public/announcements/ann14013), will follow shortly.
Sixteen years ago two teams of supernova hunters, one led by Saul Perlmutter of the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), the other by Brian Schmidt of the Australian National University, declared that the expansion of the universe is accelerating — a Nobel Prize-winning discovery tantamount to the discovery of dark energy. Both teams measured how fast the universe was expanding at different times in its history by comparing the brightnesses and redshifts of Type Ia supernovae, the best cosmological “standard candles.”
Monthly Notices of the Royal Astronomical Society (MNRAS)
These dazzling supernovae are remarkably similar in brightness, given that they are the massive thermonuclear explosions of white dwarf stars, which pack roughly the mass of our Sun into a ball the size of Earth. Based on their colors and how fast they brighten and fade away, the brightnesses of different Type Ia supernovae can be standardized to within about 10 percent, yielding accurate gauges for measuring cosmic distances.
Until recently, scientists thought they knew why Type Ia supernovae are all so much alike. But their favorite scenario was wrong.
Australian astronomers have discovered what makes some spiral galaxies fat and bulging while others are flat discs — and it’s all about how fast they spin.
The Astrophysical Journal
The research, led by the International Centre for Radio Astronomy Research (ICRAR) in Perth, found that fast-rotating spiral galaxies are flat and thin while equally sized galaxies that rotate slowly are fatter.
The study was published today in the prestigious Astrophysical Journal and was part of “The Evolving Universe” research theme of the ARC Center of Excellence for All-sky Astrophysics (CAASTRO).
ICRAR Research Associate Professor Danail Obreschkow, from The University of Western Australia, said it is a much-debated mystery why galaxies look so different to each other.
“Some galaxies are very flat discs of stars and others are more bulging or even spherical,” he said.