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The Solar Wind Is Swirly

December 22, 2012 Leave a comment

Using ESA’s Cluster quartet of satellites as a space plasma microscope, scientists have zoomed in on the solar wind to reveal the finest detail yet, finding tiny turbulent swirls that could play a big role in heating it. Turbulence is highly complex and all around us, evident in water flowing from a tap, around an aircraft wing, in experimental fusion reactors on Earth, and also in space.

In the stream of charged particles emitted by the Sun – the solar wind – turbulence is thought to play a key part in maintaining its heat as it streams away and races across the Solar System. As the solar wind expands, it cools down, but to a much smaller extent than would be expected if the flow were smooth.

Full Story: http://www.esa.int/Our_Activities/Space_Science/The_solar_wind_is_swirly
Also: http://sci.esa.int/science-e/www/area/index.cfm?fareaid=8

A Swoosh In Space: Merry Christmas From Hubble

December 22, 2012 Leave a comment

Image credit: NASA, ESA and the Hubble Heritage Team (STScI/AURA)

Image credit: NASA, ESA and the Hubble Heritage Team (STScI/AURA)

The NASA/ESA Hubble Space Telescope celebrates the holiday season with a striking image of the planetary nebula NGC 5189. The intricate structure of the stellar eruption looks like a giant and brightly coloured ribbon in space.

Planetary nebulae represent a final brief stage in the life of a star like the Sun. While consuming the last of the fuel in its core, the star expels a large portion of its outer regions, which then heats up and glows brightly, showing intricate structures that scientists are still trying to fully understand. The structure visible within NGC 5189 is particularly dramatic, and Hubble’s image of the nebula is by far the most detailed yet made of this object.

Full Story, Images, and Video: http://www.spacetelescope.org/news/heic1220/
Also: http://hubblesite.org/newscenter/archive/releases/2012/49/image/a/

New Neighbors? Closet Single Star Like Our Sun May Have Habitable Planet

December 22, 2012 Leave a comment

At a distance of twelve light-years and visible with the naked eye in the evening sky, Tau Ceti is the closest single star that has the same spectral classification as our Sun. Its five planets are estimated to have masses between two and six times the mass of the Earth — making it the lowest-mass planetary system yet detected. One of the planets lies in the habitable zone of the star and has a mass around five times that of Earth, making it the smallest planet found to be orbiting in the habitable zone of any Sun-like star.

The international team of astronomers, from the UK, Chile, the USA, and Australia, combined more than six-thousand observations from three different instruments and intensively modeled the data. Using new techniques, the team has found a method to detect signals half the size previously thought possible. This greatly improves the sensitivity of searches for small planets and suggests that Tau Ceti is not a lone star but has a planetary system.

Full Information: http://star-www.herts.ac.uk/~hraj/tauceti/

Stars Reveal The Secrets Of Looking Young

December 22, 2012 1 comment

NGC 6388, a dynamically middle-aged globular cluster in the Milky Way. Credit: ESO, F. Ferraro (University of Bologna)

NGC 6388, a dynamically middle-aged globular cluster in the Milky Way. Credit: ESO, F. Ferraro (University of Bologna)

Some people are in great shape at the age of 90, while others are decrepit before they’re 50. We know that how fast people age is only loosely linked to how old they actually are — and may have more to do with their lifestyle. A new study using both the MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory and the NASA/ESA Hubble Space Telescope reveals that the same is true of star clusters.

Globular clusters are spherical collections of stars, tightly bound to each other by their mutual gravity. Relics of the early years of the Universe, with ages of typically 12–13 billion years (the Big Bang took place 13.7 billion years ago), there are roughly 150 globular clusters in the Milky Way and they contain many of our galaxy’s oldest stars.

But while the stars are old and the clusters formed in the distant past, astronomers using the MPG/ESO 2.2-metre telescope and the NASA/ESA Hubble Space Telescope have found that some of these clusters are still young at heart. The research is presented in the 20 December 2012 issue of the journal Nature.

“Although these clusters all formed billions of years ago,” says Francesco Ferraro (University of Bologna, Italy), the leader of the team that made the discovery, “we wondered whether some might be aging faster or slower than others. By studying the distribution of a type of blue star that exists in the clusters, we found that some clusters had indeed evolved much faster over their lifetimes, and we developed a way to measure the rate of aging.”

Full Story:http://www.eso.org/public/news/eso1252/
Also: http://www.spacetelescope.org/news/heic1221/

Exploding Star Missing From Formation Of Solar System

December 22, 2012 Leave a comment

A new study published by University of Chicago researchers challenges the notion that the force of an exploding star prompted the formation of the solar system.

In this study, published online last month in Earth and Planetary Science Letters, authors Haolan Tang and Nicolas Dauphas found the radioactive isotope iron 60 — the telltale sign of an exploding star—low in abundance and well mixed in solar system material. As cosmochemists, they look for remnants of stellar explosions in meteorites to help determine the conditions under which the solar system formed.

They discovered that levels of iron 60 were uniform and low in early solar system material. They arrived at these conclusions by testing meteorite samples.

Full Story: http://news.uchicago.edu/article/2012/12/14/exploding-star-missing-formation-solar-system