Cosmic roadmap to galactic magnetic field revealed

http://feeds.feedburner.com/~r/sciencedaily/top_news/top_science/~4/Wh5EztadtKo

Scientists on NASA’s Interstellar Boundary Explorer (IBEX) mission, including a team leader from the University of New Hampshire, report that recent, independent measurements have validated one of the mission’s signature findings — a mysterious “ribbon” of energy and particles at the edge of our solar system that appears to be a directional “roadmap in the sky” of the local interstellar magnetic field.Unknown until now, the direction of the galactic magnetic field may be a missing key to understanding how the heliosphere — the gigantic bubble that surrounds our solar system — is shaped by the interstellar magnetic field and how it thereby helps shield us from dangerous incoming galactic cosmic rays. “Using measurements of ultra-high energy cosmic rays on a global scale, we now have a completely different means of verifying that the field directions we derived from IBEX are consistent,” says Nathan Schwadron, lead scientist for the IBEX Science Operations Center at the UNH Institute for the Study of Earth, Oceans, and Space. Schwadron and IBEX colleagues published their findings online today in Science.Establishing a consistent local interstellar magnetic field direction using IBEX low-energy neutral atoms and galactic cosmic rays at ten orders of magnitude higher energy levels has wide-ranging implications for the structure of our heliosphere and is an important measurement to be making in tandem with the Voyager 1 spacecraft, which is in the process of passing beyond our heliosphere.”The cosmic ray data we used represent some of the highest energy radiation we can observe and are at the opposite end of the energy range compared to IBEX’s measurements,” says Schwadron. “That it’s revealing a consistent picture of our neighborhood in the galaxy with what IBEX has revealed gives us vastly more confidence that what we’re learning is correct.”How magnetic fields of galaxies order and direct galactic cosmic rays is a crucial component to understanding the environment of our galaxy, which in turn influences the environment of our entire solar system and our own environment here on Earth, including how that played into the evolution of life on our planet.Notes David McComas, principal investigator of the IBEX mission at Southwest Research Institute and coauthor on the Science Express paper, “We are discovering how the interstellar magnetic field shapes, deforms, and transforms our entire heliosphere.”To date, the only other direct information gathered from the heart of this complex boundary region is from NASA’s Voyager satellites. Voyager 1 entered the heliospheric boundary region in 2004, passing beyond what’s known as the termination shock where the solar wind abruptly slows. Voyager 1 is believed to have crossed into interstellar space in 2012.Interestingly, when scientists compared the IBEX and cosmic ray data with Voyager 1′s measurements, the Voyager 1 data provide a different direction for the magnetic fields just outside our heliosphere.That’s a puzzle but it doesn’t necessarily mean one set of data is wrong and one is right. Voyager 1 is taking measurements directly, gathering data at a specific time and place, while IBEX gathers information averaged over great distances — so there is room for discrepancy. Indeed, the very discrepancy can be used as a clue: understand why there’s a difference between the two measurements and gain new insight.”It’s a fascinating time,” says Schwadron. “Fifty years ago, we were making the first measurements of the solar wind and understanding the nature of what was just beyond near-Earth space. Now, a whole new realm of science is opening up as we try to understand the physics all the way outside the heliosphere.”Eberhard Mbius, UNH principal scientist for the IBEX-Lo instrument on board, is a coauthor on the Science paper along with colleagues from institutions around the country.Story Source:The above story is based on materials provided by University of New Hampshire. …


Read More: Cosmic roadmap to galactic magnetic field revealed

#Agriculture, #Heliosphere, #Institute, #Interstellar, #King, #Nasa, #Neighborhood, #Pregnancy, #Process, #Science, #Space, #University

"Neighbor-plants" determine insects" feeding choices

http://feeds.feedburner.com/~r/sciencedaily/plants_animals/agriculture_and_food/~4/Tc3HwPNW4GY

Insects are choosier than you might think: whether or not they end up feeding on a particular plant depends on much more than just the species to which that plant belongs. The quality of the individual plant is an important factor as well. As is the variety of other plants growing around it. But what, ultimately, makes an insect choose one plant over another?It’s a question ecologists have struggled with for decades, and the answer could have a major impact on attempts to use insects for controlling crops or attacking outbreak species such as ragwort. Ragwort (Jacobaea vulgaris) is native to the Netherlands but its abundance in areas such as ex-arable fields can make it a pest, as it is toxic to horses and farmers can’t use fields where it grows for hay.In her PhD thesis, Olga Kostenko uses ragwort as an example to show that the ‘neighborhood’ in which a plant grows is more important for insects in the end than how the plant tastes. If, for instance, ragwort plants grow in a plant community with many tall neighbors, insects will not even notice them. Consequently, the effectiveness of using insects to control such plants is limited.Field experimentsBut before she could weigh the importance of these factors, Kostenko first had to do some pioneering research into plant quality in particular. Most knowledge about the role of plant quality so far had been based on controlled laboratory experiments. Whether it would still be as important a factor under natural conditions was unknown.Kostenko took up the challenge, planting no fewer than 1750 plants on ex-arable fields at Mossel (Ede, the Netherlands), with remarkable results. Not only did she find that plant quality wasn’t the most important factor, she also discovered that the way the plants tasted to insects was actually affected by the neighborhood in which they grew.And not just the present neighborhood: even plants and insects that inhabited the same spot in the past had an effect on the chemical composition of the next generation of plants. …


Read More: "Neighbor-plants" determine insects" feeding choices

#Agriculture, #Alzheimer, #Health, #Jacobaea, #Life, #Major, #Materials, #Neighborhood, #Number, #Ragwort