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cosmic rays is unknown, but it must be close to the solar system and could be made of dark matter. The results were reported in the 20 November 2008 issue of the journal Nature. "This is a big discovery," said co-author John Wefel of Louisiana State University. "It's the first time we've seen a discrete source of accelerated cosmic rays standing out from the general galactic background." To study the most powerful and interesting cosmic rays, Wefel and colleagues spent the last eight years flying a series of balloons through the stratosphere over Antarctica. Their NASA-funded cosmic ray detector found a significant surplus of high-energy electrons. "The source of these exotic electrons must be relatively close to the solar system—no more than a kiloparsec away,” said co-author Jim Adams of the NASA Marshall Space Flight Center. Galactic cosmic rays are subatomic particles accelerated to almost light- speed by distant supernovae explosions and other violent events. They swarm through the Milky Way, forming a haze of high- energy particles that enter the solar system from all directions. greater than anything ever seen before. One study, authored by Dr Mike Lockwood and colleagues from Rutherford Appleton Laboratory in Chilton, UK, in 1999, investigated the Sun's activity over the previous 100 years. They reported that since 1901 the overall magnetic field of the Sun has become stronger by 230 per cent. Scientists do not understand what that means for us. Some of the sunspot activity in this last cycle was greater than anything ever recorded before. But scientists claim that they don't understand what that means, either. "Obviously, the Sun is Earth's lifeblood,” said Richard Fisher, Director of the Heliophysics Division at NASA. "To mitigate possible public safety issues, it is vital that we better understand extreme space weather events caused by the Sun's activity.” Solar Cycle 24 According to NASA, the Sun is beginning another 1 1- year cycle of activity. The Sun flips its magnetic poles every 11 years. Considering that the Sun is to blame for some unfavourable climate changes on the Earth, the coming decade could spell more trouble for our planet. The years ahead could be intense. Jimmy Raeder explained: "We're entering Solar Cycle 24. For reasons not fully understood, CMEs in even- numbered solar cycles (like 24) tend to hit Earth with a leading edge that is magnetized north. Such a CME should open a breach and load the magnetosphere with plasma just before the storm gets underway. It's the perfect sequence for a really big event." Cosmic rays consist mostly of protons and heavier atomic nuclei with a dash of electrons and photons spicing the mix. Why must the source be nearby? According to Adams: "High-energy electrons lose energy rapidly as they fly through the galaxy. They give up energy in two main ways: (1) when they collide with lower-energy photons, a process called inverse Compton scattering; and (2) when they radiate away some of their energy by spiraling through the galaxy's magnetic field.” High-energy electrons are Q2 7, therefore local, but the researchers = cannot pinpoint the source in the 4 sky. = 67 circ 1900 1920 1940 1960 The Sun's Magnetic Field The Sun is a_ massive electromagnetic broadcaster which loods the planets of the solar system with heat, light, UV radiation and electrically charged particles. The Sun itself has a magnetic field, and that magnetic field creates an "egg" around the solar system that is known as the heliosphere. The heliosphere is shaped like a eardrop, with the long, thin end of he drop pointing away from the direction in which we're travelling. Any changes that occur in or on he Sun will eventually affect every person alive. The solar activity during this last sunspot cycle was NEXUS ¢ 33 Solar-source magnetic flux and sunspot numbers APRIL - MAY 2009 www.nexusmagazine.com