sun

Lost galactic hitchhikers can now rejoice when they visit our corner of the Milky Way. A new sky map created by a NASA spacecraft shows the boundaries of our solar system in comparison to the rest of the interstellar neighborhood.

The boundaries are defined by our sun's heliosphere -- a protective bubble created by the solar wind that travels outward and collides with incoming interstellar radiation. That typically invisible boundary became visible through energetic neutral atoms created in the region that speed toward the sun at velocities ranging up to 2.4 million mph.

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The first computer-generated model of an entire sunspot—a magnetic anomaly on the surface of the sun—tracks the magnetic fields in the area, helping researchers figure out how the sun releases energy around the spots. At the dark center, or umbra, the field is so strong—about 1,000 times the solar average—that it blocks the solar gases that typically bubble to the surface.

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The sun might seem like a pretty huge galactic blind spot, but we've already managed to glimpse behind it, and there's nothing there in the way of another Earth, says NASA scientist Michael Kaiser, "unless it's awfully tiny."

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For about 50 years from roughly 1650 to 1700, the Sun took a break from its typical sunspot activity. That phase of solar rest coincided with what we now refer to as "The Little Ice Age" -- a period of cooling on the Earth that resulted in bitterly cold winters, particularly in Europe and North America. Scientists attribute the Little Ice Age to two main causes: increased volcanic activity and reduced solar activity.

Could it happen again? And are we headed there now?

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If you put a steamy cup of coffee in the refrigerator, it wouldn’t immediately turn cold. Likewise, if the sun simply “turned off” (which is actually physically impossible), the Earth would stay warm—at least compared with the space surrounding it—for a few million years. But we surface dwellers would feel the chill much sooner than that.

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Finally, some good news on the climate. Good, but hesitantly good, mind you. British scientists working in a remote area of the tropical Atlantic have discovered that ozone levels there were 50 percent lower than expected. The reason for the discrepancy is due to a process in which UV rays from the sun are the catalyst for a series of chemical reactions which end with the breakdown of ozone and methane.

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Yes, the Intergovernmental Panel on Climate Change has said that man is at the root of most of Earth's warming in the last five decades. Still, some researchers say the trend can be attributed to natural causes, including changes in the flux of cosmic rays slamming into our atmosphere, but now, according to Physics World, a pair of U.K. particle physicists have dismissed that idea.

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AAAS 2008, Boston, MA

Sallie Baliunas, an astrophysicist at the Harvard Smithsonian Center for Astrophysics, is pointing to a slide called Interdecadal Magnetic Variability Berillium 10. Its supposed to communicate something about the relationship between the suns intensity and climate change. All I see is a collection of squiggly lines. It could be an EKG or a seismograph test. The man sitting next to me appears to be equally lost. Hes snoring. The woman next to him is staring at her shoelaces.

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