| Solar X-rays: Geomagnetic Field: |
Blog on the Sun and Sunspot Activity
Tuesday, February 5, 2013
It is widely believed that the Sun's magnetic field is generated by electrical currents acting as a magnetic dynamo inside the Sun. These electrical currents are generated by the flow of hot, ionized gases in the Sun's convection zone.
This magnetic dynamo has a 22 year cycle. During the first half of the cycle, the Sun's magnetic north pole is in the northern hemisphere while the magnetic south pole is in the southern hemisphere. Right around the peak of the sunspot cycle, the magnetic poles flip or exchange places so that magnetic north is now located in the southern hemisphere. This flip occurs about every 11 years. The 22 year magnetic cycle greatly influences the most prominent manifestation of the dynamo, sunspots and active regions, which migrate towards the solar equator from high latitudes over the course of the solar 11 year "sunspot cycle". Sunspots and Active Regions are manifestation of the magnetic field generated in the Sun's interior poking through the visible region of the atmosphere. Active regions are responsible for the production of intense and violent energy burst, called flares, and events where very large amounts of hot gas, trapped by the magnetic field of the active region, are released from the Sun's atmosphere and into space, called coronal mass ejections.
Sunday, February 3, 2013
Earth is currently in a period of warming. Over the last century, Earth's
average temperature rose about 1.1°F (0.6°C). In the last two decades, the rate
of our world's warming accelerated and scientists predict that the globe will
continue to warm over the course of the 21st century. Is this warming trend a
reason for concern? After all, our world has witnessed extreme warm periods
before, such as during the time of the dinosaurs. Earth has also seen numerous
ice ages on roughly 11,000-year cycles for at least the last million years. So,
change is perhaps the only constant in Earth's 4.5-billion-year history.
Scientists note that there are two new and different twists to today's
changing climate: The globe is warming at a faster rate than it ever has
before; and Humans are the main reason Earth is warming. Since the
industrial revolution, which began in the mid-1800s, humans have attained the
magnitude of a geological force in terms of our ability change Earth's
environment and impact its climate system.
Humans are affecting Earth's climate system in many ways. For example,
we transformed roughly 40 percent of Earth's habitable land surface to make way
for our crop fields, cities, roads, livestock pastures, etc. We also released
particulate pollution (called "aerosols") into the atmosphere. Changing the
surface and introducing aerosols into the atmosphere can both increase and
reduce cloud cover. Thus, in addition to driving up average global temperature,
humans are also influencing rainfall and drought patterns around the world.
While scientists have solid evidence of such human influence, more data and
research are needed to better understand and quantify our impact on our world's
climate system.
Friday, February 1, 2013
Strong electrical currents driven in the Earth’s
surface during auroral events can disrupt and damage modern electric power grids
and may contribute to the corrosion of oil and gas pipelines. Changes in the
ionosphere during geomagnetic storms driven by magnetic activity of the Sun
interfere with high-frequency radio communications and GPS navigation. During
polar cap absorption events caused by solar protons, radio communications can be
severely compromised for commercial airliners on transpolar crossing routes.
Exposure of spacecraft to energetic particles during solar energetic particle
events and radiation belt enhancements can cause temporary operational
anomalies, damage critical electronics, degrade solar arrays, and blind optical
systems such as imagers and star trackers used on commercial and government
satellites.
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