Life on Earth is the result of a wonderful coincidence.
The Earth is in a “Goldilocks” orbit around the sun. It’s not too hot or too cold. It takes just 8.3 minutes for the sun’s light to reach us. Our sun is an average, garden variety Yellow Dwarf Class star. Born 4.6 billion years ago, this star is middle-aged. In its core, the nuclear fusion rate is approximately 655 million tons of hydrogen per second, which is equal to about 100 billion hydrogen bombs per second.
Its diameter — 864,000 miles — is 109 times that of the Earth, but volume-wise we could put 1.3 million Earths inside the sun. The Earth can easily fit inside most average sunspots.
The sun is fascinating to watch through the safety of solar filters and special hydrogen telescopes. Safe viewing opportunities occur occasionally at the High Desert Museum and the Oregon Observatory at Sunriver.
The sun changes by the hour. Events on the sun are localized, short-lived phenomena on or near the surface. The most visually dramatic of these active regions are sunspots, flares and prominences caused by distorted magnetic flux lines. Because the sun is a gas, it spins faster at the equator than the poles. The speed of the sun’s rotation at the equator is once every 25.38 days, whereas the poles rotate once every 31 days. This “differential rotation” greatly distorts the solar magnetic field, driving the development of the active regions.
The exact cause of sunspots, cooler areas than the surface, is not fully understood, but sunspot numbers vary periodically. On the average, about 11 years pass between maximum number of sunspots. This is called the 11-year sunspot cycle. Currently, sunspot numbers are expected to peak in 2013.
Scientists are still learning more about the mysterious star our planet orbits. If only we could send astronauts to the sun for a close-up. Perhaps we could send them during the night, when it’s cooler.
