The Sun is Our Home Star


The Sun is our home star. This great ball of heat and light, this round mass of fire, was called Sol in ancient Rome and Helios in Greece. According to a legend from the Muskogee (Creek) peoples of the southeastern United States, the Sun was carried aloft on top of a vulture’s head, inside a silken bag woven by Grandmother Spider. On bright, sunny days, when the light is just right, you can still see gossamer rays of Grandmother Spider’s bag shining down. Even though the Sun is more than 93 million miles


(150 million km) away, we can feel its heat and light as though it were close by. Just how far away is the Sun? If there was a road that led from Earth to the Sun, your family could climb into the car and drive there. But get out your iPods and earbuds, then download a ton of songs, because a ride to the Sun is going to take awhile. Let’s say that, on the road to the Sun, the driver


brought the car up to 70 miles per hour (113 kph) and set it on cruise control for the whole ride, 24/7. At that speed, if no one stopped to get a bite of food or to take a bathroom break and the drivers rotated so that you never had to slow down or stop, you would arrive at the Sun in 152 years! How long is that? If your family had begun such a journey back in 1861 — the first year of the U.S. Civil War — you would finally reach your destination in 2013. Even from that great distance, it takes the Sun’s energy


only 8 minutes and 20 seconds to reach us on Earth while traveling at the speed of light — around 670,000,000 miles (1,078,231,000 km) per hour. Traveling at that speed, sunlight would get a hefty speeding ticket on the interplanetary highway, if only someone could catch it! How big is the Sun? It would take 109 Earths, placed


edge to edge, to reach across the face of the Sun. And if you had a bag as large as the Sun, you could fit 1 million Earths inside.


A Real Ball of Fire


At times, when a person is being very active, someone will say, “You’re a regular ball of fire.” But no one can hold a candle to the Sun. At its center or core, the Sun’s temperature is 28 million°F (15.6 million°C). At this great heat the atoms of hydrogen join together to form helium, also from the Greek, Helios. Energy is created every time hydrogen joins to form helium. This reaction, called nuclear fusion, drives the Sun’s energy. Even though 600 million tons (544,311,000 metric tons) of hydrogen change into helium every second, there is still enough hydrogen left for the Sun to last another 5 to 6 billion years.


©2011 by Michael J. Caduto


This reading and following activities are excerpted with permission from: Catch the Wind, Harness the Sun: 22 Super-Charged Science Projects for Kids Storey Publishing (North Adams, Massachusetts).


GREEN TEACHER 93 Page 39


When we catch a brief glimpse of the Sun, we see the


200-mile- (322 km) thick layer called the photosphere, which is about 10,000°F (5,500°C). Sunspots are about 2,700°F (1,500°C) cooler than the rest of the photosphere, so they appear darker. Some sunspots are wider than the diameter of Earth. They can last for anywhere from a few hours to a couple of months, and they can produce violent explosions called solar flares. A large solar flare can last for a few hours, interrupt satellite communications on Earth, and generate enough energy to power the entire United States for 100,000 years. Sunspot activity runs in cycles of about 11 years. A high point in the number of sunspots is expected from late 2011 through 2013. Surrounding the photosphere is another, somewhat


hotter layer of the Sun called the chromosphere, which is 1,000 to 2,000 miles (1,600 to 3,200 km) thick. Finally, like a shimmering halo, comes the corona, in


which the temperature shoots up to more than 1 million°F (555,500°C). Superheated gases from the corona rocket off into space as charged particles called the solar wind. We can only see the reddish chromosphere and the corona’s whitish streamers during a total solar eclipse, a time when the moon passes directly between the Sun and Earth and the Sun is completely blocked out wherever the moon’s shadow falls. But the Sun’s energy can damage eyes and cause blindness, so don’t ever look directly at the Sun, even during an eclipse.


Neon in the Sky


In the Northern Hemisphere, especially when sunspot activity is high, look for spectacular, shimmering displays of the northern lights, Aurora Borealis. In the Southern Hemisphere, catch the southern lights, Aurora Australis. These dramatic nighttime spectacles are created when


the solar wind sends charged electrons and protons racing toward Earth, where they slide along Earth’s magnetic field toward the North and South poles. There the solar particles crash into the molecules of Earth’s atmospheric gases, causing those electrons to jump out of their orbits. The energy given off by the excited electrons shows up as brightly colored curtains and ribbons of light — green, red, pink, white, and lavender. We’ve all experienced or seen


in books the brightly colored neon lights that spell out the names of city restaurants and markets. The process that creates the northern and southern lights is similar to the way a neon light works: electricity passes through glass tubes filled with gas and causes it to glow. Each gas emits a different kind of color when it glows, such as neon (reddish orange), mercury (bright blue), argon (lavender), krypton (silver white), xenon (pale blue) and helium (gold).


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52