What will you see?
A little history
more information
A cosmic coincidence
What will you see?
When the moon passes in front of the sun during a total eclipse, the portion visible is called the corona. The sun is surrounded by an atmosphere of gases. The corona is the outermost part of the sun’ s atmosphere, usually hidden by the bright light of the sun’ s surface. However, it can be seen during a total eclipse. During the nearly four minutes of totality, the sky will become dark, as if it were dawn or dusk. The temperature could drop about 10 degrees, depending on the humidity and cloud cover.
A little history
The earliest recorded solar eclipse dates to 2137 BCE, nearly 4,000 years ago, in China. Ancient civilizations in Europe, Africa and Asia saw eclipses as omens of doom or messages from their gods. Native Americans had their own beliefs and explanations. Some ancient civilizations accurately predicted solar eclipses and used them to test the validity of calendars. Astronomer Johannes Kepler wrote about the corona during an eclipse in 1605. Since then, scientists have used eclipses to make new discoveries about the sun, moon, and Earth’ s atmosphere.
more information
Websites containing information on the eclipse include: American Astronomical Association: eclipse. aas. org Brown County Visitors’ Center: browncounty. com National Aeronautics and Space Administration: science. nasa. gov Indiana State Police: Indiana. gov / isp State of Indiana: eclipse2024. in. gov, visitindiana. com / eclipse2024 Brown County Library: browncountylibrary. info Indiana Department of Natural Resources: Indiana. gov / dnr
A cosmic coincidence
A total solar eclipse, in simplest terms, occurs when the moon’ s orbit comes between the sun and the earth’ s orbit. The American Astronomical Society( AAS) calls it a rare event and a“ cosmic coincidence.”
In our solar system, there are 290 moons orbiting planets, some of which are quite small: One moon for Earth, two for Mars, 95 at Jupiter, 146 at Saturn, 27 at Uranus, 14 at Neptune, and five for dwarf planet Pluto. But Earth is the only place that has a moon the right size and distance from its planet to barely cover the sun and reveal its corona. Total eclipses occur somewhere on Earth every year or two, but on any given spot on the planet, a total eclipse could be visible only once about every 400 years, scientists say.
The AAS explains it this way:“ The sun’ s diameter( 865,000 miles) is about 400 times the moon’ s( 2,160 miles). The sun is also( on average) about 400 times farther away( 93 million miles vs. 240,000 miles). As a result, the two bodies appear almost the same angular size in the sky …. This truly remarkable coincidence is what gives us total solar eclipses.”
At new moon— the only lunar phase when a solar eclipse can occur— the paths of the moon and Earth usually don’ t line up. Given all the variables, it’ s almost surprising that we see eclipses at all, the society explains.
“ The moon orbits Earth; both swing around the sun. In a perfect universe, we’ d see totality every month. But we don’ t, and here’ s why: First, the apparent size of the sun varies during the year because Earth’ s orbit is an ellipse, not a perfect circle. Our planet is closest to the sun( perihelion) in early January and farthest( aphelion) in early July …. More dramatic is the change in the moon’ s apparent diameter due to its elliptical orbit around Earth. When the moon is closest to Earth( perigee), its apparent diameter is up to 14 percent larger than when it’ s farthest( apogee). When near perigee, the moon can easily cover the entire solar disk and create a total solar eclipse. But at apogee the moon is too small to cover all of the sun’ s brilliant face. At mid-eclipse an annulus( ring) of sunlight surrounds the lunar silhouette, resulting in an annular eclipse.”
The whole thing gets more complicated by the tilt of the moon’ s orbit, and the path of the Earth’ s movement around the sun. But roughly every six months, the new moon’ s orbit lines up and a total, annular or partial eclipse is possible at some place on Earth.
According to the National Oceanic and Atmospheric Administration, the next total eclipse visible in the U. S. will be March 2033, only in Alaska. After that, it will be August 2044 in Montana and North Dakota, then August 2045, when the eclipse will traverse from California to Florida.
March / April 2024 • Our Brown County 19