A Total Solar Eclipse is coming our way- are you ready? This happens only once every 2000 years. We’re here to help you prepare! Find answers to all of your solar eclipse questions in time for August 21st, 2017!
1. When can I see the next TOTAL solar eclipse from North America?
- The NASA Eclipse site will show you the eclipse nearest your location. The next TOTAL solar eclipse visible from the United States occurs on August 21, 2017. The pathway goes from Washington State, and exits on the east coast near the Carolinas.
2. What causes an eclipse to occur?
- Eclipses occur due to the special coincidence of the Moon and the Sun being the same angular size. The Sun is 400 times wider than the moon, but it is also 400 times farther away, so they coincidentally appear to be the same size in our sky. This is what allows us the phenomenal beauty of the total solar eclipse.
3. Can I look at the eclipse directly?
- Sure, but only if you have the right eye protection. Check out eye safety suggestions from the American Astronomical Society.
4. What do Virginia Woolf, the rotation of hurricanes, Babylonian kings and Einstein’s Theory of General Relativity have in common?
5. What are “shadow bands?”
- These are among the most ephemeral phenomena that observers see during the few minutes before and after a total solar eclipse. They appear as a multitude of faint rapidly moving bands that can be seen by placing a white sheet of paper several feet square on the ground. They look like ripples of sunshine at the bottom of a swimming pool, and their visibility varies from eclipse to eclipse. Bands are produced because the Sun’s image is longer in one direction than another. The bands move, not at the rate you would expect for the eclipse, but at a speed determined by the motion of the atmospheric eddies.
6. How long will we continue to be able to see total eclipses of the Sun?
- The orbit of the Moon is not stable. Because of tidal friction, the orbit of the Moon is steadily growing larger, so that the angular size of the Moon from the Earth is shrinking. The Moon’s orbit is increasing by about 3.8 cm (1.5 inches) per year. When the Moon’s mean distance from Earth has increased an additional 14,600 miles, it will be too far away to completely cover the Sun. At the current rate that the Moon’s orbit is increasing, it will take over 600 million years for the last total eclipse to occur.
7. What happens more often, solar or lunar eclipses?
- According to Fred Whipple’s book “Earth, Moon and Planets,” page 102-104, solar eclipses are fairly numerous, about 2-5 per year, but the area on the ground covered by totality is only a few miles wide. In any given location on Earth, a total eclipse happens only once every 360 years. Eclipses of the Moon by the Earth’s shadow are actually less numerous than solar eclipses; however, each lunar eclipse is visible from over half the Earth. At any given location, you can have up to three lunar eclipses per year, but some years there may be none. In any one calendar year, the maximum number of eclipses is four solar and three lunar.
8. Typically, how big a temperature drop do you get during a total solar eclipse?
- It would probably be equal to the typical daytime minus nighttime temperature difference at that time of year and location on the Earth. It would be modified a bit by the fact that it only lasts a few minutes, which means the environment would not have had much time to thermally respond to its lowest temperature, so it would probably only be 3/4 or 1/2 the maximum day-night temperature difference.
9. Do lunar and solar eclipses have any noticeable effect on humans?
- There is no evidence that eclipses have any physical effect on humans. However, eclipses have always been capable of producing profound psychological effects. For millennia, solar eclipses have been interpreted as signs of doom by virtually every known civilization. These have stimulated responses that run the gamut from human sacrifices to feelings of awe and bewilderment. Although there are no direct physical effects involving known forces, the consequences of the induced human psychological states have led to physical effects.
10. What is the maximum possible duration of a total solar eclipse?
- Today it is 7 minutes 31 seconds. Two thousand years ago it was 7 minutes 34 seconds. Two thousand years in the future it will be about 7 minutes 27 seconds. The shortening of the durations is caused by the Moon moving slowly away from the Earth, at a rate of about 1.5 inch per year, a phenomenon caused by ocean tides.