How often do solar eclipses happen?
Question:
Answer:
Hi Zach!
You can have between 2 and 5 solar eclipses per year. It is impossible to have fewer than two, or more than five.
It works something like this. Each 346 days, there are two eclipse "seasons" when the sun, earth and moon are in alignment to cause eclipses. During each eclipse season, there must be at least two eclipses, one of the sun and one of the moon. In addition, there is a possibility of a third eclipse in an eclipse season. So, possibly, there could be four solar eclipses.
Since there are two eclipse seasons every 346 days, it is possible to have a third season in a calendar year if the first season falls in January. In such a case, an additional solar eclipse might happen in December, making five. The last time this happened was in 1935, and it will occur again in 2206.
Not all solar eclipses are total, of course. On average, you get a total eclipse of the sun every 1.58 years, and in some years there are none at all.
In rare cases, you can get two total solar eclipses in a calendar year. The next time this will happen is 2057.
It is impossible to get three totals in a year. This is because the moon must also be closer to the earth than average to make the eclipse total. Usually, after the moon lines up for a total eclipse, the next eclipse season it will be near the far point of its orbit, so that earth will see an annular eclipse of the sun, not a total.
1 or 2 a year
Solar eclipses happen because the plane of orbit of the moon is slightly inclined with respect to the ecliptic - the plane in which the planets orbit the sun. So the moon can only block out the sun if its orbit happens to intersect the ecliptic at the new moon. This happens about once every 18 months somewhere on earth. Eclipses can be relatively easily predicted using "eclipse cycles".
There are between 4 and 7 solar and lunar eclipses a year of which 2 or 3 are usaully solar eclipses. Some of these may be "partial" or "annular" and, on average, a "total" solar eclipse occurs about every 18 months. Any specific location on earth will experience a total solar eclipse about every 200 years, but there are some spots that see 3 eclipses in less than 4 years and other spots will not see one for 2000 years.
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