The total solar eclipse that occurred on the 21 August 2017 was the first in 99 years in the US and Across the Atlantic. And there have only been eight total solar eclipses in the last 500 years that have been visible from the UK. The next not being expected until the 23rd of September 2090.
The Moon travels between the Earth and the Sun on a monthly basis, but due to its orbit being tilted to around 5 degrees, compared to the Earth’s orbit around the Sun, yet the Moon is usually too high or too low in the sky to get in the way of the Sun’s light. But about once every 18 months, it lines up directly between the Earth and the Sun allowing the Moon to cast its shadow on Earth, causing a total eclipse. Yet this can fall anywhere on earth and as only 26 percent of the earth’s surface is inhabited not many eclipses are seen.
Actually, we can only see eclipses at all because of a term called ‘cosmic coincidence’. Meaning that eclipses don’t happen on all planets yet due to utter luck and complete chance, us on earth can observe this phenomenon first hand. This cosmic coincidence is due to the Sun being approximately 400 times bigger than the Moon, yet also being to be about 400 times further away from us. This makes them appear around the same size when viewed from Earth, so the Moon is able to block out the entire Sun for short periods of time. This exact matchup does vary slightly due to the Moon’s distance from us constantly varying due to its not circular orbit. Allowing for the variation in types of solar eclipse.