The Sun is about 400 times further away from us than the Moon, and it's also about 400 times bigger than the Moon.
This strange cosmic coincidence means that both appear the same size in our sky, and is also the reason we get lunar and solar eclipses.
The Moon's orbit of the Earth is on a slightly different plane to the Earth's orbit of the Sun.
This is why eclipses are much less common than you might imagine.
We get a lunar eclipse when the Earth passes between the Moon and the Sun, preventing the Sun's light from hitting the Moon.
A lunar eclipse can only occur at full Moon, when the Moon is directly opposite the Sun in the sky.
Their frequency varies, but we get a total lunar eclipse roughly once every 18 months, and they usually last for about an hour or more.
Earth passes between Moon and Sun
We get a solar eclipse when the Moon blocks the Sun's light from hitting the Earth.
A solar eclipse can only occur when there is a new Moon, and while these also vary in frequency, we get a total solar eclipse about once every 18 months.
These last for between two and seven minutes.
Moon blocks Sun's light from hitting Earth
A lunar eclipse is visible from anywhere on the night side of the Earth, but a solar eclipse is only visible from less than 1% of the Earth, along a thin path drawn by the Moon's shadow.
Penumbra - the Sun is partially obscured
Umbra - the Sun is fully obscured
A lunar eclipse is completely safe to watch, but while a solar eclipse is much more spectacular, it should never be looked at without protective eyewear.
It begins with the Moon taking a small bite out of the western edge of the Sun.
This is known as first contact
The light fades very rapidly as we approach totality - the phase where the Moon totally covers the Sun.
Totality - Sun completely covered by Moon
Birds can become confused and go to roost, and plants close up for the night.
As the final rays of sunlight disappear, we get a beautiful diamond ring effect, before the Sun's spectacular corona - its ghostly outer atmosphere - reveals itself around the edges of the Moon.
A few minutes later, the Sun begins to reemerge and it's all over.