The point is that you can only have a solar eclipse if the Earth, Moon and Sun are exactly lined up in that order, so the Moon is in the right place to block out the Sun. That is also the definition of New Moon - that's the same time as when you can't see the Moon lit up. The Sun is lighting up only the back of the Moon that we can't see, so the side facing us is dark.
So obviously, a solar eclipse can only ever happen at the same time as a New Moon. To have a solar eclipse, the Moon MUST be in the New Moon position. If it's at any other phase, how can it block out the Sun and make an eclipse? It can't!
The only reason why we don't get a solar eclipse at every New Moon, every 29 1/2 days, is that the Moon's orbit round the Earth and the Earth's orbit around the Sun are angled a bit apart. They only cross at two places, called the nodes. Imagine a circle in space, then another circle in space in the same place but tilted a bit compared with the first circle. There's just two places where they cross, right?
So most times at New Moon there isn't a solar eclipse because the Earth-Moon-Sun line isn't perfectly straight. That means the Moon will appear to go slightly above or below where the Sun is in the sky, so there's no eclipse. To have a solar eclipse, you need New Moon AND for the Moon to be at a node. That's going to happen a lot less often! At most it can only happen twice a year.
That's not quite the correct word, 'must'. It's not that it must, it's that it just does.
A solar eclipse can only occur during the new moon phase. That's because the new moon occurs when the full moon's unlit side faces Earth. The other side is getting the full sun. When the new moon's path comes between the sun and Earth, you have a solar eclipse.
The ONLY Time a Solar Eclipse can happen is when the MOON gets Exactly between the Earth and the Sun, blocking the Sun Light getting to Earth. The Phase of the Moon at this time is called a NEW MOON.
The Opposite of a NEW MOON is a Full Moon, when the Earth is between the Sun and the Moon.
Essentially, when the moon is in between the Earth and the sun. The side of the moon facing Earth is in complete shadow, and it rises and sets with the sun - so, we basically can't see it... this phase is called "New Moon."
When the Moon eclipses the Sun, it means that the side of the Moon facing away from the Earth will be lit by the light from the Sun. That means that the side that faces the Earth will not be lit by the Sun, and that is what a New Moon is.
Answers & Comments
For a solar eclipse to occur, the moon must be on the same side of the earth as the sun, and the moon must be EXACTLY BETWEEN the earth and the sun.
the ONY time this can happen is during the New Moon phase.
Because the Moon is between us and the Sun at that point
And beautiful it is
Solar eclipses only occur during the New Moon phase, it is basic geometry.
http://www.eclipsegeeks.com/geometry-of-a-solar-ec...
The point is that you can only have a solar eclipse if the Earth, Moon and Sun are exactly lined up in that order, so the Moon is in the right place to block out the Sun. That is also the definition of New Moon - that's the same time as when you can't see the Moon lit up. The Sun is lighting up only the back of the Moon that we can't see, so the side facing us is dark.
So obviously, a solar eclipse can only ever happen at the same time as a New Moon. To have a solar eclipse, the Moon MUST be in the New Moon position. If it's at any other phase, how can it block out the Sun and make an eclipse? It can't!
The only reason why we don't get a solar eclipse at every New Moon, every 29 1/2 days, is that the Moon's orbit round the Earth and the Earth's orbit around the Sun are angled a bit apart. They only cross at two places, called the nodes. Imagine a circle in space, then another circle in space in the same place but tilted a bit compared with the first circle. There's just two places where they cross, right?
So most times at New Moon there isn't a solar eclipse because the Earth-Moon-Sun line isn't perfectly straight. That means the Moon will appear to go slightly above or below where the Sun is in the sky, so there's no eclipse. To have a solar eclipse, you need New Moon AND for the Moon to be at a node. That's going to happen a lot less often! At most it can only happen twice a year.
That's not quite the correct word, 'must'. It's not that it must, it's that it just does.
A solar eclipse can only occur during the new moon phase. That's because the new moon occurs when the full moon's unlit side faces Earth. The other side is getting the full sun. When the new moon's path comes between the sun and Earth, you have a solar eclipse.
The ONLY Time a Solar Eclipse can happen is when the MOON gets Exactly between the Earth and the Sun, blocking the Sun Light getting to Earth. The Phase of the Moon at this time is called a NEW MOON.
The Opposite of a NEW MOON is a Full Moon, when the Earth is between the Sun and the Moon.
Essentially, when the moon is in between the Earth and the sun. The side of the moon facing Earth is in complete shadow, and it rises and sets with the sun - so, we basically can't see it... this phase is called "New Moon."
When the Moon eclipses the Sun, it means that the side of the Moon facing away from the Earth will be lit by the light from the Sun. That means that the side that faces the Earth will not be lit by the Sun, and that is what a New Moon is.