Moons and Planets
The Moon (la Luna)
The Moon is the only natural satellite to the Earth. It is believed to be formed about 4.5 billion years ago from an impact the size of Mars into the earth and the debris from the collision was thrown into orbit.
- On average the distance of the moon is 238,900 Miles (384.400 km) from earth.
- The Moon’s axis is tiled at 6.7 degrees from the vertical.
- The Moon’s diameter is 2160 Miles just over a quarter of the Earth’s size.
- The average temperature is -18c.
Have you ever wondered why you can see the Moon in daylight?
The Moon is the brightest object in the sky (apart from our Sun). The reason for this is that the Moon is so close to us.
The Earth rotates around on its own axis every 23h 56m 4.098 hours. Because the Moon is moving around the Sun at the same time as us “Earth” there is no “dark side of the moon” contrary to popular belief. It is just a great album by Pink Floyd.
The side of the Earth which faces the Sun during its rotation we call the day.
The Moon orbits the earth (moves round the earth) once every 27 days 7 hours 43 minutes and 11.6 seconds. It does not produce any of its own light.
Imagine that the Moon is a giant mirror as you are only seeing a reflection from the Sun. The amount of light reflected depends on the angle the Moon is to us. This causes the phases of the Moon. The phase cycle of the Moon takes 29.5 days.
For example, when the Earth is between the Moon and the Sun, a Full Moon is seen only at night. Because the side of the Moon which reflects the sunlight is facing the part of the Earth that is facing away from the Sun.
When the Moon is between the Earth and the Sun, the side of the Moon which is reflecting the sunlight is pointed away from the Earth, so we can’t see the light. This is called a New Moon. The Moon is not visible during this phase, except during a Total Solar Eclipse of the Sun when the Moon passes in front of the Sun.
The phases, starting with the New Moon, then waxing crescent, then First Quarter, waxing gibbous, then the Full Moon. Each of the phases up until the Full Moon represent more and more visible reflection. During these phases, portions of the Earth can see the reflected area of the Moon so you can see this in the afternoon / evening time.
After the phase known as Full, the Moon starts to fade away to a waning gibbous, then Last Quarter, then the waning crescent, then back to the New Moon. Amateurs like to see how soon after new the Moon can be spotted, some friends of mine have seen it at around eighteen hours.
This is when you can see the Moon in the mornings, it is just the opposite of the previous phases. Hence you see the Moon during the day, morning or evening.
The Moon is visible in daylight nearly every day, the exceptions being close to new, when the Moon is too close to the sun to be visible, and close to Full Moon when it is only visible at night. The best times in the month to see the Moon in daylight are close to First and Last Quarter, when the Moon is 90 degrees away from the Sun in the sky. Once you’ve seen the daylight Moon, it is worth trying to see how many days in the month you can manage to spot it. Weather permitting!
This illustration will help you visually understand it:
Once in a Blue Moon! Explaining what it is?
The second Full Moon occurring within a calendar month is called a Blue Moon. The last was seen on 31 December 2009. Far from being a rare event this phenomenon occurs once every three years on average.
Another definition of the Blue Moon is the third Full Moon that occurs in a season of the year which has four full moons (usually each season has only three full moons.) The next Blue Moon will happen on August 31st 2012.
The only month that can miss a full moon is February. The next February that will have no full moon is in 2018.