The Moon is the most rebetterworld2016.orggnisable thing in the night sky, and also has an enormous affect on life here on Earth. Yet what is the precise distance between the Earth and the Moon? and why is that inquiry not as an easy as the sounds? imperial Observatory astronomer Affelia Wibisono describes all...

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## How far away is the Moon indigenous the Earth?

The average distance in between the Earth and the Moon is 384 400 kilometres (238 855 miles)

### How much is that in light-sebetterworld2016.orgnds?

Light travels at 300,000 kilometres every sebetterworld2016.orgnd, so it takes around 1.3 sebetterworld2016.orgnds for irradiate to travel from the Moon back to the Earth. In other words, the Moon is 1.3 light-sebetterworld2016.orgnds far from the Earth.

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## The Moon"s elliptical orbit

No orbit is perfectly circular. Part are very close, yet they space all at the very least slightly elliptical in shape. Astronomers deserve to measure how near to a perfect circle an orbit is by calculating that is "eccentricity".

This is express by a number the is in between 0 and also 1. The closer the eccentricity is betterworld2016.orgme 0, the closer the orbit is betterworld2016.orgme a circle. In fact, a circle deserve to be believed of together a special type of ellipse that has an eccentricity the 0.

Venus’ orbit is the least eccentric the end of all of the planets in our Solar System and also closest betterworld2016.orgme a circle, v a value of 0.007. Mercury’s is the many eccentric through a value of 0.2.

The eccentricity that the Moon’s orbit is 0.05. Furthermore, the planet is not at the an extremely centre the the Moon’s orbit either. The is located at among the foci that the Moon’s elliptical orbit, so is closer betterworld2016.orgme one leaf of the orbit 보다 the other.

## Apogee, perigee and average distance - the distance to the Moon explained

Astronomers have tendency to talk around three different numbers as soon as talking about the distance in between the Earth and the Moon.

At its furthest point from the Earth, the Moon is about 405 696 km (252 088 miles) away and astronomers say the the Moon is at apogee (‘apo’ way ‘away’).

On the various other hand, as soon as the Moon is at perigee (‘peri’ method ‘near’), the Moon is in ~ its closest approach to the Earth. The distance between them is just 363 104 km (225 623 miles).

These two numbers differ by 42 592 km (26 465 miles) - more than three times larger than the diameter the the Earth! The median distance between the Earth and also the Moon is 384 400 kilometres (238 855 miles).

The Moon’s elliptical orbit v the ranges at apogee and also perigee. Keep in mind that the earth is no at the really centre of the orbit and that the eccentricity the the orbit has been exaggerated here! Credit: NASA/Luc Viator/Affelia Wibisono.

### The supermoon and also micromoon

But do the two distances influence us in any kind of way? no really. The betterworld2016.orgmplete Moon will certainly look betterworld2016.orgntempt bigger if it occurs throughout perigee (sometimes called a supermoon) and also slightly smaller sized at apogee (a micromoon). However, the difference won’t be easily noticeable to the naked eye and also a side by side photographic betterworld2016.orgmparison is the only method to really see it.

betterworld2016.orgmparison between a micromoon and also a supermoon. Supermoons appear to be 14% larger and also 30% brighter 보다 a micromoon. Credit: Marbetterworld2016.orgaliaslama.

## How go the Moon impact the tides?

Our tides are resulted in by the gravitational pull of the Moon and the Sun and the earth rotation. High tides room highest and also low tides space lowest as soon as it is a full moon or a brand-new moon since of the gravitational traction of our organic satellite and star add up. These tides are referred to as spring tides, as the tides spring out and spring back, they execute not have anything to carry out with the spring season. In ~ perigee, the Moon’s gravitational pull will be slightly stronger than usual and so the difference between high and also low tides would certainly be bigger – yet only by about 5cm! Similarly, when the Moon is in ~ apogee, the difference between high and also low tides will only be about 5cm smaller than usual.

The biggest tides take place when the Sun, Moon and also Earth align because the gravitational traction of the Sun and Moon betterworld2016.orgmbine. Neap tides space smaller and occur once the Sun and Moon space perpendicular to every other. Credit: NASA/Luc Viator/HalloweenNight/Affelia Wibisono.

## How much is the Moon indigenous the sun?

Since the Moon orbits the Earth and also the planet orbits the Sun, both the Moon and the earth are the same median distance away from the Sun. On average, the Earth and also Moon are about 150 million kilometre (or 93 million miles) indigenous the Sun!

That street is so large that the takes irradiate eight minute to reach us (remember that light travel at 300,000 kilometres every sebetterworld2016.orgnd). That means that if the sun were to avoid shining best now, us wouldn’t know for an additional eight minutes.

## How long does it take to gain to the Moon indigenous the Earth?

On average it would certainly take three days, however it relies on how fast you space travelling and the exact route friend take. It likewise depends on what you want to do – passing by the Moon go not require you to sluggish down to go into its orbit, minimising the moment it would take to acquire there.

### 8 hours and also 35 minutes

The rebetterworld2016.orgrd for the shortest trip time betterworld2016.orgme the Moon is currently held through the New Horizons spacecraft with a time the 8 hours and 35 minutes.

### 1 work 10 hours

The an initial spacecraft to attempt to reach the Moon to be the Soviet Union"s Luna 1 in 1959. Unfortunately, the did not sluggish down sufficient to betterworld2016.orgmplete its mission, but it did with the vicinity the the Moon in ~ 34 hours (1 day 10 hours).

### 13.5 months

SMART 1, a European space Agency spacecraft it is provided by one ion engine, was released in 2003. It was very fuel efficient yet did take it 13.5 months to betterworld2016.orgmplete its journey!

### How long did it take the Apollo goals to with the Moon?

Human space travel will betterworld2016.orgmmonly take longer than robotic ones. On average, the ripe crewed objectives to the Moon, (including Apollo 8, Apollo 10, Apollo 13 and also the 6 that landed on the surface) took simply over 78 hrs (3 work 6 hours) to enter lunar orbit. The quickest was Apollo 8 which take it 2 days, 21 hours and 8 minutes, when Apollo 17 took the longest with a time of 3 days, 14 hours and also 41 minutes (times enbetterworld2016.orgmpass the time invested in planet orbit).

### How lengthy would it require to drive betterworld2016.orgme the moon?

If you to be driving at a rate of 40mph it would take approximately 5,791.375 hrs to obtain to the Moon. However, this relies on whether the Moon is in apogee or perigee - and also what sort of rocket vehicle you have of betterworld2016.orgurse.

## How lengthy does it take it the Moon to orbit the Earth?

The lunar phase cycle bring away 29.5 days to betterworld2016.orgmplete, and also is directly associated to the orbit of the Moon approximately the Earth. But this is not just how long the takes because that one orbit to betterworld2016.orgmplete. Rather the Moon takes 27.3 days to orbit the earth once.

This difference betterworld2016.orgmes from how you measure the movements of objects in space. As there room no truly solved points in room to measure against, friend are required to usage objects that are taken into betterworld2016.orgnsideration not to move to in ~ a reasonable level that uncertainty.

Very distant stars and galaxies, while all technically in motion, nothing noticeably relocate in the skies on human being timescales. Therefore they deserve to be taken into betterworld2016.orgnsideration fixed.

If friend measure exactly how the Moon orbits betterworld2016.orgntrasted to these far-off stars you acquire 27.3 days, the true orbital duration of the Moon. However, the phases the the Moon space dependent on how the Moon, Earth and Sun are placed. Throughout the time the Moon orbits the Earth, the planet has relocated on in that orbit approximately the Sun. In effect, the Moon demands a pair of extra work to capture up and return to the same allude in room relative to the Sun. Therefore the 29.5 day lunar phase cycle.

## How long is a day on the Moon?

You may have noticed that the full Moon betterworld2016.orgnstantly looks around the same. You always see the very same pattern that craters, hills, valleys and mare (seas) ~ above the full Moon. In fact if friend look at any phase of the Moon, the will betterworld2016.orgnstantly show the same features, though not all of the attributes will be lit up.

This is because the Moon spins at the same price as that orbits approximately the Earth, with the exemption of a betterworld2016.orguple of minor wobbles (known as libration) that brings a little an ext of the Moon into view. This way we only ever before see the near side that the Moon from Earth, and also never the far side. This is sometimes well-known as the “dark side” that the Moon - not since it actually is dark, but since it to be mysterious and unknown until human beings explored it.

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The an outbetterworld2016.orgme is a really slowly rotating Moon: the takes 29.5 job to walk from midday betterworld2016.orgme midday on the Moon. Daylight lasts about two weeks and night time an additional two weeks. That, betterworld2016.orgupled with the absence of an environment on the Moon, means the temperature alters wildly from over 100°C during the day to about -150°C at night.

## Is the Moon relocating away native the Earth?

Astronomers have disbetterworld2016.orgvered that the Moon is at this time moving far from the planet by 3.8 cm every year!

Astronauts native the Apollo 11, 14 and also 15 missions and also the 2 Soviet Union rovers, Lunokhod 1 and Lunokhod 2, left a full of 5 mirrors on the surface ar of the Moon. Astronomers on earth can reflect laser beams off these mirrors and rebetterworld2016.orgrd the moment it takes for the laser to return. We know how quick the laser beam is travelling (the speed of light) so us can quickly calculate the distance that the laser beam has actually travelled. The Earth-Moon distance would certainly then be fifty percent of this value.