Sometimes appearing very close by the Earth, other times appearing incredibly distant, and sometimes completely absent from the night sky, the moon is the original optical illusion. Before we developed comprehensive astronomical knowledge, it kept humans guessing since the dawn of our species. How long does light take to travel from the Moon?
Of all the celestial objects in our solar system, the moon seems the most alive, perpetually changing its face, perceived distance, and sometimes even its color, but the truth is that the moon maintains a fairly consistent distance from the Earth.
Of course, the question of the hour is… just how far away is the moon from the Earth in light years? And that’s precisely what we’ll be discussing here today.
How Many Light Years Away From The Earth Is The Moon?
You may or may not be surprised to learn that, as our closest neighbor in the solar system, the moon isn’t even a single light year away from Earth. In fact, it doesn’t get close to being a light year away.
It wasn’t just that we thought the moon was pretty cool when we chose it as our very first outer space destination.
We chose it because of how accessible it is in terms of distance. If it had been even a single light year away, we would not be able to reach it and may not even know of its existence.
While the moon is an insanely large object by human standards, on a cosmic scale, it’s a fragment of a fragment of a fragment of a spec, and there’s very little chance it’d be on our radar if it were so far away.
We can only see it on its current orbital path because the sun is perpetually bathing it in super bright light that reflects down to Earth.
So, with that cleared up, our new question becomes… just how far away from Earth is the moon?
How Far Away Is The Moon?
Remember when we said the moon “maintains a fairly constant distance from the Earth”? Well, the operative word there is “fairly”.
The precise distance between the Earth and the moon fluctuates throughout our rocky celestial’s orbit, the reason being, the moon’s orbital path doesn’t form a perfect circle.
Rather, the moon follows an elliptical path, meaning its orbit is like a squashed circle that’s wider than it is long.
In other words, the moon cycles around an egg-shaped rather than a ball-shaped circuit.
At its perigee, which is to say, the point at which it’s closest to Earth, it is 225,623 miles (363,105 km)away, and when it reaches its apogee, which is to say, the point at which it’s farthest from Earth, it is 252,088 miles (405,696 km)away, with an average distance of about 238,855 miles (384,400km) away.
Because the Moon is sometimes closer to us and sometimes farther the Moon it appears to change size. At its closest, it is about 14% larger and 30% brighter than when it is at its farthest. When it is at its closest, we call it a supermoon, and at its farthest a micromoon.
Using the average distance to the Moon, we can say that the moon is roughly 30 Earths away, which is still significant, but not so far at all compared to the distance between Earth and any other celestial bodies in our solar system.
For instance, Mars, the second outer space destination on mankind’s list, is a whopping 100,394,943 miles (161,570,000 km) away. This means Mars is over 420 times farther from Earth than the moon, and even this distance doesn’t come close to a light year.
What Is A Light Year?
Before we can figure out what fraction of a light year the moon is from Earth, we first need to understand what a light year actually is.
In a nutshell, a light year is the distance light can travel in 365 Earth days, which is one year on Earth.
Now, considering light is the fastest thing in the known universe, capable of belting through the vast expanse of space at 186,000 miles per second (299,792 km/sec), you won’t be surprised to hear that a light year is a genuinely mind-bending distance.
How Far Is A Light Year?
A light year equals 5.8 trillion miles (9.46 trillion km). This means that the moon is 3.96×10-8 light years away from the Earth. In more understandable terms, the moon is 1.25 light seconds away from us. Just for clarity 3.96×10-8 is scientific notation for 0.0000000396.
That’s using the moon’s average distance as a reference point to anchor the math. The exact figure will change depending on where the moon is in its orbit.
How Long Is A Light Year?
Because of the word ‘year’ in a light year, many think it is a time measurement. A light year is a measurement of distance, not time. As such, a better question is, how far is a light year? The answer to this question is given above this question.
How Long Would It Take To Reach The Moon?
It takes a manned spacecraft about three days to reach the moon, but the specifics of the journey duration depend on the path chosen, the speed of the spacecraft, and where the moon is in its elliptical orbit.
How Long Did It Take To Reach The Moon In 1969?
The Apollo 11 mission that took Buzz Aldrin, Neil Armstrong, and Michael Collins to the moon, making them the first humans ever to make the trip. The trip took precisely four days, six hours, and forty five minutes, traveling at about 24,200 miles per hour (38,946 km/h).
To some controversy, Neil was the first of the men to walk on the moon, with Buzz following swiftly behind him despite technically being his superior. Poor Michael Collins was left orbiting the Moon. Michael Collins is often stated as being, for a time, the loneliest human ever.
He traveled hundreds of thousands of miles there, then hundreds of thousands of miles back without ever getting to walk the moon’s surface or share in the glory that followed his two mission mates once they touched down on Earth.
Final Thoughts
That’s that cleared up — The moon isn’t even close to being a light year away from the Earth. In fact, it’s only 1.25 light seconds from our planet, which is why it’s such an accessible celestial to humankind.
To put the sheer distance of a light year into context, it’s not just the moon that isn’t that far away; none of the eight planets in our solar system gets near a light year from the sun, not even Neptune.
We will leave you with an interesting fact about the distance of the Moon from Earth. Due to the gravitational interactions between the Earth and the Moon, the Moon is moving away from the Earth at the rate of 3.78cm (1.49in) per year.
The Moon is at a distance that it can cover the whole Sun as it passes between the Earth and Sun. For information on viewing solar eclipses, see our article about solar eclipses.
Hi, my name is Jason Anderson, and I am a Physics Professor. Ever since I was a kid, I’ve been fascinated with space, the universe, the moon, you name it. I spent hours and hours at the planetarium close to my hometown, wondering what else could be out in the universe.
Since then, I’ve been an avid stargazer and astronomer, and love nothing more than spending my time charting stars, observing planets, and finding constellations.
This is why I decided to start Telescope Guru. I only wish to share this fun pastime with the world. With this site, I hope to answer all of your questions relating to astronomy, telescopes, and stargazing.
