The truth is, the “dark side” of the Moon is not perpetually dark as we once thought!
August 23rd will be a day to look forward to for India and the global astronomical community as the Chandrayaan-3 mission is set to land the Vikram lander on the lunar surface at 18:04 Indian time in the Moon’s harsh South Pole region.
If the landing is successful, India will not only join a select group of nations that have landed on the Moon (alongside the Soviet Union, the United States, and China), but will also become the first country to successfully touch down in the dark region of this natural satellite. Previous landings have all occurred in well-lit conditions surrounding the Moon’s equator.
Russia’s Luna-25 mission failed in its attempt to lower its orbit in preparation for landing in the South Pole due to technical issues. Why is the dark South Pole of the Moon so difficult to access?
What is the mystery of the dark side of the Moon? (Illustrative photo: Internet).
Known for its frigid temperatures, rugged terrain, and thin atmosphere (which does not aid in slowing down the landing craft and renders GPS ineffective), the Moon in general, and the obscured South Pole in particular, remain a challenging puzzle for modern science and technology. In return, this area may hold a “treasure trove” of water ice and various precious minerals. This is why the Moon’s dark side is becoming a target for many space powers in the 21st century.
In recent days, we have heard the term “the dark side of the Moon” used to describe something mysterious, harsh, and unknown. This area is believed to be the side that we can never see from Earth. Opposite it is a vast expanse of cold, dark space.
The harshness of the “dark side” of the Moon, as we call it, is certainly evident. It is much more difficult than landing on the “bright side.” However, the reality is that many of us may not fully grasp the essence of what we call the Moon’s “dark side,” how it operates, and how it has remained hidden from scientific efforts from Earth up until now.
What could be on the other side of the Moon? What are the conditions like there? Is it really always dark? Let’s address these questions right away.
Unraveling the Mystery of the Dark Side of the Moon
First, the fact that we cannot see the dark half of the Moon from Earth does not mean we don’t know what it looks like. In humanity’s journey to explore space, we have had the opportunity to see part of it from spacecraft launched by the Soviet Union and the United States.
In October 1959, the Soviet spacecraft Luna-3 became the third spacecraft to reach the Moon and the first to send back images of the far side of the Moon. The images were grainy and unclear, but they provided a glimpse of a part of the Moon that had never been seen from Earth before.
In 1968, astronauts aboard Apollo 8 were the first to directly observe the dark side as they orbited the Moon. So, what does the dark side of the Moon look like?
The dark side of the Moon captured by Luna-3. (Photo: NASA).
Firstly, the description of the “dark side” is often misunderstood as a shadow that permanently covers half of the Moon’s surface. It is assumed that we could easily observe the dividing line between the light and dark areas and that by crossing this boundary, one would enter the dark side—an area that we can never observe from Earth. However, this is not accurate.
This is because, just like Earth, the Moon has day and night. So, if you camp on the Moon and stay at a given spot, you will eventually see the Sun rise and set—meaning you will experience both day and night. It is more accurate to say that the Moon has a part in daylight and a part in darkness, just like Earth.
The daytime side is the side currently receiving sunlight, while the nighttime side faces away from the Sun.
What does this have to do with the side we see when looking at the Moon from Earth? This is where things can get confusing. The side of the Moon we see can sometimes be in daylight and sometimes in darkness. It all depends on when we look at the Moon.
A more precise term to describe the side of the Moon we see is the near side (the near side, to distinguish it from the far side). The near side always faces us, and the far side always turns away into darkness. This holds true even on the opposite side of the Earth.
Both the near side and far side of the Moon have day and night. Both receive sunlight at certain points in the Moon’s orbit around Earth. We cannot see the far side of the Moon, even when the Sun is shining on it, because the far side is always facing away from us.
How the Moon orbits Earth and rotates on its axis. Just like Earth rotates on its axis and orbits the Sun. (Photo: Internet).
So why do we only see one side of the Moon from Earth, and how does the Moon’s cycle relate to this?
It takes about 29 days for the Moon to complete an orbit around Earth. This is also the amount of time it takes for the Moon to make one rotation on its axis. Because the rotation period and the orbital period of the Moon take the same amount of time, we always see the same side of the Moon whenever we look at it.
This may sound confusing, but here’s a way to visualize it.
If the Moon did not rotate, we could see every side of its surface. Similarly, if the Moon’s rotation were faster or slower, we would eventually catch glimpses of the entire Moon. So why does the Moon only rotate once for each orbit around Earth?
The short answer is gravitational force.
The Moon and its fascinating formation history continue to intrigue scientists to this day. (Photo: Internet).
The gravitational pull of the Moon from Earth has slowed the Moon’s rotation to its current speed. Its rotation has been “locked” to the time it takes to orbit Earth.
Thus, there is no permanent dark side of the Moon (meaning there is no side of the Moon that is eternally devoid of sunlight).
However, the dark side of the Moon still holds many mysteries for humanity. Due to the Moon’s massive size blocking radio signals transmitted to and from Earth, it may take many more years for aerospace engineers to devise a way to explore the far side on a larger scale.
We may even start to see NASA and other agencies establish relay satellites in lunar orbit to facilitate such exploration.
Moreover, the Moon’s thin atmosphere does not aid spacecraft in decelerating, making a gentle landing on this natural satellite’s surface a highly technical endeavor. Coupled with the signal blockage from Earth, a lander must operate autonomously during its landing process. This is why landing on the Moon has never been easy.
