Preface: The Moon
I stopped, on the way home after work today. A familiar but unusual sight was hanging on the horizon. The Moon. It has been several days since I’ve seen the Moon. The clouds and weather have been crazy the past week. A few curious people stopped alongside me, wondering what made me stop. After a few short seconds later, the surmised that it was just the Moon.
If they only knew.
Moon, captured by Tiny1 Prototype.
The Moon is our nearest neighbor in space. Given the proximity and frequency of its appearance, it was no surprise that most people find it the most boring object in space.
It is anything but boring.
It has various names across various location and history of man. Some cultures follow its cycle for sowing and harvest. Other bizarre associations such as insanity and irrationality, formed the basis of the word “lunacy”. It affects our seasons, tides and almost everything we find normal on Earth today. It was the ultimate goal of the strongest space race in human history.
What we do know about the Moon is fascinating.
What we do not know about the Moon is truly out of this world.
1) It is the farthest location we have ever explored
Moon is the only place outside of Earth, that humans have ever visited. Apollo 11 landed on July 20, 1969. Six hours later, Neil Armstrong stepped out of the spacecraft and became the first man on the Moon. It was at that moment he coined the famous phrase, “One small step for man, one giant leap for mankind.”.
The farthest humans from Earth, was around the far side of the moon
Apollo 13 Crew passed the far side of the Moon at 400,171 km from Earth on 15th April 1970
Only photo taken of Neil Armstrong on the Moon. /Credit: NASA
Most of the photographs during the surface were taken by Armstrong and do not include him within the photos. The woe of every photography buff extends to lunar soil. Not sure if the Hasselblad he carried would balance on a selfie stick on the Moon, given its low gravity.
2) It is increasing the day on Earth
Moon exerts a force on Earth’s rotation, which increases the duration of a day on Earth. Don’t hit the snooze button. It only increases the length of a day by 15 micro-seconds every year.
3) It is massive
Our Moon is massive amongst the moons of other planets in the Solar System. At 1/81 of the mass of the Earth, the Moon is the largest moon relative to the size of its planet. It is the 5th largest natural satellite, just after Io of Saturn and it is larger than dwarf planet Pluto.
Moon versus Pluto (far right). /Credit: NASA
4) It appears to be the same size at the Sun
Through some coincidence, the Moon appears to be the same size as the Sun from the surface of Earth. This allows total solar eclipses to form as the Moon briefly occludes the Sun completely.
However, this coincidence occurred fairly recently, at only hundreds of millions of years ago. The Moon has always been moving away from the Earth at a slow rate. The continued departure of the Moon and the expansion of the Sun means that total solar eclipses would only last for another six hundred million years.
Last Solar Eclipse captured from Singapore by Tiny1 prototype. Singapore was just outside of the area totality could be observed.
5) It is leaving us
Although the Moon will not disappear from sight anytime soon, it is moving away from Earth at the rate of about 38mm (1.5 inch) per year. Roughly the rate the human fingernails grow. So, remember the Moon every time you trim your nails.
What we do not know about the Moon
1) Gravity Anomaly
Moon’s gravity vary significantly across its surface. It is enough that it affects the space crafts sent into its orbit. However, the cause of the anomalies is not known till date, despite it being one of the most studied astronomy objects.
Gravity map of the Moon taken by GRAIL /Credit: NASA
2) Is it alien?
The Moon’s origin is a mystery. If was formed together with Earth, it should share more similarities with Earth’s composition. However, the Moon has a much smaller iron core, compared to Earth.
If the Moon was alien, it should exhibit greater difference in composition compared to Earth. However, Earth and Moon share the same oxygen and titanium isotope ratio.
The various evidence points us in different directions on how the Moon is formed.
Our best guess is that the Moon is part of a large object known as Theia. It struck prehistoric Earth and the resultant mix of Earth and Theia accreted into the Moon as we know it today. The impact probably explains the tilt in the rotation of the Earth. The tilt creates 4 four distinct seasons that is experienced on Earth.
Impactor event, artist’s depiction. /Credit: NASA
If the Giant Impact Hypothesis is right, it’s safe to say, without the Moon, we may not experience Sakura flower blooms in Japan. Beauty on Earth, courtesy of “aliens”.
Well… that’s another thing I would stop on the way home for. Unfortunately, we live in tropical Singapore.