The world watched with awe as the United States landed the first man on the moon in 1969. But even though space travel seemingly opened up a whole new frontier, the U.S. hasn't returned to the moon since 1972. Why is this? Perhaps it's because lunar research has revealed some secrets that the general public rarely hears about. And this intriguing information could explain why no further visits are planned.
1. First Impression
No one knew exactly what the lunar surface was going to be like. That's why NASA had its Apollo 11 astronauts train on a variety of different terrain all over the U.S. before launch.
Upon landing, though, Neil Armstrong and Buzz Aldrin found that the moon wasn't nearly as dangerous as they feared – at least for their short visit.
2. Learning From Above
After studying samples from the moon, scientists discovered that the satellite has a "crust, mantle, and core — just like Earth."
So astronauts can navigate the moon without breaking through its surface or spinning out of control from the lack of gravity. Yet although these similarities stirred up scientists' curiosity, further analysis would leave them disappointed.
3. Compared To Earth
We know, of course, that the moon is genetically similar to our planet in many ways. But the lack of iron and other significant elements on the moon leaves no atmospheric gas or water. That's partly why the satellite is so barren.
It's also part of the reason that it's without any form of life – or of further interest to science.
4. Barren Moon
No living organisms have ever been found to inhabit the moon. It's possible this could be due to the lack of breathable oxygen and fertile land from water.
This is, after all, why astronauts have to wear their tightly sealed space suits to survive on the lunar surface. But there's another reason why life on the moon may be impossible.
5. Preferable Conditions
Every living creature has its temperature and climate preferences. We human beings can handle a range of conditions – but we do have our limits.
And the moon far exceeds the limits of us – or any known living creature. This is mainly due to something that the celestial body doesn't have.
6. Can't Handle The Heat
The atmosphere around Earth protects it from burning solar rays and the freezing cold of space. But since the moon lacks this layer, there's nothing to shield it against these outside forces.
Temperatures typically range from -298 °F at night to 224 °F during the day. That's not the best environment for any traveler!
7. Shaking Things Up
One similarity that the moon has with Earth makes it dangerous in another regard. As quiet as the moon can be compared to Earth, this celestial body isn't completely still.
In fact – with its similar form of layered crust, mantle, and core – the moon has a tendency to shake up.
8. Shaken Up
Don't confuse moonquakes with our planet's earthquakes. These bad boys are on another level!
Without water to soften the impact of moonquakes, they can last up to three times longer and the resulting devastation can be much worse. NASA studied moonquakes after the Apollo missions – and what they found was intense.
9. Measuring Chaos
The Apollo Space Program placed seismometers to measure the magnitude of the quakes. By the time the research project was retired in the late '70s, NASA had counted 28 moonquakes of varying magnitudes.
Unfortunately, in addition to these lunar events, there are far more natural catastrophes to look out for.
10. Attack From Above
Everyone knows that the moon is covered in craters.
And while the playful idea of comparing the moon to cheese is always nice, it's better to understand what that's really about. It's actually very simple: the moon is vulnerable to constant asteroid collisions.
11. Important Protection
We'd hate to sound like a broken record, but the lack of a protective atmosphere really does make a difference. Chances are that the Earth has the same amount of asteroid collisions as the moon – but you'd never know it.
That's because our atmosphere shields us from them. The constant changes on Earth's surface also cover up most of the evidence.
12. Covering Up
Even when an asteroid or a meteorite makes a landing close to home, there won't be any remains or craters left behind. Geological activity, such as weather and volcano eruptions, erode signs of impact on Earth. But since the moon has none of this, all the evidence is left on its crater-covered face.
And even though astronauts have so far been able to evade these hazardous showers, there's one peril that can't be ignored on the moon.
13. Tiny Threats
Even if they avoided a great meteor or asteroid, astronauts still have to worry about micrometeorites and solar wind irradiation. These come about when the relentless conditions break up a deep layer of the moon's soil. The solar wind doesn't just sweep up gray dust and rock fragments, you see.
It could also contain pieces of volcanic glass. Astronauts found that the aggressive pressure of these conditions was a lot to bear – to the point that even their equipment would suffer.
14. Space Mess
Micrometeorites have previously broken up rocks and melted patches of ground. It also created small glass fragments that would go just about everywhere.
The shards invaded nooks and crannies of the lunar module, the spacesuits of the astronauts, and even went through the seals of sample boxes. The material also had a "static cling" that made it a challenge to remove.
15. A Haunting Relic
There is also the matter of the visible trash piles on the moon. And most of the debris is comprised of “space junk” — small bits of discarded satellites and machinery — that was actually created by man. This also includes backpacks, golf balls, cameras, and rockets. But the most chilling part?
The ashes of a dead scientist lie somewhere on the moon's surface. NASA took the remains of Eugene Shoemaker up there to honor his many contributions to space flight.
16. Unreliable Technology
But there's one machine up there that's in perfect working order. The Laser Ranging Retroreflector is a device that uses a set of mirrors to reflect laser pulses from Earth.
This device has helped scientists measure the exact distance between Earth and the moon. The retroreflector's big advantage is that it is really just mirrors, so it doesn't require any power.
17. Seeing From Afar
Just like organisms, most machines don't last too long in the brutal lunar environment. So scientists are grateful for the Laser Ranging Retroreflector.
It's improving their knowledge every day about the moon's orbit and rotation. But it has also revealed a concerning reality.
18. Galactic Shift
Thanks to the retroreflector, scientists started to notice a great change in distance between the Earth and the moon. They calculated that the satellite is floating further and further away from us — by about 1.5 inches every year.
But while the rest of us are shocked by this revelation, one man knew it all along.
19. Called It
Nearly 300 years ago, English astronomer Edmond Halley first suspected the moon was moving.
His study of ancient eclipses aroused his suspicions – and they were eventually confirmed in the 1970s. Apparently, this phenomenon has been happening for longer than we could have guessed.
20. Pushing Away
For billions of years, gravity from Earth has forced the moon away. Simply put, rising tides slowing the Earth's spin have caused the moon to spin faster and farther away from our planet.
This poses great changes for our planet's future. They also mean that another manned mission to the moon isn't happening anytime soon.
21. Science Non-fiction
The hope for space travel hasn't died, but the funding, for the most part, has. NASA has hopes to create a live-in space station, but the government support seemingly isn't there.
It's not the thrilling sci-fi epic you might want to hear, but so long as Capitol Hill has its focus elsewhere, it may be some time before we can walk among the stars again. Still, there's another celestial body that may be more practical to visit...
22. Signs Of Water
Will we put a man on Mars? Well, given our advancing technology and shrinking natural resources on Earth, futurists have proposed colonizing our neighboring planet. We know Earth is the only planet in our solar system capable of sustaining human life, and that's largely because our home has a sufficient amount of water.
It's clear when we look at a photo of Mars that the landscape is dry and barren. However, evidence suggests it wasn't always that way.
NASA's Photos
The terrain on Mars' surface reveals that the planet, at one time, had flowing water!
There were several spacecraft sent by NASA to investigate the surface of the Red Planet, and they've sent back photos of long deep grooves that could have only been created by the power of flowing water. Could it still be there?
23. Frozen Water Exists
The rovers NASA sent to Mars over the years were tasked with several different missions while they traversed the rocky terrain, and one of them was keeping an eye out for any signs of life.
The presence of water always indicates possible life, and although Mars doesn't have any flowing water, the poles contain some in a specific state.
Icy Poles
Patches of frozen water lie at both the north and south poles, and scientists hope these imply that there are other ice blocks around the planet as well.
The thin atmosphere prevents the water from thawing, but questions still remain as to whether there are certain times of the year the ice may melt slightly and allow microbes to grow.
24. Mars' Atmosphere
We know the current atmosphere of Mars is far too toxic for any substantial elements of life to exist.
However, the presence of frozen water at both of the poles means at some point in the past, the environment was suitable enough to sustain the liquid. So, what happened?
The Sun's Role
Scientists believe the sun played a huge role in the drastic change.
Over the last few billion years, the powerful rays of the sun were thought to have stripped hydrogen out of the atmosphere. Over time, the missing hydrogen molecules would drastically deteriorate the environment.
25. Extreme Terrain
Photos prove the terrain on Mars is far more rugged than Earth's, and much of that actually has to do with the planet's gravitational pull.
Because the pull is only 37 percent as strong as Earth's, volcanoes —like the Olympus Mons pictured here — can grow 16 miles high!
Highs And Lows
And, those incredible distances are the same in the opposite direction. This massive canyon called the Valles Marineris is four miles deep in certain parts!
It's not just the depth that's impressive either; NASA reported that the valley's width equals the length of the United States and makes up roughly 20 percent of Mars' diameter!
26. Double Moons
While we all know Earth has a moon, Mars doubled down on its collection and has two orbiting it.
Their names are Deimos and Phobos, and because they have very similar compositions to other asteroids found in the solar system, NASA believes Mars' gravity forced these satellites into their orbits long ago.
Bye Bye Phobos
However, scientists predict a grim ending for Phobos.
Sometime in the next 30 million to 50 million years (a relatively short time when talking about the solar system), the larger moon will either smash into the planet's surface or fall apart completely due to the gravitational tidal force.
27. Fallen Pieces
Throughout Mars' history (which is a really, really long time), numerous asteroids struck the planet's surface.
When the asteroids broke apart into millions of pieces upon impact, most of the debris was pulled back into the Red Planet thanks to its gravitational pull. But, some stragglers managed to escape.
Escaping The Pull
Because Mars' pull isn't as strong as Earth's, some fragments escaped and made their way into the solar system.
Most floated away into space's abyss, but some actually landed on Earth, and a handful of lucky people over the years have stumbled across these galactic treasures.
28. The Hollywood Illusion
While there has been a slew of movies about trips to Mars, there's never actually been an astronaut who's stepped foot on the planet's surface.
NASA's sent land rovers that successfully touched down, but sending a human to the Red Planet poses a lot of problems.
A Merciless Environment
The planet's environment is way too hazardous, and until some major leaps in technology are made, it's best to keep people far away. The average temperature is 50 degrees below zero!
And, even if temperatures were ideal, 95 percent of the atmosphere is comprised of carbon dioxide, which would kill an astronaut almost immediately.
29. Early Theories
NASA has spent years researching Mars, and it seems like there's always something new to learn. When the space organization first sent probes many years ago, the photos taken showed lots of craters.
This misled scientists into believing the planet was quite similar to the moon. However, that theory changed in 1971.
Mariner 9
In November of that year, a space probe named Mariner 9 captured an enormous dust storm engulfing the planet.
Scientists were also able to make out the tips of dormant volcanoes peeking through the top of the storm. This completely changed the way NASA — and the world — viewed the Red Planet.
30. Methane
When scientists discover the presence of methane anywhere in space, it means there's a possibility of biological or geological activity.
For years, researchers wondered if Mars contained any substantial level of methane that could potentially produce microscopic lifeforms. Unfortunately, even with all the technology we have today, there's no definite answer.
Confusing Data
Oddly enough, methane measurements taken by probes have come back with confusing data, and no one really knows why.
When information taken by the Curiosity rover was sent to NASA, there were all sorts of spikes in methane levels around the immediate area. However, scientists have yet to know where the gas originated or the cause for the fluctuations.
31. Human Colonization
Despite the fact some scientists talk about colonizing Mars at some point in the future, it's just an idea that at the present moment only Hollywood can make happen.
Hopefully in the future humans will traverse the Red Planet, but as of now we rely on rovers and probes to gather vital information, and NASA's had great success with them.
Successful Rover Landings
NASA is the only agency that successfully landed rovers on Mars' surface, and they've done it on several occasions.
The first time was in 1976 with Viking 1 and Viking 2, but there was also the Pathfinder-Sojourner in 1996, the Mars Exploration Rovers Spirit and Opportunity in 2004, and Curiosity in 2012. These expeditions have captured some mind-boggling sights.