20+ Unsettling Facts About Mars Are Making Us Question What's Really Out There

We all 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.

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?

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.

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.

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?

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.

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!

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!

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

The creepy "face" on Mars is probably the most famous image, first captured by the Viking 1 and 2 orbiters. Although the face is unmistakable in early low-res photos, new high-quality images have shown the mountain structure actually doesn't look much like a face at all.

Okay, obviously these aren't real berries on the surface of Mars, but they sure do look like them! There's an entire field of these little spherical, blueish rocks but scientists are still working on how they got this way.

The Opportunity rover caught this dust devil on camera, confirming scientists' theories that the little twisters occur on Mars. Future rovers now come with their own protections for dealing with such weather hazards.

Conspiracy theorists went crazy when images of this bone-shaped rock appeared on Mars' surface. The fact is that there are a lot of rocks on Mars. A LOT. Some of them are bound to look like stuff we recognize.

We all know about crop circles, but what about morse code... from space? These sand dunes on Mars look eerily similar to morse code, prompting scientists to translate them to this message: "NEE NED ZB 6TNN DEIBEDH SIEFI EBEEE SSIEI ESEE SEEE."

After getting ahold of this image of what clearly looks like a pyramid, some people insisted it was a message from an alien civilization. NASA, however, has downplayed it. "It is a rock," said Dr. Jim Bell, right, of the Curiosity program.

Located near Mars' south pole, this perfectly shaped hole caught the attention of scientists, who could see the frozen carbon dioxide ice at the bottom. We've so far only seen The Hole from orbit, but it's estimated to be a few hundred meters across.

One has to admit, this rock does look like an iguana! “To say it’s just a rock would be very closed minded to the evidence at hand,” said owner of the UFO Daily Sightings Blog, Scott C. Waring.

This 1.2-mile wide island looks strangely like it just came off the waffle iron and is ready to be drenched in maple syrup. In reality, it's near an ancient volcano so it probably got that way from criss-crossing lava flows.

If you look closely, you might be able to make out this rock formation that looks like a fossilized fish. Don't jump to conclusions, though. NASA says that Mars never had enough oxygen in its atmosphere to support complex life. "Thus, large fossils are not likely."

Recent discoveries at the massive Gale Crater site indicate that liquid water persisted on Mars for perhaps a million years or longer, and didn't disappear all at once, changing a commonly held assumption about the planet's evolution.

NASA's Opportunity found this rock that looks strangely like a jelly donut, but when it went back to check it out, it was gone. Did an alien eat it? Nah, turns out the rover's wheels accidentally ran it over and flipped it in another direction.

These scaly-looking hills have been nicknamed "The Dragon Scales" for their uncanny similarity to reptilian skin. However, it's thought that this region was eroded by ancient rivers, resulting in the scaly features.

If those "dragon scales" weren't weird enough, these lines on the surface that were captured in 2017 look strangely like scratch marks. Scientists think they are the result of dry ice sliding down the slope of this mountain.

This striking rock caught the attention of NASA's Curiosity rover as she was exploring the area. The rock (named Jake Matijevic after a prominent engineer) is made of unusual minerals typically found in Earth's core.

This strangely shiny object nicknamed "Little Colonsay" was picked up by the Curiosity rover and looked very out of place among the other red rocks in the area, leading them to believe it was a meteorite. More studies have to be done to truly determine where it came from.

Speaking of meteorites, check out this egg-shaped rock that Curiosity discovered. The strangely smooth, globular object was scanned by the rover's laser-firing spectrometer and found to be an iron-nickel meteorite fallen from the Red Planet's sky.

A field of these strange, spheroid rocks were discovered in 2012 at the Kirkwood outcrop. They're quite different from the "blueberries" found elsewhere on Mars, as they're smaller and more densely accumulated.

Just like on Earth, when temperatures start to warm up in the spring, melting ice and frost (made of CO2 on Mars) can trigger avalanches down steep cliffs, like this one here photographed in 2010.

These interesting swirl shapes look almost too perfect to not have been made by intelligent design, but they've been confirmed to be the result of ancient flowing lava.