The European Space Agency pulled off a remarkable feat when they successfully docked the Philae spacecraft on a comet. Due to odd circumstances surrounding the event (including the ESA claiming to have heard strange sounds coming from the comet), theorists argue that the comet was actually an alien object.

One of the most widely circulated UFO conspiracy theories out there is that Jesus was actually an alien. While it seems far-fetched, it would explain pretty much all of His miracles.

While humans have only officially visited the moon, UFO theorists believe that mankind has gone much farther. They claim that a dozen astronauts were sent to a planet 37 light-years away called Serpo during the Kennedy administration. They were supposedly part of an exchange program implemented by grateful aliens who were saved after their spacecraft crashed in Roswell, New Mexico, in 1947.

A man named Immanuel Velikovsky wrote a book about his theory that many of the cataclysmic events in the Bible really did take place, but were caused by celestial bodies having an effect on our planet.

HAARP stands for High Frequency Active Auroral Research Program, and it's a program based on studying the ionosphere. After a Russian Mars probe was unable to leave the atmosphere, some suggested that HAARP researchers stopped the probe from carrying out its mission.

This massive anomaly on Saturn's north pole has a lot of people scratching their heads to this day. Some have scrutinized photos of the Eye of Saturn and noticed geometric shapes and patterns, leading to suspicions of a mythological power sitting at the center of the formation.

While the United States has one of the most sophisticated terrestrial militaries in the world, when it comes to space warfare, we're woefully unqualified. Or are we? According to some theorists, NASA's mission for space exploration is merely a front. Allegedly, their real aim is to build and maintain a fleet of interstellar warships that are in orbit above Earth as we speak. The evidence offered for this supposed space fleet is a cryptic reference to something called the Solar Warden Program that was mentioned in a leaked document from the U.S. State Department.

Some space conspiracy theorists believe that a NASA mission to protect the moons of Jupiter was actually a preliminary test for the Lucifer Project, which is basically a plan to turn Jupiter into another sun.

Some say that to cover up the fact that no human has ever been to the moon, NASA has refused to use the Hubble telescope to take pictures of the moon rovers left behind from previous missions. Theorists are suspicious, since this would be a simple way for NASA to quell any doubts about the moon landing.

An alleged former NASA employee who identified herself as "Jackie" claimed that she saw evidence of colonies on Mars years ago. She didn't specify whether the colonies contained Martians, humans, or both, and judging by her other theory, the attacks on 9/11 didn't really happen. We're not so sure if she can be trusted.

Theories abound about the mysterious disappearance of Malaysia Airlines Flight MH370. The most interesting one claims that it was abducted by a UFO. The proof that believers offer for this particular theory is that the Malaysian Air Force detected an unidentified flying object on their radar just before the plane disappeared. If that's true, this theory would account for the lack of physical evidence.

Some theorists suggest that while climate change is happening on Earth, there is also evidence of climate change occurring on other planets in our solar system, leading them to theorize that the root of this shift can be found in the solar system itself.

By far our favorite, this conspiracy theory suggests that back in the 1980s, President Barack Obama was part of an elite team that was teleported to Mars in order to make contact with Martians.

In 1946, America mounted a large, unprecedented expedition to Antarctica. The official reason was to beat the Soviets there. However, Nazi supporters maintain that the expedition was put together to destroy a secret Nazi UFO base. Theorists also claim that the so-called "attack force" was repelled by superior Nazi technology. In reality, bad weather forced the expedition to come to a halt.

A few theorists believe that there was once a whole Martian civilization on Mars, but because of a nuclear event, all life on the planet was destroyed, and it was left barren.

During a live feed of Earth's atmosphere, a strange object appeared just above the Earth, and NASA quickly cut off the feed. Some argue that this was NASA trying to cover up a UFO sighting.

The Black Knight is a large satellite that's believed to have been orbiting Earth for the last 300,000 years. No one knows how it got there, but it's been detected by NASA multiple times.

This one is weird. In 2009, a strange, blue light formed in the night sky over Norway. While the explanation is likely meteorological, conspiracy theorists believe it to have been a failed attempt at implementing Project Blue Beam. The theory states that the New World Order plans to show a holographic projection simulating an alien invasion as a means to seize power. Clearly, they are still working out the kinks in their plan.

The 2012 Olympic Games were a triumph of human achievement. However, for conspiracy theorists, it was anything but. According to these folks, the 2012 Olympics were to be the stage for an alien invasion – but not a real one. They believed that the Freemasons and other powerful groups orchestrated a “false flag” alien invasion, a hoax that would terrify everyone into submission and pave the way for a single world government. Since the invasion didn’t happen, the theorists were obviously a bit off target.

During a 1955 speech, General Douglas MacArthur supposedly made a comment about an Earth-wide war against aliens. He urged the world to unite, because the next massive war could be a battle for Earth's survival. Conspiracy theorists believe that this was a reference to some specific knowledge that MacArthur had about the existence of aliens.

Perhaps the most popular of all space conspiracy theories is that the footage of the first moon landing in 1969 was fabricated. Theorists claim that if you look at the video closely, it becomes obvious that the film is not from the moon, but from a soundstage.