"I don't know, right now I'm very into- to the universe." The universe has literally trillions of galaxies, and if the Milky Way is any indication, they may each have billions of planets in them. There's got to be life somewhere, right? But where should we look? "Solar system is so humongous big, right?" Welcome to WatchMojo's top 5 facts In today's installment, you'll have to give us a little leeway on what constitutes 'a fact'. Since humanity is yet to discover life on other planets, there aren't a whole lot of interesting 'facts' on the subject. So in today's installment, we're counting down our picks for the 5 most interesting ideas and theories about finding life on other planets. "Sir? It's wonderful." Number 5: Our best chances for discovering alien life are on Mars. "Woah, look at that brain. He must be real smart." Let's just hope they're friendly. On Mars, there's methane and water, all be it in the form of ice and vapor, which are big flags when it comes to the possibility of life. Many organisms produce methane, and water is needed for the survival of every organism we know of. While the presence of these chemicals does not necessarily mean that there is life on the planet, they do hint at it. Even if that life is microscopic in size. Also, the planet is riddled with caverns. Many of which, contain pockets of lava. If life were to exist on Mars, it would probably be found under the planet's surface and near one of these nice, warm lava pockets. The planet's crust would work to protect against most solar radiation, and lava would provide heat and energy in much the same way that volcanic vents create ecosystems at the bottom of Earth's oceans. "I'd say this was 5 years and 3 trillion dollars well spent!" If life isn't on Mars, then there's a good chance we'll never find it. The nearest solar system that has Earth-like planets is almost 5 light years away, and it would take about 40,000 light years for us to travel there with our current technology. "Get there faster!" (screams) Number 4: If we want to contact alien life, we should assume they act like us. "E.T. phone home." We detect the existence of many planets, not by seeing them, but by studying the dimming of light as they transit in front of their host stars. "Ladies and gentleman... Mercury." We can calculate many things about a planet by examining this light absorption. We can learn things ranging from the planet's surface temperature, to its size and density. Using this information has helped us to detect dozens of planets that have the potential for life. A paper recently published in the journal 'Astrobiology', claims that the best way to make contact with intelligent life would be to assume that other planets are watching us in the same way, and to point our radio receivers and transmitters towards our transit zone. Which is the thin slice of space where we would be most detectable through this method. The paper's authors say this would be light years better than our current system of pointing radios in random directions and crossing our fingers. "E.T., it's working!" Number 3: We might find E.T.s by spotting their city lights. Radios might not even be the best way to find aliens. We've been using radio signals less and less over the past few decades, and if aliens exist, they might also be using methods to communicate that don't involve radio. One new idea to look for E.T.s, is by searching for the lights from alien cities. We know that cities like Tokyo can be seen as far away as the Kuiper belt, using only telescopes, and we can calculate the amount of light that should be on the dark side of planets that are much farther away than that. Unfortunately, with our current technology, an alien city would have to put out about 10 times more light than Tokyo for us to see it. But hey, maybe our technology will improve soon. Or... maybe aliens will come and give us better technology, and then we can use that to find the- oh... never mind. Number 2: Our assumptions about life may lead us to look in the wrong places. "Speculation: Could it be alive?" "It couldn't be alive, it's inorganic." When we think about which planets might have life, we mostly look at planets that are similar to Earth. These are planets that are close to their sun, but not too close, and have plenty of hydrocarbons. But what if the extraterrestrials are not built out of the same things as us at a molecular level? Maybe life can develop with a silicon base, or maybe it can develop without water. "But unlike life on Earth and elsewhere, it appears to be completely inorganic." This is where bodies like Titan come in. Titan is one of Saturn's moons and is nothing like Earth. The average temperature of the planet is about 17 degrees below freezing. "God damn, the water's f**kin' cold" And the water that exists there is obviously frozen as hard as stone, and unusable by any life. What Titan does have, is an abundance of methane. Which, while it would be gaseous here on Earth, is liquid at the cold temperatures on Titan. These liquids could be the building blocks of strange, alien life that would be unimaginably weird from our perspective. Like, really weird. Like, 'the ending of 2001: A Space Odyssey' weird. Number 1: Alien life might not even need a planet. It's possible that the background radiation of the cosmos can cause life to spontaneously develop in the vacuum of space. I mean, if cosmic rays can make Jessica Alba and Kate Mara invisible, who knows what else it could do? Laboratory tests have shown that when water, methanol and ammonia react with ultraviolet radiation, they can develop into a variety of different sugars. Including some parts of RNA. All of these elements commonly float around in clouds out there in space, and experiments have even shown that these reactions can occur at temperatures as low as those in outer space. Granted if these organisms can exist, they must be very simple, because the radiation of space is just as likely to destroy DNA as it is to create it. But it does mean that the building blocks for complex life could be in abundance throughout the universe. Moreover, some astrobiologists believe that these rudimentary lifeforms could further evolve on volcanic planets that don't even have access to suns, and these 'rogue planets' could very well be all over the place. So rudimentary lifeforms might just exist in trillions and trillions of surprising places. "Oooh." So, what do you think? "I've got access to MOTHER now, and I'll get my own answers, thank you." Will we ever find the most basic forms of alien life? "Yes." For trillions and trillions of top 10's and silicon-based top 5's published every day, be sure to subscribe to WatchMojo.com. "Excuse me, where are your nuclear implosion couplers?" "For a garden hose?"
