You may have caught Louis C.K.'s tweetstorm earlier today. For no apparent reason, the comedian and actor started musing about Mars and the origins of life on Earth. Check out some of the tweets below:
It really feels like Mars used to be a here that got globally warmed by some very us-y people-things.— Louis C.K. (@louisck) October 8, 2014
What was left turned into here and our moon and got seeded by marsian corpse DNA. And later we'll use our moon to go back.— Louis C.K. (@louisck) October 8, 2014
In case you didn't quite catch that, C.K. suggests that "us-y people-things" once lived on Mars, but that they died from global warming... on Mars. He also posits that DNA from Martians reached Earth and "populated" our planet. And even though he was probably just gunning for some laughs, the amazing thing about this theory is this: He might not be completely wrong.
Let's examine the facts, shall we?
A 'globally warmed' Mars
Mars' average temperature is minus 80 degrees Fahrenheit (minus 60 Celsius), which means it's actually much colder than Earth. This makes a lot of sense since Mars is located farther away from the Sun. Still, global warming isn't about a planet being hot — temperature is all relative anyways — it's about a planet getting progressively and significantly warmer over time. So was Mars once a lot colder?
Unfortunately that's really hard to tell. We have very little information about Mars prior to the 1970s. What scientists do know is that Mars isn't experiencing any form of warming right now, despite what some climate skeptics might tell you (that argument has been used to "demonstrate" that climate change isn't caused by humans).
Instead, the regional temperature changes that do occur are a product of Mars' very thin atmosphere — which makes the planet more susceptible to temperature changes — and its extremely large oval-shaped orbit, which causes it to experience larger fluctuations in temperature as it approaches and then moves away from the Sun. Moreover, depending on their severity, Mars' many dust storms also tend to cause the planet's temperature to fluctuate from year to year.
Given that lack of historical data on Mars' climate, however, I'm calling this a tie.
Life on Mars
This is the first part that C.K. might be right about. There exists evidence that water was once present on Mars. This fulfills a pretty crucial part of the life-supporting equation, because unless you're a tardigrade or a rotifer, surviving without water is rarely possible. Yet, water on its own isn't enough evidence for life on Mars. You also need something like a fossil to prove that bit.
Enter NASA geologist David McKay. In 1996, his team of researchers found complex organic molecules and what appeared to be fossilized microbes in a Martian meteorite that had landed on Earth. This, the researchers said, might be a sign that Mars once harbored life. That whole idea is still up for debate (it's highly contested, actually), however, and current scientific consensus says that we don't have enough evidence for life on Mars. That might change, of course, especially since one of the main objectives of the NASA Curiosity rover is to find signs of ancient life on the Martian surface.
So right now C.K. isn't completely wrong. He just isn't right.
Mars as the source of life on Earth
Because McKay's meteorite was found on Earth, some researchers have suggested that life on Earth may have originated on Mars (or vice versa). And more recently, a biochemist named Steven Benner pointed out that an element named molybdenum wasn't present in its life-constructing, oxidized form when life first appeared on Earth. It was present on Mars, however.
"It's only when molybdenum becomes highly oxidized that it is able to influence how early life formed," he said in a statement at the time. "This form of molybdenum couldn't have been available on Earth at the time life first began, because 3 billion years ago, the surface of the Earth had very little oxygen, but Mars did."
Thus, it's possible that life on Earth originated on Mars, which means that C.K.'s claims kind of make sense if you look at them in a certain light. Unfortunately, there isn't enough evidence at this time.
What little evidence we have of life on Mars comes from organic molecules and what might be interpreted as fossilized microbes. The idea that a humanoid form would have evolved on Mars, and then somehow devolved prior to making it to Earth isn't supported by any respected source. Sorry, C.K.
The tweets that followed are by far the kookiest, but from what I can tell, C.K. suggests our solar system is a space ship, and once our planets align just right, we will get some sort of powerboost from the Sun. This, he says, will send us to a "bigger" and far away place that I'm guessing is better than our current location.
And it feels like we are gonna keep bopping around on moons til we realize the whole solar system is actually a spaceship.— Louis C.K. (@louisck) October 8, 2014
The sun is the engine and if you wait til it all lines up just right and you push "go" you can ride it to a bigger far place.— Louis C.K. (@louisck) October 8, 2014
I would really like to emphasize that these are not opinions or theories. It's just a feeling I have.— Louis C.K. (@louisck) October 8, 2014
It probably goes without saying, but there's no scientific evidence to support C.K.'s feelings. I therefore urge you all to enjoy the jokes, and walk away.
I'm not high.— Louis C.K. (@louisck) October 8, 2014
Update 5:36PM: A planetary scientist at NASA, Paul Niles, emailed us with more information. As it turns out, what's perhaps most incoherent about C.K.'s tweets is that "global warming in the Mars case would have made it MORE habitable rather than less habitable." He also pointed out that given that water once flowed on Mars' surface, it's likely that Mars was much warmer in the past. C.K's whole global warming "feeling" isn't looking too good right now.