7 Theories on Time That Would Make Doc Brown's Head Explode

7 We May Not Live in the Present

What if we told you that what you think of as "the present" is actually slightly in the past? Basically, your life isn't a live feed: It's a delayed broadcast that your brain is constantly editing and censoring for your convenience.

The delay isn't much -- what's 80 milliseconds between you and your brain? Nothing, right? Well, a group of neuroscientists disagree. They've come up with some freaky time-altering experiments to prove that this difference can change your perspective of cause and effect. For example, in one experiment the volunteers were told to press a button that would cause a light to flash, with a short delay. After 10 or so tries, the volunteers were beginning to see the flash immediately after they pressed the button -- their brains had gotten used to the delay and decided to edit it out. Yes, that's a thing your brain can do.

But that's not the freaky part. When the scientists removed the delay, the volunteers reported seeing the flash before they pressed the button. Their brains, in trying to reconstruct the events, messed up and switched the order. They were seeing the consequence first and the action second.

Not convinced? Try this: Touch your nose and your toe at the same time. Logic says that you should feel your nose first, because it's right there in your face (hopefully) and therefore the sensory signal doesn't have to travel too long before reaching the brain, whereas your toe is at the extreme opposite end. The physical distance a message has to travel on neurological pathways is much longer from toes than from nose, and yet you feel both things at the same time. According to neuroscientist David Eagleman, that's because your brain always tries to synchronize the sensory information that it gets from your body in a way that will make sense to you, but it can only do that by pushing your consciousness slightly into the past, like a radio station that's always on a five-second delay in case somebody curses on air.

The bizarre real-world implication is that the taller you are, the further back you live in the past, since it takes longer for the information to travel through your body -- and if you're a little person, you live closer to the present.

But we're only talking about our perception of time here. It's not like time itself can actually slow down or speed up in reality ... right?

6 The Higher You Live, the Faster You Age

If you want to experience a real time warp, simply walk up some stairs. It turns out that time isn't the same all over -- it actually runs faster in higher places. In a recent experiment, scientists placed two atomic clocks on two tables, then raised one of the tables by 33 centimeters ... and found out that the higher clock was running faster than the lower one at a rate of a 90-billionth of a second in 79 years.

These are the most precise clocks ever made, and the only difference between them was their distance from the Earth. That means people who live in higher places age slightly faster than people at the ground level. So for anyone keeping score, that's giant people 0, dwarfs 2.

This is called time dilation, and it happens because (as Einstein's theory of relativity predicted) gravity warps time as well as space. The closer you are to the ground, the more you are affected by the Earth's gravity and the slower time moves. On the other hand, as you get higher, gravity's pull weakens and time speeds up.

Keep in mind that this is an insignificant amount of time we're talking about here. It has absolutely no bearing on your life -- unless you rely on GPS equipment, that is. Because a clock inside a GPS satellite runs at 38 microseconds per day faster than the same clock would run on Earth, a computer has to constantly adjust everything to make up for that difference. Otherwise the consequences would be disastrous: In only one day, the entire system would be off by 10 kilometers, and it would just get worse from then on.

Oh, and by the way, gravity isn't the only thing that can mess up time ...

5 The Faster You Go, the Slower Time Moves

Another thing GPS satellites have to take into account is speed: The faster you travel, the slower time moves. Now you almost certainly knew that already, thanks to Einstein -- if you're going the speed of light, time pretty much stops. But it turns out that you don't need an ultra fast spaceship to slow down time -- your shitty car will do.

Using the extremely precise atomic clocks we just mentioned, scientists have proven that the same thing happens to you every day, on a much smaller scale. Making one of the clocks move at only 36 kilometers per hour (around 20 mph) caused it to slow down its tick by almost 6 x 10^-16. In numbers we can understand, that translates to "Not a whole lot, but still, holy shit, you guys."

So, let's say you're driving to work at around 40 mph -- that right there is apparently enough to cause time to move 0.0000000000000002 percent slower than it would if you were standing still.

In another experiment, one atomic clock was taken on a plane trip around the world while the other one stayed home (admit it -- if you had an atomic clock, you'd constantly be thinking up shit like this). Even though the clocks were perfectly synchronized at first, the traveling clock came back from its 50-hour, 800-kilometer trip missing 230 or so nanoseconds.

So the clock gained time from being farther from the Earth than the other one, but it lost even more just by going faster. What's even weirder is that from the perspective of the clock on the plane, the clock back home is the one that's running faster than normal. You don't actually feel time slowing down or speeding up: Only someone outside your conditions can tell the difference. And that leads us a little further down this rabbit hole ...

4 Time Doesn't Run at the Same Speed for Everyone

A trippy consequence of the stuff we just explained is that, apparently, different people can witness the same events happening at different speeds. Einstein claimed that events that appear simultaneous to a person in motion may not look simultaneous to someone who is standing still. So reality may actually be a mess of people walking around in slightly different timelines that sometimes synch up or intersect, depending on their conditions. This would help explain why everyone from Cream looks like a mummy now except for Eric Clapton.

Neuroscientist Warren Meck conducted studies to prove that brain time is relative. In one experiment, he trained lab rats to push a small lever after a certain period of time -- and found out that the exact same interval could be timed differently depending on the rats' conditions. This means that 10 seconds can sometimes seem like 30 seconds, and 30 seconds can sometimes seem like 90 seconds, and so on. But you didn't need lab rats to know that: Surely you've been cornered at parties by someone who wants to tell you what really happened on 9/11.

Well, according to Meck, this happens because there isn't a single "clock" that tells the time in our brains: There are multiple brain clocks, all running at different speeds. So basically, the guy in the speeding train, the guy way up in the GPS satellite and the guy at the party working out an exit strategy all coexist inside our heads and our brain decides which one to believe at any given time.

There are lots of other things that can alter our perception of time, like drugs, mental disorders, old age or even distance. With all these variables, time is constantly in flux for everyone. So the next time you're late for something, just lay that nugget of truth on anyone waiting for you. They may think you're an asshole, but at least it won't be for your tardiness.

3 Faster-Than-Light Neutrinos Could Mean Time Travel Is Possible

Laws of physics and our general understanding of how the world works hinge on the principle that nothing can actually travel faster than the speed of light, except maybe mall Chinese food through your digestive tract. But prepare to shit your pants a second time, because the most fundamental principle of the universe may no longer be on the table. Scientists at CERN (the ones responsible for the Large Hadron Collider) and OPERA may have accidentally discovered that, under certain circumstances, subatomic particles known as neutrinos can maybe, possibly, potentially travel faster than the speed of light.

Right now there are ongoing slapfights in the scientific community over the validity of this discovery, so until the dust settles, we can't know for certain if the results were right. Sadly, the most we can do at Cracked is sit on the sidelines with zero doctorate degrees in our hands and heckle. What we do know, however, because scientists have pointed it out, is that an interesting side effect of these faster-than-light neutrinos is that it might mean we can get our motherfucking time travel on.

But before you start deciding which dinosaurs you want to see, or which episodes of Dinosaurs you want to see (depending on how lazy you are), keep in mind that we're not talking about time machines, unfortunately. Scientists say that, at least at first, we'd probably only be able to send short messages back in time and not people or sports almanacs.

Think Twitter instead of Terminator. But even then, neutrinos are invisible and pass right through matter, so it wouldn't be all that useful for things in the distant past, where they wouldn't even be noticed. With no way to detect or read the messages, it'd be pointless to send them much further than the recent past. But that brings up an important question of why we're not getting hundreds of microscopic messages today from our future selves ...

2 Time Stops Outside of a Black Hole

A common misconception with black holes is that they suck up everything around them like a vacuum, but that's not entirely accurate. What's really going on is that black holes are so incredibly dense that there is a point of infinite gravity at the center, called a gravitational singularity, and that's what pulls stuff in -- everything from asteroids to light itself. And we've already established that gravity and time don't play well together. So what happens to time when it gets tangled up with a gravitational force so extreme that not even light itself can get free of it?

It stops. Encircling any given black hole is an area known as the event horizon. It is, for all intents and purposes, the point of no return for a black hole. After the event horizon, the gravitational forces are so powerful that nothing can ever escape.

And because of that insane amount of gravity, an interesting quirk of reality emerges when someone outside an event horizon watches someone inside of one. Imagine your astronaut buddy is David Bowie. Now, say David Bowie calls you (your name is Ground Control for the purposes of this exercise) and tells you he's floating in the most peculiar way -- directly into a black hole.

If you were watching David Bowie from a safe distance away, you'd see something really weird as he crosses the event horizon: David Bowie's descent would get slower and slower, and then he'd just stop, and he'd appear to be floating there forever.

From your perspective, it would actually take him an infinite amount of time to fall into the black hole. David Bowie, meanwhile, would notice nothing different, assuming he hadn't been ripped apart yet. Time would pass normally for him, and he'd still be a snappy dresser to boot.

In fact, if you could somehow exit the event horizon of a black hole after entering it, you'd find that the universe outside had probably aged a significant amount while a much shorter time had passed for you. It's a foolproof way to travel into the future, except that a black hole can be as small as a tennis ball, and you'd surely be crushed to death.

Though there's just as good a chance that we may never have the opportunity to wander through time willy-nilly, because ...

1 One Day, Time Itself Must Die

Time waits for no man, as the old proverb says. It can get all weird under certain circumstances, sure, but that steady beat will keep on going long after we're dead.

But not too long.

See, the way scientists determine various formulas for how the universe works is via probabilities. The problem is that, if you assume that space-time is infinite, everything -- from the mail arriving on time to our sun going supernova and wiping us all out -- suddenly has an equal probability on a universal scale.

Since the universe doesn't work like that and it was fucking with all their formulas, scientists have decided that there must be another answer, and the best they could come up with is that time isn't infinite.

So how long have we got? In four out of five possible calculated scenarios, time is most likely to end in about 3.3 to 3.7 billion years. Whew. But in the fifth scenario, time could end before you finish this sentence.

So it turns out we live in a reality that's like an old pocket watch, and one day it's just going to wind down. In fact, when it happens, we won't even see it coming. The scientists describe it like watching someone falling into the event horizon of a black hole, like we covered earlier. Things slow down and eventually just ... stop.

The whole of reality will just turn into one big Zach Morris time stop, minus a sassy teenaged guy speaking directly to an implied television audience. We won't even be aware of what's happened. Everything will work one second and won't the next. We'll all just be frozen in place, completely still. Forever and ever. If nothing else, this should be good incentive for you to literally shit or get off the pot, because you run the risk of being immortalized like that forever.

Maxwell Yezpitelok lives in Chile, and you can bother him on Twitter. To read more from Ashe, check out Weird Shit Blog on Tumblr, Twitter and Facebook.

For more facts that will rock your friggin' world, check out 6 Time Travel Realities Doc Brown Didn't Warn Us About and The 6 Weirdest Dangers of Space Travel.