# Next

#### MathematicsModern PhysicsQuantum MechanicsTime

Next, recently released on DVD, gives Nicolas Cage with the power to see the future. While our lives don't contain as many snipers and exploding cars as his, that seems like a pretty handy ability.

The laws of physics are meant to predict what will happen. So if you learn the ins and outs of physics, then you should be able to predict all the questions on your next test, right?

Predicting the Future

Problem One: Data Collection

If you're going to predict everything that'll happen next, you have to know everything that's happening now. Everything.

Look around - how long would it take to measure everything in the room? Will everything stay the same while you do it? Won't you change some things to measure others? Even if you promise to be really careful, there's an absolute limit to how good a job you could do – a concept that defines the Heisenberg Certainty principle.

Did you know? The Heisenberg Uncertainty Principle states that the more exactly you know an objects location, the less exactly you know its momentum. One of the key principles in quantum mechanics is that you CAN'T know everything - not ever. You can't know the exact position and momentum of an object at the same time, and the better you know one, the worse you know the other.

But this definition of 'exact' is really exact - right down to the level of an electron. While you might claim that you're not moving at all, at the microscopic level, you actually are. Because your position isn't exactly certain down to a tenth of a decillionth (it's a real word!) of a meter means you’ll never really know your position.

Problem Two: Living in Chaos

Ok, so let’s say hypothetically that you’ve collected all your data. But what if you’re not totally accurate? The tiniest changes in initial data can become important very quickly, as described in the chaos theory. In simple systems, small changes lead to small differences. However, in complex systems, it’s a little different.

For example, when playing pool, if you hit the cue ball on a slightly bad angle, you'll miss the pocket by a little bit. You can learn to make the same shot each time but can you break the balls the same way twice? No matter how precisely you try to set and hit them the same, the tiny differences in position and contact lead to dramatically different results each time.

Did you know? The first study of chaos was in 1961 by Edward Lorenz. To save time, he rounded off a number from six decimal places to three places in a weather simulation, and was surprised to find wildly different results. So be careful when you round things off!

Problem 3: Time

The third challenge in working out the future is that it's already on its way, and you have to work quickly to arrive at the answer before it happens which is where the laws of motion come into play.

Computers can take up the slack by processing millions of calculations per second, but anybody who's played a video game that started to “stutter” (or had to turn down the graphics detail level) will know that there's a limit.

Predicting the Future: Will it Ever be Possible?

So do we have to give up on telling the future? No - but we have to decide what we want to know. While we can't simulate everything exactly as it would happen, we can choose limited systems with reasonable approximations and get useful results up to a point.

Weather Forecasts are a good example of thinking ahead into the future. However, even with weather predicting technology improving all the time, it still represents a real example of the difficulties of chaos.

Did you know? The same Havok physics software suite used in Halo 2 and Half Life 2 is used in The Matrix Trilogy and Charlie and the Chocolate Factory. But what if you could bring the world you wanted to simulate down to a single molecule for a few minutes? You’d get rid of the problems with collecting data, because you can now specify its state. The Heisenberg limit and chaos aren't problems because you aren't running for long. But what use could that be?

A lot, if the molecules you're testing are possible cancer treatments. Cancer Busters are running effort to find drugs with potential to fighting cancer, simulating millions of possible chemicals. So simulations can't see the future, but by helping to develop medicine and cure cancer, they might give some people one.