What is Simulation?
The term simulation is used in different ways by different people. As used here, simulation is defined as the process of creating a model (i.e., an abstract representation or facsimile) of an existing or proposed system (e.g., a project, a business, a mine, a watershed, a forest, the organs in your body) in order to identify and understand those factors which control the system and/or to predict (forecast) the future behavior of the system. Almost any system which can be quantitatively described using equations and/or rules can be simulated.
The Purpose of Simulation
The underlying purpose of simulation is to shed light on the underlying mechanisms that control the behavior of a system. More practically, simulation can be used to predict (forecast) the future behavior of a system, and determine what you can do to influence that future behavior. That is, simulation can be used to predict the way in which the system will evolve and respond to its surroundings, so that you can identify any necessary changes that will help make the system perform the way that you want it to.
Example
For example, a fisheries biologist could dynamically simulate the salmon population in a river in order to predict changes to the population, and quantitatively understand the impacts on the salmon of possible actions (e.g., fishing, loss of habitat) to ensure that they do not go extinct at some point in the future
Well, what if it is? What if this life is just a simulation of the real thing? What if you, in an incredibly meta act, are reading this on a computer while residing inside of a computer? Once inserted, the thought niggles away at us—we can’t think our way out of this quagmire. “What if you were unable to wake from that dream? How would you know the difference between the dream world and the real world?” asks Morpheus in The Matrix. Dude.
But now researchers say they've sussed out the whole situation for us. Theoretical physicists Zohar Ringel and Dmitry Korvizhini, who are based at Racah Institute of Physics Hebrew University in Israel and Oxford University in the United Kingdom, claim to prove the concreteness of our reality in a recent Scientific Advances study.
To understand what they found, it helps to first recognize what a computer is: it's essentially a machine that performs calculations. In order for a computer to simulate reality, then, the machine would need to have enough power to actually create the phenomena that we experience within its simulated environment. What the researchers discovered, however, is that storing the information required to simulate certain behaviors of even a couple hundred electrons would take more atoms than exist in the universe. For better or for worse, this world is real. Probably.
the quantum Hall effect. The regular Hall effect (normally just called the Hall effect) explains how, under the right circumstances, metals can display some interesting electrical behaviors. For example, if you take a a metal bar and send a current flowing through it, you expect electrons to keep moving straight ahead in the direction of the current. But when you apply a magnetic field perpendicularly to the current, the Hall effect predicts that the electrons will turn and start moving perpendicularly to both the current’s original direction and the magnetic field. The quantum Hall effect takes the standard Hall even further: when you take conductive material into an environment that’s both very cold (near Absolute Zero, or -459.67 F), and has a strong magnetic field, particles behave even more oddly. Kovrizhi and Ringel were trying to get a better grasp on why.
Two plus two is pretty easy to solve (the answer, in case you’re wondering, is four). These sorts of equations are fine for relatively simple systems—we can do them with a calculator, if not in our minds. But these kinds of easy calculations start to break down when dealing with the weird quantum behavior that occurs at the very very small (we’re talking about systems smaller than the goings on of individual atoms) level. There are more unknowns—and you can have an infinite number of particles interacting. That’s what is known as the many body problem.
“When you do physics and you don’t know how to solve something, you say, maybe I can just have my computer solve it for me and that will give me some intuition,” Ringel told Popular Science. So he and his colleague turned to quantum Monte Carlo, a family of computational methods that use random sampling to study complex quantum systems that can’t be solved directly. But the researchers discovered that for every particle they added to the system, the simulation became exponentially more complex. It essentially doubled in complexity with each new particle (not unlike the reproductive rate of a tribble), making the problem unresolvable.
It's not that people hadn't attempted to solve for quantum Hall before.
People have tried solving it using laptops, and big clusters of computers. Ringel and Kovirzhi didn't necessarily expect to succeed, but they hoped to figure out why it had never been done. It could be that humans aren't smart enough, or that physicists just haven't yet found the right mathematical mapping. The new study makes it clear that it's just not possible to simulate the effect. And to the study authors, that suggests it would be impossible for a computer to create our world.
Simulation Hypothesis
While many people take reality at face value, others believe the far more intriguing theory that we are living in a computer simulation. It’s a concept straight out of “The Matrix” (though its origin reaches much further back), and one of its supporters is Tesla and SpaceX CEO Elon Musk.
Musk elaborated on the idea during the interview:
The strongest argument for us being in a simulation, probably being in a simulation, is the following: 40 years ago, we had Pong, two rectangles and a dot…That is what games were. Now, 40 years later, we have photorealistic 3D simulations with millions of people playing simultaneously, and it’s getting better every year. And soon we’ll have virtual reality, augmented reality. If you assume any rate of improvement at all, the games will become indistinguishable from reality.
The contemporary version of the simulation hypothesis was introduced by Nicholas Bostrom, a British philosopher, in 2003. Simply put, the hypothesis states that there is a likelihood that advanced future civilizations would run equally advanced computer simulations of past civilizations. So, much like we play video games about ancient populations, they might do something similar, just much more technologically advanced. Some people even think that the events of the 2017 Oscars are proof of this theory.
Ringel and Kovrizhi showed that attempts to use quantum Monte Carlo to model systems exhibiting anomalies, such as the quantum Hall effect, will always become unworkable.
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Science cannot tell us if we’re living in The Matrix
PHYSICS
They discovered that the complexity of the simulation increased exponentially with the number of particles being simulated.
If the complexity grew linearly with the number of particles being simulated, then doubling the number of particles would mean doubling the computing power required. If, however, the complexity grows on an exponential scale – where the amount of computing power has to double every time a single particle is added – then the task quickly becomes impossible.
The researchers calculated that just storing information about a couple of hundred electrons would require a computer memory that would physically require more atoms than exist in the universe.
The researchers note that there are a number of other known quantum interactions for which predictive algorithms have not yet been found. They suggest that for some of these they may in fact never be found.
“Who knows what are the computing capabilities of whatever simulates us?”
If you, me and every person and thing in the cosmos were actually characters in some giant computer game, we would not necessarily know it. The idea that the universe is a simulation sounds more like the plot of “The Matrix,” but it is also a legitimate scientific hypothesis.
VIRTUAL MINDS
A popular argument for the simulation hypothesis came from University of Oxford philosopher Nick Bostrum in 2003, when he suggested that members of an advanced civilization with enormous computing power might decide to run simulations of their ancestors. They would probably have the ability to run many, many such simulations, to the point where the vast majority of minds would actually be artificial ones within such simulations, rather than the original ancestral minds. So simple statistics suggest it is much more likely that we are among the simulated minds.
LIFE, THE UNIVERSE AND EVERYTHING
If it turns out we really are living in a version of “The Matrix,” though—so what? “Maybe we’re in a simulation, maybe we’re not, but if we are, hey, it’s not so bad,” Chalmers said.
“My advice is to go out and do really interesting things,” Tegmark said, “so the simulators don’t shut you down.”
But some were more contemplative, saying the possibility raises some weighty spiritual questions. “If the simulation hypothesis is valid then we open the door to eternal life and resurrection and things that formally have been discussed in the realm of religion,” Gates suggested. “The reason is quite simple: If we’re programs in the computer, then as long as I have a computer that’s not damaged, I can always re-run the program.”
And if someone somewhere created our simulation, would that make this entity God? “We in this universe can create simulated worlds and there’s nothing remotely spooky about that,” Chalmers said. “Our creator isn’t especially spooky, it’s just some teenage hacker in the next universe up.” Turn the tables, and we are essentially gods over our own computer creations. “We don’t think of ourselves as deities when we program Mario, even though we have power over how high Mario jumps,” Tyson said. “There’s no reason to think they’re all-powerful just because they control everything we do.” And a simulated universe introduces another disturbing possibility. “What happens,” Tyson said, “if there’s a bug that crashes the entire program?”
So you can think that are we really living in a simulated world?....
So be in the next part about computer simulation.
To be continued....
A STAR is a huge , massive body of luminescent matter radiating enormous amount of energy every second . Earth was born some 4.6 billion years ago as an interstellar cloud of gas and dust coalesced to form the Sun and rest of the solar system.
The mean distance between sun and earth is 149,642,000 km . This is known as one astronomical unit .
how we can create an artificial Earth!
1. GRAVITATIONAL FORCE
this could be my last 
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