Sunday, November 22, 2015

Gargantua


Interstellar is a groundbreaking film, mostly for its correct use of physics. The physics of this film are also pretty hard to understand if you're not a physics person like me. I'm going to try my best to analyze black holes, specifically the black hole in the other galaxy, Gargantua.

Gargantua is a black hole which is at the center of the galaxy that Cooper and his team are trying to find a viable planet to reestablish the human race on. Gargantua is a massive black hole, and Miller's planet is as close as it could be without being pulled apart and destroyed. Every hour on Miller's planet is seven years back on Earth. Kip figures out that Gargantua must have the mass of 100 million suns. The circumference of a black hole is related to the mass by the Schwarzschild Radius.

You use this formula once you've found the black hole's circumference. Then using C=2πR it gives you R, then you can find out the black hole's mass. Kip has suggested that Gargantua's radius would be 150 million kilometers. 

Black holes do not emit any light, so the only way to see them is to interpret the way light behaves around it. "Gargantua casts a black shadow on the field of stars and it also deflects the light rays from each star, distorting the stellar pattern that the camera sees". The stars move at very high speeds so they look as if they are moving very fast in some spots, others seem like they are just floating, and some seem frozen. Gargantua must be a very fast spinning black hole in order for the crew to have such a drastic time loss when they get very close to it. 

Thats about all that I understand from the physics of the movie, sorry if it sucks. 

Monday, November 2, 2015

Global Warming

Many people are focused on the temperature change that they have experienced in their lifetime, and do not take into consideration that, maybe, the earth's rising temperature is normal? If you go back as far as the Paleozoic and Mesozoic times, scientists have come to the conclusion that the earth was 2-6 degrees celsius hotter than it is now. On the other side of the spectrum, during the ice ages of the Pliocene and Pleistocene times, the earth was 2-3 degrees celsius cooler than now.

This graph shows global temperatures going as far back as 400,000 years.


The fluctuations in the Earth's temperature are said to be caused by the Milankovitch cycles. These are long term variations in the Earth's orbit, which causes climate change over the period of hundreds of thousands of years. There are three different ways that the Earth's orbit can change: eccentricity, precession, and tilt. Because of these, the Earth's orbit changes and ice ages can occur. 

Sunday, October 4, 2015

2001: A Space Odyssey - 0/5 Stars

2001: A Space Odyssey is one of the most highly critically acclaimed films made, it is ranked 22nd by the American Film Institute. I can see why, because when it was made, the special effects were very ahead of its time. But I did not like the movie at all, it was slow, boring, and I'm still not entirely sure what the plot was. It seems like Stanley Kubrick wanted to make a really long movie so he wasted time by making us look at the same thing for minutes at a time and listening to beeping or breathing. As boring as it was, the movie still showed very good physics.

An example of the good physics that this movie shows is the artificial gravity. The artificial gravity acts as a normal force. When an object follows a circular path, there must be a force pulling it into the center, otherwise it would just go in a straight line. They achieve this by spinning the spaceship, forcing the passengers to the outside, which simulates gravity.


An example of bad physics would be the men standing on the moon. They look as if the moon has the same force of gravity as the earth. We know that because of it's size, the moon has about 6 times less gravity than the earth. The men walking towards the obelisk would have been bouncing around rather than walking regularly. 

Another thing Kubrick does pay attention to is the fact that no sound can be transmitted though space.  Space is a vacuum, and sound waves need particles to bounce off of in order to produce a sound wave to hit our eardrums. In each scene, there are no noises except for Dave's talking over a radio or him breathing in his suit. 

This film is loved by many, but it was way to slow and boring to even be able to follow the plot, if it even had one. 

Sunday, September 27, 2015

The Physics of The Flash

We all know The Flash can run super fast up the sides of buildings, across water, and able to catch bullets. As far as going up the side of a building, we know that as one rises, they slow down due to gravity until they reach a height where the final speed is zero. As he approaches the side of a building, as long as he maintains a speed grater than v^2=(2gh), he should be able to make it to the top of the building while still following the laws of physics.


According to Newton's 3rd Law, every action has an equal and opposite reaction. In order to walk, the ground must exert the same amount of force you put on it and you must have friction. The Flash must have friction in order to go super fast. One of the supervillans he must fight is Captain Cold, who shoots a layer of ice in front of him, rendering him unable to get any friction on the ground, and unable to use his super speed. 

In order to walk across water, the water must move out of your way. If a liquid has a higher viscosity, it requires more energy to move it out of the way. The Flash is able to run faster than it takes the water molecules to displace and move out of the way, so therefore he can keep moving on top of them. The water acts more like a solid than a liquid at these speeds, you can see this by slapping a pool of water really quickly. 



For The Flash to catch bullets, he would need to speed up to match the bullet's velocity so the net speed between him and the bullet is zero. He can then easily pick the bullet out of the air and save the innocent bystanders. 

Kakalios, James. "Flash Facts-Friction, Drag, and Sound." The Physics of Superheroes. N.p.: Gotham, 2006. 57-68. Print.

Sunday, September 20, 2015

Armageddon

NASA has proposed many different possible ways of deflecting an asteroid from earth. There are two ways to do this, nuclear and non-nuclear.

If NASA were to use nuclear power, there are four effective ways to try to get the asteroid off course. A surface explosion, a delayed surface explosion, a subsurface explosion, and an explosion where the bomb does not touch the asteroid.

The best option for a non-nuclear defense plan is a series of kinetic impacts. This is basically just ramming things into the asteroid until it's path is changed to avoid hitting earth. Other ways are using a laser or a huge mirror to focus energy on the surface of the asteroid to try to break off pieces of it.

My favorite plan that NASA came up with was the subsurface nuclear explosions, because that is what they tried to do in the movie. Except NASA would use it to try to move the asteroid off course instead of breaking it in half, like what they did in the movie. Nuclear weapons are the only thing that would provide the amount of energy needed to divert an asteroid of that size. NASA proposed the Hypervelocity Asteroid Intercept Vehicle (HAIV). This would create a crater on the surface of the asteroid where the nuclear bomb would be detonated after.

Using this, they would be able to neutralize an asteroid that is 1,000 feet across if they know about it at least 30 days in advance.
This would create enough energy to hopefully change the asteroid's velocity, pushing it away from the earth. You would need megatons of energy in order to achieve this.

Unfortunately, due to Article IV of the Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies, detonating nuclear weapons in space is illegal. But maybe NASA could try and change some minds if the fate of the planet was in jeopardy. 

Sunday, September 13, 2015

Eraser

Arnold Schwarzenegger is the protagonist of an action film where he erases people and gives them new identities. The main weapon of choice is a rail gun. The physics of a rain gun is pretty complex and the movie follows these physics very poorly. When Arnold shoots the rail gun, he would have had to flown backwards when the bullet leaves the gun.

Ma= Arnold's Mass
Mb= Bullet's Mass
Vai= Initial velocity of Arnold
Vbi= Initial velocity of the bullet
Vaf= Arnold's final velocity
Vbf= Bullet's final velocity



Arnold would have had to have flown backwards at 30,000 meters per second.

When it comes to how fast the victim would have flown backwards, the movie is wrong again. Assuming the bullet stuck in the victim, Vfv=Vfb=Vf, the movie's physics is all inaccurate. 

Mv=Victim's mass
Mb= Mass of the bullet
Vfv= Final velocity of the victim 
Vfb= Final velocity of the bullet
Vib= Initial velocity of the bullet
Viv= Initial velocity of the victim



The victim would have had to been flying backwards at 37,000 meters per second. 

Sunday, September 6, 2015

Mission Impossible III


In Mission Impossible III, Tom Cruise has to retrieve The Rabbit's Foot from the bad guy in order to save his wife's life. In one of the many climatic scenes, he has to swing from a building that is 226 meters tall to the building the Rabbit's foot is located in, which is 162 meters tall. The two buildings are 47.55 meters apart. It took him approximately 20 seconds from the time he left the top of the building to the time he released himself from the rope onto the second building. Would he have been going fast enough just from jumping off the building to make the swing to the other building? 

My second question comes from the same scene. When Tom Cruise is jumping off the building and the rope runs out and becomes taut, would that have broken his spine? It takes more than 3000 newtons to fracture the cervical spine and become paralyzed. Tom Cruise weighs approximately 67 kg. If we ignore air resistance, his acceleration would have been 9.81 m/s^2.

F=m*a
F=(67 kg)(9.81 m/s^2)
F= 660 newtons
The fall would not have broken his spine, leaving him able to save the day and his wife.


In another climatic scene, Tom Cruise is rescuing another agent and throws a grenade which I assume is magnetic, as it is pulled towards a metal pole and sticks. It takes less than two seconds to throw it about 6 meters. My question is why did it go straight to the pole after throwing it in a curve and in a mostly metal warehouse?