Sunday, November 22, 2015

Whole Worms

In short, simple terms a wormhole is a shortcut from one part of the universe to another. You go in one side and come out the other.
If only they were that simple. This post would've been a lot easier.
A wormhole is a point in spacetime where gravity acts as a sort of tunnel, connecting two points in spacetime, so that the trip from point to point through the wormhole is much quicker than without it. To put it into more understandable terms, I like to use John Wheeler's (mentor to Kip Thorne, author of The Science of Interstellar) example of an ant eating though an apple. In this example, the ant's universe is the 2D surface of the apple, and the wormhole is a hole that leads from one side of the surface to the other. The ant could walk around the entire surface, or just straight through the hole. This is the basic idea behind a wormhole: the shortcut through the universe. The apple's insides is not like the rest of the ant's universe, it is in 3D, a dimension above what the ant perceives. For wormholes in our 3D universe, wormholes are 4D, which is exactly why we have to explain them in terms of 2D and 3D.

The first person to answer Einstein's equations that described a wormhole (but Einstein didn't say it was that) was Ludwig Flamm, who described wormholes as spherical shapes that contained no gravitating matter. Much later, John Wheeler and Robert Fuller found that wormholes are created, contracted, and then destroyed. Because of two singularities reaching each other through space and time, a wormhole is created, it expands, shrinks, and then cuts off. They said that this process happens so quickly that not even light has time to make it through before the cut off, and thus nothing can traverse a wormhole.

The only way for travel through a wormhole to be possible is if the wormhole did not cut itself off so quickly, but then there is the issue of bending light rays outward. While something like a sun or black hole can bend rays inward, to bend rays outward would require negative energy. Material with negative energy is called "exotic material" and has actually been created, granted in small amounts, in laboratories (says Thorne).

In short: wormholes are like holes in apples except scaled into a dimension we cannot perceive, and if one were to be traversable we would need a lot of "exotic material" and good fortune.

Sunday, November 15, 2015

Star Tech

Believe it or not, space is mostly just empty space. It's a vast nothingness with nothing in it, which makes for exciting television I'm sure. And not only is it as empty as space can be, but it also very very large. So, how does a film make space exciting and colorful? Well, warp drive of course.
The use of warp drive is a way for Star Trek to show the emptiness of space without showing the emptiness of space. It shows the ship traveling incredible distances in mere seconds, so that they can cut to the action very quickly. It also conveniently allows the characters to appear exactly where they need to be nearly instantly. Need to travel across the galaxy to save a planet real quick? No big deal, warp drive. In the 2009 Star Trek movie, warp drive is used to quickly arrive at Vulcan to provide aid before it is too late.
Warp drive is said to work by producing a ridiculous amount of energy in a fusion reaction of matter and antimatter in a "warp coil" brought about by "dilithium crystals", a rare chemical element. This power generates "warp fields", also known by their catchier and much more understandable nickname "subspace displacement fields". These fields distort the space around the ship, effectively surrounding the ship with a "subspace bubble", which is indeed the actual term they use. This magic space distortion bubble allows the ship to travel at speeds faster than light. However, traveling faster than light isn't exactly as simple as magic space bubbles, because in the real world we have Einstein's theory of relativity. Essentially, the faster something goes, the more mass something gains, and the more mass it gains the more energy it needs to be propelled... eventually we would need infinite energy to go faster than light, so how can something travel faster than light?




Another piece of fictional technology created almost entirely for plot reasons is the famous transporter. It's basically a teleporter that allows the characters to skip the whole landing process. It is another example of fictional technology created to skip over boring or repetitive scenes, or to get characters to or out of a place very quickly. In the 2009 Star Trek movie the transporter is used to save Kirk and Sulu as they are falling towards their certain demise. At the very last second, they are teleported onto the ship alive. Spock also uses this technology to quickly teleport to Vulcan, and to teleport himself and others to safety. It "works" by dematerializing, transmitting, and reassembling the teleported, or "beaming" them. While tests have apparently been successful in teleporting quantum information between photons, transporting atoms, and keeping them in the right place, would be incredibly difficult. Also, while people in Star Trek can be teleported from planet to planet with ease, in real life theoretically sending particles in a quantum state would travel by something like radio wave, and thus wouldn't exactly make it that far.


Sources: 
http://www.livescience.com/34005-science-fiction-fact-teleporters-beam.html
https://cosmosmagazine.com/physical-sciences/why-can%E2%80%99t-anything-travel-faster-light
http://memory-alpha.wikia.com/wiki/Warp_drive
http://memory-alpha.wikia.com/wiki/Transporter

Sunday, November 8, 2015

Is Bombing Thousands of People Morally Right or Wrong??

At a first glance I feel like most people, certainly myself, would immediately be repulsed at the idea of killing a ridiculous amount of people with a bomb. However, context and circumstance can change everything, so it's only fair to give a more in-depth look at the situation.

In "Fat Man and Little Boy", the scientists are tasked with making an incredibly powerful bomb to aid the US in a war. In short, simple terms: they need to make a powerful weapon to stop a force that threatens them. Initially I would say I'm against the creation and use of such a weapon, but then I considered the scenario in "Gojira".
In "Gojira", a rampaging monster must be stopped in order to save as many people as possible. In short, simple terms: they need to make a powerful weapon to stop a force that threatens them.

The scenarios of "Fat Man and Little Boy" and "Gojira" are surprisingly similar when thought of like this, but there is, of course, one striking difference between to two: In one a literal monster is slain, in the other human beings are killed.

One can argue that both are in self defense: a weapon to stop a threat. However, that argument essentially equates human beings to the monster that is Godzilla. Godzilla is undeniably at fault for the destruction it causes, but could every corpse created by the bomb be held accountable for their country's actions? Furthermore, does dropping a bomb on thousands of people not make us the monster?

That being said, if I were a scientist offered to do research with weapon applications, I would hesitate to either accept or decline. It is hard to say whether or not I would be okay with my research leading to the deaths of a human, let alone thousands. Perhaps if my country were in undeniable danger I would, but I would not be proud of it. Eventually I would have to consider what was at stake. It is really selfish to want to protect yourself and your loved ones? But what right do I have to take other lives, aren't they just trying to do the same? I would not try to distance myself as the creator from the "droppers" of the bomb. I was a cog in the process, and at least some fault would fall to me.

Maybe if it were the only option to save my country and me, and maybe if I had nowhere else to bring my science I would do it. That isn't to say, however, that I would have a peaceful sleep for the rest of my nights.

Perhaps sometimes we humans have to do things we may not think is right just for the sake of survival. Perhaps it is wrong for us to consider our survival more important than others', but perhaps we shouldn't ignore that most basic human instincts.

It's easy to say "I'm above killing others" and move on, but, unfortunately, sometimes the situation is a bit more complex.

Sunday, November 1, 2015

GLOBAL WARMING

Whether we like it or not, global warming is kind of a thing and it seems to be getting real serious real quick. One of the biggest problems is ice on land melting and going into the oceans, thus raising not only the sea levels, but also all sorts of issues, like flooding.

The heat is being caused by the ridiculous amount of carbon dioxide that we're producing. Over the past thousands of years carbon dioxide levels have NEVER been so high, and the heat-trapping nature of it is really screwing our planet over.
A graph by NASA illustrating the terribly high level of carbon dioxide we suddenly have now a'days.

Thanks to the burning of fossil fuels for our electricity and transportation, deforestation, and many other industry-related processes our carbon dioxide production is way higher than the amount of absorption the earth can keep up with. 
It's only getting worse, as well. In the last few years the increase of carbon dioxide production isn't exactly coming to a halt.


As we continue to outpace the Earth's absorption rate of carbon dioxide, we continue to raise temperatures a melt a bunch of ice that really doesn't need to be melted. 

Fortunately, many environmentalists are working on solutions to cut down on the use of fossil fuels to slow down our production of carbon dioxide, but a lot of damage has already been done.  

Sunday, October 4, 2015

2001: A Space Oddity

        "2001: A Space Odyssey" was certainly a memorable experience. I say that because I feel that I was, in a sense, scarred from that movie. It was not necessarily a painful scar, but a definitely a confusing and slightly scary one. It took me on a journey of varying emotions. I felt curious, happy, sleepy, concerned, angry, sad, bored, and absolutely and utterly perplexed. As I walked away from the movie, I simultaneously felt that I had enjoyed the experience and that I had been disappointed by it. While it had been, in some ways, a great movie, in other ways it felt... off. And no, I'm not just talking about the giant fetus or whatever. I mean the movie had a few things missing, a few questions that SHOULD have been answered, and a few missed opportunities.
        If I were to type out an entirely detailed summary of this movie, I would run out of paper. And this program produces new pages infinitely. In short, "2001: A Space Odyssey" is about human evolution. It begins with the primitive creatures that would one day become humans discovering the monolith, and than the concept of a tool (a bone in this case). Fast forward to the very distant future (relative to the monkeys at least), and we are introduced to the more familiar human being interacting with very futuristic but still fairly relatable things. There is a spaceship, future space skype, the amazing Grip Shoes, and so on. We find that the humans have discovered a monolith on the moon, and that it points to Jupiter. Astronauts Frank, Dave, and a bunch of other less important people make the long journey with HAL 9000, an AI computer that thinks it can do nothing incorrectly. What could possibly go wrong? So on the way there Frank and Dave believe HAL has screwed up enough to deserve disconnection. HAL magically reads their lips with his ominous, red robot eye and gets reasonably upset (I mean come on! Those human idiots are about to effectively KILL the smartest person in the room! You GO, AI!) and decides the only reasonable thing to do is to "disconnect" THEM. He kills all the astronauts on life support, murders Frank, and he WOULD have murdered Dave, but he was too clever. Dave eventually shuts HAL down, and the movie continues on. Then the movie just loses it's mind and I don't even know how to explain what happened. Colors are flying by, Dave looks scared, I look equally as scared, it's just a confusing mess. Finally Dave ends up in a room and he keeps seeing his older self until he is a giant space-fetus. It was a predictable ending.
        Before I get into the physics review of the movie, I want to first address what I feel is the biggest problem with it. HAL is probably the most interesting things in the entire movie, but he is merely an obstacle in the big picture. An AI that goes rogue because he KNOWS that he is statistically more probable to complete the mission successfully than the humans is a fantastic plotline, but the movie decides to forgo the opportunity of expanding upon this for something else. What does it focus on instead? Well, that is the problem. I as the viewer am not entirely sure. There seems to be remnants of a very creative and interesting plot, but it simply is not all the way there. It hints at extraterrestrial beings inventing this strange monolith, and it hints at them either watching or aiding human evolution (with the monolith appearing near the ape-like creatures and then shortly afterwards discovering the tool and so on), but none of this is really explored. The monolith is simply there and it does nearly nothing but advance the plot, and the supposedly aliens do nothing but have the monolith be there. Then near the end of the movie it looks like Dave discovers some sort of other dimension outside of time and space, and he turns into the infamous star baby fetus whatever. How is that better than exploring HAL? I absolutely believe HAL should have been in the movie more. Two astronauts battling a computer in a game of wits for their lives sounds fantastic, and could even tie in (in some symbolic way) to the game of chess they had earlier in the movie. But I digress.
        The movie does have some pretty realistic, or at least convincing, space physics, though. I'm actually really impressed by their use of centripetal motion to produce artificial gravity.


This circular room is spinning in space at such a velocity than the force acted on the man (centripetal force) is equal to the force due to gravity on Earth, thus artificial gravity. A second good physics example is a short one, and that is the accurate portrayal of sound in the vacuum in space. In real life sound cannot be heard in space, because sounds are basically vibrating air. They show this in the movie just as it would happen in real life.
     The movie as a whole has some pretty great physics, so it was really difficult for me to go back, but there is one clear example. While on the moon the astronauts casually walk as if they were on Earth. But this is, of course, not possible. They should be bouncing around in a silly fashion during their serious scene, but I suppose that's exactly why the omitted it.
     Overall I think I really did enjoy this movie. I do feel it should have explained just a teency bit more (but not too much! It's fun to leave things to the imagination), and I would have appreciated more of a focus on HAL, but it wasn't terrible. The long shots portray a certain atmosphere I can't quite describe, and in reflection it seems like most people just have short attention spans.

I give "2001: A Space Odyssey" a  2001 out of 10.

Sunday, September 27, 2015

"The Day Gwen Stacy Died - Impulse and Momentum"

It is never the fall that kills them, but the stop.

"The Physics of Superheroes" by James Kakalios explores the unfortunate death of Spiderman's girlfriend Gwen Stacy. The dastardly Green Goblin holds Gwen over the end of the George Washington Bridge to bait Spiderman into battle. During the duel, he drops her over the edge, forcing Spiderman to leap into action and rescue her! He heroically shoots a web at her, catching her mere seconds before he hits the ground! She calms to a halting stop, and Peter Parker breathes a sigh of relief.
But it is never the fall that kills them, but the stop.
He reels up not his smiling, beautiful girlfriend, but her lifeless corpse.
As Kakalios wrote: "A death that was demanded... not by the writers and editors or by the readers, but rather by Newton's laws of motion."

Kakalios uses the equation v^2=2gh to find out Gwen's velocity as she plummets to her doom. He assumes that she is caught after she falls ~300 feet, and knowing that g is accelaration due to gravity, he finds that she is falling at almost 95 mph (a little over 42 m/s)!
He then uses Newton's second law to find how large of a force is used to stop Gwen's descent.
F=MA
He rewrites it to be:
(Force)(Time) = (Mass)(Change in Speed)

While the right side of the equation is momentum, the left is impulse.
As I understand it, if you have little time to slow something down, you'll need a bigger force to stop it. Spiderman had very little time to stop Gwen from falling, which is terrible for her spine.

Kakalios finds that if Gwen's change in speed goes from 95 to 0 mph in about half of a second, and if his estimate of her weight (50kg) is correct, then 970 pounds of force is applied to her. SNAP.

Spiderman is not a stupid man, and he learns the physics error of his ways, and finds himself more successful in the future.
In one incident that involved an unlucky winder washer, Spiderman, instead of applying all of that impulse to the man, falls down to him, matches his speed, and then uses his web to swing away. This applies the ridiculous impulse to his super-spider arm, which can take it.

In hindsight, though, somebody as supposedly smart as Spiderman really should have understood that catching Gwen like that would kill her. I guess he was just under a lot of pressure.

The Physics of Super Heroes, James Kakalios, Gotham Books, 42-52.

Sunday, September 20, 2015

Kinetic Impact

While it's really easy to just look at a giant space rock and say "let's just blow it up", there are far more interesting and complex options, including just hitting it with something
People smarter than me call it kinetic-impact, and it could be a fairly effective way of knocking an asteroid off its course without the use of nuclear explosives. The idea is that we would ram something into the asteroid as hard as we could to push it into a different orbit or off its course, thus missing Earth. This basically becomes a huge example of a collision problem. Which means, of course, that NASA would need to know the mass and velocity of the asteroid so they could send something big enough and with enough force that it would actually work. Plus, they would need to know years, maybe decades, in advanced to actually pull this off. However, even if they gathered all of the relevant information, there could still be one issue. It would probably be safer to lodge our projectile into the asteroid (what if our projectile were to come back towards us?), so the surface of the asteroid would alter the outcome immensely. If it were too hard, our projectile might not be able to lodge into it. If it were too fragile, the asteroid might shatter, and then we have a whole other problem on our hands.

While no research seemed to show that this has been properly tested before, it seems we got fairly close with the Deep Impact mission of 2005. They launched a probe straight into a comet to see what it was made of, as stated by aeronautical engineer Rusty Schweickart “In a way, the kinetic impact was demonstrated by the Deep Impact mission back in 2005, but that was a very big target and a small impactor that had relatively no effect on the comet. So, we haven’t really demonstrated the capability to have the guidance necessary to deflect a moderately sized asteroid.”

Essentially, the main idea behind this plan is that we could knock it away without the risks that come with blowing it up. It certainly is not as effective as the use nuclear explosives (which, honestly, we would probably use if the time comes), but it is a different take on the idea.

I don't have a witty tagline to write at the end like I usually do.  ¯\_(ツ)_/¯

Sunday, September 13, 2015

Physics: Erased


Everybody knows of the classic railgun, and anybody who knows what they're talking about knows that Eraser is indisputably the best move ever created in the history of mankind. Here is an example why:

During one climatic scene of the movie, Arnold Schwarzenegger must use two railguns at once to fend off the baddies. This scene totally makes physical sense and here is why.
First, we begin with a picture to help visualize the scene:



Now that you can perfectly visualize the scene at hand, we can try to put some numbers behind it. Here is what we already know:

M,a (Mass of Arnold) = 100 kg (estimated with Google).
M,b (Mass of Bullet) = 0.01kg (estimated by rounding the weight of a heavy bullet.)
Vi,a (the initial velocity of Arnold) = 0 m/s (as he is not moving before he shoots.)
Vi,b (the initial velocity of the bullet) = 0 m/s (as it does not move before it is shot.)


M,v (Mass of Arnold's victim) = 80 kg (the approximate weight of the average man.)
M,b (still) = 0.01 kg
Vi,b = 3x10^7 m/s (as the movie says the bullet moves close to the speed of light)
Vi,v = 0 m/s (as he is not moving before he is shot.)

Now, to prove that this masterpiece of a movie is realistic, we must use that information to see if the law of conservation of momentum is kept. (Pf = Pi)
I'll start by finding the final velocity of the victim with the bullet lodged in him.

Vf = (M,b)(Vi,b) / (M,v + M,b)

Vf = (0.01kg + 3x10^7m/s) / (80kg + 0.01kg)

Vf = 37,000m/s
(This also tells us what Vf,b on Arnold's side is)
Already we've come across perfect physics, as the victim in the movie abso- wait. No he doesn't. This is right at all. That's ridiculous. This means that the baddie should have flown back at impossible speeds after the bullet lodged in him.

Now we'll do the same for Arnold. If the momentum is conserved, then the recoil should be pretty hefty.

Vf = -(M,b)(Vf,b) / (Ma)

Vf = -(0.01kg)(3x10^7m/s) / (100kg)

Vf= -3x10^4 m/s
Arnold doesn't seem to move at ALL when he fires not just one of these guns, and he fires two! If he doesn't fly back, his arms should at least be ripped from their sockets as if they were made of wet paper. Could it be that the greatest movie ever does not contain accurate move physics??

I rate Eraser -3x10^4 out of 10 on physics accuracy.

Saturday, September 5, 2015

Physics Impossible 3

Agent Ethan Hunt has simply one task standing in his way before he can save his wife and show off how cool he is: steal the MacGuffin and bring it to the bad man. The challenge before him is to infiltrate the high security building where the rabbit's foot is located, but Tom Cruise isn't about to simply walk in. He decides to swing from the taller building next to desired one, intending to land on the roof. Assuming he has a rope that can withstand the tension of this stunt, how long does the rope need to be for him to accomplish the feat? Fortunately for physics-loving viewers, Zhen Lei lays out most of the information we need:

The building Hunt needs to be on is 162m tall.
The adjacent building he will be swinging from is 226m tall.
The distance between the two is 47.55m long.

This tells us one thing: the rope has to be longer than 47.55m (plus a little extra to ensure that he lands ON the roof and not on the ground 162 meters below).

Hunt starts his impossible mission by running away from his target and jumping off the starting building. This allows him to swing towards the correct building. He would probably need to jump relatively far to make the swing. The farthest distance a human being has jumped is 8.9m, so we can assume it is less than, but somewhere around near it (considering the amazing physical ability Hunt has shown off in this movie).

So, Hunt would need a rope that can cover the 47.55m gap, give him about 10 feet (3.048m) of leeway to ensure a "safe" landing, and include the distance of the jump he makes at the beginning. 
A better question would be where he got a rope that long on such short notice. 

-

In another scene, Hunt displays the aforementioned amazing physical ability. This time the only thing preventing him from getting to his wife is about a mile and a half of Shanghai. He appears to be very quick in the scene. TOO quick. Could he have run that distance in that amount of time? 

Over the phone, Benji is directing Hunt to the location of his wife. At one point he tells Ethan to run 3/4 of a mile, and then another 1000 yards after that. That, in addition to the small amount of running before and after those sprints, is about 2.5km, or about a mile and a half. After a quick google we find that the world record for the fastest mile ran was done in 3:43. Well, the movie shows the great Tom Cruise running 2.5km in about 1 minute and 10 seconds. 
And I would have gotten winded by just running up the stairs in the beginning of the scene. 

-

Finally, in the bridge scene where Hunt is under attack by bullets, missiles, and whatnot, we are met with one more glaring case of bad movie physics. At one point during the dramatic action sequence, Hunt must run and jump over an incredibly large gap to catch the baddies (which he fails to do anyway). Is it possible for him to jump over a gap that size? 
The gap is about the length equal to that of a couple cars bumper to bumper. The average car length is somewhere between 4.5m and 4.8m, so this sets its size at good ten-ish meters at the very least. As I mentioned before, the record for the longest jump is 8.9m, so even though Hunt only barely made the jump, he probably just destroyed a world record. 

I suppose it's called Mission Impossible for a reason (and I'm sure that joke has never been said in this class before).

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