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# Some relativistic properties and phenomenon

A while back I posted a discussion called "Quantum Mysteries", which ended up not really getting off of the ground. So now that I have as many followers as I do, I'd like to post something kind of like it again, but with a bit more broad of an explanation. It would be worthwhile to read the whole thing. Many of you have heard of things like time dilation, black holes, length contraction, space-time, the Big Bang, and how nothing travels faster than light. I have a pretty good model to explain all of this. Imagine the whole universe as a sheet of latex. From here on out, we're going to call this "space-time fabric". When the Big Bang happened, the universe was a little tiny dot. When it couldn't contain the energy, and the amount of heat and pressure became more powerful than the enormous amount of gravity holding it all together, it exploded, expanding at the speed of light, and it continues to expand to this day. So this space-time fabric that was all bundled up is now stretching, being blown up like a balloon, not gaining any mass, but growing in volume. Imagine you took a static portion of this expanding space-time, and put a sun smack-dab in the middle of it. The gravity of the sun actually curves the space-time fabric into itself, like placing a bowling ball on a trampoline. Other smaller bodies with less mass roll towards this sun, which we call "gravity" (ever heard of that?). Now, imagine this: the fabric is continuously being pulled by an invisible force, and it has an unbelievably tiny amount of friction, so it doesn't really affect the planets that are sitting on it, except for the tiniest amount. Let's say that this pulling is what time is. Before I go on, there are two things to keep in mind. First of all, the universe isn't a two-dimensional sheet, it's more like a bunch of sheets on top of one another. Secondly, when I say the fabric is being pulled to represent time, it's not in any certain direction. You could say that it's "omnidirectional", like it doesn't have any direction. It's not like you could say "Oh, time is that way!". Anyways, things that are heavy enough (like black holes) can actually rip through this fabric! Now that the stage is set, I'm going to introduce you to time dilation. Physicist have discovered that time can go at different speeds, and when an object is near intense gravity, times slows down, and when it's going near the speed of light, times speeds up! Imagine that you're an ant that can walk on space-time. Your friend, also a space-time-walking ant, is walking near a black hole, at the same speed that you're walking at. But his path dips down, whereas your path is the straight. That means that he has to travel further through space-time to go the same distance as you! And if he went in the black hole, he'd be below the event horizon and time would pass around him, but he wouldn't travel through time. That explains time dilation near large bodies, but what about going at high speeds? Earlier, I mentioned that this space-time has a super tiny amount of friction. Let's say that you're a space-time-walking ant, but you can walk at 90% the speed of light. You're going fast enough to actually have an effect on space-time, like pushing your finger into a table cloth, and making it bunch up. "A Wrinkle in Time", by Madeleine L'Engle, is based on this principle of folding space-time to get from one place to another by traveling less distance. Now I want to talk about how light is the ultimate speed. A couple of years ago, the scientific community thought that there were things, like neutrinos, that could actually go faster than light, but it turned out to be a mistake. This is the hardest part to explain. I'll start by explaining $$E=mc^{2}$$. Einstein's famous equation. All that it states is that the more energy you put into an object, the more mass it gains, and the more mass that is gained, the more energy is needed to push that larger object, which is why things absolutely cannot go faster than light. But what about if you shine a flashlight in a train going 50 miles per hour. Doesn't that exceed the speed of light? Let's recall our formula for speed: $$speed=\frac{distance}{time}$$. If it's not the time that's changing to make it seemingly possible to go faster than light, then it must be the distance. Therefore a ruler on a train going 50 miles per hour is actually shorter than one that's not on the ground! Crazy right?! It's called length contraction, and it's one of the most insane ideas that have been proven. Think about it! There are no laws that say it can't happen! If time can change, so can length! I hope that this article has given you something to think about. Post your reaction! ;)

Note by Finn Hulse
3 years, 1 month ago

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Hypothetically, though, there are theoretical particles that always move faster than light called tachyons. (Cool illustration below)

Tachyon

##### Image Credit: Wikipedia

Here are some interesting articles on tachyons:

$$\rightarrow$$Wikipedia- This explains the general concept of the tachyon.

$$\rightarrow$$Do Tachyons Exist?- Some interesting equations.

$$\rightarrow$$Tachyons May Not Exist After All- If so, then, theoretically speaking, time is an illusion. · 3 years, 1 month ago

Tachyons are awesome! I don't think that they are real, because if they have mass, then they would become the size of planets in under a second. So... that's weird. :P · 3 years, 1 month ago

That is pretty interesting, but isn't the equation for speed d/t. · 3 years, 1 month ago

Wouldn't this also mean that time would change, and that the ruler would be a bit older than one on the ground. · 3 years, 1 month ago

Yup. Exactly! Both of these changes are minuscule, though. In fact, the time dilation from the speed of the train would be counteracted by the gravity of the earth. Check out Sharky's problem about the pig in the train. · 3 years, 1 month ago

Yeah. Like miles per hour, meters per second, etc. · 3 years, 1 month ago

Oh yeah. I was kind of rushing. Did you really read the whole thing? · 3 years, 1 month ago

Yea, is that all from books because it reminds me of the book that I'm reading. · 3 years, 1 month ago

Not all. Most of it is, except for the explanation of time dilation near heavy bodies and at high speeds. Nobody has ever considered that space-time is being "pulled". · 3 years, 1 month ago

Good point, wasn't Einstein the one that was the first to consider that space and time were intertwined. I guess it does make sense that space-time is being "pulled" because it ways so much on outcomes. · 3 years, 1 month ago

Yes. · 3 years, 1 month ago

Read the whole thing! It's very worthwhile! · 3 years, 1 month ago

Enjoyed reading, though I knew some of it....Thanks! · 3 years, 1 month ago

You're very welcome! · 3 years, 1 month ago

Hmm a very interesting article, I would say. But I do not really think you showed that nothing can travel faster than the speed of light...Of course we need the postulate that light travels at a constant speed in vacuum in all inertial frames, and then only we can have $$E=mc^2$$. And by the way I believe that you know that $$E=mc^2$$ isn't the whole story, but either $$E_0=m_0c^2$$ or $$\Delta E=\frac{m_0c^2}{\sqrt{1-\frac{\Delta v^2}{c^2}}}$$. By the second equation you can easily show that nothing can accelerate from a slower speed of light to the speed of light, as you will need infinite energy. It also 'shows' why things cannot go faster than the speed of light or you will be taking the square root of a negative number. Thirdly, it shows that photons have to massless since they cannot have infinite energy.

Apart from these, the Big Bang Theory itself does not convince me. Where does this energy come from? Why does it grow that the original singularity cannot contain it and explodes? What decides it when to exactly explode? (for this one you might argue that there was no time, but if there was no time, how does the energy increase until a certain point that it cannot be contained?) Hopefully there would be some interesting discussion about this.

A very good job anyway, I feel like sharing my article of demonstrating special relativity using the Minkowski diagram, which requires a tiny bit of calculus and just high school geometry. · 3 years, 1 month ago

Great! I'll see about including this! As for your question on the Big Bang Theory, nobody knows. Of course, I welcome any theories any users have. ;) · 3 years, 1 month ago

Finn, as Omkar asked are you really 13 years old ? When I read this article I really felt as such I am reading a scientist's article. Hats off to you !!!!! · 2 years, 9 months ago

Hi Finn! Are you really 13? If yes then great job writing this article. If you are really interested in Quantum Mysteries and other scientific mysteries, be sure to check out a show that came to DISCOVERY SCIENCE channel, named THROUGH THE WORMHOLE WITH MORGAN FREEMAN. Its the best place where you can understand very bizarre topics very easily. They have an episode on almost every scientific mystery. Be sure to check it out. · 3 years, 1 month ago

I just did! It's amazing! Dude! And yes, I'm 13 years old. · 3 years, 1 month ago

The best thing that I like about THROUGH THE WORMHOLE is its simplicity. · 3 years, 1 month ago