Why cant we go faster than light, why is that the max speed achievable?
In: Physics
The faster you go, the heavier you get and the slower time travels. You just don’t notice it until you reach higher speeds.
If you understand that, then you can understand that somewhere down the road, there is a limit. That limit has been calculated to be the speed of light.
At this point there’s no way to know for sure because we haven’t had the chance nor have the ability to move large complicated objects anywhere close to that speed.
this is difficult to ELI5 without visuals… I find this video is a really good explanation
the gist is that space and time are intimidating intertwined. it is like they are the two components to a space/time vector. the vector itself is uniform in length, but depending on the direction, you get more in one component than the other.
When an object is stopped, the value of space/time is all time; meaning no movement.
When the object is zero time, it is all movement and once that orientation is fully space, there nothing left to give… hence maxim value.
The increased mass is a consequence of this, and not really the reason for the limitation.
in normal every day physics we are told that force= mass * acceleration. And since we want to accelerate, we change things around to become accaleration= force/mass.
However once we get to these really fast speeds (significant fractions of the speed of light) something called the gamma factor (y) comes into play. So the new formula looks as follows: acceleration= force/(mass*y)
This factor increases exponentially the closer to the speed of light you get. and since y gets bigger the closer to the speed of light you are, the more force you need to get something to go faster. And eventually you would neet literally infinite force to actually reach the speed of light.
According to Special Relativity, as an object approaches the speed of light, its mass increases accordingly. So reaching the speed of light would make its mass increase to infinity. The only way around this is for massless particles like photons. Any object with mass will become increasingly massive (towards infinity) the closer it gets to the speed of light.
The problem with this is that the more mass there is, the more propulsion you’ll need to keep it accelerating. So infinite mass would need infinite propulsion which for obvious reasons is not possible to achieve
Here is the explanation:
First, as you go faster, your mass increases, and becomes infinite at light speed. That means that the energy required to accelerate anything to the speed of light apart form photons (which have no mass) will require an infinite amount of energy, which doesn’t exist in our universe.
Second, as you go faster, time slows down, and at light speed time doesn’t pass at all. In other words, time stops existing at speeds beyond that point, and so – naturally – the same happens to the concept of speed.
Buy A Brief History of Time by Stephen Hawking. Its written for normal people to grasp theoretical physics.
As you can see from the responses, answering one question just leads to more. Its a great book, truly.
We don’t know why it’s the maximum speed, we do know that going faster than it would break causality, meaning time would go in reverse for whatever is going faster than the speed of light. If you break causality then effects can happen before their cause, which is not possible (as far as we know).
Everyone here is saying “your mass increases” and that isn’t really true. We can pretend like it does, but the truth of the matter is it becomes more difficult to slow you down as you move faster.
Really, the speed of light is effectively infinite, in the sense that no matter how fast you go, no matter how much you accelerate, you’ll always perceive light to be moving the same speed. You literally cannot catch up to it.
What happens instead as you continue to accelerate, is that your perception of time relative to those not moving begins to slow down, and your perception of distances begins to shrink.
If you were traveling “infinitely close to the speed of light”, what you would experience is the entire universe contracting down to an incredibly short distance. In this way, every unit of compressed distance you travel equates to substantially large uncompressed distances. You would reach the end of the universe in mere moments. It would take the blink of an eye, and poof, you’ve traveled billions of light years.
However, from the perspective of someone not moving, your journey would take billions of years, and they would see you traveling along the entire length of the uncompressed distance.
So to wrap up : Acceleration at near light speed results in space compressing and time dilating rather than speed increasing
All answers here except the one by u/Steve_Jobs_iGhost will work mathematically but are factually wrong. Mass does not increase with velocity. Conservation of mass is a thing in physics and this would completely break it, so no no not a correct explanation.
There is the always weird explanation that says: Everything always moves at a total speed of light speed through a combination of time and space. I.e. if you are standing still you are moving at lightspeed through time and if you are moving at lightspeed through space you are standing still in time. In a weird way THIS also works out perfectly mathematically but leaves the rather unsatisfying open question: Why does everything move at exactly light speed through space + time and not another speed?
The real reason why nothing can move faster than light is because.. Time travel is impossible! Or… Because when adding speeds together 1 + 1 does not equal 2!
Actually both of those are true I just haven’t chosen yet which one I will be working towards. It both starts with the same anyway.
First we need to look at what light actually is. Light is that thing my mom makes me turn off at x pm to go to sleep! Yes that too! But so what is light? Let’s say we have no idea because that would be like starting with episode 4: A new hope. Which really is the one you should start at but I digress.
What is electricity is where we should start! The electron menace.
Now electrons have something called electric charge. This is a fundamental property of electrons (just as it is for protons). An electric charge also causes an electric field around it that is dependent on how strong the charge is and how far away from the charge we are.
Now a MOVING electric charge will cause the electric field to change because the distance to the charge changes and as shown experimentally a moving electric charge also causes a magnetic field.
Magnets on the other hand work a bit differently they always have a dipole i.e. they are always a + and a – together, but what also happens is when you move a magnet you get a changing magnetic field but you also get an electric field.
THAT is where we were with physics before shit started getting weird.
TBC.
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