Endercreeper01

I have recently heard of something called a Tipler cylinder, which allows time travel to the past. How is it possible for something to create time travel to the past, according to our current understanding of general relativity? Time is dilated by a factor of [latex]\frac{d\tau}{dt}=\sqrt{g_{00}}[/latex] in general relativity, so how is it possible to make the factor negative?

Do you have any mathematics behind your hypothesis? If it doesn't, it is not a good explanation, as an idea about something in physics requires mathematics.

Light can be slowed down if it travels through a medium. However, no known material makes light static when it travels through it.

We can't travel faster then light because of special relativity. The energy required to accelerate an object to a velocity v is given by [latex]E=\frac{1}{2}mv^2[/latex] In classical mechanics. However, this is only an approximation, and one term in an infinite series. In non-expanded form, the equation for kinetic energy in special relativity is given by [latex]E=mc^2 \left(\frac {1}{\sqrt{1-\frac {v^2}{c^2}}} - 1 \right)[/latex] Where c is the speed of light. As v approaches c, the kinetic energy approaches infinity for something with mass, so we can assume that it takes infinite energy to accelerate a mass to the speed of light. Because it is impossible to have infinite energy, we cannot travel at the speed of light. When you try to plug in a velocity greater then the speed of light into the equation, you end up with a complex number. We do not know what it means to have an energy with an imaginary value, but we are unable to obtain imaginary energy values in other ways, meaning it is impossible to accelerate a non-imaginary mass to the speed of light or beyond. However, it is only impossible to travel at the speed of light in a vacuum. In a medium, light travels slower, although the propagation speed is alway c. Because light is slower in a medium, it is possible to travel faster then it, if you are in a medium.

In special relativity, nothing is able to travel faster then the speed of light. However, if we imagined something traveled faster then light, strange consequences arise. For example, in special relativity, time is dilated by a factor of [latex]\frac{d\tau }{dt}=\sqrt{1-\frac{v^2}{c^2}}[/latex] When the velocity is greater then the speed of light, the time dilation factor becomes imaginary. What exactly would it mean if the time dilation factor was imaginary? What would be observed by a stationary observer if an object did travel faster then light?

My favorite scientist is Albert Einstein. He revolutionized physics with relativity.

Special relativity treats acceleration differently then classical physics does. In special relativity, the velocity of an object after moving for a time t at an acceleration a is [latex]v=\frac{at}{\sqrt {1+\frac{a^2t^2}{c^2}}}[/latex] This is to ensure that the velocity never exceeds the speed of light, even in the presence of acceleration.

It is most likely a hoax. There is no scientific evidence that mermaids or mermaid-like creatures exist.

Is there any scientific evidence that video games actually cause violence? Or is it just a nocebo, where people who believe bad video games will make them aggressive become violent when they play bad video games?

I've heard that warp drives need negative energy in order to contract space-time in the front of a spacecraft. But, space-time expands when you have charge, doesn't it? In the Ressner-Nordstrom solution, the metric is given by [latex]ds^2=-\left(1-\frac{2GM}{rc^2}+\frac{Q^2G}{4\pi \epsilon _0 r^2 c^4}\right)dt^2+\left(1-\frac{2GM}{rc^2}+\frac{Q^2G}{4\pi \epsilon _0 r^2 c^4}\right)^{-1} dr^2 +r^2(d\theta ^2 + r^2sin^2\theta d\phi ^2)[/latex] Which means space-time is contracted by charge. Why is it that warp drives are not able to use charge instead of negative energy?

Why would time be used to describe things in physics if it didn't exist?

The show Ancient Aliens has provided no scientific evidence that aliens have visited earth in the past. It is possible, but extremely unlikely, since there is no proof that aliens have visited the earth.

It is a consequence of general relativity. In special relativity, acceleration bends space-time. Einstein reasoned the same must be true for gravity, based on the equivalence principle. One way to define this curvature is by having an equation for the square of an infinitesimal length in space-time. This is called the metric, and is written as [latex]ds^2[/latex]. When there is no gravitation, the metric is given by (in spherical coordinates) [latex]ds^2=-dt^2+dr^2+r^2(d\theta ^2+ sin^2 (\theta ) d\phi ^2)[/latex] However, this is changed when space-time is curved. The metric of curved space-time is given by [latex]ds^2=\sum g_{ab} dx^a dx^b[/latex] This represents the sum of coordinates multiplied by the metric tensor component for that certain coordinate. Time is one coordinate, and the curvature of space-time makes time dilated. Time dilation is given by [latex]\frac{d\tau }{dt} = \sqrt{g_{00}}[/latex] which means time is dilated by a factor of the square root of the time component of the metric tensor. This is why time is dilated.

What exactly are you trying to say?

Do you have any mathematics behind your idea? If not, it is not a hypothesis, as hypothesese in physics need mathematics behind them.

You can't reverse the time dilation effects from a black hole in order to go back in time. Time dilation in general relativity is given by [latex]\tau = \int_0^t \sqrt{g_{00}} \ dt[/latex] You can never get [latex]\sqrt{g_{00}}[/latex] to be negative, even if [latex]g_{00}[/latex] is negative. If the time component of the metric tensor is negative, you will end up with an imaginary number for the time dilation factor.

Does your idea have a mathematical framework surrounding it? If not, it isn't a hypothesis, much less a theory. Hypothesis in physics need to have mathematics, and theories need everything a hypothesis has plus experimental evidence. If you are going to type mathematics on the forums, I suggest latex, as to make it readable.

When water expands, it forms a lattice. The atoms are further apart in the lattice then if they were all floating around, so the density increases.

It does not need to slow down when spinning, since it gains mass just by spinning. The mass increase is included in the calculation of momentum in special relativity.

No, physics works by deriving equations, testing them, and then establishing them as facts. Listing random numbers does not count as math. You need to state equations with variables. Because you seem to be avoiding the formulas, I will provide them for you. Force is the measure of how much momentum changes with time. [latex]F=\frac{dp}{dt}=ma[/latex] Where momentum is equal to mass times velocity and a is acceleration. Angular momentum is a measure of how much rotation something has, and is given by [latex]L=I\omega[/latex] Where [latex]\omega[/latex] is the angular velocity and [latex]I=\sum mr^2[/latex] Torque is the measure of how much angular momentum changes with time. [latex]\tau = \frac{dL}{dt}=I\alpha[/latex] where [latex]\alpha[/latex] is the angular acceleration. In special relativity, an object gains mass when in motion. The increase in mass is given by [latex]m=\frac{m_0}{\sqrt{1-\frac{v^2}{c^2}}}[/latex] Where c is the speed of light, and m0 is the rest mass. These are the equations that you need to be focusing on. If you aren't using these equations, you are relying only on verbal communication in order to share information. Words aren't always clear, so you should use equations to more easily communicate information.

It is most likely a hoax. It is nearly impossible for that rock formation to happen, and even if it did, it does not prove the existence of god.

Just like Strange said, all matter attracts gravitationally. The exterior gravitational force of a black hole is the same as the exterior force of anything else with the same mass and distance from the center of mass. Black holes are simply compressed into a singularity.

Oh yes, I wasn't paying attention. My formula would not be correct then.

If you have m functions, and you all raise the functions to a power of a, and then add them together, the nth derivative would be [latex]\frac{d^n}{dx^n} \sum_{i=1}^m (f_i (x))^a [/latex] Using the chain rule, this is given by [latex]\frac{d^n}{dx^n} {\sum_{i=1}^m (f_i (x))^a} = {\sum_{i=1}^m \frac{a!}{(a-n)!} (f_i (x))^{a-n}}[/latex] This is derived from the fact that the nth derivative of f(x) to the power of a is [latex] \frac{a!}{(a - n)!} (f(x))^{a-n} [/latex] Which was found using the chain rule. The nth derivative of the sum of a set of these functions would then be given by [latex]{\sum_{i=1}^m \frac{a!}{(a-n)!} (f_i (x))^{a-n}}[/latex] Which gives us our final answer for this problem.