# What happens after exceeding the speed of light?

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1. Feb 23, 2016

### hubot

I'm curious about one thing. What happens after exceeding the speed of light? What are you opinions about this? What does it mean as the formula $$m=\frac{m_0}{\sqrt{1-\frac{v^2}{c^2}}}$$ goes after subsitute to equation example mass to m_0 and speed higher than speed of light to v negative mass? This question may be pseudo-science which does not mean that I do not know physics. It's not typical physics section but science fiction section.

2. Feb 23, 2016

### BvU

You litterally run out of time.
And if you look at your expression again: m goes through infinity and does not become negative but imaginary
And so on and so forth. Science fiction

3. Feb 23, 2016

### Ryan_m_b

Staff Emeritus
Nothing can travel faster than light. That equation, and many like it, stop working the moment you start plugging in impossible values.

4. Feb 23, 2016

### jbriggs444

That is the formula for relativistic mass. The concept of relativistic mass is one that has been largely discarded. Instead one uses the concept of total energy (the sum of rest energy plus kinetic energy).

$E = \frac{m_0}{\sqrt{1-\frac{v^2}{c^2}}}$ for v not exactly equal to c.

and

$E^2 = m^2c^4 + p^2c^2$ for all v

A particle with a real-valued mass would have an imaginary energy if it were moving at greater than the speed of light. In addition, it would be travelling backward in time according to at least some inertial reference frames. If one could transmit signals using such particles, it would lead, in principle, to causality violations.

Last edited: Feb 23, 2016
5. Feb 23, 2016

### kith

Hypothetical particles which move faster than light are called "tachyons". You can read about their properties here:
https://en.wikipedia.org/wiki/Tachyon
https://en.wikipedia.org/wiki/Tachyonic_antitelephone

These particles are hypothetical because they
(a) haven't been observed
(b) are fundamentally incompatible with the Standard Model

6. Feb 23, 2016

### my2cts

You risk an astronomical speeding fine !

7. Feb 23, 2016

### DrGreg

The fine is imaginary.

8. Feb 23, 2016

### davenn

as is the speed

9. Feb 23, 2016

### phinds

I'm beginning to wish this thread were imaginary

@hubot, the trouble with your question is that you are asking for a physical answer resulting from extrapolating a math equation in a way that does not represent reality. As Ryan pointed out, your really can't do this in any meaningful way. It's like asking "if the laws of physics don't apply, what do the laws of physics say about <insert nonsense of your choice>".

10. Feb 23, 2016

### sophiecentaur

If you break those laws you will have to do time.

11. Feb 23, 2016

### OCR

Lol ...

12. Feb 23, 2016

### Legendin

If energy cannot be destroyed and energy being light can travel at the speed of light what happens if light can be accelerated across a distance farther than it can travel there at its speed? ........and no math because math cant explain every dam thing in the universe.
SO your traveling at the speed of light your a mass of energy and then you break free of what ever is holding you at that speed and skip farther than you can travel at the speed of light.

13. Feb 23, 2016

### Legendin

What if light takes a short cut is it not traveling faster than it would if it hadnt?

14. Feb 23, 2016

### davenn

no need to double post

light doesn't accelerate across any distance ... the speed of light is constant in free space so your Q doesn't make sense

you cannot travel at the speed of light because you have mass .... again your Q doesn't make sense

Dave

15. Feb 23, 2016

### davenn

please think about what you want to say before typing it, again, this is nonsense

Dave

16. Feb 23, 2016

### Staff: Mentor

Total nonsense thread is closed. To the newbie posters -- please do some reading of the scientific posts here at the PF, including our FAQs and the Intights articles. We discuss mainstream science here, not crazy questions from newbies who have not done any reading.