Matter travelling faster than speed of light

[Ayden]

How can we know that nothing travels faster than the speed of light (3 x 10^8 m/s)? If there were certain physical phenomena that could travel faster than light, we wouldn't be able to perceive it, since light has a limited fixed velocity. So, what if dark matter and dark energy are just phenomena that actually travel faster than light and we can't detect them through light wavelengths. We can measure its gravitational effects, but not its emission spectra.  

[studiot]

12 minutes ago, Ayden said:

How can we know that nothing travels faster than the speed of light (3 x 10^8 m/s)? If there were certain physical phenomena that could travel faster than light, we wouldn't be able to perceive it, since light has a limited fixed velocity. So, what if dark matter and dark energy are just phenomena that actually travel faster than light and we can't detect them through light wavelengths. We can measure its gravitational effects, but not its emission spectra.  

 

1)So what would happen when this superfast matter hit something ?    Wouldn't we see evidence of this ?

2) If this superfast matter emitted light wouldn't it travel at normal lightspeed? So why couln't we measure that ?

Edited February 7, 2021 by studiot

[Ayden]

1) I'd assume it would have detectable effects such as gravitational waves or warping of the fabric of spacetime that we could detect by observing the paths of light emitted from other sources.

2) The light itself may travel at lightspeed, but the matter itself may exceed it. The only place we can detect the object would be in its most recent place in lightspeed time, even if it has moved beyond that. I'm still formulating this, it needs some work clearly. 

[studiot]

55 minutes ago, Ayden said:

1) I'd assume it would have detectable effects such as gravitational waves or warping of the fabric of spacetime that we could detect by observing the paths of light emitted from other sources.

2) The light itself may travel at lightspeed, but the matter itself may exceed it. The only place we can detect the object would be in its most recent place in lightspeed time, even if it has moved beyond that. I'm still formulating this, it needs some work clearly. 

1) That's an assumption not an answer.  If this stuff is buzzing about the universe it must collide with other stuff, just as does ordinary (sub light) matter. So are you saying that the laws of conservation of momentum do not apply to such collisions either with ordinary types of matter or with more superluminal matter ?  I asked why this assumption is justified.

2) I didn't ask about detecting the dark matter in question 2. I asked about detecting the emission radiation, that you say exists from superluminal matter.  Or are you saying that there is none whatsoever in our part of the universe ?  Again why can't /haven't we detected this ?

However thank you for your answers.

Edited February 7, 2021 by studiot
spelling

[swansont]

The best science we have tells us the conditions under which massive objects might move faster than c, and we have no evidence that anything fits these conditions.

[Janus]

3 hours ago, Ayden said:

How can we know that nothing travels faster than the speed of light (3 x 10^8 m/s)? If there were certain physical phenomena that could travel faster than light, we wouldn't be able to perceive it, since light has a limited fixed velocity.

What makes you think this?

The fact that the object itself is traveling faster than c would not prevent us from seeing it.  Imagine that it is passing by you at a right angle to your line of sight.  Some of the light emitted  by the object just before it is even with you is emitted at nearly a right angle to its path and reaches you. as light travels at c(relative to you) no matter what the speed of the object that emits it.

Some the light emitted by the object just after it passes you is also emitted at an angle so that it reaches you.  Basically this means that as it passes you, you will still see it move across your line of sight.  By using its distance from you, and the speed it appears to cross your line of vision, you would be able to work out that it is moving greater than c with respect to you.

[michel123456]

3 hours ago, Janus said:

you would be able to work out that it is moving greater than c with respect to you.

 

 

How?

[beecee]

7 hours ago, Ayden said:

How can we know that nothing travels faster than the speed of light (3 x 10^8 m/s)? If there were certain physical phenomena that could travel faster than light, we wouldn't be able to perceive it, since light has a limited fixed velocity. So, what if dark matter and dark energy are just phenomena that actually travel faster than light and we can't detect them through light wavelengths. We can measure its gravitational effects, but not its emission spectra.  

 

7 hours ago, Ayden said:

1) I'd assume it would have detectable effects such as gravitational waves or warping of the fabric of spacetime that we could detect by observing the paths of light emitted from other sources.

2) The light itself may travel at lightspeed, but the matter itself may exceed it. The only place we can detect the object would be in its most recent place in lightspeed time, even if it has moved beyond that. I'm still formulating this, it needs some work clearly. 

For such speculation to be real, we would need to discard Einstein's SR, which of course is a special case of GR. Any matter would need to have mass and take up space...light has zero rest mass. As matter approaches light speed, it gets heavier from our perspective. At 'c' we would need an infinite amount of energy. Hypothetically speaking the Tachyon is a particle created at FTL and maintains that speed. Problem of course is that it conflicts with relativity and our laws of physics.

Our successful models of gravity, Newtonian and GR work in near all cases. It would be illogical imo to drop them simply to explain, or attempt to explain DM and/or DE, when both can be encompassed by GR anyway. None of that in anyway curtails physicists and scientists from speculating,  and hypothesising certain scenarios. There are scientific papers everyday that do that, but there they remain, gathering dust, until evidence is found supporting a particular scenario, or invalidating GR.

Just as an aside, and as an amateur, I dont see SR/GR as invalidating Newtonian mechanics [afterall we use it everyday, including most all space endeavours] rather it gives us a more accurate picture of gravity beyond that given by Newtonian. Afterall we could use GR calculations in all our Earthly and space endeavours and get the same answers, but the complications in those calculations and methodology would take far more time and effort then the simplistic quick Newtonian method.

 

[Janus]

54 minutes ago, michel123456 said:

 

 

How?

Assume the object passes at a distance of 1 light sec from you.  When is is at a point just a bit shy of being even with you light leaves it, and takes just a bit over 1 sec to reach you Eye.

A moment later, it is the same distance past the point of being even with you. The distance between it and you is the same distance as it was during the previous moment, So the light leaving it at this moment takes the same amount of time to reach you.  Since the propagation delay is equal in both positions, time time difference between you seeing the object at each position is equal to the time it took to move between the two positions. You can measure the angle between these two sightings, and knowing the closest approach distance (1 light sec), you can work out how far the object moved in that amount of time. 

 

There would also be a "double image" effect.

For example, assume the object again passes at a minimum distance of 1 light sec from you.  But this time it starts at a point 1 light sec from the point of closest approach and is moving at ~ 2.415c.  The light leaving it at that moment takes ~ 1.414 sec to reach you.  In 0.414 sec at 2.414c, the object will reach the closet approach point, and the light leaving it then arrive at your eye 1 sec later, or 1.414 sec after it was 1 light sec from this point.  In other words, the light that left it when it was 1 light sec short of closest approach, and the light light that leaves it at closest approach both reach your eye at the same moment.

[MigL]

The 'speed of light' is NOT just the speed of light.
It is the maximum speed for any information transfer.
If we can't see it ( somehow ) because it is travelling faster than light, it cannot have any other effect on us either.

[Markus Hanke]

17 hours ago, Ayden said:

How can we know that nothing travels faster than the speed of light (3 x 10^8 m/s)?

It’s mostly a matter of self-consistency. It is indeed possible to formulate field theories that retain local Lorentz invariance (i.e. they don’t outright violate SR), have real mass, and respect all conservation laws, yet allow for superluminal excitations. The trouble with these models is that they are not self-consistent, in the sense that they don’t have a well defined causal structure. To put it simply, the existence of tachyons (even if they don’t violate any other physics) would allow you to construct physical paradoxes that can’t be resolved in a self-consistent manner - which essentially rules out such models. This is one of those cases that are mathematically possible, but physically meaningless, so tachyons almost certainly do not exist.

[Ayden]

This was my first ever post on this forum, and I completely forgot about it until today. And I just wanna say that seeing several replies made me really excited. Thank you guys for identifying the flaws in my proposition. I am studying to be an astrophysicist and have been searching for people who share the same passions for astronomy and physics as I do, so I figured forums would be a great idea. I really appreciate having much more knowledgeable and intelligent individuals critique my ideas, because that will definitely help me grow in this field. So thank you!