How FTL (faster than light) travel could happen?

[Herdazian he/him]

So at this point we know that there will be four major mistborn arcs. The final arc will be a space opera that will have FTL. The question then is that how might this FTL work.

One of the major problems against FTL is that proposed by Einstein ( I think). If I remember rightly, it basically stated that any increase in speed results in a gain of mass and slowing of time for that object due to this phenomenon FTL travel is impossible. This is because at the speed of light the gain of mass has become so much that time, for that object, effectively stops. As far as I can remember, this is the gist of it. 

Now, how I might the Scadrians overcome this problem. Simple answer, Iron Feruchemists. As per Copper mind, Iron stores physical mass. Somehow the people of Scadrial are going to figure out how to apply Feruchemists outside of their own bodies. The spaceships can then be divested of their gained mass and allowed to reach faster than light speeds. Propulsion of the ships could also be done through various means including a combination of Nicrosil and Steel.

 

[King Cole he/him]

You can't go beyond 0 mass so you could only go lightspeed this way 

[Tsidqiyah he/him]

Nested time bubble around an Aluminum ship and Nicrosil and Steel for propulsion... don't ask the details cause i don't have them yet.

[KhanBoltNo4503]

On 24/08/2017 at 3:01 PM, Tsidqiyah said:

Nested time bubble around an Aluminum ship and Nicrosil and Steel for propulsion... don't ask the details cause i don't have them yet.

Why would a time bubble be needed? Aluminium just creates a dead zone in it, meaning it would either be faster or slower than the rest of the time bubble, not the outside world.

Using ettmetal and F-Iron, you could rid the ship of all weight besides the weight of the iron itself, meaning you could never truly get to 0 mass

But ettmetal and Steel would work for propulsion, but only if there was a piece of metal to push off, or you were using such a vast wealth of power that you could afford to use nicrosil to flare it all and push off the trace elements in space.

[Fatling he/him]

Is your ability to store weight in iron dependant on the mass? Cause if not then you could get close to the speed of light  by just using a single iron atom (though that still wouldn't be faster than light). I just always imagined Brandon would do something hand-wavey with the cognitive realm or something, I don't really get all that realm stuff but it seems plausible. Or he could just have Scadrians discover a new metal that somehow magically makes it possible

[Calderis he/him]

1 hour ago, Fatling said:

Is your ability to store weight in iron dependant on the mass? Cause if not then you could get close to the speed of light  by just using a single iron atom (though that still wouldn't be faster than light). I just always imagined Brandon would do something hand-wavey with the cognitive realm or something, I don't really get all that realm stuff but it seems plausible. Or he could just have Scadrians discover a new metal that somehow magically makes it possible

The mass of the metal determines the maximum storage capacity. 

A single atom would be filled remarkably quickly. 

[MPHRD]

There was a reddit comment Sanderson said was close. It involves a large bendalloy bubble around the ship, which when the ship is going threw its faster then light from the perspective of the people outside the bubble. But the distance this ship would cross is still the same so from the ships perspective its not FTL. Instead of cryo, a second smaller cadmium is around the crew so from their perspective its normal time (or less). Normally bubbles can't move but as we saw with the train if you have enough momentum it is possible to move the bubble (so feruchemical iron might be used on the ship). I am not sure of the propulsion in space but thats an easier problem then FTL.