Question about Mass/Energy

Dadoalex

Gold Member
Jan 11, 2021
14,875
6,307
208
Something rolling around in my mind.

"As the velocity of a body approaches c the relative mass also approaches infinity "

So let's assume we have a vehicle that can withstand the dangers of space and it's using something akin to a ram-scoop engine so has unlimited fuel.

As the ship approaches C, it can go no faster so the energy is turned into mass, more and more mass as it consumes more and more fuel.

This is described in a book called Tau Zero

With our ship gaining more and more mass with each passing second a question arises...

Would not the ship, at some point, collapse into a black hole?
 
Something rolling around in my mind.

"As the velocity of a body approaches c the relative mass also approaches infinity "

So let's assume we have a vehicle that can withstand the dangers of space and it's using something akin to a ram-scoop engine so has unlimited fuel.

As the ship approaches C, it can go no faster so the energy is turned into mass, more and more mass as it consumes more and more fuel.

This is described in a book called Tau Zero

With our ship gaining more and more mass with each passing second a question arises...

Would not the ship, at some point, collapse into a black hole?
There is a lower limit to the mass of a black hole. It's several stellar masses. Ramscoops can never reach anywhere near C because there is only so much energy to be scraped from the interstellar medium. At some point an equilibrium will be reached and any further attempt at acceleration will be futile.
 
  • Thread starter
  • Banned
  • #3
There is a lower limit to the mass of a black hole. It's several stellar masses. Ramscoops can never reach anywhere near C because there is only so much energy to be scraped from the interstellar medium. At some point an equilibrium will be reached and any further attempt at acceleration will be futile.
Lots of galaxies and star systems with plenty of matter to scoop up and given relativity little time would pass on the ship.

At some point I reach almost C but keep moving from star system to star system sucking up mass and turning it into energy that, in turns only adds to my mass. At some point the mass would become so great that it would consume whole planets and even small stars.

I'm asking whether there is a limit to the amount of mass that can be forced into a limited volume a limit is reached and...something happens and what is that "something."
 
Lots of galaxies and star systems with plenty of matter to scoop up and given relativity little time would pass on the ship.

At some point I reach almost C but keep moving from star system to star system sucking up mass and turning it into energy that, in turns only adds to my mass. At some point the mass would become so great that it would consume whole planets and even small stars.

I'm asking whether there is a limit to the amount of mass that can be forced into a limited volume a limit is reached and...something happens and what is that "something."
There is a phenomena in sailing vessels called "hull speed". It's the point where additional sail area will not make the boat go faster. It's using all the available energy. You have the same dynamic with a ramscoop. The scoop creates drag at relativistic speeds just like a boat in water. For that reason even the most unbelievably efficient ramscoop can only reach a fraction of C. I haven't even mentioned the problem of reaction mass for propulsion. The purely theoretical questions of what it takes to travel near C involves a lot of ludicrously large numbers verging on infinity. None of it should be considered to be practical.
 
Something rolling around in my mind.

"As the velocity of a body approaches c the relative mass also approaches infinity "

So let's assume we have a vehicle that can withstand the dangers of space and it's using something akin to a ram-scoop engine so has unlimited fuel.

As the ship approaches C, it can go no faster so the energy is turned into mass, more and more mass as it consumes more and more fuel.

This is described in a book called Tau Zero

With our ship gaining more and more mass with each passing second a question arises...

Would not the ship, at some point, collapse into a black hole?

Possibly.

Good book.
 
There is a lower limit to the mass of a black hole. It's several stellar masses. Ramscoops can never reach anywhere near C because there is only so much energy to be scraped from the interstellar medium. At some point an equilibrium will be reached and any further attempt at acceleration will be futile.

There is a lower limit to the mass of a black hole.

That's no longer the consensus.
 
There is a lower limit to the mass of a black hole. It's several stellar masses.

It's not just a matter of MASS but of RATIO--- a given mass in a certain volume. The ship would increase in mass (inertia) until such point that its own mass kept it from attaining c and going any faster, but would not likely ever gain near the mass needed to overcome the strong force and collapse into a singularity for the volume of space it takes up.
 
It's not just a matter of MASS but of RATIO--- a given mass in a certain volume. The ship would increase in mass (inertia) until such point that its own mass kept it from attaining c and going any faster, but would not likely ever gain near the mass needed to overcome the strong force and collapse into a singularity for the volume of space it takes up.
I can't talk about this thought experiment as if it were doable. The act of gathering such an enormous amount of energy in one place would certainly cause all of local space to collapse into a singularity long before something like a ship could reach lightspeed. At the upper end of an exponential growth curve the numbers get so large they are almost meaningless
 
Star-Torn-Apart-by-Black-Hole-777x437.jpg

The fastest objects observed in the universe are blobs of superheated plasma, ejected from black holes in the cores of extremely active galaxies known as blazars. These blobs, with as much mass as the planet Jupiter, have been observed moving at 99.99% of the speed of light.
 
Last edited:
So let's assume we have a vehicle that can withstand the dangers of space and it's using something akin to a ram-scoop engine so has unlimited fuel.

As the ship approaches C, it can go no faster so the energy is turned into mass, more and more mass as it consumes more and more fuel.
I'm asking whether there is a limit to the amount of mass that can be forced into a limited volume a limit is reached and...something happens and what is that "something."
Supermassive black holes collide and merge. Ram-scoop or no, a mass approaching c, relative to a black hole, gets sucked into the "event horizon."
The event horizon is the spherical outer boundary of a black hole loosely considered to be its "surface." It is the point, according to NASA (opens in new tab), that the gravitational influence of the black hole becomes so great that not even light is fast enough to escape it.
Questions then arise, like:
  1. Hell, if there are all these "gamma rays", "plasma", and stuff blasting out along the axis in both directions then nothing can be getting sucked in at those points, right?
  2. And does an "accretion disk" grow outward over time or does it just collect crap that works its way in?
  3. If the latter, then it would seem that circular portion of the "event horizon" corresponding to that plane would likely be the only place that matter actually gets sucked into the hole, right?
  4. If the former, then matter may get sucked in pretty much anywhere between the axis and the disk's plane, no?
 
Wait a minute, if you get infinite mass as you approach c, how come the superheated blobs are only Jupiter sized?
 

Forum List

Back
Top