Taking my girlfriend to Alpha Centauri on the Millennium Falcon 2

[Gian]

17 hours ago, swansont said:

 

17 hours ago, Halc said:

Time lords live in a universe with significantly different laws of physics. Same for Star Wars/Trek.

The problem is that there are two kinds of mass: proper mass (frame invariant) and coordinate mass (frame dependent). Use of the term 'mass' was sort of ambiguous until around 1950 when the term was formally assigned to mean proper mass. But using it to mean coordinate mass (as Einstein did) persists in pop sources to this day, and chatbots will likely still use it since those pop sources are the larger percentage of its training data.

 

 

Hi Mr Swansont and Mr Halc!

looks like co-ordinate mass is a location like the balancing point at the centre of a mass rather than the mass itself.

And whatever its nature the consequences are the same for space travel; that is in getting to c, mass  of my spaceship becomes infinite and so infinite energy is needed.

Co-ordinate mass and resting mass are still both mass?

Is that right?

Cheerz

GIAN🙂XXX

[swansont]

36 minutes ago, Gian said:

 

Hi Mr Swansont and Mr Halc!

looks like co-ordinate mass is a location like the balancing point at the centre of a mass rather than the mass itself.

And whatever its nature the consequences are the same for space travel; that is in getting to c, mass  of my spaceship becomes infinite and so infinite energy is needed.

Co-ordinate mass and resting mass are still both mass?

Is that right?

Cheerz

GIAN🙂XXX

The coordinate mass is just a proxy for total energy (rest mass energy and kinetic energy), so it’s redundant. The mass that shows up in most of the equations is the rest mass. 

Coordinate mass has nothing to do with center of mass calculations. “coordinate” and “proper” are used to refer to issues involving frames of reference 

[Halc]

1 hour ago, Gian said:

looks like co-ordinate mass is a location

No, not at all. As swansont points out, the term is used to refer to mass issues involving frames of reference.

Mass of any kind is a resistance to acceleration. Coordinate mass is simply a coordinate dependent mass that you've been speaking of:

1 hour ago, Gian said:

in getting to c, mass  of my spaceship becomes infinite

Say your proper (physical) mass is 80 kg and so is your coordinate mass relative to the frame of your shoe.  Relative to the frame of some muon, your mass is still 80 kg but your coordinate mass (some sites call it relativistic mass) would be say 500 kg. Notice that all we did was an abstract change of reference frames (coordinate systems) and there was no requirement for energy or acceleration. Mass is physical and frame independent: it is 80 kg in any frame.  But coordinate mass is a frame dependent abstraction,  ranging from 80 on up to any arbitrary value depending on the coordinate system chosen.

Notice also that no mention of location was made in any of that.