Would a star, similar to our own, be observed to "burn" differently at relativistic speeds?

I am only thinking this because the observed relativistic mass would change.

  • $\begingroup$ There is no such thing as relativistic mass; there is relativistic Doppler effect though. $\endgroup$ – Kyle Kanos Dec 15 '15 at 2:36
  • $\begingroup$ Related: physics.stackexchange.com/q/180698/520 physics.stackexchange.com/q/222809/520 physics.stackexchange.com/q/3436/520 Short-short version: you are the victim of bad (and decades abandoned) terminology. $\endgroup$ – dmckee Dec 15 '15 at 2:42
  • $\begingroup$ @KyleKanos: in the same meaning as heavy protons in the LHC ? answer would be perhaps no because the star "burns" in its frame unless it collides with another one or it spins at a relativistic speed :) $\endgroup$ – user46925 Dec 15 '15 at 2:42
  • $\begingroup$ finally, this question is similar to Photons inside a box $\endgroup$ – user46925 Dec 15 '15 at 3:21

The increased, "relativistic mass"* would not make the star burn brighter overall. Relativistic Beaming, however, would make the star appear brighter to viewers in its direction of motion, and dimmer to observers from whom it is moving away.

Additionally, because of time-dilation for the moving object, the star would actually appear dimmer to the (stationary) observer. Because time for the star seems to be moving more slowly to the observer, the star would seem to live longer --- thus to conserve the total energy output, its luminosity would appear lower.

*This is, really, poor and outdated terminology. 'Mass' is just good-old, rest-mass, and the effects you are thinking about should be considered as effects to the momentum and/or energy. See the comments by @KyleKanos and @dmckee.

  • $\begingroup$ What about an observer moving in a direction orthogonal to the direction observer-star? $\endgroup$ – thermomagnetic condensed boson Dec 16 '15 at 2:59

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