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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.

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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*This is, really, poor and outdated terminology.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.

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  • $\begingroup$ 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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