Simultaneous in all inertial frames

Oct 2018
The question I have says that a comet is travelling at speed v and people are having a party to celebrate the crashing of the comet. If the comet has to travel 8x10^11 m then how long do they need to have a party for, for the party to be simultaneous with the crash in all inertial frames?

My attempt:
Wouldn't it be an infinitely long party? This is just my general assumption. I'm not too sure how to use the Lorentz Transformations to help me


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Apr 2009
Boston's North Shore
That can't happen. Simultaneity is frame dependent.
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Jun 2016
As PMB indicates, you would have to be very careful about how you define "simultaneous"
Each "inertial frame" would have its own "instant of simultaneity" with the impact.

If you were to have 2 comet impacts, each being celebrated by parties in the different inertial frames,
then the length of time between parties in different frames would differ.
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