Einstein is riding in a space-ship in at a constant speed of 67% the speed of light. His friend, Bose, is riding (also constantly) at 86% the speed of light. Their paths are parallel, and they are going perfectly straight. Bose, as a prank on Einstein, takes out his laser-gun, and fires it at Einstein when he is 180,000 kilometers ahead of him, at just the right angle so that it goes directly into Einstein's eyes. From Einstein's perspective, what is the speed of the light at the exact moment it hits his eyes?

Details and assumptions

• Assume that light travels at 300,000,000 meters per second, and that it is not affected by the space-ship's windshield.

• The universe that Einstein and Bose are in is relativistic.

• The space-ships have no gravity, nor does anything else in the universe.

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