What's the Fabric of space made out of?

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the longest wavelengths of the spectrum are red. Since the longest are red and the longest tend to prevail in the observation of it, the color comes out to be red.

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Red has the longest wavelength of visible light, but beyond it there are radio waves, which also show a shift in wavelength towards the longer end of the spectrum. Using the known position of spectral lines (Fraunhofer lines are a great example from the visible part of the spectrum), we can tell how far a wave has shifted. As the shift in wavelength is the same across the spectrum, the most likely cause is either the expansion of space, or a Doppler effect. If intergalactic gasses could change wavelength significantly, they would have a different effect on radio waves than visible light (radio waves can travel through solid walls, the waves of visible light cannot).

We don't know. Interestingly enough, if the Sun were to explode now, we would have no way of knowing for 8 minutes.We can measure the speed of objects in space relative to other objects. Figuring out where we are in the Universe is theoretically impossible; we know that we live in the middle of the observable Universe, but that's about it.

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Please correct me if I'm wrong, I'm here to learn.

The same applies both in the vacuum of space and the atmosphere of Earth. If you throw a ball at a spaceship, the spaceship's measurement of the ball's speed will vary depending on the velocity (velocity includes direction) of the ship. For example, if the ball is thrown at 40mph, and the ship is flying towards the ball at 40mph, then the ship will measure the ball's speed as 80mph. If the ship is flying away from the ball at 30mph, then it will measure the ball's speed as 10mph.Whereas if you shoot a laser at a train, the train will see the beam moving at the same speed regardless of the train's velocity.Sylas set the second scene in a vacuum because air on Earth will slow the speed of light to slightly less than 299,792,458km/s. The difference is hardly anything, and it's irrelevant to what we're talking about anyway.

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Please correct me if I'm wrong, I'm here to learn.

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I am assuming that the space shooter is also in space in the area of the spaceship.

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Even if a laser is fired at a spaceship from the surface of Earth and up through our atmosphere to the vacuum of space, the observer in space will still get the same measurement of the speed of light whether (s)he's speeding towards the source of the beam, away from it or perpendicular to it. But it's much easier to just set the thought experiment in space to begin with.It should be noted that the mechanism through which light slows down in air isn't the same as wind resistance acting on a material object.