In a vacuum, yes, a ray of light travels in a straight line. This is a fundamental principle of optics. Light travels at its fastest speed in a vacuum, and its path is undisturbed by any medium.
However, in reality, things get a bit more complicated:
* Light bends when it passes through different mediums. This is called refraction and is why a straw in a glass of water appears bent.
* Light can also be scattered by particles in the air. This is why we see the sun's rays as beams, even though they are traveling in straight lines.
* Gravity can also bend light. This is a phenomenon predicted by Einstein's theory of relativity and has been observed through gravitational lensing.
Therefore, while we often think of light as traveling in straight lines, it's important to remember that this is a simplified model. The actual path of light can be influenced by various factors, making it more complex than just a straight line.
