How does light travel in a vacuum?

Light travels in a vacuum in straight lines at approximately 299,792 kilometers per second, which is the speed of light. This phenomenon is a fundamental principle of physics, derived from the behavior of electromagnetic waves. In a vacuum, there are no obstacles or interacting particles to scatter the light, allowing it to propagate in a straight path.

The ability of light to maintain a consistent speed in a vacuum is crucial for understanding a wide array of optical phenomena, including reflection, refraction, and the creation of images. This straight-line propagation allows us to perceive objects and gauge distances in typical optical systems, such as lenses and mirrors.

The other options do not accurately describe the behavior of light in a vacuum. Light does not spread out in waves as a primary characteristic in a vacuum, nor does it move in circular motion or random directions. Understanding that light moves in straight lines is essential for grasping key concepts in optics and can help in visualizing how light interacts with various materials and environments.