What is the evidence that light travels in a straight line?

Shadow Formation: One of the most common pieces of evidence that light travels in a straight line is the formation of shadows. When an opaque object blocks the path of light, it creates a shadow behind it. The shadow is a clear indication that light did not bend around the object but instead traveled in a straight line.

Pinhole Camera: The concept of a pinhole camera also demonstrates that light travels in a straight line. When light passes through a small hole and projects an image on the other side, it shows that light traveled straight from the object, through the hole, to the projection surface.

Rectilinear Propagation: This is a principle in physics that states light always travels in straight lines unless it is refracted or reflected. This is why we see stars as points rather than smears across the sky, despite their light traveling vast distances to reach us.

Laser Beam: A laser beam is a strong piece of evidence that light travels in a straight line. The beam of a laser light does not disperse or bend but instead continues in a straight path until it hits an object.

Astronomical Observations: Observations of solar and lunar eclipses provide evidence that light travels in straight lines. The clear edge of the shadow of the Earth or the Moon is due to the straight-line path of light from the Sun.

Reflection and Refraction: The laws of reflection and refraction also indicate that light travels in straight lines. The angle of incidence equals the angle of reflection, and the refraction of light follows Snell's law, both of which are based on the principle of light traveling in a straight line.