People in ancient times used observation of the moon's cycles and the sun's position to estimate the length of a year. However, it wasn't until the development of sophisticated astronomical observations that the length of a year could be determined accurately, leading to the Gregorian calendar with a year length of 365 days and a leap year of 366 days every four years.

Correct. Don’t know what i’m being downvoted for lol.

Sound waves have a lower frequency than light waves, and this means that they can travel through solid objects and around corners. This is why you can hear sounds that are coming from behind walls or other objects. On the other hand, light waves have a much higher frequency and are not able to penetrate solid objects as easily, which is why light can be blocked by walls, curtains, and other objects. So the lower frequency of sound waves allows them to persist even after they've been reflected by solid objects.

Light is like a laser beam that travels in straight lines and can be stopped by things like walls and curtains. But sound is like a wave that travels through the air and can go through things like walls and doors. So, when you close your curtains to block the light, it works, but the sound can still come through because it can travel through the walls and doors. That's why you can still hear noise even when you try to block it.