What does it mean to say that angular momentum is conserved?
Give an example you might see on Earth. How could conservation of angular momentum help astronomers understand the development of the solar system? (this the part of the question that I don't understand)
The solar system was formed when a gas cloud collapsed under its gravity. The initial angular momentum caused the cloud to collaps into a disk.
So what does this have to do with helping astronomers understand the development of the solar system? When the Earth rotates on its axis, is this part of angular momentum being conserved? Does angular momentum show the astronomers how the earth and other planets rotate?
To say that angular momentum is conserved means that in a closed system, the total angular momentum remains constant over time. Angular momentum is a property of rotating objects and can be thought of as the measure of the tendency of an object to keep rotating. The conservation of angular momentum implies that if an object in a closed system changes its rotation speed or direction, another object in the system must change in the opposite way to keep the total angular momentum constant.
On Earth, one example of conservation of angular momentum can be seen in figure skaters. When a figure skater is spinning on ice and extends their arms, their rotation speed slows down. This happens because the skater increases their moment of inertia (resistance to change in rotation) by spreading their mass farther from the axis of rotation. According to the conservation of angular momentum, to compensate for this increase in moment of inertia, the skater's rotation speed decreases to keep the total angular momentum constant.
In terms of the development of the solar system, the conservation of angular momentum plays a crucial role. According to the nebular hypothesis, the solar system formed from a rotating cloud of gas and dust. As this cloud collapsed under gravity, it started spinning faster due to the conservation of angular momentum. As the cloud contracted, its rotation speed increased, leading to the formation of a flattened disk. Eventually, this disk coalesced to form the Sun and the planets.
By studying the angular momentum of the solar system today, astronomers can gain insights into its early stages of formation. Since the total angular momentum of a system remains constant, astronomers can estimate the original angular momentum of the collapsing cloud. This information helps in understanding the initial conditions and the mechanisms involved in the formation of the planets and other celestial bodies in the solar system.