The internal structure of a protostar maintains hydrostatic equilibrium even as more material is falling onto it. Explain how this can be.

Gravitational force is one of the key players in the formation and maintenance of a protostar. This force pulls all the gas and dust inward towards the center of the protostar. Imagine it like a cosmic vacuum cleaner, constantly sucking material into the core. As more material gathers, the gravitational force increases due to the added mass. This force is crucial because it initiates the process of bringing material together to eventually form a star. The larger the mass of the protostar, the stronger the gravitational pull it can exert on the surrounding material.

The pressure gradient acts as a counterbalance to gravitational force within a protostar. This force is generated from the core, which has extremely high temperatures and densities. Essentially, the pressure gradient force pushes outward, acting against the inward pull of gravity. As more material falls onto the protostar, the core becomes denser and hotter. This increase in core temperature leads to a stronger outward pressure. Therefore, as the gravitational force increases due to added mass, the pressure gradient also rises to balance it out. This balancing act is essential for maintaining the structure of the protostar.

Stellar formation is the process that transforms a cloud of gas and dust into a fully-fledged star. This incredible journey begins in a molecular cloud, a cold region filled with gas and dust. Due to gravitational instabilities, parts of the cloud start to collapse, forming dense regions. These dense regions grow more massive as they pull in additional material through gravitational force. Eventually, these collapsing regions form what are known as protostars. The process is slow, taking millions of years, but is fascinating as it marks the birth of stars that can shine for billions of years. Each step in stellar formation is a balance between various forces, mainly gravitational force and pressure gradient.

A protostar is the stage in stellar formation that occurs before a star is fully developed. Think of it as a star in its infancy. In this stage, material is still falling into the core from the surrounding molecular cloud. The core of the protostar is not yet hot enough to start nuclear fusion, the hallmark of a true star. However, the core is extremely dense and hot, creating a high-pressure environment. The balance between the inward gravitational force and the outward pressure gradient force keeps the protostar in hydrostatic equilibrium. Over time, as more material falls in, the core temperature will eventually get hot enough to start nuclear fusion, leading to the birth of a star.

Stellar equilibrium, often referred to as hydrostatic equilibrium in the context of stars, is a state where two forces balance each other out within a star or protostar. These forces are the inward gravitational force and the outward pressure gradient force. When a protostar or star is in this equilibrium, its structure remains stable. If more material falls onto the protostar, both gravitational force and pressure increase, but they also balance each other out, keeping the protostar stable. This equilibrium is not static; it's dynamic, constantly adjusting to any changes. This dynamic balance ensures that stars can remain stable over incredibly long periods, providing them the stability required to sustain nuclear fusion over their lifetimes.