Planetesimals form from the gases and debris left over from the development of a new star. There is little doubt that celestial bodies are being formed by the accretion or coalescing of the dust and gases.
Legacy astronomy views the sun and all the planets as having formed approximately 4.5 billion years ago. They all formed together at the same time and as such are the same age.
Celestial astronomy views the sun as having formed first. Then planetesimals began to form after the sun was further established in its development. Planetesimals would begin developing later in the evolutionary process of the development of the star.
Celestial astronomy views time as a key piece of the puzzle in the development of the solar system. As such the time when the sun started forming and the time when each planetesimal starting forming is critical to the understanding of how the solar system and planets form.
Since it can not be known with precise accuracy, legacy astronomy just estimates when it happened and says the sun and all the planets are the same age and they are all in the same order from which they evolved from planetesimals.
Celestial astronomy describes this as a static state system. Celestial astronomy views the solar system as a dynamic state system. The sun would have evolved first and would be the oldest. Each of the planets and moons would have evolved separately and would be of separate ages. Also, the planets and moons would not have started in the locations they are in now. Rather, there would be a repeating pattern that is definable that would allow for a description of how a planet and moon are created so that you can define the start time of the object and measure its life accurately.
So as we look for the next phase of planetary evolution, the protoplanet, we need to keep a few key points in place that differentiate celestial astronomy and legacy astronomy.
- Static State System
- Dynamic State System
- Definable repeating pattern
If you notice the terminology they are using right from the beginning, "planetesimal," there is no path for the creation of a moon. Don't the moons form from planetesimals as well? Should there be moonetesimals?
Do planetesimals become comets and asteroids as well? Do we need another term like celestimals to describe the starting phase of a celestial body and then as it develops allow it to branch off into the various types of celestial bodies it becomes when it first originated as a planetesimal?
Also aren't some of the planetesimals being flushed into the sun? Aren't some of the planetesimals being floated into the galaxy or universe prior to the development of the Kuiper belt or Oort cloud? Does the floating of a planetesimal explain the accelerated return question we posed in the accretion disk article?
Does this fluid flushing and floating of a dynamic state system allow for a repeatable pattern to begin to emerge already beginning to explain planetary evolution in a solar system?
Recently an interstellar comet arrived in our solar system. This was described as the first interstellar comet ever to arrive in our solar system. Couldn't the legacy astronomy community be incorrect about this and there were interstellar comets transiting our system as soon as it began to develop? Wouldn't an interstellar comet have a better chance of developing into a planet or moon faster than a planetesimal?
These are many of the key questions we need to keep in mind as we move from planetesimal to protoplanet.