Who we are ? Where did we come from ? How it all started and why? Origin of Solar System may give most appropriate answers to these questions. From Encounter Hypothesis to Nebular Hypothesis to Protoplanet Hypothesis, the understanding of planets’ origin has been different.
Encounter Hypothesis is very simple in terms of explanation. A rouge star passing close to the Sun, and gas, from both the Sun and the star, gets removed from both that results into formation of planets.
Nebular hypothesis believes in gravitation force. As per this a gas cloud starts contracting due its self-gravity and turns into a disc which has central mass. Due to centrifugal force, rings around this central mass is formed. And this peripheral ring forms planets and the central mass is Sun.
Similarly, Protoplanet Hypothesis explains the formation of the Solar System. Though it sustains many components of Nebular Hypothesis, it is more complex in nature.
Any new hypothesis improves in comparison to previous ones; also the complexity of the new model surges due to the addition of new information.
NASA is again striving hard to unveil reason(s) behind the origin of our Solar System. This time, NASA is targeting asteroids (rocky bodies orbiting the Sun). Samples from asteroids would be collected and brought back to the earth for a study.
For this study, NASA launched OSIRIS-Rex in the second week of September 2016. This mission cost more than $800 million to NASA. It is going to be a six plus years of the project.
The mission will start from Bennu- a carbonaceous asteroid. The samples from Bennu would be brought on the earth by 2023.
Probably we will get another hypothesis. What we get out of this new research is a way ahead, but one thing that is clear is that “Solar System is still a mystery and would remain”.