Understanding Hypotheses and Theories

What is a Hypothesis

• An explanation based on limited evidence
• A starting point for further investigation
• Not scientifically tested or proven
• It can be accurate or inaccurate

What is a Theory

• A set of ideas explaining facts or events
• Formulated after extensive research and analysis
• Scientifically proven with evidence
• Can be used for understanding, explanation and prediction
• Theories can be proven wrong depending on the proof

How Solar Systems Form

• Solar systems originate from nebulas, which are clouds of gas and dust in space.
• Our solar system likely formed from the solar nebula, composed of gases like hydrogen and helium, and dust containing elements like carbon and iron.
• Two forces drive the formation of solar systems from nebulas: Gravity and Pressure.

Gravity

• Gravity pulls matter together
• The particles in a nebula are very small and spaced apart
• Gravity is weak but sufficient to prevent the nebula from drifting apart

Pressure

• Pressure pushes matter apart
• Particles in a nebula constantly move and collide, creating pressure within the nebula
• Pressure is higher with closer particles increasing collisions

Balance Between Gravity and Pressure

• High pressure makes the nebula expand, lessening pressure
• Gravity pulls particles together increasing pressure
• When the nebula reaches the right size, pressure and gravity equilibrate, keeping the nebula stable

Upsetting the Balance

• Supernovas can disrupt the balance in a nebula
• This causes compression in small regions of the nebula, creating globules
• Globules become dense, gravity causes them to collapse, leading to increased temperature
• The hot, dense globule can eventually become a star

Formation of the Solar System

• Our solar system took about 10 million years to form from the solar nebula
• Important events during formation include:
  • Initial cloud of gas and dust
  • Compression into a dense disk
  • Formation of the sun at the center of the disk
  • Formation of planets from remaining material