How was the Solar System formed?
Solar system formed about 4.6 billion year ago, when gravity pulled together low-density cloud of interstellar gas and dust (called a nebula)(movie). The Orion Nebula, an interstellar cloud in which star systems and possibly planets are forming. Initially the cloud was about several light years across.
What must a model of Solar System formation explain?
Any model of Solar System formation must explain the following facts: 1. All the orbits of the planets are prograde (i.e. if seen from above the North pole of the Sun they all revolve in a counter-clockwise direction). 2.
Who proposed the nebular theory of Solar System formation?
The current standard theory for Solar System formation, the nebular hypothesis, has fallen into and out of favour since its formulation by Emanuel Swedenborg, Immanuel Kant, and Pierre-Simon Laplace in the 18th century.
What pushed volatiles out of the inner Solar System?
In addition, particles from the Sun (the solar wind) pushed volatiles out of the inner solar system. When the volatiles reached the cold temperatures of the outer solar system — out beyond an invisible boundary called the “frost line” — they condensed onto the nascent giant planets.
All the foregoing constraints are consistent with the general idea, introduced in Other Worlds: An Introduction to the Solar System, that the solar system formed 4.5 billion years ago out of a rotating cloud of vapor and dust—which we call the solar nebula —with an initial composition similar to that of the Sun today.
What are the processes of solar nebula collapse and accretion?
The processes of solar nebula collapse and accretion explain why there is so much space in space, where we find the various types of planets and other small bodies, and why the planets all lie in about the same plane and orbit the Sun in the same direction.
How did the inner Solar System become a protoplanet?
The interiors of these more mature bodies were becoming ordered — differentiated — into protoplanets. The process of collision and accretion continued until only four large bodies remained in the inner solar system — Mercury, Venus, Earth, and Mars, the terrestrial planets.