Earth Science Lesson 2: Solar System Origins

Study Notes

The solar system formed around 4.6 billion years ago from a giant rotating cloud of gas and dust known as the solar nebula.
Gravity caused the solar nebula to collapse, leading to a spinning disk; the central region formed the Sun, while remaining materials created planets, moons, asteroids, and comets.
Evidence supporting the Nebular Hypothesis includes observations of protoplanetary disks around young stars and the distribution of angular momentum within our solar system.

Buffon’s encounter (1749) described a sun-comet interaction that ejected matter to form planets.
James Jeans (1917) proposed a sun-star interaction drawing matter from the Sun to form planets.
T.C. Chamberlain and F.R. Moulton (1904) suggested a larger star passing near the Sun created gaseous filaments that formed planetesimals.
Ray Lyttleton (1940) theorized that interactions between companion stars could create proto-planets, eventually leading to Jupiter and Saturn.

The Protoplanet Hypothesis refines the Nebular Hypothesis, positing that planets formed through the accumulation of smaller planetesimals in the early solar nebula.
Planetary differentiation explains the distribution of terrestrial planets near the Sun and gas giants further out.
This hypothesis aligns with computer simulations of planetary formation processes.

Mars Exploration: Since the 1960s, unmanned probes have been sent to Mars to assess habitability, with NASA's Viking program achieving a successful landing in 1975. Recent findings indicate seasonal flow of liquid brine water on Mars.
Rosetta's Comet Mission: Launched on March 2, 2004, by the European Space Agency, Rosetta aimed to study comets and succeeded in landing the Philae probe on comet 67P/Churyumov–Gerasimenko on November 12, 2014. Findings revealed the comet's water isotopic composition differs from Earth's.
Pluto Flyby: On July 14, 2015, NASA's New Horizons provided the first close-up images of Pluto, revealing a complex terrain with ice mountains and vast crater-free plains, indicating recent geological activity over the past 100 million years.