The Solar System Formation and Structure

Formation and Structure of the Solar System

• The Solar System was formed approximately 4.6 billion years ago from a dense region of a molecular cloud that collapsed, resulting in the Sun and a protoplanetary disc.
• The Sun is a G-type main-sequence star that maintains equilibrium through the fusion of hydrogen into helium in its core.

Planets in the Solar System

• There are eight planets in the Solar System, classified into three categories: terrestrial planets (Mercury, Venus, Earth, and Mars), gas giants (Jupiter and Saturn), and ice giants (Uranus and Neptune).
• Terrestrial planets have solid surfaces, while gas and ice giants do not have a definite surface due to their composition of gases and liquids.

Mass Distribution in the Solar System

• The Sun and Jupiter/Saturn account for over 99.86% and nearly 90% of the Solar System's mass, respectively.

Dwarf Planets and Small Solar System Bodies

• There are at least nine confirmed dwarf planets in the Solar System: Ceres, Orcus, Pluto, Haumea, Quaoar, Makemake, Gonggong, Eris, and Sedna.
• The Solar System also comprises various small bodies, including asteroids, comets, centaurs, meteoroids, and interplanetary dust clouds.
• The asteroid belt is located between Mars' and Jupiter's orbits, while the Kuiper belt lies just outside Neptune's orbit.

Moons and Satellites

• Six planets, seven dwarf planets, and other bodies have natural satellites, commonly referred to as 'moons'.

Boundaries and Regions of the Solar System

• The heliosphere is the region of space influenced by the Sun's charged particles, the solar wind.
• The heliopause marks the boundary of the Solar System, located around 75-90 astronomical units from the Sun.
• The theorized Oort cloud is the source of long-period comets, extending from 2,000 to 200,000 AU from the Sun.

Neighboring Stars and Galaxies

• Proxima Centauri is the closest star to the Solar System, located 4.25 light-years (269,000 AU) away.
• Both the Sun and Proxima Centauri are part of the Milky Way galaxy.

This quiz covers the formation and structure of our Solar System, including the Sun and the objects that orbit it. Learn about the process of star formation, the classification of the Sun, and more!