Characteristics of the Solar System Earth Science

Overview of Solar System Characteristics Disk shape of Solar System Two types of planets Planetary ring systems Space debris Common age

Shape of Solar System Disk shape is a product of solar nebula. The planets revolve around the sun in the same counterclockwise direction because they formed from the same rotating nebula. All planets except Venus rotate counter clockwise around their axes. Venus rotates clockwise or retrograde. Planetary orbits lie in the same plane because the solar nebula collapsed into a disk.

Two Types of Planets Terrestrial inner planets and gaseous outer planets. Condensation and accretion of matter in the inner nebula was mostly of solid particles with high vaporization points (metals and silicates). Condensation of gaseous matter occurred in the outer nebula. Jupiter and Saturn grew rapidly through gravitational collapse. Uranus and Neptune grew more slowly through accretion of gasses and ices.

Planetary Ring Systems All the Jovian (outer) planets have rings. These planets are massive enough to attract and hold on to orbiting particles. The location of the outer planets means particles in the ring are not easily affected by solar winds and sunlight. The inner planets do not have rings because they are too small in mass and too near the sun.

Space Debris Asteroids are the vestiges of rocky planetesimals. Asteroids are very large, irregularly shaped, and most orbit the sun between Mars and Jupiter. Comets are the remnants of icy planetesimals. Meteors (shooting stars) are actually small specks of metal or rock entering Earth’s atmosphere. Before a meteor enters Earth’s atmosphere it is called a meteoroid and called a meteorite if it hits the Earth.

Common Age Mineral samples from Earth, Mars, moon, and meteorites radioactively date to approximately the same age. This approximate age is 4.5 billion years old. Mathematical estimates of the sun’s age are 5 billion years + 1.5 billion years old.

Summary The solar nebula hypothesis of a contracting nebula from which planets formed is the theory for how our solar system developed. Nebular properties and processes that occurred over time explain the characteristics of the solar system that we observe today. It is possible to see parts of these processes happening outside our solar system and confirming our observations.

Bibliography JPL Photojournal. Retrieved June 10, 2008, from http://photojournal.jpl.nasa.gov/jpegMod/PIA06890_modest.jpg The Formation of the Solar System http://zuserver2.star.ucl.ac.uk/~rhdt/diploma/lecture_1/ Seeds, Michael A. (2005). The Solar System. Belmont, CA: Brooks/Cole-Thompson Learning