Lesson 4 – Solar System
September 27, 2016
Sun - A nearly perfect sphere of hot plasma with internal convective motion that generates a magnetic
field via a dynamo process.
Its diameter is about 109 times that of Earth, and its mass is about 330,000 times that of Earth
o Three quarters of the Sun's mass consists of hydrogen; the rest is mostly helium, with much smaller
quantities of heavier elements, including oxygen, carbon, neon, and iron.
o The Sun is a G-type main-sequence star known as a yellow dwarf.
o A spot or patch appearing from time to time on the sun's surface, appearing dark by contrast with its
Radius – 6.9 x 10 109 times Earth
Mass – 2 x 10 : 300,000 Earths
Luminosity- 3.8 x 10 watts
It does not have natural satellites
o It has no moons
Mercury is made of heavier materials, like iron and has a large iron core
Mercury is the closest planet to the sun and goes around the sun once every 88 Earth days.
o A day on Mercury lasts a lot longer than a day on Earth.
The surface of Mercury looks like Earth's moon. It is covered with impact craters, made by rocks falling
Mercury might have water on the shadowed side of the planet, near the poles
o Onside of mercury never seen the sun due to its rotation
MESSENGER (Mercury surface, Space Environment, Geochemistry and Ranging Mission) spacecraft flew
by Mercury in 2008 and 2009.
o In March 2011, it began to orbit Mercury and finished the mission in 2016 where it took full pictures
of all of Mercury
Venus has a slow rotation, rotating retrograde and no natural satellite
It is often called Earth’s sister planet because it is similar in size, mass, proximity to the sun
Radius of 0.95 RE and mass of 0.82M o Dense at 90 atm with Earth at 1 atm
o It has a denser atmosphere than Earth with 96% carbon dioxide
o Venus is known as the hottest planet and is surrounded with reflective sulfuric acid clouds
There is no magnetic field – any space ship would melt in about 2 hours in it’s presents
as well as no plate tectonics
It also holds intense greenhouse effect
o Venus has a dry volcanic landscape
Mars is a terrestrial planet with a thin atmosphere,
o Surface features reminiscent both of the impact craters of the Moon and the valleys, deserts,
and polar ice caps of Earth.
o The rotational period and seasonal cycles of Mars are likewise similar to those of Earth
Mars is the site of Olympus Mons, the largest volcano and second-highest known mountain in the Solar
System, and of Valles Marineris, one of the largest canyons in the Solar System.
Mars has two moons, Phobos and Deimos, which are small and irregularly shaped
o These may be captured asteroids
At one point there was liquid water on the surface of Mars about 4000 million years ago
o September 28, 2015, NASA announced the presence of briny flowing salt water on the Martian
o Mars has no magnetic field, so high energy particles can reach the atmosphere
The sky on Mars would be pink and Dunes would be black
There is a thin atmosphere of Co2
The step in research on Mars would be to get samples to test it and compare it to Earth
Radius – 0.54Re, Mass – 0.11Me
Largest planet with a mass one-thousandth that of the Sun,
o Radius – 11.2 Re, Mass – 318 Me
o Jupiter is a gas giant
Jupiter is primarily composed of hydrogen with a quarter of its mass being helium, helium comprises
only about a tenth of the number of molecules.
Jupiter may also have a rocky core of heavier elements but it lacks a well-defined solid surface o Because of its rapid rotation, the planet's shape is that of an oblate spheroid - but noticeable
bulge around the equator.
The outer atmosphere is visibly segregated into several bands at different latitudes, resulting in