Our Solar System

The Sun The Sun is our home star; the center of the solar system which the planets and other bodies orbit The Sun is by far the largest object in the solar system; it accounts for 99.7% of the solar systems mass

Terrestrial Planets Terrestrial planets are the planets closest to the Sun They are made mostly of rock and metal, have solid outer surfaces, and can have oceans and an atmosphere Very small compared to gas giants

Planets: Mercury First terrestrial (rocky) planet The smallest planet in our solar system No moons No atmosphere due to proximity to the Sun Surface temp. up to 450°

Planets: Venus Second planet from the sun Terrestrial/rocky Thick atmosphere of 97% carbon dioxide Runaway greenhouse effect gives Venus average surface temps. Of 460° On Venus it rains acid instead of water and lead melts and flows like water! No moons

Planets: Earth The “Third Rock from the Sun” Terrestrial/rocky Thick atmosphere of nitrogen and oxygen Only planet confirmed to have surface liquid water Only planet confirmed to harbor life! One, very odd, Moon

Planets: Mars 4th planet from the Sun Terrestrial/rocky, 2 moons Thin atmosphere of carbon dioxide Confirmed to have ice at its poles, strong evidence that liquid water once flowed on Mars Scientist speculate life may have also originated on Mars in the very distant past and may still be home to a few very specialized microbes!

The Asteroid Belt The asteroid belt separates the inner and outer solar system It is between Mars and Jupiter The asteroid belt is populated by millions of irregularly shaped rocky objects called asteroids The is a dwarf planet inside the asteroid belt called Ceres. It is the only dwarf planet outside the Kuiper belt Unlike all other asteroids, Ceres is a sphere

Gas Giants Much larger than the terrestrial planets Mostly made of hydrogen and helium gas They produce a large gravitational pull The Gas Giants: Jupiter, Saturn, Uranus, Neptune Some data suggests that large moons of gas giants has liquid water and may harbor life.

Planets: Jupiter 5th planet from the Sun Largest planet in the solar system The planet is mostly hydrogen and helium gas and possibly has a small, rocky core Has 63 moons, the most in the solar system Jupiter is famous for its red spot which is is a storm twice the size of Earth which has been raging for at least all of recorded history. Some scientists hypothesize that Jupiter is a failed star!

Planets: Saturn 6th planet from the Sun Mostly hydrogen and helium most likely with a rocky core Has 60 moons Most well known for its characteristic rings Saturn has the largest most complex rings of any planet in our solar system Saturn's largest moon Titan is the only moon known to have an atmosphere

Planets: Uranus 7th planet from the Sun Made of hydrogen, helium, and methane Has 27 moons Has small, dim rings Only planet with a tilted orbit around the Sun

Planets: Neptune Very similar composition to Uranus The two planets are almost twins, except Neptune is more frozen Has 13 moons Has very faint rings The last planet discovered in our solar system thus far

The Kuiper Belt The Kuiper Belt is like a second, larger asteroid belt past Neptune. Consists of small rocky/icy objects as well as most of the dwarf planets Dwarf Planets in the Kuiper Belt: Small, terrestrial planetoids; Pluto, Makemake and Haumea, Eris (the largest known dwarf planet) Pluto

Comets and The Oort Cloud Comets: small, icy objects mostly found in the far reaches of our solar system in the Oort Cloud; occasionally they are thrown into the inner solar system by the gravity of Neptune and other objects. The Oort Cloud is basically the end of our solar system, although there are gas clouds past it in interstellar space Haley’s Comet

Hypothetical Solar System Objects- Not part of notes! Planet X: The ancient Sumerians referred to it as Nibiru and listed in their diagrams of the solar system Scientists have collected data which points towards its existence, but have by no means confirmed it. Postulated forms of Planet X include: a roughly Earth-sized, terrestrial or icy planet in the Kuiper Belt past Pluto A 5th gas giant planet beyond Neptune known as Tyche a brown dwarf star called “Nemesis” in or past the Oort cloud that is our Sun’s binary partner (most solar systems have 2 stars i.e. the are binary) and even speculations that Planet X is a giant terrestrial planet inhabited by extraterrestrials! Vulcan: a tiny hypothesized planet or dwarf planet between the Sun and Mercury. We have looked, but no one has found it!

Effects of Orbits Ocean tides are caused by the gravitational force of the moon and the sun. As the moon orbits Earth and the Earth orbits the sun, water in the ocean is pulled up and down by gravity. Seasons are caused by the by the tilt of the Earth on a 23.5° axis relative to the sun. As the Earth orbits, the sun light does not hit the northern and southern hemispheres equally.

A closer look at seasons

A closer look at seasons

Eclipses and Moon Phases The moon goes through phases – lunar cycles of more or less light on the surface – due to the shadow of Earth cast by the sun as the moon orbits Earth Lunar Eclipse: when the Earth passes directly between the sun and the moon, causing complete darkness Solar Eclipse: when the moon passes between the Earth and the Sun the moon completely blocks the Sun (its weird that the Moon is positioned to perfectly cover the Sun during these eclipses) There was a total solar eclipse in most of South Carolina on August 21, 2017 There is not an eclipse every time the moon orbits the Earth because the moon’s orbit is not in the same plane as the Earth’s orbit around the Sun

Days and Years What we call a “day” is the roughly 24 hour period it takes the Earth to rotate once around it’s axis . What we call a “year” is the roughly 365 days it takes for the Earth to orbit the Sun 1 revolution. Technically those would be “Earth days” and “Earth years”; days and years would be different lengths of time depending on the planet you are on.