Solar System

Event Overview
This event will address the Sun, planets and their satellites, comets, asteroids, the Oort Cloud, the Kuiper Belt, meteoroids, meteorites, and meteors.

For this event be sure to acquire a glossary containing many astronomical terms, a list of famous astronomers and their accomplishments, a table of planetary facts (mass, volume, year length, etc.), detailed diagrams of the sun and solar features, and astronomy formulas.

Some Information You Need to Know
The Solar system was formed about 4.57 billion years ago in a nebula, the center of which was the protosun. Surrounding it were the materials that would be the planets, planetesimals. When the Nebula was sent into a spinning motion (possibly by a large star) The heavier, rocky materials gravitated to the center, and the lighter gaseous materials fell to the outer solar system. In the Inner solar system, the small planetesimals continued to gather more material becoming the 4 rocky terrestrial planets (Mercury, Venus, Earth, and Mars). In the outer solar system the rocky materials gathered to form planets, but the lighter gas materials were attracted by the gravity of the cores to form the Jovian planets(Jupiter,Saturn,Uranus{pronounced your-uhn-us, not: your-anus},and Neptune). Between Mars and Jupiter is a group of planetesimals that never formed a planet. They formed the asteroid belt. The leftover materials that did not form planets formed the Oort Cloud and Kuiper (kai-per) belt. These two bodies are the source of many comets, the dwarf planets Pluto, Ceres, Eris, Haumea, and Makemake, and the questionable planet Sedna.

Bodies of the Solar System

 * The Sun: is the largest body in our solar system, and contains 99% of the mass. It is made up of Layers, starting from the outside(with Temperatures), Corona(1,000,000 C),Photosphere(6,000 C),Convection Zone(1,000,000 C),Radiative Zone(2,000,000 C),and the Core(15,000,000 C).It produces heat from the fusion of hydrogen atoms. The heat is transferred by the process of convection, through the radiative and the convective zone, where it is radiated out through the photosphere and corona to the planets in the form of rays.This site should contain the solar features that I have not listed here:

(Please note that all of the largest/smallest classifications are including Pluto!)

Inner Planets

 * Mercury: is the 2nd smallest planet with a radius of 2439 km and the planet closest to the sun at a distance of 57.9 million kilometers. It's year is 88 earth days long, and its day is 59 earth days long. The Surface gravity of mercury is 1/3 of Earth's, so it cannot hold on to an atmosphere. Therefore its surface is scarred with the craters of meteors that would have broken up if it had an atmosphere. The surface temperatures at day and at night are very different, the day temp is 227 C and the night temp is -173 C. It's most noticeable feature is the largest impact crater on its surface, the Caloris basin.


 * Venus: is the 3rd smallest planet in the solar system with a radius of 6051 km, and the 2nd closest to the sun at a distance of 108.2 million kilometers. It is the only planet whose day is longer than its year. Its day is 243 Earth days, and its year is 225 Earth days. It was often called Earth's sister plane because of its close proximity to Earth, and because of its similar diameter and mass. People even thought it could hold life!, but sadly people discovered that the greenhouse effect on Venus raised the surface temp to the highest in the Solar System.


 * Earth: is the third planet from the Sun, and the fifth largest at a radius of 6378 km. It is the only planet in the universe known to support (supposedly) intelligent life. We use it as a basis for many measurements of planets and other things in the solar system (ex. the AU, the average distance between the Earth and the Sun, 93,000,000 miles or 149,600,000 km). The year is equal to 365.256 Earth days, and its day is 1 earth day (But you already knew that).


 * Mars: the fourth planet from the Sun at a distance of 227,392,000 km, is often called the Red Planet, because the large quantities of iron oxide in its soil. The Romans saw it as blood, so they named it for their god of war, Mars. It is the third smallest planet, with a radius of 3397 km. It has a day length of about 25 hours, and a year equal to 687 Earth days. It has been suggested that Mars may hold intelligent life, but it hasn't been proven.

Outer Planets

 * Jupiter: is the fifth planet from the sun at a distance of 778.3 million km, and the largest with a radius of 71,492 km. Jupiter holds most of the non-solar mass in the solar system. It gives off more energy than it receives from the sun, so it is believed that Jupiter is a failed star, that it could have formed a star, but wasn't under the right conditions. Contrary to popular belief, Jupiter has three small rings around it, made of tiny particles. Its day is the shortest in the solar system at about 10 hours, and its year is equal to 12 earth years. It has an atmosphere composed of hydrogen and helium. The outer layer is the thin visible cloud bands that we see this is also the zone that contains the circular storm known as the Great Red Spot. This is followed by a thick layer of liquid hydrogen. Beneath that is a nearly same size level of liquid hydrogen that, because of the pressure, behaves like a metal. Then beneath that is an iron-silicate core.


 * Saturn: is the sixth planet from the sun, 1.427 billion km away. It is also the second largest at about 60,330 km radius. Its day is only 10 hrs and 40 min., and its year is about 30 Earth years. It is the least dense planet, and if placed in a large enough body of water, it would float. It has the largest and most spectacular ring system in the solar system. They have a diameter of 275,000 km, but they are only a few hundred meters thick. The rings are made up of particles that vary in size, from dust like particles, to the moons Janus and Epimetheus. Saturn, like Jupiter, is made up of only Hydrogen and Helium, and gives off more energy than it receives, but it isn�t as large as Jupiter, so it is not believed to have ever had the potential to be a star.


 * Uranus: (still not pronounced your-anus) is the 3rd largest planet (25,560 km radius), and the seventh from the sun (2.87 billion km away). It was the first planet discovered after prehistoric times, because it is so far away from Earth. It was discovered by William Herschel. Uranus is known for having its axis of rotation parallel to its plane of orbit. Its 9-ring ring system is also parallel to its plane of orbit. These rings are different from those of Jupiter and Saturn, because they are more like hoops than rings of particles, and they have large gaps between them. Its day is about 18 hours long, and its year is 84 Earth years long. Its outer atmosphere is composed of hydrogen, helium, and methane, which gives it its blue green color. Beneath the outer layer is a layer of high pressure solid water, methane, and ammonia. Then, beneath that layer is a ball of rocky material that is very similar to Earth, but its surface is distorted by the dense inner ocean of water and methane.


 * Neptune: the 8th planet from the sun, at a distance of 4.479 billion km, and the 4th largest at a radius of 24,765 km was discovered in 1846 after calculations in Uranus's orbit revealed that its motions were disturbed by a more distant planet. Its day is about 19 hours, and its year is 165 Earth years. The outer third of Neptune is made of hydrogen, helium, water, and methane, which, as on Uranus gives it a blue tint. The inner two thirds are made of molten rock, liquid water, liquid ammonia, and methane. Neptune's most apparent feature is a storm similar to the Great Red Spot, The Great Dark Spot.

Dwarf Planets

 * Ceres: The largest object in the Asteroid Belt, containing 30% of its mass. When it was discovered in the early 1800s, Ceres was considered a planet, but was reclassified as an asteroid 50 years later. Since 2006, it has been considered a dwarf planet. Ceres orbits the Sun once every 4.6 Earth years and its day is about 9 hours.


 * Pluto: When it was still considered a planet, Pluto was the ninth planet from the Sun and the smallest planet. Very little is known about Pluto and its similarly sized moon Charon (pronounced karen). It was discovered in 1930 by Clyde Tombaugh, and is the only planet discovered in the 20th century. It is a part of the Kuiper belt, and is one of many similar Kuiper Belt objects. The only thing we know about Pluto is that it has a highly eccentric orbit, which crosses Neptune�s orbit every 200 years or so, for 20 years. It also has two smaller moons, Nix and Hydra.


 * Haumea: An "egg-shaped" dwarf planet in the Kuiper belt. The odd shape is believed to come from a high rotational speed, which flattens the poles and creates a bulge around the equator. Haumea has a year of about 283 earth years. It also has two moons, Hi'iaka and Namaka.


 * Makemake: Makemake has no moons, making it unique among the larger Kuiper Belt objects. It orbits the sun every 310 years.


 * Eris: Eris is in the scattered disc, a region beyond the Kuiper Belt. Since Eris is larger than Pluto, its discovery led the IAU (International Astronomical Union) to define "planet" and reclassify Pluto as a dwarf planet. Its only satellite is Dysomnia.

Helpful Tips
This event often contains many questions/tasks not listed on the event sheet, so you should study anything that could be interpreted as related to our solar system. If you do this (And have a decent reference book) you should be guaranteed to get a top ten finish.

Links
the 9 planets

the solar system

views of the solar system

soinc's solar system page