Download Solar System Essays, Symeonides Answers

Essay Questions from 11/8
Answer in paragraph form
1) The universe started with the Big Bang and has been expanding ever since.
Give a general description of our universe. Discuss distances, how matter is
distributed in space, and what tools we used to find this out.
Vocabulary to use: Light year, galaxy, star, nebula.
The universe contains everything that we can tell exists. All of the matter,
and all of the energy. Mostly the universe consists of empty space. Really empty,
with no atoms in it at all. But there are areas where matter is clumped together.
This empty space can stretch for hundreds of light years in all directions before
you find a concentration of matter. A light year is almost 6 trillion miles long.
Nebulas are areas where a lot dust and gas collects, often after the
explosion of a star. Nebulas are still mostly empty space, but with enough matter
to form stars and planets. Stars are where most of the matter in the universe is
found. For example, over 99% of the matter in our solar system is contained in the
sun. All of the planets and asteroids are less than 1%. Stars are collected into
galaxies, which contain 100s of billions of stars. These galaxies are where most of
the matter in the universe is concentrated.
2) Give a chronological explanation of how our solar system formed and why
the terrestrial and gas giant planets ended up where they are.
Start with the explosion of the star before Sol, and the creation of the solar
nebula.
Vocabulary to use: Gravity, planetessimal, protoplanet, collisions
About 5 billion years ago, a star exploded near where our solar system is
now. It left behind all of the chemical elements that the star had been made of,
the gasses, the dust and the atoms of metals. This material was the solar nebula,
the nebula that our solar system formed from. Most of the matter in this nebula
was near its center and the center started pulling other material towards it,
through magnetic attractions and by gravity. This caused the whole nebula to
start spinning and to flatten into a disk.
Eventually the center of the nebula became dense enough and hot enough
for the sun to begin burning, through the fusion of Hydrogen into Helium. It pulled
all of the matter near it into the sun so that today 99% of all the material in the
solar system is in Sol, our star. As the solar nebula continued to spin, the matter
left over started to pull together through gravity to form chunks of rock, metal and
gasses. The bigger these chunks got, the stronger their gravity. They started to
attract each other, adding their material together. We call the biggest chunks
planetessimals – tiny planets. As the planetessimals continued orbiting the sun,
they added together through collisions, cleaning up their orbits and getting larger.
The largest of these objects are called protoplanets (proto meaning early or
before). The protoplanets were the beginnings of the planets we have now. They
were finished after their gravity pulled all of the material in their orbits to them.
3) Write two paragraphs, one giving a description of a typical terrestrial
planet, and another describing a typical gas giant planet. Include a
description of the layering of the typical planet in each category.
The typical terrestrial planet has a iron and nickel core that makes up at
least a quarter of its diameter. This core can be solid, liquid or both. Outside of
the core is a thick layer of rock. This rock can be either solid or soft, like silly putty.
Which a planet will have depends on both the size of the planet and where it is.
Larger planets lose heat more slowly and keep this soft layer of rock (the mantle)
longer. The surface of a terrestrial planet is solid. It may have many craters. The
atmosphere of a terrestrial planet is thin, only 10’s of miles thick at the most, and
made of the heavier gasses. This is because most of the lighter gasses like H and
He, escaped to space when the planets were young and hot.
The typical gas giant planet is many times larger than the Earth. Gas giants
have very small metal or rocky cores, since most of these materials stayed near the
center of the solar nebula as the solar system formed. Then there is a thick layer
of liquid or frozen gasses. This would be the planet’s surface. The atmosphere of
gas giants is hundreds of miles thick and is over 90% hydrogen and helium. These
planets are closer in composition to the sun than to the terrestrial planets, but
they are not big enough to start fusion explosions and light up like the sun.
(Jupiter is only 30,000 degrees at its center, it would need to be over 100,000
degrees to start burning.