Solar System - Unit 2 Test Flashcards
Briefly outline the catastrophic theory to explain the formation of the solar system
accidental catastrophes such as stellar near-collisions:
a rotating nebula underwent gravitational collapse into a star with an accretion disk, from which planets condensed or formed by coagulation of dust particles into increasingly larger bodies
Briefly outline the non-catastrophic theory to explain the formation of the solar system
natural, non-catastrophic events such as nebular condensation:
proposed by Immanuel Kant (1755) and expanded by Pierre LaPlace (1796).
A large, slowly rotating solar nebula contracted due to gravitational attraction, as it contracted, it sped up (conservation of angular momentum). When the centripetal force on the outer rotating edge exceeded gravitational attraction, a ring of gaseous matter split off, matter eventually coalesced into a planet. The process repeated itself, making concentric rings all of which formed planets. The central core formed the sun and satellites are miniature recurrences of the larger phenomenon.
Briefly describe the Medieval system of the universe.
In this geocentric (earth-centered) model, the earth was the motionless center of the universe, with the rest of the universe revolving around it in spheres.
Briefly describe how Ptolemy explained the motion of the planets.
Ptolemy used epicycles to explain the retrograde motions of planets. Epicycles Explain Retrograde Motion. As a planet moves around on its epicycle, the center of the epicycle (called the deferent) moves around the Earth. When its motion brings it inside the different circle, the planet undergoes retrograde motion.
Why was the heliocentric model of the solar system rejected?
Planets do not move in exact circles around the Sun, they move in oval paths called ellipses
If the Earth is rotating about its axis, and orbiting around the Sun, then the Earth must be in motion
The Church disapproved of this theory because the Holy Scriptures state that the Earth is at the center, not the Sun.
What was Copernicus’ model of the solar system?
proposed a heliocentric system, that the planets orbit around the Sun; that Earth is a planet which, besides orbiting the Sun annually, also turns once daily on its own axis; and that very slow changes in the direction of this axis account for the precession of the equinoxes.
Why is Newton’s Universal Law of Gravitation so significant?
one of the most important and fundamental laws in classical physics as it explains the movement of objects as a result of an “invisible force”
simple equation, but devastatingly effective: plug in the numbers and you can predict the positions of all the planets, moons and comets you might ever want to watch, anywhere in the solar system and beyond. And it allowed us to add to those celestial bodies too, heralding the space age.
State Kepler’s three laws of motion
- planet’s distance from the sun will change throughout its orbit
- speed of a planet in its orbit is not constant
- planet’s period can be calculated if it’s distance to the sun is known, and vice versa
State how Kepler’s three laws of motion have significance for space travel.
Describe how planetary bodies orbit the Sun. They describe how (1) planets move in elliptical orbits with the Sun as a focus, (2) a planet covers the same area of space in the same amount of time no matter where it is in its orbit, and (3) a planet’s orbital period is proportional to the size of its orbit (its semi-major axis).
show the effects of gravity on orbits. They apply to any object that orbits another: planets orbiting the Sun, moons orbiting a planet, spacecraft orbiting Earth.
What was the nature of the raw material of the planets?
About 4.6 billion years ago our solar system formed from a cloud of gas and dust which slowly contracted under the mutual gravity of all of its particles. The cloud was made largely of hydrogen (H) with some helium (He)
What is the Kuiper belt?
a circumstellar disc in the outer Solar System, extending from the orbit of Neptune at 30 astronomical units (AU) to approximately 50 AU from the Sun
What is the Oort Cloud?
Is a spherical shell surrounding everything in our solar system, made up of icy pieces of space debris
What 3 rules define a planet?
It must orbit a star (in our cosmic neighborhood, the Sun). It must be big enough to have enough gravity to force it into a spherical shape. It must be big enough that its gravity cleared away any other objects of a similar size near its orbit around the Sun.
Why was Pluto “demoted” to being a dwarf planet?
Pluto is now classified as a dwarf planet because, while it is large enough to have become spherical, it is not big enough to exert its orbital dominance and clear the neighborhood surrounding its orbit.
Name the two spherical asteroids or dwarf planets.
Spherical asteroids: (3) Juno and (48) Doris
Dwarf planets: Pluto, Ceres, Eris
Why did the church leadership seek to silence Galileo?
His ideas went against their beliefs, that the Earth was the center of the universe and he agreed with ideas of Copernicus.
What is a light year? How would you calculate it?
A light-year is the distance light travels in one year. How far is that? Multiply the number of seconds in one year by the number of miles or kilometers that light travels in one second, and there you have it: one light-year. It’s about 5.9 trillion miles (9.5 trillion km).
Describe our Sun in detail.
The Sun is a yellow dwarf star, a hot ball of glowing gasses at the heart of our solar system. Its gravity holds everything from the biggest planets to tiny debris in its orbit
Our Sun is a 4.5 billion-year-old star – a hot glowing ball of hydrogen and helium at the center of our solar system. The Sun is about 93 million miles (150 million kilometers) from Earth, and without its energy, life as we know it could not exist here on our home planet.
The Sun’s activity, from its powerful eruptions to the steady stream of charged particles it sends out, influences the nature of space throughout the solar system.
What is the purpose of the Parker Solar Probe?
swoop within about 4 million miles (6.5 million kilometers) of the Sun’s surface to trace the flow of energy, to study the heating of the solar corona, and to explore what accelerates the solar wind.
List the planets in order starting closest to the sun.
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto(?)
Provide a few details of each planet,
Mercury: the smallest and fastest planet in the solar system
Venus: extremely hot, Venus is unusual because it spins in the opposite direction of Earth and most other planets. It also has a very slow rotation making its day longer than its year.
Earth: only astronomical object known to harbor life
Mars: huge dust storms which last for months and can cover the entire planet.
Jupiter: gas giant, made up almost entirely of hydrogen and helium
Saturn: bright, beautiful rings that circle its equator.
Uranus: equator is nearly at a right angle to its orbit
Neptune: dark, cold, and very windy.
Could we live on any other planets? Why, or why not?
Living beings need the atmosphere to be of a specific composition, with oxygen to breathe and live, the atmosphere and the plants provide them with this gas. The temperature of the planet matters a lot too, living beings would cease to exist if the temperature on the planet was too high or too low for them to handle.
Among the stunning variety of worlds in our solar system, only Earth is known to host life. But other moons and planets show signs of potential habitability.
