2: Exploring the Solar System Flashcards
What is an epicentre?
This was used in the geocentric model, where we thought planets orbited the Earth in circles that increased in diameter.
What was one thing that the geocentric model explained incorrectly?
Retrograde Motion - Ptolemy’s idea(s) didn’t align with what was happening.
Why was the heliocentric model more accurate than the geocentric?
The heliocentric model put distance into account - that’s the reason for the retrograde motion.
What sequence does the Sun belong to?
Main sequence
What are the 6 things we can separate the Sun into?
Core, radiation zone, convective zone, photosphere, chromosphere, and corona.
How hot does the core of the sun get?
13600º K
What part of the sun produces the light?
Photosphere
How hot is the photosphere?
6000º K
What are the outer layers of the sun? What are they called? How long do they extend?
The chromosphere and the corona are past the photosphere. They extend millions of kilometres from the sun.
When can see the corona of the Sun?
Solar eclipse
What are the 3 ways the International Astronomical Union categorized things in our galaxy?
Planets, Dwarf Planets, and Small Solar Bodies
What is the IAU definition of a planet?
A planet is a celestial body that:
- Orbits around the sun
- Has an adequate mass for the gravity to maintains a hydrostatic equilibrium (close to round shape)
- Has nothing in its’ “neighbourhood” of the orbit.
What is the IAU definition of a dwarf star/planet?
A dwarf planet is celestial body that:
- Orbits around the sun
- Has an adequate mass but doesn’t maintain a hydrostatic equilibrium
- Has not cleared its’ “neighbourhood”
- Isn’t a satellite
What is the IAU definition of a small solar body?
Something that orbits around the sun and is not a satellite (moon)
What direction do planets orbit the sun?
Counter clockwise all around the sun’s equator.
What order are the planets in?
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
What does Mercury, Venus, Earth, and Mars all have in common?
They are all terrestrial which means that the ground is somewhat hard. They are all made from the heavier metals like Iron, Silicon, Magnesium, Nickel and Sulfur.
What does Jupiter, Saturn, Uranus, Neptune all have in common?
They are all gas giants where hydrogen and helium is very abundant. They are at least 4 times larger than the Earth. They are most famous for their rings (Saturn)
How large is Jupiter compared to the Earth (diameter)?
11.2 times larger
What is Pluto classified as now?
Dwarf Planet
How many dwarf planets do we have now?
4
How many dwarf planets are estimated?
200
Which two dwarf planets are icy?
Eris and Makemake
Which dwarf planet has the ability to maintain a sphere?
Ceres
What is a SSSBs?
Small solar system body
What is a small solar system body?
- Asteroids in the belt between Mars and Jupiter (1 million asteroids greater than 1 km in size)
- Meteorites: Smaller asteroids that are only 10m
- Comets that are made of ice. When comets approach the sun, we can see “tails” of water vapour from the Earth. It is suspected they may come from the Kuiper Belt which has a lot of debris similar to the asteroid belt, but is very icy).
What problem are scientists having with “the outer limits of the solar system”?
The scientists do not know how to define “outer limits” Is it the place at the end of the Sun’s particles or gravitational field?
What is an “AU”?
It stands for astronomical unit. This is the distance between the Sun and the Earth.
How far is the Sun from the Earth in km?
149 598 000 km
How far away, in AU, is the Kuiper Belt?
30 AU - 45 AU
What do we mean by the “scattered disk”? Where is it? What is it?
The scattered disk is thought to be part of the Kuiper Belt. Objects in this disk have more elliptical orbits. Due to this, they could potentially extend 100 AU. These stars often have weird orbits possibly due to Neptune’s gravitational field.
How far is Eris, the small dwarf planet?
68 AU.
What is so significant about the Voyager I?
May 2008, it was found 15.9 billion km away from the sun (106.5 AU). This is the farthest such an object has travelled.
When was the Voyager I launched?
1977
What is the heliopause?
The heliopause is the place that the Sun’s “solar wind” intersects or “feels” an effect from a nearby star.
How far does the heliopause extend?
153 AU - 158 AU.
What is the Oort Cloud?
Spherical cloud that engulfs the entire solar system.
How far does the Oort Cloud extend?
100 000 km or 1.87 light years.
What is non existent past the Oort Cloud?
The Sun’s gravitational forces.
What happens if a star disturbs the orbit of the Oort Cloud?
It enters the mini system and becomes one of them.
What is Newton’s Second Law of Gravity?
“Two bodies attract each other with a force that is directly proportional to the mass of each body and inversely proportional to the square of the distance between them”
How does a protosun form?
It starts off as a Nebula. Then, as it has more chemical reactions, the force becomes larger. As Newton’s second law of gravity states, the star starts to attract even more material(s). The core starts to get larger and denser.
What also happens during a protosun?
The nebula contracts and pushes in on itself. With this, the object will rotate faster. This is what keeps the star together.
When the nebula contracts, why would the object rotate faster? What is a real world analogy?
This would be like when figure skaters do spins, and hold their arms in so they can turn faster.
What are the names of the theory/theories that are not supported?
Capture Theory and Rapid Spinning
What is the capture theory?
Planets and objects are just stuck in the Sun’s gravitational forces, and can never leave.
Why is the capture theory disproved?
When the objects and planets orbit the sun in this case, it would not be uniform like clockwise or counter clockwise around the equatorial region of the star, it would be entirely random, and we know it isn’t.
What is the rapid spinning theory?
Big chunks of the Sun just broke off, and then eventually created planets.
Why is the rapid spinning theory disproved?
If this was the case, then the planets and pieces would be entirely scattered and would also orbit the sun in a mess. As well, if this was the case, the chemical composition of the planets and objects would be identical, but we know that the first 4 planets are terrestrial while the last 4 planets are “gas giants”
What is the name of the theory that seems to support our solar system?
Accretion
What is the accretion theory?
Materials come together because of gravitational forces due to ‘pro planetary’ discs.
Which planet gets hit more often with craters: Earth or Mercury?
Earth
Why does Earth still look so “young”?
Because of the geological processes that Earth does to repair itself.
What are the 4 geological processes?
Gradation, Impact Cratering, Tectonism, and Volcanism
What is gradation?
The movement of the materials on Earth’s surface by erosion, movement, and deposition.
What, on the Earth helps with gradation?
Wind, water, glaciers, gravity
What is impact cratering?
When things from the solar system collide with the Earth.
What is tectonism?
When the tectonic places shift, creating “faults”
What are 2 things that are caused by tectonism?
Faulting and Fractures.
What is volcanism?
The creation of volcanoes and distinct lava floes by movement of the tectonic plates.
What are the 2 things we see when we look up at the Moon?
The light spot(s) and the dark spot(s).
What causes the dark spots that we see when we look at the moon from Earth or in pictures?
There has been a lot of meteorite impacts with the Moon. When the meteorite hits the moon, it creates flat plains (maria). Rock samples have concluded that rocks from this area are “basaltic”, similar to the ones that volcanoes produce in Hawaii. The rocks are a much darker shade, which is what we see.
Which mission(s) helped discover the dark spots?
Apollo Missions
What is maria?
The flat plains that are caused by meteorites hitting the Moon.
What are riles?
These are long “trench-like” valleys. These are visible on maria.
What causes the light spots that we see on the moon?
Due to the impacts of meteorites, and the lack of atmosphere/gravitational force(s), the areas around the edge of the meteorite rise. This is what the light things represent on the Earth.
What are thrusts?
The raised elevations on the Moon
How high can thrusts go?
5km.
What is melting (S/L/G)?
Solid - Liquid
What is evaporation (S/L/G)?
Liquid - Gas
What is Sublimation (S/L/G)?
Solid - Gas
What is freezing (S/L/G)?
Liquid - Solid
What is condensation (S/L/G)?
Gas - Liquid
What is deposition (S/L/G)?
Gas - Solid
What is the name of the largest crater on the moon?
Aitken Basin
How deep is the largest crater on the Moon?
2100 km.
What is regolith?
Lunar Soil. Basically grey/brown particles with dust-sized bits.
What was the name of the mathematician that was trying to apply math to explain Copernicus’s heliocentric model? Who was his assistant?
Tycho Brache with assistant, Johannes Keppler.
What did Keppler do?
Created 3 laws to explain the motion of bodies around the Sun.
What is Keppler’s First law?
Planets go around the Sun in ellipticals. The Sun is one of the focal points.
What is Keppler’s Second law?
During the same period (or time), the amount of distance covered is the same.
What is Keppler’s Third law?
P^2 = R^3 where P: period of planet’s orbit; R: Radius of Orbit
What is perihelion?
When a body is closest to the Sun.
What is aphelion?
When a body is farthest away from the Sun.
What is apogee?
When the moon is the closest to its host planet.
What is perigee?
When the moon is farthest away from its host planet.
