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