Astronomy - Gr.9 Flashcards
What is a solar system?
A solar system is a group of planets circling a star.
How did the planets begin to form?
Planets formed from the gases and other left over matter after the sun formed.
How are distances measured in a solar system?
Astronomical unit (Au) which is aprox 150 million km (average distance between earth and sun)
What are planets?
Planets are large, round, celestial objects that travel around a star.
What are the planets in order?
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
What are the terrestrial/rocky planets?
Mercury
Venus
Earth
Mars
What are the gas giants/ gaseous
Jupiter
Saturn
Uranus
Neptune
What are Dwarf Planets?
Dwarf Planets are celestial objects that oribit the sun, has a sphereical shape but does** not dominate its orbit.**
What does an object have to be to be cosidered a planet?
- Be in orbit around a star
- Have enough mass be pulled into a stablespherical shape by gravity.
- Dominate its orbit ( its mass must be greater than anything else that crosses its path)
What are two naturally occuring objects that orbit the sun?
Asteroids and Meteors
Obit the sun but too small to be planets
What are asteroids?
They are giant irregular shaped rocks that are full of rock and metal.
Called planetoids ot minor planets
What is the asteriod belt?
Millions of asteroids culmped in a ring orbiting in the gap between mars and jupiter.
2-6 years to orbit around the sun.
What is the largest asteroid?
ceres 952km in diamter
What are meteorids
small bodies that travel through space.
Most are smaller than dust particles
Most meteoroids are broken peices of asteroids that colide with each other.
What is a meteor?
A meteoroid that has entered the earths atmosphere
shooting star
As a meteor enters the earths atmosphere, it burns up. if the meteor doesnt completly burn up we call it a ______
meteorite
Did you know?:
asteroids are leftover rocks from the creation of our solar system. (peices that didnt get used to creating planets)
yes or no?
a very intense meteor shower is called a meteor storm
What is a comet made up of?
solid ice, gas, dust, water vapour and gases
What do comets orbit?
The sun, but libve in an area called the Oort cloud beyond pluto.
Did you know?
Comets are only visible when they are near the sun, their tails always point away ftom it.
The sun is a huge shpere of mostly ________
hydrogen gas
The sun emits energy in the forrm of _______________
Electromagnetic radiation (EM)
How many days does the sun take to rotate?
25 days
Name the layers of the sun
- Core (where nuclear fusion occurs)
- Radiation zone
- Convection zone
- photosphere (the lower atmospher and what we see)
- Chromosphere (an orange red layer of atmosphere)
- Corona ( the upper most part of the atmosphere)
What happens at the convection zone?
Heated materials rise, reaches the surface, cools and sinks back inside
What happens at the photosphere?
surface looks like boiling water and at this layer, radiation escapes.
What is the sun made up of?
Chromosphere (inner atmosphere)
Corona (outer atmophere)
What is nuclear fusion?
Within the suns core, high temperatures and pressures causes particles to collide and fuse.
this process emits enormous amounts of heat making the core the hottest.
What is a sunspot?
Dark, cooler areas in the photosphere.
Caused by disturbances to suns magnetic field.