2.5 - Stars and planets Flashcards
In which galaxy is our solar system?
The Milky Way galaxy
What does our solar system consists of?
Four inner rocky planets and four outer gas giant planets as well as an asteroid belt, containing thousands of huge rocks, dwarf planets and comets.
What do the planets in our solar system orbit around and what type of body is it?
The planets orbit around the sun
The sun is a star
What type of force pulled together the cloud of dust and gas to form the sun?
Gravitational force of attraction
What is the order of the planets in our solar system?
My - Mercury Very - Venus Easy - Earth Method - Mars Just - Jupiter Speeds - Saturn Up - Uranus Naming - Neptune
The planets go around the Sun in slightly squashed circular elliptical orbits. What is an elliptical orbit?
An orbit that is the shape of an ellipse. An ellipse is similar to a slightly stretched circle
What are comets?
A high speed ball of ice and rock which as it melts leaves a trial of dust and gas behind it
What are asteroids?
Lumps of rock which orbit the sun in the asteroid belt
How does a solar system form?
A dense hydrogen-rich cloud of ___ and ___ contracts under gravity. As the gas gets compressed, its temperature ________ and the dust cloud begins to spin. A ______ begins to form at the centre of this spinning dust cloud. _____ _____ starts, and a star is born. The planets begin to form from the swirling dust clouds around the star.
gas and dust
increases
protostar
nuclear fusion
What word is used to describe a cloud of dust and gas?
A nebula
What type of reactions take place at the start of a star’s life cycle as dust and gas is drawn together
Fusion reactions
Gravity is greater closer to the star. Most of the dense material in the dust cloud is attracted strongly and ends up here. The left over ____ (dust/ gas) created rocky planets near the sun and the left over ____ (dust/ gas) created gas giants further away from the sun
Dust
Gas
What is a light year?
The distance light travels in one year
What is an astronomical unit (AU)?
The mean distance from the Earth to the Sun
What unit of measurement is used to measure distances between the sun and planets ?
The Astronomical Unit (AU)
Alpha Centauri is 4.4 light years away from us. Can you work out this distance in metres?
4.4 ly × 9.46 × 10^15 m / ly
= 4.16 × 10^16 m
What colour stars are the hottest? Blue or red?
Blue stars are the hottest stars
Red stars are the cooler stars
Put these things into order from smallest to biggest:
Milky Way Earth Solar system Universe Sun
1) Earth
2) Sun
3) Solar System
4) Milky Way
5) Universe
What factor determines the type of lifecycle a star undergoes?
The size (and therefore mass) of the star