GCSE OCR Physics P1 The Earth in the Universe

annaryann's version from 2016-05-24 13:57

Section 1

Question Answer
What is in the centre of our Solar System?The sun
What are the 8 planets in our solar system described as?Spherical and have nearly circular orbits around the sun
Which planets are solid rock?The four planets closest to the sun
Which planets are gas giants?The four outer planets
What are asteroids?Irregular lumps of rock, mostly in near- circular orbit between Mars and Jupiter
What are comets?Small objects made of rock and ice, with very elongated orbits around the sun
What are dwarf planets?Small spherical lumps of rock in orbit around the sun
How much of the solar system's mass is in the sun?99%
What is the order of the heaviest planet to least heaviest?Jupiter, Saturn, Uranus, Neptune, Earth, Venus, Mars and Mercury
What is the order of largest orbit to lowest orbit?Neptune, Uranus, Saturn, Jupiter, Mars, Earth, Venus and Mercury
What is the Milky Way?One of the thousands of millions of galaxies which make up the universe
What are distances to objects outside the solar sytem measured in?Light years
What is a light year?The distance that light travels in a year- one light year is 9.5 million million km
What is the speed that light travels through space?300,000 km/s
Why can we only observe what stars were like in the past when light left them?Because light takes a very long time to reach us from the stars
Where does all the evdence we have about distant stars and galaxies come from?Radiation which astronomers can detect
What can two stars which have a different relative brightness have in common?Real brightness
What do telescopes in space do?Take measurements without distortion from the Earth's atmosphere
What is the parallax effect?As the earth orbits the sun, nearby stars move slightly against the fixed background of distant stars
Where does the Sun's energy come from?hydrogen
How is helium formed?Hydrogen nuclei are jammed together so hard that they combine in pairs- this is called nuclear fusion
Where were all chemical elements with atoms heavier than helium made?in stars
When is nuclear fusion only possible?When there are very high densities and temperatures
How do heavy stars end their lives?as a supernova
What is a supernova?A massive explosion where all the different chemical elements are made
How and when was the solar system made?From a collapsing cloud of dust and gas about 5000 million years ago
What is redshift?The increase of a wavelength from a galaxy moving away
What does redshift provide evidence for?That all parts of the Universe are expanding with galaxies moving apart from each other as time goes on