Space And Beyond Flashcards
(29 cards)
What people thought the earth was flat and held up by 12 pillars. What is their evidence
The Indians. The ground did not seem to move
What people thought that the earth was supported by the back of a turtle. What is their evidence
Thailand. The ground did not seem to move
What people thought that The earth was in the middle of the solar system. What is their evidence
The Greek. The sun, Moon and stars appear to move across the night sky.
What is the geocentric model of the universe
The Earth is the center of the universe and is stationary. The planets, sun and stars revolve around Earth
What is the heliocentric model of the universe
a theory that places the Sun at the center of the Solar System
What is a theory
An attempt to explain phenomena in our universe. Theories can’t actually be proven, but they can be disproven. If a theory is disproven then we look for another explanation. If a theory gains evidence that supports it then it becomes strongly accepted by most scientists as the dominant theory.
What happened in the beginning of the Universe
13.7 Billion years ago a tiny fireball of infinite density exploded. Intense heat & light flew out in all directions After 300,000 years temperatures dropped enough for atoms to form. Clouds of hydrogen and helium gas formed.
What is the big bang theory
The theory states that to begin with all the matter in the universe was concentrated into a single incredibly tiny point. This began to enlarge rapidly in a hot explosion (called the Big
Bang). The Universe is still expanding today.
What is the first stage of a star
Protostar
What do stars become if they are the same size as our sun
Red giant then a white dwarf and then a black dwarf
What do stars become if they are bigger than our sun
Red supergiant then a supernova then either a black hole or a neutron star
What happens with stars with lower mass
Stars with low masses remain in their main sequence for much longer, as their core is cooler than that of more massive stars. However, eventually, after billions of years, they run low of hydrogen fuel in their core. At this stage, they begin to move off the main sequence into the next phase of their lives.
When a rocket takes off what forces are active
● Force of the Earth on the rocket
● Force of the rocket on the Earth
● Force of gases on the rocket
● Force of the rocket on the gases
What are the uses of satallites
To take pictures of planets, weather, TV, Google maps, Data
How does something stay in orbit?
A satellite maintains its orbit by balancing two factors: its velocity (the speed it takes to travel in a straight line) (centripetal force) and the gravitational pull that earth has on it.
What is a geostationary satallite
Stays above the same point on the Earth
Speed of orbit matches the Earth’s rotation, so orbit time is 24 hours.
Used for communications satellite TV, weather forecasting, intelligence and GPS.
What is a LEO satallite used for
There are lots of satellites, such as the International Space Station, in low Earth orbit (LEO). This is an orbit below 1000km from Earth. They are used for communications, military reconnaissance, spying and other imaging applications
What is a Low polar orbit satellite
Low orbit around the Earth passing over North and South poles.
• Earth rotates underneath them as they orbit.
• Used for large-scale mapping and global weather monitoring.
What are the risks of space travel
Wrong calculations, solar flare, rely on parachutes to slow their decent, top of rocket can explode during lift off, spacecraft can overheat due to friction.
What is a solar flare
A sudden, intense release of energy in the suns atmosphere
Who is Galileo Galilei
Galileo used a telescope with two lenses. This is called a refracting telescope. The objective lens produces a real image of a distant object. The eyepiece lens magnifies the image of the object. This is how Galileo could observe the moons in orbit around Jupiter.
Before that most people thought that the Earth was at the centre of the Solar System.
What is refraction
The change of direction of a light ray when it passes across a boundary ater between two transparent substances (including air).
Why does refraction happen
The redirection can be caused by the wave’s change in speed or by a change in the medium.
What is the major problem of the refracting telescope?
There are problems with Galileo’s telescope. For example, different colours of light are refracted by different amounts. So the image of an object that emits different colours might not be clear. Instead of using lenses, it is better to produce an image with a curved mirror. This is called a reflecting telescope.
