P1.3 Flashcards
What is the benefit of having a telescope in space
Clear images taken as there is no clues in the way and there are no particles for light to refract or reflect off
How is a start formed
A nebula (Cloud of mostly hydrogen) begins to pull together as gravity builds. The rate of being pulled together increases and the nebula becomes denser and hotter, eventually becoming a protostar. Once the pressure and temperature becomes high enough at the centre of the protostar, fusion occurs and becomes a normal star
Life cycle of stars like ours
Stable for about 10 billion years. After this the hydrogen is mostly used up and fusion is no longer able to occur, this means the pressure inside reduces and can no longer withstand the gravity. The core begins to collapse and the outer layers will expand into a red giant. Stays like this for about 1 billion years. A shell of gas is then thrown off and the rest of the star will continue to collapse into a white dwarf and cool for about 1 billion years into a black dwarf
Life cycle of massive stars
Protostar forms a massive star. These are hotter and brighter than ours and use fuel faster. They then become a red super giant. After that they begin to collapse and the outer layers explode out in a super nova. The remains of the star pull together. It will either become a black hole if the gravity is strong enough or it will become s super dense star called a neutron star
How can we tell if light is moving away
It’s wavelength is longer than expected, it has shifted to the red side of the spectrum, red shift
How do we know a galaxy is moving away from us
There are gaps in the spectrum of light from the sun. Other galaxies have these same gaps in the same place but because they are further away, they are shifted right. We can see they are moving away as we can see the lines shifting right
What is the Big Bang theory
Most widely believed and suggests the universe was formed 13.5 billion years ago. Says that the universe started as a tiny point of concentrated of energy that exploded outwards. States the universe is always expanding and that no matter is ever created
What is the steady state theory
The universe was always here and is always expanding and producing new matter
Difference between an average star and massive star
Average stars only fuse hydrogen, deutrinium and tritinium. Once they run out, it becomes red giant. In massive stars, they will keep fusing even when hydrogen is done, they willl fuse helium and then the next present element and so un until it gets to iron, then it becomes red supergiant
What happens in a supernova
Explosion fuses elements into all the other elements such as gold and silver
What decides if super nova becomes black whole or neutron star
If greater than four times our star, it becomes black hole, if less it becomes a neutron star
