Astronomy Flashcards
What is the Big Bang Theory?
The Big Bang Theory states thats the universe formed when an infinitely dense point suddenly and rapidly expanded in a single moment. All the matter and energy that exists today was created during the early minutes of that hot, fast expansion.
What’s the difference between Geocentric and Heliocentric?
The Geocentric theory is when they believed that the earth was the centre of the universe and everything revolved around it and the Heliocentric theory is the one to be true that everyone still believes today that the sun is the centre if our universe and the solar system revolves around it.
How is a star formed?
All stars form inside of a collapsing nebula which is a cloud of dust and gases. After it collapses, the part with the most matter starts dragging in materials towards it by gravity. This results in mass growing and creates a cycle of heating, spinning, heating and turns into a protostar which is the first stage. Eventually, the temperature rises to millions of degrees Celsius and a nuclear reaction starts.
Describe the life cycle of a star
There are 3 main life cycles of stars. There is the low, medium and high mass stars. Low mass stars use their nuclear fuel more slowly than the others so they burn a lot slower which means they can last up to 100 billion years. Medium mass stars burn their fuel faster than low mass stars and having a life expectancy of about 10 billion years. High mass stars have a life expectancy of about 7 billions years. As gravity pulls matter into the centre and squeezes the core, this accelerates nuclear reactions, making these stars the bigger, bluer and hotter than the others.
What are some characteristics of stars?
Some characteristics are if they’re really hot, they’re blue, and if they’re average temp. they’re red, brightness of a star can depend on how big they are and how close they are to earth, they are mostly made up of hydrogen and helium, huge spheres of glowing gas and they all emit light.
What is an asteroid?
a small rocky body orbiting the sun.
What are meteors?
A meteor is a small piece of rock that enters earth’s atmosphere and begins to burn up as a result of friction.
What are meteorites?
a meteor that survives it’s passage through earths atmosphere and hits the ground
What is a meteoroid?
travelling through solar system and would change into a meteor if came into earth.
What are comets?
Comets are a celestial object made of ice and dust
What are the Terrestrial planets?
There are four terrestrial planets in our Solar System: Mercury, Venus, Earth, and Mars. These are the 4 inner planets
What are the gas giants?
large planets with low density and mostly hydrogen and helium such as Jupiter, Saturn, Neptune, Uranium
Whats the Planets order from closest to the sun?
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto
Feature of each planet?
Mercury- closest to the sun, no atmosphere. Venus- Earth’s twin, very hot because surrounded in thick clouds. Earth-only planet where solid,liquid and gas occurs, lots of biodiversity and life. Mars-very thin atmosphere, very cold temps. Jupiter- largest planet, mainly hydrogen and helium. Saturn-biggest ring around it (over 800 all together or ice and dust) high winds due to fast rotation. Uranus-mainly hydrogen and helium, unusual rotation. Neptune-farthest from the sun, mainly hydrogen and helium
What is a low mass star?
Low Mass Stars use their nuclear fuel much slower than the bigger stars do which means they last for a lot longer. They can live up to 1000 billion years old. Since there is less pressure pushing against them because of less gravity, they are smaller and shine very weakly. They shine as weak as a red dwarf, when they collapse, the heat isn’t strong enough to regenerate.
