Ch 21 Space Flashcards
what is astronomy
the study of the universe and everything in it
what is the big bang theory
the idea that billions of years ago space and matter came together in a mass and it exploded
what is a galaxy
a large group of stars, dust, gas and dark matter held together by gravity
what is our galaxy called
the Milky Way
what is antimatter
the mirror image of matter.
what happens when matter and antimatter meet
they destroy each other and are changed into pure energy
what is a celestial body
any natural body outside of the Earth’s atmosphere
what is a moon
a natural satellite which orbits a planet
what is a star
a ball of heat radiating gas that is held together by gravity
they contain hydrogen and helium
what is a nebula
a cloud of gas and dust in outer space
explain the life cycle of a star
nebula»_space; yellow dwarf»_space;> red giant»_space;> white dwarf»_space;» black dwarf
what is a light year
the distance that light travels in a year
what are asteroids
lumps of rock that orbit the Sun
what are the three types of asteroids
C type- made of carbon compounds
S type - made up of stone material
M type - made up of metals
what is a comet
a small lump of ice and dirt that orbits the Sun
explain the parts of a comet
the nucleus = made of dust and ice
the coma = fuzzy outline caused by sun radiation made up of carbon dioxide, dust and water vapour
the tail = made of gas and dust
what are the four inner planets called
terrestrial planets because they are made of rocks
Mercury Venus Earth Mars
what are the outer planets
gas giants because they’re made of gases such as hydrogen and helium
Jupiter Saturn Uranus Neptune
what is gravity
a non contact force of attraction between objects
what is a force field
a region in space where an object feels a force
how do you calculate gravity
weight (N) = mass (kg) x gravity (N/kg)
