asteroid (n)
/ˈæs.tər.ɔɪd/

one of many large rocks that circle the sun

astronaut (n)
/ˈæs.trə.nɔːt/

a person who has been trained for travelling in space

atmosphere (n)
/ˈætməsˌfɪə(r)/

the air round the Earth or round another planet

cosmos (n)
/ˈkɒz.mɒs/

the whole universe

crater (n)
/ˈkreɪ.tər/

the round hole at the top of a volcano

debris (n)
/ˈdeɪ.briː/

broken or torn pieces of something larger

Earth (n)
/ɜːθ/

the planet third in order of distance from the sun, between Venus and Mars; the world on which we live

exploration (n)
/ˌek.spləˈreɪ.ʃən/

the activity of searching and finding out about something

galaxy (n)
/ˈɡæl.ək.si/

an extremely large group of stars and planets

gas (n)
/ɡæs/

a substance in a form like air that is neither solid nor liquid

gravity (n)
/ˈɡræv.ɪ.ti/

the force that attracts objects towards one another, especially the force that makes things fall to the ground

horizon (n)
/həˈraɪzn/

the line at the farthest place that you can see, where the sky seems to touch the land or sea

meteor (n)
/ˈmiː.ti.ɔːr/

a piece of rock or other matter from space that produces a bright light as it travels through the Earth's atmosphere

moon (n)
/mun/

the round object that moves in the sky around the Earth and can be seen at night

ocean (n)
/ˈəʊ.ʃən/

the large mass of salt water that covers most of the earth’s surface

rocket (n)
/ˈrɒk.ɪt/

a large cylinder-shaped object that moves very fast by forcing out burning gases, used for space travel or as a weapon

lunar (n)
/ˈluː.nər/

of or relating to the moon

orbit (v)
/ˈɔː.bɪt/

to follow a curved path around a planet or star

outer space (n)
/ˈaʊ.tər speɪs/

the part of space that is very far away from Earth

planet (n)
/ˈplæn.ɪt/

a very large round object that moves around the Sun or another star