a nebula
a nova
a quasar
a black hole
a light-year
it is 30 light-years away
a planet
planetary
a comet
the tail of a comet
an asteroid
a meteor
a meteorite
an orbit
in orbit round sth
(the) Earth
Jupiter
Mars
Mercury
Neptune
Pluto
Saturn
Uranus
Venus
The Milky Way
the Great Bear, the Plough (br), the Big Dipper (am)
the Pleiades
the Southern Cross
the Pole Star
the Dog Star
Orion
the Zodiac
a star chart
an astronomer
astronomical
an observatory
a telescope
a planetarium
flexible, pliable
flexibility
elastic
elasticity
plastic
plasticity
thin
thinness
thick
thickness
delicate
fragile
fragility
crumbly, flaky
flakiness
to bend
to stretch
to give, to yield
hard
hardness
to harden
tough
toughness
to toughen
firm
firmness
stiff
stiffness
to stiffen
rigid
rigidity
limp
limpness
malleable
malleability
supple
suppleness