how many stars did people used to be able to see in the night sky?
2,500
fill
to spread all through
how big is one of Mars' canyons?
4,000km long and 200km wide
to touch someone or something in a forceful or violent way after moving at a high speed
hit
why do we need the dark?
so that we can sleep well
what are scientists studying to help reduce light pollution?
covers for streetlights
to influence or to produce an effect on
affect
how many planets (including dwarf planets) are in our solar system1?
according to some astronomers, there are 13
create
to make something that did not exist before
what is the passage 'Our Solar System mainly about?
the similarities and differences between Earth and Mars
what effect is light pollution having on us?
it makes it difficult for us to see the stars at night
effect
a result produced by a cause
which of the following two statements is true?
1) there are no craters on Mars
2) Mars has very large canyons
number 2 is true, Mars does have very big canyons
number 1 is false, because Mars does have craters
having a level or even surface
flat
What are scientists worried about when i comes to light pollution?
how it affects our health
how does light help us?
1) helps us to see things
2) gives plants energy
to cause something to be directed at something specific
focus
how big is Mars when compared to Earth?
Half the size
wide
measuring a certain distance from one side to the other
which three things do Earth and Mars have in common?
1) they both have mountains
2) they both have canyons
3) they both get hit by asteroids
1) they save energy
2) they focus light toward the ground
3) they stop light going up into the sky
what are the three positive effects of the light covers that are put on some streetlights?
electric
of or related to electricity
describe the three main differences between Mount Everest and the large volcano on Mars
1) Mars' volcano is three times taller than Mount Everest
2) Mount Everest has very steep sides, but Mars' volcano doesn't
3)Mars' Volcano has a flat top, while Mount Everest has a sharp top
a minor planet that moves around in space
asteroid
is the following statement true or false? Why?
"scientists think that the asteroid that hit Mars was half the size of Pluto'
False: the asteroid was bigger than Pluto