space

Question 1

once in a blue moon

Answer 1

something that rarely happens

Question 2

live on another planet

Answer 2

when somebody is not realistic

You’re living on another planet if you think that mom is going to give you money to buy a new car.

Question 3

under the sun

Answer 3

everything that exists or is possible

We talked about everything under the sun.

There is nothing under the sun [=nothing at all] that we cannot do.

Question 4

over the moon

Answer 4

when you are very happy about something

Question 5

to reach for the stars

Answer 5

to work toward a goal

Question 6

to see stars

Answer 6

see flashes of light

Question 7

to have one’s head in the clouds

Answer 7

to live in a fantasy world

He is not right for this job; he has his head in the clouds. Source: theidioms.com

Question 8

the sky is the limit

Answer 8

anything is possible, there are no limits

Question 9

out of this world

Answer 9

something that is exceptional

Question 10

come back down to Earth

Answer 10

when somebody has to start doing something boring after doing something fun

After our wedding, it took us a long time to come back down to earth again.