8th grade: Life on other planets - lesson 1 (Wee ...

Many scientists want to work on a .......... because it has a great view of the stars.

This is the fourth planet from the Sun

Our planet, Earth, is becoming more and more ............ The world's population will reach 11 billion by 2100

Mars is much smaller than Earth, so the gravity there is very low and there isn't much .............

This is the planet we live on.

............. pulls us down to the ground.

Human can't live on some planets because they don't have enough ......... to breathe.

You will be very cold in space because the ........... is very low.

This planet is very hot and close to the sun.

We need to breathe this to live.

Today, most people live on .........

Venus is often called Earth's "sister planet". The two planets are almost the same size, so the gravity is very ............ to Earth's.

We use this to measure if something is hot or cold.

You can recognize ........... by its yellow clouds. It's the 2nd planet from the sun.

........... is often called "the Red Planet." It's the 4th planet from the sun.

Earth's ............. is growing more and more quickly every year. I think that someday in the future, we will need to leave Earth and travel to new planets.

People live on this machine in space.

This stops you from flying in the air.