Most of the planets that have been discovered have been gas giants like Jupiter, rather than terrestrial planets like the Earth. Why do you think that it is easier to detect gas giant planets?

Which of the following is not a natural satellite?

Mention any two achievements of Hubble Telescope.

Which satellite is used for geographical survey?

The earth takes $1$ year to make a complete revolution around the sun whereas Pluto takes nearly $248$ of our earth years to orbit the sun. What is the main reason for this?

What is an artificial satellite? Name any two types of artificial satellite and state their functions.

What is the name of $400 \mathrm{km}$ thick bright layer around the sun?

Why do tail of comets formed, when it comes closer to sun?

Rewrite the statement correctly by changing the underlined word.

About $71\%$ of the earth's surface is covered with land.

Give reasons: Life is possible only on the earth.