[170525] 태양계

Talk about the solar system.

The solar system that Earth is a part of includes eight planets.

They are Mercury, Venus, Earth, Jupiter, Saturn, Uranus, and Neptune.

In English, the planets were named after Roman gods.

Earlier, it was thought that there were nine planets.

However, due to the change in the definition of planets, a ?? demoted put off.

-> However, due to the change in the definition of planets, astronomers demoted Pluto.

The planets all revolve around the Sun.

Some planets have natural satellites.

For example, the Moon revolves around the Earth.

Each planet has different ?? conditions.

-> Each planet has different atmospheric conditions.

There's no different of prove that live is any planet safer earth.

-> There's no different of proof that life exists on any planet except for Earth.

Space exploration is in its early stages.

A lot of mains are known about a solar system.

-> A lot remains unknown about our solar system.