Mercury is the smallest planet in our solar system. It's a little bigger than Earth's Moon. It is the closest planet to the Sun, Mercury is one of the rocky planets. Intense changes in temperature from day to night make it impossible for life as we know it.

Astroboy breaks up with her friends and searches for signs of life on the planets.

The planet Venus we have reached is very hot. This is due to its atmosphere with dense greenhouse gases.

Astro boy made a stop on Mars in his space travel. Maybe Mars is a suitable planet to live on, he thought. He saw that there was water and gravity on Mars. But it was very cold. That's why he had to leave the planet.

Astro boy came to Jupiter in space travel after leaving Mars. He began to wonder if I could live on this planet. He saw that it was a very large planet. It was large, but it also had an atmosphere of poisonous gases. When he realized that this planet was not suitable for living, he continued his journey.