1. HOW'S THE PORRIDGE?

Earth is called a 'Goldilocks planet' because:

Earth is called a 'Goldilocks planet' because:
Mars once had running water that carved canyons and other features into its surface. What happened to the water?
Earth isn't the only body in the solar system with rivers and lakes. Which other world has similar features?
Earth and Venus are rocky planets of about the same size, but Earth's average surface temperature is about 59° F, while Venus' is 1,350° F, hot enough to melt lead or aluminum. Why the difference?
Which circumstances could end life on Earth?
Earth's magnetic field shields us from solar wind and helps hold onto the atmosphere and water. To what do we owe this invisible protector?
Earth is the only body in the solar system thought to have oceans of liquid water.
Earth is smack in the middle of the "habitable zone" around the sun, where temperatures are right for liquid water to exist.
Exoplanets that have a lot of volcanic activity and exist in systems with many asteroids are bad prospects for looking for extraterrestrial life.
Small Earth-sized planets are common in the galaxy.