But the recent discovery of possible biological phosphine in the clouds of Venus reminds us that at least some of these components also exist elsewhere in the solar system. Mars is one of the most Earth-like worlds in the solar system. The planet has a 24.5-hour day, the polar ice caps expand and contract with the seasons, and a variety of surface features have been created by water throughout the planet's history. Europa was discovered by Galileo Galilei in 1610, along with three other larger Jupiter moons. It is slightly smaller than Earth's moon and orbits Jupiter at a distance of about 670,000 km, every 3.5 days. Like Europa, Enceladus is an ice-covered moon with an ocean of liquid water below its surface. Enceladus orbits Saturn and was first noticed by scientists as a potentially habitable world after the unexpected discovery of huge geysers near the planet's south pole. Titan is Saturn's largest moon and the only moon in the solar system with a significant atmosphere. The atmosphere here contains a thick orange fog of complex organic molecules and a methane weather system instead of water, with seasonal rains, dry periods and dunes. caused by wind on the surface.

Mars is called the Red Planet because of its reddish surface. There have been many explorations to Mars by humans since the mid-20th century. Scientists hope that we can find another planet to accommodate human life.There are major reasons why the climate on Mars is unsuitable for human life. Temperatures on Mars can be as low as -87 degrees Celsius and rarely get above 0 degrees Celsius. But the bigger problem is the lack of oxygen. 95% of the atmosphere is carbon dioxide (C02), and this is poisonous to breathe. Moreover, there is no water on Mars even though scientists have found traces of it.However, as early as the mid-19th century, scientists discovered that Mars had some similarities to Earth. A day on Mars is 24 hours, 39 minutes and 35 seconds, almost the same as a day on Earth. Mars also experiences seasons just as Earth does. However, the seasons are twice as long because a year on Mars lasts about twice as long as an Earth year.