When viewed from space, there are several notable differences between Earth and Mars:
Size: Earth is larger than Mars. Earth has a diameter of approximately 12,742 kilometers (7,918 miles), while Mars has a diameter of about 6,779 kilometers (4,212 miles). This size difference is visible when comparing the two planets.
Atmosphere: Earth has a dense atmosphere composed mostly of nitrogen (78%) and oxygen (21%), with trace amounts of other gases. This atmosphere is crucial for sustaining life and weather systems. Mars, on the other hand, has a thin atmosphere consisting mostly of carbon dioxide (95.3%) with very little oxygen and other gases. The Martian atmosphere is not capable of supporting human life as we know it.
Surface features: Earth is characterized by diverse surface features, including vast oceans, continents, mountains, and a variety of ecosystems. Mars, on the other hand, is a rocky planet with a barren, desert-like surface. Mars has large volcanoes, such as Olympus Mons, and a massive canyon called Valles Marineris. It also has polar ice caps composed of water ice and carbon dioxide ice.
Liquid water: Earth is unique among the known planets in our solar system because it has abundant liquid water on its surface, in the form of oceans, lakes, and rivers. Mars, while it has evidence of past liquid water, does not currently have large bodies of liquid water on its surface. However, there is evidence of water ice in the polar regions and underground, and liquid brines may exist temporarily under certain conditions.
Magnetic field: Earth has a global magnetic field generated by its rotating liquid iron outer core. This magnetic field helps protect the planet's atmosphere from being stripped away by solar winds and also plays a crucial role in supporting life by shielding it from harmful solar radiation. Mars, on the other hand, has only remnants of a magnetic field, resulting in a thinner atmosphere and increased vulnerability to solar winds.
These are some of the primary differences between Earth and Mars when viewed from space. Each planet has its own unique characteristics that make them distinct in terms of habitability and geological features.