Mars in relation to the Earth

Today, the Earth’s sister planet Mars is very different from our home, but perhaps this was not always the case. Mars was once very similar to the Earth. Perhaps there was once life on Mars.

Today, Mars and the Earth are very different planets. Mars is smaller, covered by ice and dust and further away from the Sun than the Earth. Its surface temperature currently ranges from 20 degrees during the day to -140 degrees at night, and the planet is a sterile and hostile environment without water or an atmosphere. At the same time, the planet has no internal magnetic field to protect its surface against harmful particles from space. But this has not always been the case.

Facts about Mars and Earth:

Mars:  

Days: 24 hours/37 min 
Year: 687 days
Radius: 3390 km 
Temperature: -140 to +20 degrees celcius 
Surface pressure: ~8 hPa


Earth:

Days: 24 hours
Year: 365 days
Radius: 6378 km 
Temperature: -88 to +80 degrees celcius 
Surface pressure: ~1013 hPa

 

Several billion years ago when the planets and the Solar System were formed, scientists believe that Mars was very similar to the Earth, with a substantial atmosphere and a surface partially covered by water. Even today surface fissures are visible on the planet, presumably caused by running water. Scientists have also found evidence to suggest that Mars once had an internal magnetic field in the form of powerful crustal fields, i.e. areas where the Martian surface once was and still is magnetised. The question is: What happened on Mars to transform it into the cold barren desert we know today?

A key factor in Mars’ development is its current lack of atmosphere. The fact that Mars does not have any atmosphere to speak of means that the surface pressure is so low that liquid water cannot exist on the planet surface. Scientists have also found evidence of atmospheric particles accelerating away from Mars and being blown out into space, which means that any water particles in Mars’ atmosphere can be carried away from the surface by the solar wind and out into the Solar System at a speed in excess of 400 km/s.

When the solar wind strikes a planet’s atmosphere, it creates a shield, protecting the planet against the particles borne by the wind and draping the magnetic field lines from the Sun around the planet. In the case of the Earth, the shield is formed far away from the Earth’s surface due to the Earth’s magnetic field, but on Mars, which lacks this protection, the shield is formed closer to the planet surface, and the electrically charged particles in the solar wind interact with the atmosphere and the mini-magnetospheres caused by the crustal fields on Mars’ surface.

https://www.space.dtu.dk/english/research/universe_and_solar_system/magnetic_field/mars_in_relation_to_earth
18 FEBRUARY 2020