Solar System Planets Habitability Analysis

This article will detail my personal anaulysis of the potential habitability of some of the planets and moons in our Solar System. I will focus my analysis on the planets Earth and Mars, and the moons Europa, Enceladus, and Titan.

Planet Earth

Planet Earth is special and unique. There are 18 criteria that Earth meets that contributes to its status as a habitable planet. The criteria are as follows:

[1] The Earth orbits in the habitable zone of the Sun – the zone where liquid water is possible given a sufficient atmosphere
[2] The Earth is not tidally locked with the Sun – meaning one side of our planet does not always face the Sun
[3] The Earth has an axial tilt of 23.5 degrees – this tilt makes it possible for Earth to have seasons
[4] The Earth has an orbital eccentricity of 0.0167 – this is a measure of how closely an orbit is to a perfect circle – a perfect circle = 0
[5] The Earth is a Terran-sized planet
[6] The Earth has a mass of 5.972 Sextillion metric tons
[7] The Earth has a diameter of 7,918 Miles
[8] The Earth has a density of 5.52
[9] The Earth has gravity of 9.807 meters per/second/second
[10] The Earth has an atmosphere comprised of 78% Nitrogen, 21% Oxygen, and 1% Argon
[11] The Earth has an atmospheric pressure at sea level of 14.7 pounds per square inch
[12] The Earth’s atmosphere has an ozone layer that protects us from UVR radiation from the Sun
[13] The Earth has a magnetic field of 0.25 to 0.65 gauss – this field protects us from the solar wind that would destroy the ozone layer
[14] The Solar flares from the Sun are moderate compared to some other stars
[15] The average surface temperature on Earth is 57 degrees
[16] The Earth has oceans of liquid water
[17] The Earth has a rocky surface
[18] The Earth is home to a variety of plant life that remove carbon dioxide from the atmosphere and exhale oxygen into the atmosphere

Planet Mars

Jupiter’s Moon Europa

Saturn’s Moon Enceladus

Saturn’s Moon Titan

Proxima Centauri Planet Habitability Analysis

The Proxima Centauri Star System is home to 1 Planet, Proxima b, and is located 4.2421 light years from Earth.

This article will detail my personal analysis of the potential habitability of the Planet Proxima b. I invite your comments on my analysis. My analysis is only a starting point for a detailed discussion for the habitability of the planet in this star system. This analysis will be based upon the current known data regarding Proxima b. I will begin with an analysis of the Proxima Centauri star first, since the parent star has a direct relevance on the habitability of the planets in orbit around it.

Proxima Centauri Star

The Proxima Centauri Star is a M5.5 Red SubDwarf star. It is smaller than our Sun but is young and energetic. This star produces extreme and frequent solar flares. By comparison, our Sun is middle-aged and produces moderate solar flares.

Planet Proxima b

Planet Proxima b

The planet Proxima Centauri b fascinates us due to the fact that it is the closest planet to our Solar System and that it is roughly Earth-sized. However, the more we learn about Proxima Centauri b, the more we are realizing that it may be nothing like our Earth.

Proxima b is a Cold Terran planet as far as we know, whereas Earth is a Warm Terran planet. Proxima b may have an average temperature of -51 degrees Fahrenheit. It orbits its star at 0.0485 AU which is in the habitable zone, the zone where liquid water may be possible given a sufficient atmosphere. However, we still don’t know if it has an atmosphere. If it has an atmosphere, it may have a higher temperature. That being said, we know that its parent star, Proxima Centauri, is a very active Red SubDwarf star that regularly gives off extreme solar flares. These solar flares regularly blast Proxima b with intense solar radiation, which may have stripped Proxima b of any atmosphere it once held. By contrast, our Sun gives off moderate solar flares.

In addition, Proxima b is what we call “Tidally Locked,” meaning that one side of the planet probably faces its star all the time, similar to the way our Moon always shows the same side to the Earth. This means that if the planet doesn’t have an atmosphere, that the side facing the star would be blasted with heat and the other side of the planet would never see sunlight and would be freezing. However, if the planet has somehow retained a sufficient atmosphere, it may be able to redistribute heat around the planet, and therefore may have a chance of having liquid water.

Proxima b also orbits its star every 11.2 days, meaning that its year is very short, compared to Earth’s 365 day year orbit around our Sun.

Proxima b has a mass that is 1.3 times that of Earth, which is similar to Earth but not exactly like Earth. It has a diameter of approximately 8,710 miles, which is considered “Earth-like,” but again not exactly like the Earth. For comparison, Earth has a diameter of 7,918 miles.

In conclusion, Proxima b is most likely not similar to Earth and most likely does not have life as we know it. However, there is still a lot of data that needs to be collected before we know for sure. That being said, there is still the possibility that Proxima b may surprise us. We have the examples of the Jovian moon Europa, the Saturnian moon Enceladus and Titan that may harbor some type of life. We definitely should not rule out life as a possibility just because a planet is not exactly like the Earth. Therefore, Proxima b may still have the potential to have life. We should keep an open mind.

What do you think about Proxima b? Does it have an atmosphere? Is the atmosphere habitable? Does the planet have liquid water? Does Proxima be have life?


Brian Done
Amateur Astronomer

Planet Janssen

I wanted to give a shout out to my dear friend Jantzen! She was very excited to learn that scientists have discovered a planet that has her same name! Well, almost. The name of the planet is Janssen.

Janssen orbits two stars known as 55 Cancri A and 55 Cancri B. 55 Cancri A is a G8V Yellow Dwarf Star and 55 Canri B is an M3.5V Red SubDwarf Star. The 55 Cancri Star System is 40.2470 light years away from Earth. A light year is equal to 5.879 trillion miles! Therefore, the planet Janssen is 236.612113 trillion miles from Earth!

Planet Janssen

The planet Janssen is a scorching hot SubNeptunian Planet. It has an average temperature of 1,588 degrees Fahrenheit! By comparison, Earth has an average temperature of 57 degrees Fahrenheit, and hot Venus is “only” 847 degrees Fahrenheit, half as hot as Janssen.


Brian Done
Amateur Astronomer