Oasis in the Desert

Stemming off of last week's post, I would like to discuss something that particularly fascinates me in astronomy: what makes a planet (or moon) habitable for life as we know it.

The most important factor in planet habitability is the presence of water. Water is extremely polar molecule, which allows it to act as a great solvent. I'm not going to get into the chemistry (because, frankly, I don't know it), but water's ability to act as a solvent is vital because it promotes the complex chemical processes that go into the birth of life. Simply put: without water, there is no life.

The presence of water also hints at a few factors that are necessary for life.


One of these is the distance of the world from its host star. There is only a particular distance from each individual star where a planet would be suitable for life. This region is known as the habitable zone, or the goldilocks zone.

In this region, the temperature of the planet is suitable for liquid water to be sustained. As you can see, liquid water is essential for life as we know it.

Another key aspect for life is the type of host star the planet orbits. It takes billions of years for life to form. The more massive the star, the shorter its life span. If you have a planet orbiting a massive star with conditions suitable for the formation of life, the planet may not have enough time to generate life before the star becomes a giant and changes the conditions on the planet. This publication talks about this in more detail.

As you can see, it takes a very complex combination of factors to allow the formation of life. Earth is a very specific gift that we have been given. That is why it is important that we keep researching this field of astronomy and possibly locate planets that may support life. Earth will not last forever. When the time comes that we need to relocate, this field of astronomy may be our saving grace.