Earth life is carbon based, in that carbon-carbon and carbon-hydrogen bonds dominate in the molecules of life. However, such molecules are quite inert and unreactive.
To make them reactive at typical Earthly temperatures they need “heteroatoms” (“hetero” is Greek for “different”). Oxygen, Nitrogen, Sulphur and Phosphorus typically play such a role.
Astronomy is the study of planets. The “Planets” side tells us how to seek out planets and find details about them, such as their mass and size.
Having the tool of knowledge from astronomy helps us to gain a better understanding of how the universe works.
It is a wonderful study to know more about the universe we live in and to understand our place amongst the stars.
Take an interest in the world that surrounds you and you may find there is a sparkle out there to explore.
Biochemistry, on the “Life” side of the map, tells us about the evolution of life and the process by which it arose on Earth.
The process of human development and the evolution of our species have a clear pattern. This pattern is opening more doors to more questions but most importantly it is bringing about understanding in a subtle, clear and yet gradual way.
Biochemistry is the tool to understanding.
To travel to other stars speed is a major necessity.
The fastest travel speeds about 4000 years ago when our ancestors, Neanderthals, we’re wandering the earth was on foot. Now our fastest speeds are measured by transports in the order of kilometres per hour.
Today the fastest spacecraft are Voyager 1 and Voyager 2. These travel about 10,000 times faster that what you could do on foot. In other words, we are as far from interstellar flight as cave man was from the space age. That’s how far we have to go.
Habitable zone is that distance from the star where it’s not too hot and you don’t boil off the water. Not too far out, so it’s not too cold, so all the water gets frozen. That zone around the star where the temperatures are in the range where you can have liquid water and hence, where life might exist.
You will note that within the habitable zone around our sun are Venus, Earth and Mars were all capable of having liquid water.
Venus got too hot, because of the greenhouse effect. Mars is too small, so it may have had it, but it lost its interior heat. And so the only one remaining and it is squarely in the habitable zone is Earth.
There are about 100 billion stars in the Milky Way Galaxy. About 30% of all stars have planets.
Hydrogen of course is the most abundant isotope element in the universe by far.
Going a little bit farther out, there are a hundred billion stars in the Milky Way and given our current detection rates of how many stars have planets it could be around 40-50%.
This means that billions of stars have moderate sized planet zones, habitable zones where life bearing planets might exist.
There are a couple of things to consider. Water would give rise to life on a planet. At least it’s not that life can’t exist in liquid methane or use something other than carbon. That’s entirely possible, but the most likely way to look is to look for things that are similar to us and that sort of means follow the water. Where is the liquid water? And so that’s what we are looking for. And that is what defines the habitable zone around a star.
