Chapter 7, Problem 1RQ

Why do we expect the elements of life to be widely available on other worlds? How does the requirement of organic building blocks further constrain the prospects of habitability?

To determine

The reason to expect the elements of life to be widely available on other worlds and also requirement of organic building blocks and the way in which they constrain the prospects of habitability.

Answer to Problem 1RQ

Every start system has at least some amount of all elements used by life and the nature of formation of solar system is also the reason to expect elements of life in other worlds and requirement of basic organic building blocks constrain the prospects of habitability in other worlds.

Explanation of Solution

The basic environmental requirement of life is the presence of atmosphere where humans can breathe, abundant surface water that is drinkable, combination of surface pressure and temperature and some set of chemical elements from which cells are formed.

The four basic chemical elements that make up $96\%$ mass of living organism are oxygen, hydrogen, carbon, and nitrogen and the presence of these elements is a basic requirement for life in general.

The reason to expect the presence of elements of life on other worlds is that all the other worlds are formed through the same process of accretion of gases and condensation sameas Earth.

All chemical elements except hydrogen and helium were produced by stars. Therefore they are present everywhere.

The most important element, such as, oxygen, nitrogen and carbon are also the third, sixth and fourth most abundant element in the universe while all the other heavy elements are quite rare compared to helium and hydrogen but they are also present in every star system.

Hence, every start system has at least some amount of all elements used by life and the nature of formation of solar system is also the reason to expect elements of life in other worlds.

According to nebular theory of formation of solar system, the planets were formed by the process of condensation of gas in the solar nebula when solid particles condensed and these particles then accreted into planets, comets, moons and asteroids.

As long as condensation and accretion occur, there is always a possibility to find elements in other worlds.

The chemical elements are not the only thing which makes the life habitable other requirements such as water, atmosphere and, combination of surface pressure and temperature are the basic requirements which constraints the prospects ofhabitability.

One more important requirement is the presence of these elements in molecules that are used as building blocks of life; most of the organic molecules are created by some chemical reactions on the surface or somewhere deep in the oceans and some molecules are created by heat and pressure.

Chemical reactions would likely occur only on worlds with atmospheres or oceans. Therefore, requirement of basic organic building blocks constrain the prospects of habitability in other worlds.

Conclusion:

Thus, every start system has at least some amount of all elements used by life and the nature of formation of solar system is also the reason to expect elements of life in other worlds and requirement of basic organic building blocks constrain the prospects of habitability in other worlds.