For many years the question of whether we are alone in the universe has been bothering mankind. From the times when humans first realized how big the universe is and how many planets it contains, many hypotheses started to be developed, many types of research began, and general interest in this subject rapidly skyrocketed. Logically thinking, there are billions of stars in billions of galaxies, and even if a small part of those stars has Earth-like planets, then there is a probability that hundreds of other civilizations may exist (Harris, n.d., para. 1). During several last decades hundreds of extra-solar planets have been discovered.
Yet, the theory that life exists on other planets hasn’t been proved. In recent years, many scientists agreed that the presence of liquid water on a planet is the perfect condition for developing life. Previous researches have indicated that “water in different states has been directly detected multiple times all over the universe (even in the outer layers of cool stars!), we have never found liquid water anywhere in the universe” (Faulkner, 2009). To become suspected to be inhabited, a planet has to match several favorable for life criteria: presence of gas atmosphere, presence of water, temperature and atmospheric pressure that can sustain liquid water. Life depends on water, energy and organic molecules.
The chance of appearance of something like DNA that has a capacity to reproduce itself is unlikely. However, in the universe with enormous number of stars and opportunities, it seems expectable to occur in several stellar systems (Hawking, n.d., para. 9). Besides, in 1961 Frank Drake has presented the formula (the Drake Equation) that calculates the potential number of extraterrestrial civilizations and is an “effective tool for stimulating curiosity about the universe around us” (SETI, n. d., para 4).
The Sun energy is one of the main life-supporting factors on our planet, but the line between perfect balance and deadly cataclysm is very thin. We keep hearing stories about global warming and the melting of glaciers. There are many arguments whether these theories are true or false, but it is scientifically proved that if the climate on our planet became at least several degrees warmer – it would lead to disastrous consequences.
Every second hundred of billions of tons of hydrogen is converted into helium in the core of the Sun, generating a lot of energy. This process has started billions of years ago. Even though the Sun is huge and powerful, its resources have limits. The Sun’s stages of life change, its size changes, so does its brightness, and, of course, these changes directly affect all the neighboring planets, including the Earth. Scientists have made a prognosis that in 1.1 billion years our Sun will shine ten percent brighter. It sounds like good news, but in reality, it is not good at all (Cain, 2012).
The vapor water that absorbs ninety percent of infrared radiation in the outer layers of our atmosphere will undergo an unusual amount of sunlight, and decompose to hydrogen and oxygen. Hydrogen is light, so it will disappear in space. The amount of water in our hydrosphere will become decrease, and, accordingly, rains will not happen as much. Rains serve to wash carbon dioxide from our atmosphere. Less rain will lead to the accumulation of carbon dioxide and an increasing greenhouse effect, which will cause catastrophic overheating on the surface of the Earth, the vegetation will dry out; all the ice around the Poles will melt.
Reference List
Cain, F. (2012), Life of the Sun. Web.
Faulkner, D. (2009), Can Life Exist on Other Planets? Web.
Harris, W. (n. d.) What Are the Odds There Is Life in Outer Space? Web.
Hawking, S. (n. d.) Life in the Universe. Web.
SETI: Drake Equation. (n.d.). Web.