Question

What are the major sources of Hydrocarbons?

Answer 1

Hint: We need to know that hydrocarbons are compounds that mainly consist of Carbon and Hydrogen. Although they might contain other elements than Hydrogen and Carbon, it is the C and H that defines them as organic.

Complete answer:
We have to know that alkenes are the simplest Hydrocarbons in which Carbon bonds with Hydrogen. The complexity of Hydrocarbons increases with the growth of the chain.
The Most basic Hydrocarbons are:
Ethene ( $C{H_2} = C{H_2}$)

Methane ($C{H_4}$)

Ethane $(C{H_3} - C{H_3})$

Butane $(C{H_3} - C{H_2} - C{H_2} - C{H_3})$

Hydrocarbons are derived from organic processes on earth but in the solar system it is derived from inorganic processes.
About $90 - 95\% $ of methane on earth is generated from organic sources, like petroleum. Under anaerobic conditions oil, gas and coal are produced. Petroleum is obtained from ancient buried organisms under the sea bed, hence oil and gas are called fossil fuels. Methane is produced by bacteria under anaerobic conditions in the environment with little or no oxygen. They feed on decomposing organic matter, such as leaves, wood, and grasses. Half of the world’s methane is produced by natural sources such as rivers. Streams, gas hydrates on the ocean floor, and permafrost. Inorganic origins include volcanoes and deep-sea vents. Theoretically, when crystalline minerals are exposed to heat and pressure in the presence of water and carbon dioxide a small amount of methane is produced.
Methane is commonly found on other planets in the solar system like Jupiter, Saturn, Uranus and Neptune. Recently it was also found in Pluto and is also present in the Kuiper Belt. Hydrocarbons like methane and ethane form heteropolymers when exposed to solar UV radiations to form tholins, found in the Titan’s surface.

Note:
We need to know that the hydrocarbons are highly combustible and produce Carbon dioxide and water on heating. They are efficiently used as fuels. Because of the huge carbon dioxide emissions and degradation of the environment nowadays, we are shifting to new and reliable sources like solar, wind and hydro energy to meet our fuel needs.