Methane

Methane is a chemical compound with the formula CH₄, made of one carbon atom bonded to four hydrogen atoms. It is the simplest alkane and the main part of natural gas. Because there is a lot of methane on Earth, it is used as a fuel, even though it is tricky to capture and store since it stays a gas at normal temperatures and pressures.

Methane is important for our planet because it acts like a blanket in the atmosphere. Even though we can't see it, methane traps heat by absorbing infrared radiation, which helps warm the Earth. However, too much methane can cause problems by making the planet warmer faster.

Most of the methane in our atmosphere today has come from human activities since the year 1750, and it now makes up a big part of what causes the Earth to warm up. Cutting down on methane pollution can help slow down warming and make the air cleaner.

Methane isn't just here on Earth. Scientists have found it on other planets, like Mars, which helps them learn more about whether life might exist elsewhere.

Properties and bonding

Methane is a simple molecule shaped like a pyramid, with one carbon atom connected to four hydrogen atoms. It is a clear, odorless gas at normal temperature and pressure. Although it has no smell on its own, a special smelly substance is added to natural gas so people can detect leaks easily.

Methane can catch fire when mixed with air in certain amounts. It turns into a solid when cooled, forming different structures depending on the conditions. Its ability to absorb certain colors of light helps give planets like Uranus and Neptune their blue hues.

Chemical reactions

Methane can undergo several important reactions. The most common is combustion, where methane burns in oxygen to produce carbon dioxide and water. This reaction releases a lot of energy and is used in many engines and heaters.

Methane can also react with halogens like chlorine under the right conditions, forming new compounds through a process called free radical halogenation. These reactions are important in making certain chemicals.

Uses

Methane can be cooled and stored as a liquid, known as liquefied natural gas or LNG. It is commonly moved through gas pipelines, where it is the main part of natural gas.

Methane is widely used as a fuel for many things, like heating homes, cooking, powering cars, and generating electricity generation in power plants. It is cleaner than other fuels because it produces less carbon dioxide when burned. Methane can also be used as a fuel in rockets when mixed with liquid oxygen. In industry, methane helps make hydrogen gas, which is used in creating chemicals and processing food. It can also be used in special cooling systems as a refrigerant.

Generation

Methane can be created in different ways, either by nature or by humans. One way is through geological processes, where heat and pressure break down organic materials deep underground, creating what we call natural gas. Another way is biological, where certain tiny living things, called methanogens, produce methane as they get energy. These organisms live in places like landfills, soil, the stomachs of animals such as cows, and even deep in the ocean.

Humans can also make methane through industrial methods. For example, we can combine hydrogen and carbon dioxide to create methane, a process used in some factories. Methane is also made as a by-product when we change coal into other useful fuels.

Occurrence

Methane makes up most of natural gas, about 87% of it. We get methane mostly from places underground called natural gas fields, and also from coal seam gas. It is often found with other fuels like hydrocarbons, and sometimes with helium and nitrogen. Methane can also be made when organic matter breaks down without air.

People move methane in big amounts using pipelines or special ships that carry it in a liquid form. Only a few countries use trucks for this.

Atmospheric methane and climate change

Main article: Atmospheric methane

Methane is an important greenhouse gas that has helped raise global temperatures by about 30% since the industrial revolution. It is much more powerful than carbon dioxide at trapping heat, especially over short periods. For example, one tonne of methane can have the same warming effect as over 80 tonnes of carbon dioxide over 20 years.

Most of the methane in our atmosphere comes from human activities, like farming and energy production. Since the 1980s, scientists have been watching how much methane is in the air, and they have seen big increases. Many countries have promised to cut down on methane to help slow down climate change.

Extraterrestrial methane

Methane is found in many places in our Solar System and could possibly be collected from places like Mars or Titan to provide fuel for space travel.

We have found methane on all the planets and most of the larger moons. In space, between the stars, we have also found methane using special telescopes that look at infrared light. On Mars, robots like the Curiosity rover have measured changes in the amount of methane in the air. Scientists think methane on Mars might come from natural processes or maybe even tiny living things, though we don’t have proof of that yet. In the future, methane could be used as fuel for rockets on Mars missions.

On Titan, one of Saturn’s moons, there is a lot of methane. It is part of the air and also exists as liquid in huge lakes on the surface. These lakes of methane and other compounds make scientists wonder if there could be a kind of life there that uses methane instead of water.

History

The discovery of methane is credited to Italian physicist Alessandro Volta. He was inspired by reports of strange air in marshes and, during a fishing trip to Lake Maggiore in 1776, collected gas from the marsh to show that it could catch fire.

Later, in 1812, scientist Humphry Davy identified that "firedamp" — a dangerous gas in mines — was mostly methane. The name "methane" was created in 1866 by chemist August Wilhelm von Hofmann, based on the chemical methanol.

Etymology

The word methane comes from two parts: the ending "-ane", which is used for a group of chemicals called alkanes, and the word methyl. Methyl comes from old words meaning "wine" and "wood" because scientists first found this chemical in a substance made from wood.

In science, CH₄-C is a short way to talk about how much carbon is in methane. It can also show the ratio of methane to carbon, which is always 1.33. Scientists measure methane in the air using units like teragrams (Tg CH₄) or millions of metric tons (MMT CH₄).

Safety

Methane is a gas that can be dangerous because it can push out oxygen in the air, making it hard to breathe. It is also very flammable and can explode when mixed with air. Because of this, methane explosions have caused serious accidents, including mining disasters. Engineers work hard to prevent accidental releases of natural gas to keep people safe.