Life found in methane ice! In the abundant ice that burns found on the bottom of the Joetsu Basin in the Japan Sea, scientists have discovered life. Finding microbial life in the methane hydrates on earth increases the odds of life being found on other planets. In this True Strange News article, we look at why methane may or may not be a sign that extraterrestrial life exists, depending on the conditions of the planet or moon on which it is detected. We will also review the creation of stars and touch on how all the different atoms in the universe can come from hydrogen.
Life and Methane
Up to 95% of the 1,750 parts per billion by volume (ppbv) of methane in Earth’s atmosphere are of biological in origin, but methane (CH4) doesn’t always originate from life forms. It is abundant on the giant planets in our solar system, for example and the methane on Jupiter, Saturn, Uranus and Neptune all result from primordial solar nebula material. (Source)
Why couldn’t the methane on Earth come from that same source when our solar system first formed? The answer is heat.
At the high temperatures of the inner solar nebula the small proto-planets (Mercury, Venus, Earth, Mars) were too hot to hold the volatile gases that dominated the solar nebula. Only refractory (high melting point) materials like iron and rocky silicates were stable. Consequently, the terrestrial planets are made primarily of metallic cores and silicate mantles with atmospheres thin or absent. In the outer solar nebula temperatures were cool enough for the abundant gases to accumulate and be held by proto-planets. As a result the Jovian planets (Jupiter, Saturn, Uranus, and Neptune) are gas giants, made mostly from hydrogen, helium, and hydrogen compounds like methane (CH4) and ammonia (NH3). (Source)
This is one reason the methane in natural gas on earth is thought to be of mostly organic origin.
When natural gas methane combines with water and freezes where the temperature is low enough and the pressure is high enough, you get combustible ice. It can be found all over our planet.
This ice is being studied as an energy source. It is also a potential source of fresh drinkable water (but watch out for, potentially, bacteria and viruses that will “revive” after millions of years.)
Bacteria, life found in methane ice, were found feeding off oil impurities in samples from the Japan Sea. The microbes were helping to build their own home by producing oxidized carbon, a key component of the spheroidal microdolomite aggregates where they live.
The following image shows a high-intensity light source microscope picture of a spheroidal microdolomite found in methane ice.
Bacteroidetes sp. are concentrated on the inner rims of microdolomite grains, where they degrade complex petroleum-macromolecules present as an impurity within yellow methane hydrate. … microdolomites within the gas hydrates in the Joetsu Basin, Japan Sea, can grow by mineralising petrogenic carbon within isolated microhabitats provided by the methane hydrate. This microhabitat is unique in that the carbon is being taken from otherwise recalcitrant phases of carbon present within petroleum, and not via processes found outside the microhabitat such as sulphate reduction or anaerobic oxidation of methane. (Nature)
Methane, Sometimes A Fingerprint of Life
Will the methane on Mars and Saturn’s moon Titan (detected by astronomers as early as 1944), or Saturn’s moon Enceladus (fresh ice and methane) , turn out to have a biological origin, as on Earth?
Do Volcanoes Emit Methane?
A bit, but not much. Volcanoes do not emit much methane. On earth, they are not a significant methane source. A science direct article says that methane concentration in volcanic gases is generally in the order of a few tens of ppmv. (Source) Methane produces a blue flame when it is burning and there are cases of blue flames around volcanoes, but in the case of a Hawaii volcano, this was said to be from buried vegetation. In the case of electric blue flames from a volcano in Indonesia, the cause was said to be burning sulfur.
Methane from Space Dust and Meteorites
While the rocky planets didn’t get methane when they formed, there is another source possible, to explain methane on them without life. Mars gets a lot more UV radiation than the earth due to its lack of a protective ozone layer. On Mars, one theory says that high-energy UV radiation causes methane to be released from “innumerable, small micro-meteorites and interplanetary dust particles that land on the Martian surface from space,” and not from Martian life forms. On the other hand, the 2,000 tons of micrometeoritic dust are estimated to reach the Martian surface every year plus methane meteorites was estimated to provide less than 1 percent of the detected amount of methane on Mars.
Life that Makes Methane
On earth, we know that methanogenic archaea (methanogens)–single-celled microorganisms similar to bacteria that live in environments with low oxygen levels–produce methane as a by-product of their metabolism. They are “extremely widespread on Earth.” Methanogenesis is the final step in the break down of organic matter. Methanogens do not use oxygen. In fact, oxygen inhibits their growth.
On 13 April 2017, NASA confirmed that the dive of the Cassini orbiter spacecraft on 28 October 2015 discovered the Enceladus plume which has all the ingredients for methanogenesis-based life forms to feed from.
Natural gas, a clean burning fossil fuel, supplies roughly half of the energy consumed in the USA and by composition it is mostly methane.
Could Life that Makes Methane Survive on Mars?
Mars has a very low surface pressure of just 7 mbar and even at the top of Mount Everest on earth, the pressure is 300 mbar, so any methanogenic lifeforms would need to survive in low pressure. Under simulated low pressure Martian conditions, it was discovered that methanogenic life can indeed exist. This increases the chances of life on Mars. It also means that if the red planet turns out to be sterile, it would be relatively easy for us to terraform, starting by planting methanogenic life. (Source)
Snowball Earth and Methane
On at least three occasions our planet was completely covered with ice. While the sun would have to be 1.5 times brighter than it is to melt a snowball earth, the CO2 emitted by volcanoes built up in the atmosphere and eventually did the job. This theory fits the geological evidence better than a competing theory that large amounts of methane, which is a strong greenhouse gas, bubbled up through ocean sediments from beneath the permafrost ice cover to heat the atmosphere.
The lifetime of atmospheric methane is relatively short; most of it dissipates after about a decade. But while it sticks around, methane is more than 80 times as effective at trapping heat than carbon dioxide, which has a lower capacity for heat storage but can linger in earth’s atmosphere for hundreds of years. (Source)
Methane… is much less dense than air, and rises to the upper atmosphere quite readily. There it usually heats up and decays to carbon dioxide and water (Chemistry teacher)
This is relevant to finding life on other planets. If methane naturally floats up from a planet or moon’s surface and gets broken by UV light there (photolysis) and dissipates after about a decade without being replenished, persistent methane on a non-gas giant could indicate life on another planet.
Why is There Methane on Gas Giants?
Does life found in methane ice on earth mean there could be life generating the methane on large planets in our solar system? Why do the gas giants in our solar system retain primordial methane? In the graph below, you can see that if the gravity is strong enough and temperature low enough, the escape velocity is then high enough to hold the methane gas so it doesn’t float up, disperse and get broken by UV light. This graph also shows why Uranus and Neptune are blue from a higher percentage of methane than Saturn and Jupiter.
Where does the Carbon Come From?
Carbon is an atom with six protons in the nucleus and six electrons orbiting it. Methane is hydrogen and carbon. We know that stars contain hydrogen and this element is estimated to make up 75% of the universe. Here is a chart of the abundance of elements showing carbon is estimated to be the fourth most abundant element after Hydrogen, Helium and Oxygen in the Milky Way, our current galaxy.
If you have enough helium, you can make carbon. Once the star produces enough helium, carbon can be made through the triple-alpha process. In this process nuclear fusion reactions convert helium-4 nuclei (alpha particles) into carbon.
How do you get enough helium made? It all starts with hydrogen. When there is enough hydrogen drawn together in space by gravity, it reaches a critical threshold (about 8% our Sun’s mass) then it ignites nuclear fusion, forming a new star.
Stars burn and convert hydrogen to helium. Interestingly, if we look in more detail, we see that “hydrogen-fusing-into-helium makes up less than half of all nuclear reactions in our Sun and that it’s also responsible for less than half of the energy that the Sun eventually outputs.” Most energy, by percentage, comes from reactions where hydrogen is converted into other forms of hydrogen, and helium into other forms of helium. (Helium-3/helium-3 fusion into helium-4 = 39.3% of the Sun’s total energy, for example)
It’s strange and amazing to consider that the simplest atom, hydrogen, the simplest and most abundant element in the universe, when given the right conditions and time, results in a cascade of more and more complex elements and the reactions of those elements, under the right conditions, develop into things like a diamond planet (or not), and self-organizing systems due to various atomic and other forces. Eventually, you get amino acids, RNA, DNA, proteins, lipids, the building blocks of life as we know it, and life found in methane ice … by humans.
So here we are. Life forms, looking for other life forms out there, somewhere. If the same rules exist throughout the universe, rules that caused the elements to form and resulting molecules that enabled life to exist on earth, the odds seem good that we are not alone.
The bottom line
Life found in methane ice on earth means that we don’t need to search only for planets with oxygen atmospheres in our quest. Methane, where it is not explained by release from space dust, meteorites, comets or by cold gas giants retaining it from the early solar system formation, may be a sign of methanogenic lifeforms.