I love it when a theory considered by to be a little crazy turns out to be true, couldn't help but share this one.
Paper summarizing Golds theory (He also has a book that explains the theory in depth)
Summary of the paper -
I became familiar with Thomas Gold through during my study of steady-state cosmology theory. Gold graduated from Cambridge and later would be a head professor at Harvard and Cornell. He spent the early part of his career working on MASER during which his focus was on microwave emissions and radiophysics. In the later part of his career his focus became planetology.
His theory of the deep hot biosphere was developed in the 80’s in which he predicted the existence of a massive underground biosphere full of microbes living off the thermal energy of chemical processes in the crust – as materials percolate up and other materials percolate down energy disequilibrium’s occur leading to chemical reactions upon contact.
The possibility of this biosphere was implicated by the discovery of live surrounding thermal vents at the bottom of the ocean, such vents and lifeforms being discovered 12 years prior to the development of Golds theory. Since it was discovered that life didn’t need sunlight but instead could sustain itself off thermal energy created by the earth the question of how deep this rabbit hole goes naturally arises. Such thermal energy and stable systems exist not only around vents at the bottom of the ocean but also underground in the earth’s crust. As such, could such life exist there as well? Gold consider this depth limit of this biosphere to be 5 to 10 km down given no observed microbial can survive at a heat greater than 150 degrees Celsius. At such depth’s microbes would exist in stable systems of rock containing methane, hydrogen, and other fluids. Such rock systems have stable pressures and temperatures, as such they provide perfect ecosystems for such microbes to exist.
During Golds development of the theory he of coursed looked for evidence that alluded to the existence of such a biosphere. One interesting idea he had was that the high concentration of certain mineral deposits found in the earth could be byproducts of microbes. These deposits had confused planetologists and geologists a like because their existence implied a constant large lowering of the local entropy where they were found, and no such chemical processes or energy sources known could cause such things with such consistency. Golds pondered the possibility of microbes being responsible for the phenomena because it is a characteristic of biology to cause decreases in local entropy. Another, even more radical, idea was that oil and natural gas deposits too are byproducts of the biosphere. Not only do you have the problem of entropy when it comes to such deposits, but you also have a problem of depth. For biodegradation to be the cause of these deposits, a large amount of oxygen must be present, and the availability of the amount needed does not exist at the depths in which these deposits develop. Couple this fact with the constant observation of microbials present in oil after its extracted and Gold has a case.
Interesting enough the existence of this biosphere has since been confirmed by scientists and just as Golds predicted its depth seems to go just past 5km. Scientists think that 70% of all microbes that exist live in this underground ecosystem but 99.9% of those microbes and their functions are unknown. This leads us to a set of natural questions that Gold himself asked. What role do these microbes play in the chemical composition and development of the earth? How do such chemical processes effect internal and external systems such as the atmosphere? Does microbial life exist everywhere it can exist? Do such biospheres exist on other planets and worlds in our solar system?
Wiki reference for current science surrounding the underground biosphere
Video explaining what is known and unknown about the biosphere -
