The discovery that life can exist and even flourish in environments devoid of sunlight has long been a topic of fascination for scientists. A recent study published in Science Advances by Chinese researchers has shed new light on this phenomenon, revealing how microbes in deep subsurface areas derive energy from chemical reactions driven by crustal faulting. This groundbreaking research challenges the conventional wisdom that “all life depends on sunlight” and offers critical insights into the existence of life deep below Earth’s surface.

Led by Professors Hongping He and Jianxi Zhu from the Guangzhou Institute of Geochemistry, a team of researchers simulated crustal faulting activities to understand how free radicals produced during rock fracturing can decompose water, generating hydrogen and oxidants like hydrogen peroxide. These substances create a distinct redox gradient within fracture systems, which can further react with iron in groundwater and rocks – oxidizing ferrous iron (Fe²⁺) to ferric iron (Fe³⁺) or reducing ferric iron (Fe³⁺) to ferrous iron (Fe²⁺), depending on local redox conditions.

In microbe-rich fractures, the researchers found that hydrogen production driven by earthquake-related faulting was up to 100,000 times greater than that from other known pathways, such as serpentinization and radiolysis. This process effectively drives iron’s redox cycle, influencing geochemical processes of elements like carbon, nitrogen, and sulfur – sustaining microbial metabolism in the deep biosphere.

This study has far-reaching implications for our understanding of life on Earth and beyond. Professors He and Zhu note that fracture systems on other Earth-like planets could potentially provide habitable conditions for extraterrestrial life, offering a new avenue for the search for life beyond Earth. The research was financially supported by various sources, including the National Science Fund for Distinguished Young Scholars and the Strategic Priority Research Program of CAS.

In conclusion, this groundbreaking study has challenged our understanding of life’s dependence on sunlight and revealed a previously unknown source of energy for microbes in deep subsurface areas. As we continue to explore the mysteries of the deep biosphere, we may uncover even more secrets that will rewrite the textbooks on life on Earth and beyond.

The story of a star that survived its own supernova explosion is one of cosmic resilience. Located within the Milky Way galaxy, this remarkable star shone even brighter after being struck by a massive explosion in 2012. Its journey to becoming a supernova survivor began thousands of years ago, and it has captivated scientists ever since.

The spiral galaxy NGC 1309, situated about 100 million light-years away in the constellation Eridanus, is home to this incredible star. In stunning images captured by the NASA/ESA Hubble Space Telescope, the galaxy reveals its intricate details: bluish stars, dark brown gas clouds, and a pearly white center. The image also showcases hundreds of distant background galaxies, each one a cosmic wonder in its own right.

The remarkable story of this supernova survivor begins with two significant events: SN 2002fk in 2002 and SN 2012Z in 2012. While the first event was a perfect example of a Type Ia supernova, which occurs when the core of a dead star (a white dwarf) explodes, the second event was different – it was classified as a Type Iax supernova.

Unlike its Type Ia counterpart, SN 2012Z did not completely destroy the white dwarf, leaving behind a ‘zombie star’ that shone even brighter than before. This phenomenon has never been observed before, and scientists have used Hubble observations to study this extraordinary event in detail.

In fact, these observations also made it possible to identify the white dwarf progenitor of a supernova for the first time ever, providing valuable insights into the cosmic processes that shape our universe. The story of this star’s survival is a testament to the awe-inspiring power and complexity of the cosmos.

The universe’s history is divided into distinct periods. The Big Bang marked the beginning of the universe around 13.8 billion years ago. Initially, temperatures were incredibly high and densities were unimaginable. However, just a few seconds later, the universe had cooled down enough for the first elements to form, primarily hydrogen and helium. These elements remained completely ionized at this point, as it took nearly 380,000 years for temperatures in the universe to drop enough for neutral atoms to form through recombination with free electrons.

The oldest molecule in existence is the helium hydride ion (HeH+), formed from a neutral helium atom and an ionized hydrogen nucleus. This marks the beginning of a chain reaction that leads to the formation of molecular hydrogen (H2), which is by far the most common molecule in the universe.

Recombination was followed by the ‘dark age’ of cosmology, where the universe became transparent due to bound electrons but lacked light-emitting objects like stars. Several hundred million years passed before the first stars formed. However, simple molecules such as HeH⁺ and H2 were crucial for star formation during this early phase.

In order for a gas cloud in a protostar to collapse to the point where nuclear fusion can begin, heat must be dissipated. This occurs through collisions that excite atoms and molecules, which then emit energy in the form of photons. At temperatures below around 10,000 degrees Celsius, however, this process becomes ineffective for dominant hydrogen atoms.

Further cooling can only take place via molecules that can emit additional energy through rotation and vibration. Due to its pronounced dipole moment, the HeH⁺ ion is particularly effective at these low temperatures and has long been considered a potentially important candidate for cooling in the early universe.

During this period, collisions with free hydrogen atoms were a major degradation pathway for HeH⁺, forming a neutral helium atom and an H2⁺ ion. These subsequently reacted with another H atom to form a neutral H2 molecule and a proton, leading to the formation of molecular hydrogen.

Researchers at the Max-Planck-Institut für Kernphysik (MPIK) in Heidelberg have now successfully recreated this reaction under conditions similar to those in the early universe for the first time. They investigated the reaction of HeH⁺ with deuterium, an isotope of hydrogen containing an additional neutron in the atomic nucleus alongside a proton.

The experiment was carried out at the Cryogenic Storage Ring (CSR) at the MPIK in Heidelberg—a globally unique instrument for investigating molecular and atomic reactions under space-like conditions. For this purpose, HeH⁺ ions were stored in the 35-metre-diameter ion storage ring for up to 60 seconds at a few kelvins (-267 °C), and were superimposed with a beam of neutral deuterium atoms.

By adjusting the relative speeds of the two particle beams, the scientists were able to study how the collision rate varies with collision energy, which is directly related to temperature. They found that the rate at which this reaction proceeds does not slow down with decreasing temperature but remains almost constant.

“This result brings us closer to solving the mystery of star formation,” explains Dr Holger Kreckel from the MPIK. “The reactions of HeH⁺ with neutral hydrogen and deuterium therefore appear to have been far more important for chemistry in the early universe than previously assumed.”

This observation is consistent with the findings of a group of theoretical physicists led by Yohann Scribano, who identified an error in the calculation of the potential surface used in all previous calculations for this reaction. The new calculations using the improved potential surface now align closely with the CSR experiment.

Since the concentrations of molecules such as HeH⁺ and molecular hydrogen (H2 or HD) played an important role in the formation of the first stars, this result brings us closer to solving the mystery of their formation.