Scientists draw on experimental results to answer important scientific questions. When an extraordinary claim happens, the scientist answered experimental questions with seemingly, incredible answers: potential Martian fossils.
Meteorite ALH84001, discovered in Antarctica in 1984 by NASA scientists, was ejected from Mars about 15 million years ago by an asteroid or meteor strike. According to scientists, ALH84001 was orbiting in our solar system space during most of that time. Surprisingly, the meteor fell to Antarctica only 13,000 years ago.
Seemingly, Martian microfossils were found in Meteorite ALH84001 in 1996. While the claim by NASA scientists of microfossils is not completely correct – evidence was presented by the scientists that lent credence to a potential find of past life. Eventually, the claim was fomented by public opinion and even the president Clinton White House commented on the find.
We need to first define microfossil?
What are Microfossils?
The Merriam Webster Dictionary of the English language defines microfossil:
Noun, A small fossil that typically can be studied only microscopically and that may be either a fragment of a larger organism or an entire minute organism
While many of us have seen a fossil, we rarely ask ourselves what about microfossils?
An Extraordinary Claim?
Meteorite ALH84001, analyzed thoroughly by NASA scientists in 1996 – seemed to contain micro-fossils within the rock. The shapes-contained in and chemical analysis within the rock resembled past life forms, according to NASA scientists.
The evidence for potential past life was the following:
(1) The shapes of Martian fossils resembled earthen micro-fossils – namely cyanobacteria.
(2) The Martian fossils encapsulated trace amounts of Polycyclic Aromatic Hydrocarbons.
(3) The so-called fossils possessed magnetic properties – much like earthen Magnetites.
(4) All important chemical components from the fossil contained chemicals from Mars only- no cross contamination from Antarctica
According to NASA scientists, Mars was inhospitable to life in 1996. In essence, the claim of fossilized lifeforms was extraordinary. If Mars harbored life, scientists believed the planet must have, at one time, resembled the Earth. Mars, in 1996, appeared dry and inhospitable — and without liquid water or breathable air.
While having liquid water is a major prerequisite for life, Mars’ past remained mysterious.
However, let’s look at the incident.
What are the Chemical Components Behind Martian Fossils?
Earthly fossilization processes occur as minerals from the soil seep through the membranes of the dead organism. That process is permineralization. Martian permineralization processes are unknown.
In a 2012 publication from NASA, the scientists drew the following conclusions-
- The purported fossils were calcium carbonate encapsulations of Martian geology- its formation may be either biological or a strictly inorganic process.
- Within the encapsulations are trace amounts or polycyclic aromatic hydrocarbons, Martian minerals containing iron, silicon, sulfur, and more carbonate.
- The chemistry of formation is typical to both Earth and Mars- however its real origins are in doubt.
- There is no evidence for Martian cyanobacteria.
- Water needed to be present for the formation of the Martian ‘fossils.’ Water is present on Mars today and was in the distant past.
- Humans or robotic missions must retrieve Martian soil and rocks — regiolith.
What Can We Say About Mars?
One can look at photographs of Mars from current NASA missions – one gets the sense of a desolate planet that once had water flowing in certain areas. The Martian geology also shows signs of water levels that receded over long periods of time and a lot of sand in other areas, as well. However, we see no signs of past life- no bones or macro-fossils in any area.
In a 2018 publication by NASA scientists, we note that if there was ever life on the planet, we need to dig and extract Martian rocks from below. NASA scientists cite the extreme ultraviolet radiation from the sun and cosmic rays from universe that penetrate the Martian soil (up to the first 9 feet, at least).
That is an answer to why we don’t see Martian life – life that we do not recognize or understand. Life based upon DNA.
Ordinary Science To Prove or Disprove Extraordinary Claims?
The statement, “extraordinary claims require extraordinary evidence” was stated by Carl Sagan in his landmark series, Cosmos- A Personal Voyage. The statement needs to be restated – presently, scientists cannot prove or disprove whether Mars has life. A flat statement of life on a distant planet is an unproven claim -thus ordinary experimentation that can take up to several decades to prove or disprove the claim.
The passage of time renders an experiment extraordinary or unsolved. However, recent experimentation on similar meteorites point at the life’s signatures in chondrite meteors. Chondrite meteors bear primarily carbon-bearing molecules– ones similar to ALH84001.
ADDITIONAL READING & REFERENCES:
J. WILLIAM SCHOPF, et. al. Astrobiology. 2005. Raman Imagery: A New Approach to Assess the Geochemical Maturity and Biogenicity of Permineralized Precambrian Fossils.
FIONA L. PLOWS, et. al. Geophysica et Cosmochimica Acta. 2003. Evidence That Polycyclic Aromatic Hydrocarbons in Two Carbonaceous Chondrites Predate Parent-Body Formation.
MONICA M. GRADY, et. al. Astronomy and Geophysics. 1997, Microfossils from Mars: A Question of Faith.
MIKHAIL Y. ZOLOTOV and MIKHAIL V. MIRONENKO. Journal of Geophysical Research. 2007, Timing of Acid Weathering on Mars: A Kinetic-Thermodynamic Assessment.
THOMAS STEPHAN, et. al. Meteoritics and Planetary Science. 2003, TOF-SIMS Analysis of Polycyclic Aromatic Hydrocarbons in Allan Hills 84001.
K.L. THOMAS-KEPRTA, et .al. Geochimica et Cosmochimica Acta. 2009, Origins of Magnetite Nanocrystals in Martian Meteorite ALH84001.
JACEK WIERZCHOS and CARMEN ASCASO. International Journal of Astrobiology. 2002, Microbial Fossil Record of Rocks from the Ross Desert, Antarctica: Implications in the Search for Past Life on Mars.
JOHN W. MOREAU and THOMAS G. SHARP. Astrobiology. 2004, A Transmission Electron Microscopy Study of Silica and Kerogen Biosignatures in 1.9 Ga Gunflint Microfossils.
A. STEELE, et. al. Science. 2012, A Reduced Organic Carbon Component in Martian Basalts.
CHRISTOPHER R. WEBSTER, et. al. Science. 2018, Background Levels of Methane in Mars’ Atmosphere Show Strong Seasonal Variations.
PAUL VOOSEN. Science. 2018, Nasa Curiosity Hits Organic Paydirt on Mars.