Astronomers have come a long way since the hunt for signs of life on Mars began decades ago.
From detecting liquid water to testing fungi on Mars-like conditions, the pieces of this vast Martian puzzle have yet to be completed.
Now, photos showing strange cauliflower-shaped structures on the red planet may or may not be the clue that scientists are waiting for.
The Key To Finding Life On Mars
Around eight years ago, NASA's Spirit rover found deposits of opaline silica inside the Gusev crater on Mars.
The news is remarkable only because the silica's shape and outer layers are strange: the outer layers reveal tiny nodules similar to the heads of cauliflowers, seemingly sprouting from the red soil.
Scientists are uncertain how the strange shapes, aptly called micro-digitate silica portrustions, formed. The Spirit rover detected the silica protrusions near the "Home Plate" region of Mars' Gusev crater. Geologists believe that geysers or hot springs may have once scorched the surface of the red planet in this area.
Previous studies conducted by Arizona State University astronomers Jack Farmer and Steven Ruff in the Chilean desert suggest that the silica might have been created by microbes. Incidentally, some researchers claim that the Chilean desert resembles the type of soil found in Mars.
At the American Geophysical meeting in December last year, the pair of Arizona State U astronomers presented the case that the silica hypothesis is our best shot for identifying evidence of past life on the red planet.
If this is indeed true, the Martian cauliflower structures could become the biggest discovery ever made in astronomy.
Proving The Biology Of Opaline Silica
Another evidence that could support the hypothesis is the fact that experts have previously found cauliflower-like structures in Wyoming and New Zealand, both also linked to microbes.
Unfortunately, the biology of the Martian silica is difficult to prove because the object is millions of miles away from Earth.
Kurt Konhauser, Geobiology journal editor-in-chief, doesn't think there is any way to test where Martian microbes may be found using modern Earth instruments.
"Having worked on modern hot springs, I have seen all forms of structures that look biological but are not," said Konhauser. "Because it looks biological doesn't mean it is."
Farmer and Ruff aren't concluding their hypothesis yet. What they're saying is that perhaps these growths are mineral greetings from ancient aliens and that investigation must be done.
Although the Spirit rover has stopped roaming around Mars, NASA said a new rover called Mars 2020 is expected to launch to the red planet in the coming years to gather samples and eventually return them to Earth.
Meanwhile, Farmer and Ruff will continue their Mars studies here on Earth. The two will investigate the landscape at El Tatio in the Atacama Desert, another terrain which they say resembles early Mars, in order to find whether organisms are linked to the formation of silica.
Since the silica found in Wyoming and New Zealand was sculpted by microbes, it was possible that this was the case at El Tatio. If the results of the duo's studies are positive, then the chain of their logic-loop will become smaller, bringing us one step closer to unraveling the Martian puzzle.