Hey guys! I was wondering what you guys think about this.
So, I was researching the chemical composition of Europa and I had an interesting thought. We clearly see reddish-brown staining on and around the cracks in Europa’s surface. This indicates that the staining must be endogenous as it isn't found anywhere else on the surface. There is so far no consensus as to what the staining may be. The chemical composition of the stained ice seems to be water ice bound to some other material. Salts like magnesium sulfate match spectral analysis (sulfuric acid hydrate has also been suggested), but these are either white are colorless, so some other material must be present in addition to the sulfate. For example, Enceladus also has ice, cracks, and salts, but no red staining.
I have a hypothesis. We have a place here on Earth that is, chemically, very similar to Europa. That place is Blood Falls at Taylor Glacier in Antarctica. You see, Blood Falls has sulfate and sulfur compounds just like Europa. It also has red staining like Europa. But the red staining is due to the iron content of the brine. Iron is scraped up from the bedrock by the glacier and is infused in the water. When the water comes into contact with the oxygen in the air, the iron oxidizes and gives the water a red color.
Europa has a rocky interior under its ocean. If that interior contains iron, then I assume we can expect the water to contain iron from being in contact with Europa’s interior for billions of years. If that is indeed the case, when the water is exposed to Europa’s oxygen atmosphere through the cracks, it can oxidize and give a red color, just like at Blood Falls.
Furthermore, I considered the microbial life present at Blood Falls. I looked into what potential chemical signatures there are that might indicate that there is in fact life there without having to observe the microbes directly. It turns out the microbes survive by a process that turns sulfate ions into sulfite ions. The sulfite ions then react with the ferric ions that is scraped from the rock by the glacier turning the sulfite back into sulfate and the ferric ions into ferrous ions. Therefore, it may be possible to detect the microbes' presence by identifying the presence of sulfite ions and ferrous ions.
Given the similarities between Blood Falls and Europa, this could be a possible test for the presence of life on Europa. It may be possible to detect these chemical signatures spectroscopically, allowing us to possibly detect an indication of the presence of life without having to land something on Europa.
So what do you guys think about this possible explanation for the red staining on Europa and a possible test for the presence of life on Europa?
