The implication is that there’s liquid water right under the surface if Europa. That would be fairly exciting if confirmed. Im not sure theres a single place on earth with water but not without life.
The interesting question is that since water is such a fantastic medium for earth-based life, how can we make sure that any probe sent from here to say, sample the water on Europa won't contaminate it. It's my understanding that even though all planetary landers are sanitized it's almost impossible to make sure no life survives on them. Which I guess isn't too much of an issue on the moon or Mars, but any microbes would have much better chances of surviving in the water environment of Europa.
Makes me wonder if even a probe never landing would 'shed' some biological material that eventually makes its way onto the surface.
Then again, there's plenty of theories that asteroids and other impacts have caused enough of a splash to throw trace life bearing materials into space and eventually onto other planets or moons.
My current theory is that we will find traces of e.g. bacteria all over our solar system, but it'll be genetically traceable back to Earth. That said, if it turns out life as we know actually started on e.g. Mars, that would be huge and probably a big accelerator for more missions there.
It seems more likely that the opposite would happen. Life that has evolved on Mars would probably be better suited to Mars than life that evolved on Earth.
That depends on the nutrients available. Water is one necessity for terran life, but you also need some building material and a source of energy.
And obviously absence of anything toxic. In short lot of things need to align.
Now, even if there are conditions favorable for our bacteria, the question of competition remains. Hypothetically, the invaders can carve niche in local ecology, as they often do on Earth, or they might utterly fail, as happens even more often on Earth.
If there are organisms on Europa already, and that is a big 'if', they would have several billions of years worth of head start adapting to the environment and molding it to their image. Conversely, newly introduced bacteria, already damaged by exposure to deep space and deprived of nutrients for many months or years, would see it for the first time.
It isn't given that this experience would work out for them, to say at least.
Not optimistic about the possibility of life in Europe. Tenuous atmosphere so little protection from the Sun. Also radiation is maybe too strong. Europa receives around 600 rem of radiation per day.
It's so much radiation it shines:
"Europa Glows: Radiation Does a Bright Number on Jupiter's Moon"
> Not optimistic about the possibility of life in Europe.
Is that a typo or a comment on the current political situation?
Anyway, a couple of meters of water would block all radiation, and the energy source would be tidal forces from Jupyter, not the Sun (which is what would also keep the core warm enough for liquid water. Also why Io has intense volcanic activity).
Obviously not on the surface in the vacuum and frozen ice but down in the liquid interior you're protected from the radiation by all those kilometres of water. On Earth we had kemosynthetic life for hundreds of millions of years before photosynthesis was evolved so the lack of sunlight isn't a problem, provided Europa has undersea vents or the equivalent. Scientists seem to think it has some volcanism down there but of course More Research Is Needed.
I'll continue to believe that this is bioluminescence.
How well does water shield radiation like this? For much of it (electrons, UV photons) a thin film on the surface could be enough protection. A layer of salty ice should be more than sufficient, I would think.
Water shields extremely well. I don't think we'll find living things on the surface, but the oceans are what is exciting, especially possibly hydrothermal vents, which have lots of life on Earth. A surface mission would be looking for signs of life, not life.
All that ice and water is what would protect life, not an atmosphere. Europe has huge warm water oceans, in some estimates more water than Earth. It may have hydrothermal vents from tidal heating, providing everything required for life. Or so the story goes.
Both Europa and Titan are technically ocean worlds, but the likelihood of Titan containing life is much lower I think, given it is so cold that methane is the main surface liquid.
Its such an unbelievable sad topic. Especially since its quite clear that nobody will be stopped by this consideration. Just think of the drilling into the ocean below the Antarctic ice. Contamination is carelessly accepted by opportunistic bureaucrats.
Light is not needed. Life on Earth got along fine without photosynthesis for hundreds of millions of years, and the hypothesis that life first appeared on Earth on the seafloor around thermal vents is quite plausible, even if we might never know for sure.
Yes, although I think it's still debated whether there actually were any "total snowball" events or whether even the most severe ones still had open ocean near the equator.
I'm not quite sure that I had this original thought myself or read it somewhere but an alternate definition of life is the ability of membranes to hold water. One of the first things to happen upon decomposing is the organism can't hold water anymore. I find it an interesting criteria that for example classifies virii as non living.
"Biologists have known since the 1930s the lake is "not dead yet". Instead, it's full of microbes that get along quite happily in the salty soup, for it keeps out competitors that would take over in a more hospital aqueous environment. In general, the water contains 1,000 to 10,000 archaea* per ml, a much lower concentration of life than in seawater, but quite respectable, all in all, for a place where one molecule in three is not water. Occasionally, when conditions are right, the sea blooms red with life. This happened in 1980 and 1992."
