Lifeforms or not lifeforms that's the question.

   

Lifeforms or not lifeforms that's the question. 

Phosphine and life signatures are quite different things than an intelligent alien with spacecraft and well-detected cities. That means there can be lifeforms on some ocean planets. But those lifeforms cannot ever communicate with us. The thing is this: The exoplanet K2-18b is the most promising target for life hunters, but that planet is about 124 ly. from Earth. 

That means. We cannot ever be sure if there is some kind of plankton that exists in that planet's oceans. For confirming that thing. We should travel to exoplanet K2-18b. That planet's atmosphere might be hostile to lifeforms. And the only place where those primitive, maybe procaryotic organisms can exist is the ocean. 

So what does that mean? We cannot confirm the possible life forms at least in the distant worlds. There are suspicions about lifeforms also on some moons in our solar system. The fact is that those lifeforms that can exist in Europa, Triton, and Enceladus or hover in gas giants atmosphere might have a very slow metabolism. 

Astronomer Carl Sagan introduced an idea about hovering medusas on Jupiter and Saturn. And probably Neptune and Uranus's atmosphere. The idea of the lifeforms in the icy moon's ocean is based on the idea that the low gravity and low pressure allow the ocean to stay liquid in low temperatures. If there are some organisms their metabolism will be very slow. Those organisms might use even years to travel meters. Those creatures can be the ice crystals that the DNA controls. Those lifeforms can exist at very low temperatures. 

When we think about things like lifeforms in Venus we must remember that Venus is far from Earth. Its atmosphere is carbon dioxide or monoxide. If you jump out from an airplane at Venus you will not fall as on Earth. You will burn when you are too close to Venus's surface where the temperature is about 600C. 

A dense atmosphere slows speed differently than Earth's atmosphere. Venus's atmosphere is flatter than Earth's. Venus's mountains like Maxwell Montes are not very friendly places for lifeforms. The temperature in those mountains is about 380C. 

The bacteria-type lifeforms can hover at the higher level of Venus's atmosphere above its clouds. There the temperature is much lower than on Venus's surface. 

Sometimes there have been plans to make some stations in the Maxwell Montes area. There the pressure and temperature are more comfortable than on Venus's lowlands. But if we find bacteria from Venus's atmosphere there is the possibility that those bacteria traveled from Earth to that planet hiding in the probes that were not properly sterilized. Another thing is that in some cases phosphine can be the remnant of the bacteria that might died when some probe like Venera hit Venus's atmosphere. 

If those probes were not sterilized they could leave the trail of the living bacteria behind them. And if those bacteria died in the space journey their remnants could leave phosphine signs in Venus's atmosphere. But for making good decisions researchers require those organisms. 

And 600C can destroy any bacteria remnants in that planet's atmosphere. It destroys the DNA that there is no evidence of the bacteria especially if they traveled from Earth.  So maybe the only thing that we can find on Venus is phosphine. That phosphine can form in cells that can be gone or turned into ash a long time ago. 

https://www.universetoday.com/articles/fresh-findings-fuel-debate-about-life-on-alien-world

https://www.space.com/venus-clouds-phosphine-evidence-debate