The search for alien intelligences continues and though we have not found any alien civilizations yet, the search continues. The ability of life to exist in harsh climates is astounding, there are fish on this planet that live in sulfuric acid, and the lifeforms that exist around black smokers on the sea floor in water near the melting point of lead. So the possibility is there that there could be lifeforms on other planets that can exist in extremely harsh environments that we could not stand. it has been theorized that the atmosphere of Venus could harbor life that floats in the sulfuric acid clouds, that is not impossible, more likely than life existing on the surface with crushing pressures and an oven like climate. Even a Neutron star with a surface gravity of 1000,000,000,000 times Earth`s gravitational pull could theoretically have lifeforms that exist on the surface. They would be microscopic beings, but the possibility is there that they could exist. This is a mind-blowing possibility and something that we should investigate in the future. The novel by Steven Baxter, Flux deals with the possibility of such lifeforms on a Neutron star, although this form of life in the story was seeded on the planet by humans. The novel Dragon’s Egg by Robert L. Forward that detailed a race of beings the size of sesame seeds that evolved on the Neutron star.
This is possible, the amount of energy present on such a stellar body is such that some form of energy could create an intelligent creature, of obviously extremely small size. They would not be able to survive unless they were in the massive gravity, so they would not be able to travel to other planets. This forum thread: Life on a neutron star, covers this possibility, but this sort of life is not the sort of thing that we could see up close and personal for obvious reasons. But conventional planets could easily have some form of alien life that we could study in the future. This paper tells the story of the fish that are living in an extremely acidic lake happily. This means that if an alien planet had an ocean of acid, it could still have life adapted to the conditions. A black smoker is a hydrothermal vent on the ocean floor with lifeforms clustered around the hot water that can be up to 464 degrees Celsius, hot enough to melt lead, yet the lifeforms growing on the smoker stack are able to withstand the temperature of the water. This picture is an example of the lifeforms that cluster around the vents for warmth and the nutrients that are expelled from the bowels of the Earth. This picture shows a typical black smoker stack. This is the type of life that could exist on the Jovian moon Europa, this is a moon composed of floating ice about 5 miles thick that could have a massive ocean underneath the ice.
This is why there are plans to send a space probe to the moon that will release a machine that will melt it`s way through the ice and then release a submarine that will explore the ocean under the ice and send back information about the conditions under the thick covering of ice. Any lifeforms that exist on Europa would never see the Sun or the massive bulk of Jupiter hovering above, only the diffused light coming down through the thick ice. On Space.com, there is an article exploring this possibility, with nice diagrams of the moon. Humans would not be able to visit the surface of Europa due to the massive amounts of radiation, but an unmanned probe would be able to manage the landing and exploration easily. The cracks in the surface of the ice are full of what looks like dirt and possibly organic matter, although more complex life would not survive due to to the magnetosphere of Jupiter. The Mars Opportunity rover has snapped a picture of the surface of Mars showing the desert like conditions present on our next door neighbor. http://www.space.com/16446-mars-panorama-picture-opportunity-rover.html. This picture makes the surface look perfectly liveable, but it is actually quite inhospitable considering that the atmosphere is as thick as our atmosphere at 100,000 feet altitude.
This does not detract from the experience of seeing the surface of another planet that is a more realistic candidate for settlement than Venus.