14 DAY TRIAL // Though many experts argue that carbon-based lifeforms are the most like to continue evolving, others believe that there are chemicals beside carbon that can underly life. Silicon is a good example for it, but other chemicals may be capable of this as well.
Famed physicist Stephen Hawking is one of the experts who argue that other lifeforms must be based on carbon as well. He says that the chemical “seems the most favorable case, because it has the richest chemistry.”
But many do not agree with this assessment. Ammonia, silicon and hydrocarbons are just some of the substances that can conceivably support life. One of the key advantages of silicates, for example, is their ability to form rings, chains and sheets naturally.
Crystalline silicate layers may in fact have acted as the first lifeforms here on Earth as well, before finally evolving into carbon-based organism. Even so, the chances of carbon underlying the development of lifeforms elsewhere is extremely remote.
“One possibility is that the formation of something like DNA, which could reproduce itself, is extremely unlikely. However, in a universe with a very large, or infinite, number of stars, one would expect it to occur in a few stellar systems, but they would be very widely separated,” Hawking says.
But many biochemists warn that the search for life is too entrenched in the way we view our own world. If we truly want to get to know other planets, then we shouldn't assume that the ensemble of conditions which make life here bearable for us have the same effect elsewhere as well.
They add that carbon may be replaced by arsenic, chlorine, sulfur, nitrogen and phosphorus, just some of the chemicals that have the potential to form organic structures. These formations could then evolve under certain sets of conditions into more complex lifeforms.
Another complex issue experts have to deal with is water. Could there be that other chemicals may provide an equally-solid background for all-new types of biochemistries? Experts seem to think so.
Some of the chemicals that could potentially do this include hydrogen fluoride methanol, hydrogen sulfide, hydrogen chloride, and formamide, among others, Daily Galaxy reports.
From this angle, objects such as Titan – Saturn's largest moon – make for prime candidates for the existence of alternative lifeforms. The celestial body is covered in liquid hydrocarbons, and features an atmosphere much like Earth.
The major exception is that methane and ethane make up the basic chemicals, rather than water. As such, this is what rain on Titan is made of. A exobiology mission to this moon may actually reveal alien life.