Alien worlds may exist billions of light years away or at the bottom of your coffee cup. The latest chemical and biological research suggests that extraterrestrial life may exist all around us or even inside human bodies.

Biologists found out long ago that many microorganisms, including bacteria, can survive in the hostile space environment.

University of Arizona researchers suggest that alien microorganisms travelling inside asteroids were able to withstand freezing space temperatures and searing heat during re-entry, eventually settling on the terrestrial surface. Moreover, it appears that such microorganisms are arriving all the time.

Biochemists say alien life forms could appear on Earth as a result of several evolutionary processes, and that they either dwell among us or even inside human bodies.

Scientists have started doubting the theory of evolutionary development as the primary means for creating life on this planet. New data on space microorganisms can revolutionize our understanding of the origin of life.

The extraterrestrial life concept and the theory that life on Earth may have originated in outer space would receive additional backing if scientists manage to prove that terrestrial life had gone through several evolutionary cycles.

In that case, it would be appropriate to inquire about alien life forms' hideouts, and why they have not been sighted to date.

But the point is that they are not hiding from anyone. Scientists speculate that, owing to their unusual biochemical processes, alien microorganisms can thrive in acid lakes or near volcanic fissures and cracks on the seabed. They have not been discovered yet because current biochemical methods can only detect known forms of life.

It appears that alien microorganisms ten times smaller than terrestrial bacteria may be responsible for various human diseases that still go untreated. For instance, they may cause kidney stones. However, scientists must find a way to detect these life forms, which cannot be seen with the naked eye.

Italian chemists from the University of Turin have made a sensational conclusion that numerous amino acids were probably brought to Earth from outer space and became one of the main building blocks of life.

Quantum-chemical calculations showed that amino acids originating inside gas-dust clouds deep in space could have been captured by interstellar dust and reached Earth where primary conditions for the creation of life had already existed.

Mexican scientists working in this field have confirmed the findings of their Italian colleagues. They say amino acids are not destroyed in interstellar space, and that some of these extraterrestrial compounds might have reached Earth.

It turns out that, apart from organizing highly expensive and dangerous space missions in the quest for extraterrestrial life, humankind must also focus on its home planet.

Although no traces of extraterrestrials may be found here, life might have existed on Earth long ago but had disappeared for some inexplicable reason.

Unique traces inside geological layers would enable scientists to track down alien life forms. If such microorganisms had a different metabolism, they could have influenced the chemistry of rocks or could have created mineral deposits in a way that known living organisms cannot.

This makes it imperative to explore Earth, primarily its remote areas and those with adverse living conditions, in search for new exotic life forms. It is common knowledge that 17 animal species, including previously unknown ones, become extinct every 60 minutes.

If the extraterrestrial microorganism theory is proved, it will become obvious that this planet and space have always been interlinked.

The opinions expressed in this article are the author's and do not necessarily represent those of RIA Novosti.