We assumed all life worked exactly the same way. Professor Carol Cleland thinks we might share our world with strange invisible microbes. She calls this hidden dimension a shadow biosphere and it uses completely different rules.

Our biology revolves around proteins made from twenty specific amino acids. Scientists think unusual life forms could use a completely different combination to survive. Nature actually has around one hundred amino acids available so a new biological recipe is possible.

You might wonder how researchers could miss an entire branch of life. The truth is our lab tools only detect the exact biology we already know. If scientists test weird microbial life it will not trigger a response and usually just gets tossed in the trash.

Scientists are searching very specific places to find these hidden organisms. One prime target is desert varnish which is a dark coating found on dry rocks. Researchers have debated its origins for years and it might just be the perfect hiding spot.

Experts agree that even these bizarre life forms would still rely on carbon. Alternative elements like silicon cannot create the massive variety of materials needed for chemistry. These hidden microbes are likely carbon based entities with a very alien twist.

Sometimes chemicals have the exact same formula but take on different shapes. A normal amino acid can come in a left handed or right handed version. This simple change means our standard scientific tools completely fail to recognize it.

We normally view the origin of life as a single lucky event. Paul Davies suggests life could have started multiple times early on. If life started more than once here then the universe is probably packed with aliens.

Read More: Scientists explore the possibility of unusual life forms hiding on Earth