Aliens - Do They Exist?

Aliens - Do they exist? Is mankind alone in the universe? Are there civilizations more advanced than ours?
are there other intelligent beings somewhere in this infinite universe looking up into their night sky and asking the same kind of question?

What are aliens?...
Alien life, or extraterrestrial life, is hypothetical life, that could possibly exist outside of Earth, and which did not originate on Earth. Alien life could range from simple forms of life, such as bacteria to intelligent beings. In theory, alien life could be more or less advanced, than life on Earth. The science of extraterrestrial life is called, astrobiology.

Do aliens exist?...
Research that aims to discover extraterrestrial life has been ongoing since the mid-20th century, and the topic has been a point of interest in works of science fiction.

To this day, no life outside of Earth has ever been found, and there's no evidence that alien life has ever visited or contacted our planet. However, developments in our understanding of the universe do still support the idea that alien life is possible.

In 1995, astrophysicists Michael Mayor and Didier Queloz, discovered the first exoplanet. The vast, inhospitable world, known as 51 Pegasi b, was proof that planets orbited sun-like stars beyond our solar system, Since then, over 4,000 more exoplanets have been discovered, including Earth-like planets that could have the potential to harbor life.

In recent years, astronomers have spent lots of time trying to discover traces of simple forms of life, known as ‘biosignatures’ elsewhere in the universe. However, if an alien planet was home to intelligent life, that built a technological civilization, could there be ‘techno signatures’ that could be detected from Earth?

NASA have given scientists a grant to begin to study techno signatures, to see if there are any
indications that technology has been used on other planets. This exciting new venture in the search for extraterrestrial intelligence, S E T I, will focus on thousands of exoplanets, both in and out of the habitable zone, where life has the potential to form.

The project will start by focusing on two possible techno signatures that may suggest technological activity on other planets. These are:
Solar panels... Any extra terrestrial civilization must find a way to produce energy. Like humans, aliens might also need energy from their parent star, which will give rise to spectral signature. If researchers can find any spectral signature, anywhere in observable Universe, that means we are a step away from finding an intelligent life...

Pollutants... We can detect chemicals, in our atmosphere by the light the chemicals absorb. These include chemicals like methane, and oxygen, as well as artificial gases like choro fluro carbons. If researchers find any chemicals like CFCs, that may suggest the presence of an industrial civilization. potentially taking us a step closer to discovering if aliens exist.

probably, it is reasonable to think, that aliens exist somewhere in the universe.
There are 300 billion stars in our galaxy alone, with new planets being discovered travelling around them. There are around 4,000 exoplanets just in our galaxy. When we consider the fact that there are around 200 billion galaxies, in the universe as a whole, it would be short-sighted to assume that life only exists on Earth.

A technique called spectroscopy allows us to measure the atmosphere of exoplanets, to see if they contain the same kind of substances that appear in Earth’s atmosphere. While this doesn’t confirm that there’s alien life, it does highlight that it’s possible.

Even on Earth, life exists in places we previously thought impossible.
We’ve found microbes surviving in places on Earth where it was otherwise thought impossible. Lifeforms based on familiar DNA have been discovered deep in the ocean, in trenches untouched by sunlight.

While many scientists are optimistic about finding life elsewhere in the universe, it’s not a given that it’ll be intelligent life. It’s only a small fraction of Earth’s history that has featured intelligent life; for billions of years, our planet was home to very simple bacterial life. For alien life to contact Earth it would have to be very advanced.

Even if intelligent lifeforms exist, their conditions may make it difficult to contact us,
Despite 300 billion stars, multiple solar systems and around 10 billion years, in which a civilization may have formed in our galaxy, there are lots of other important factors we must consider.

Astronomer Maggie Aderin-Pocock thinks it’s important for us to think outside the box. For example, she poses the idea that planets near active stars may harbor life that exists below the ground, which would make more it difficult to detect.