While most (all) of the 144 sightings are the result of experiment defence technology - there is a long history of that, what is the likelihood aliens could visit us?

Many astronomers, astrobiologists, and astrophysicists would agree that some sort of life somewhere exists. However, life does not always mean humans or intelligent creatures.

Plants, trees, dogs, animals, and even bacteria all share this planet with us. And that is just current life on Earth.

Earth has been around for 4.6 billion years, and life emerged about a billion years later. There has been lots of life on Earth, more than humans.

Even dinosaurs were on Earth for about 165 million years, compared to the two million years humans have been around.

So why do we always jump to the idea of green-eyed, human-form creatures when we hear the word alien?

Given how long dinosaurs were around, dinosaurs are more likely to be on another planet or moon as opposed to something like humans.

Humans are a very self-centred species - we think a lot of ourselves. We think that the world, and by extension other worlds, revolve around us. Therefore, we think that all life on other planets must look, act, and think like us.

My good friend Charley Lineweaver would say, if you ask an elephant what makes it special - it would say its trunk. It's strong, helps them eat, drink, and lift things. So, if you asked an elephant to picture an alien, they would all have trunks.

There is more to it, though. The idea of aliens has been dramatically shaped by science fiction. Both how we portray aliens in science fiction, and how those portrayals shape our view of them.

When aliens seemingly visit us here on Earth, they are hostile creatures out to harm or take over our planet. When we Earthlings travel and explore other worlds, we are innocent explorers. How come it is not the reverse? It is a matter of projection - we are projecting our own worries and fears, not necessarily scientific ones.

But why would aliens want to visit us in the first place? Space is so big, it is unlikely any life would be close. Alpha Centauri, one of the bright pointer stars near the Southern Cross, is a triple-star system and the closest to our Solar System, a mere 4.2 light years away.

MORE SUNDAY SPACE:

With our current rocket technology, it would take tens of thousands of years to get there. Current projects are trying to get that time down to decades. Even if you could travel at the speed of light, it would still take four years just to get to Earth.

If you are on a planet 100 or 1000 light years away (our Milky Way is 100,000 light years across), at minimum it would take 100 to 1000 years just to reach Earth.

Any life would need to find a way to not only survive for that time, but have a reason to visit us.

We think we are so very important that everyone, and everything, in the Universe would want to visit us.

I don't think we are that special.