1. The possibility of life on other planets
Are they out there?

2. Since the dawn of humanity, humans have looked up at the stars and wondered, “are we alone?”. The human imagination has always been interested in the possibility of other sentient life forms, inspiring countless plays, books and films, but in the late 20th century, with the advent of new technology, countless minds set out to answer the question once and for all.

3. Francis drake
In the 1960s an astronomer, called dr. Francis drake, began a search for intelligent signals using a radio telescope. However, it proved unsuccessful. The next year he was meant to be hosting a meeting of SETI (the search for extraterrestrial intelligence). Without knowing it, in preparation for this meeting he would make an important discovery towards the search for alien life.

4. The equation...
In preparation for this meeting, he decided he needed an agenda, so he wrote down all the things you needed to know to predict how hard it will be to find alien life. Looking at them, it became pretty obvious that if you multiplied all these together you got “N”, the number of detectable civilisations. This became known as “the Francis drake equation”.

5. The actual equation...

6. The problems
Because the final 4 values of the equation were so hard to predict, they gave an estimate of between 20 and Also, considering that humans as intelligent life have only been around for years, and have been broadcasting for a fraction of that time, and the universe and the galaxy are billions of years old, the chances of two civilisations that can talk to each other being together at the same time are astronomically low.

7. Rare earth
There is another argument, the rare earth hypothesis, which states that the chances of life forming on earth were so low that we are alone in the galaxy and probably the universe. However, if the universe is truly infinite, then however low the chances, life will exist somewhere, and, technically there will be an infinite amount of it. Another interesting point is that if the universe is infinite, everything that could happen will happen, and will repeat an infinite amount of times, so somewhere out there is a planet called earth on which lives someone who looks and thinks exactly like you. Are these aliens?

8. Too advanced?
A final argument against us contacting aliens is that they are simply too advanced for us to contact. We may not even acknowledge each other as living. We might be searching for radio waves when in actual fact they use quantum entanglement to communicate, or we might arrive on a planet teeming with life and not realise this.

9. AI
If human beings do invent AI, it will probably outlast its human creators for millions of years, maybe participating in their downfall. If we do discover intelligent life, the chances are that it will be AI, which has super ceded it’s creators millennia ago. Also, AI doesn’t have to exist on planets, as it can float freely in space, a wondering mind, so it will be much harder to search for.

10. Any questions?