Life in the Universe How much life is there? What are the probabilities? A conservative estimation.

Sombrero galaxy 29 milion light years away

Star nursery in our Milky Way

Life in the Universe How many planets can have or have life on them? The chemical elements in our solar system and galaxy are similar all over de Universe. Our solar system is very “normal” no exception to the many other solar systems we discovered. The physical laws that govern our Universe are everywhere the same, except in the center of Black Holes.

Planets around other suns The formation of most stars is similar to ours, and most stars form planets around them out of the dust disc. Almost all stars have planets flying around them. The estimates are, that there are much more planets then stars. (There can even be life on a moon around a planet, see Jupiter’s moon Europa, contains water and energy and probably basic life forms)

The “Goldilocks” Zone or circumstellar habitable zone. We need to know how many planets around the stars are situated in the “Goldilocks” zone. This zone or area, is the distance of a planet from it’s sun and have the possibility to sustain liquid water. The more conservative numbers estimate that there is 1 rocky planet with liquid water in the Goldilocks zone for every 1000 suns. The most conservative estimate that life would evolve on such a planet would be 1 in a million.

How much life would there be? There would be 40 000 000 000 000 planets with life in our observable Universe. Where does this number come from? There are approximately 200 billion stars in a galaxy There are approximately 200 billion galaxies in the Universe. So 200 000 000 000 x 200 000 000 000 = 4 with 22 zero

How much life could there be? We divide the number of suns by 1000, to find a rocky planet in the CHZ. We divide this number 4 with 19 zero by 1 000 000 change of life evolving on a planet in the Goldilocks zone. Then we have a 4 with 13 zero’s And that is 40 trillion Or 40 000 000 000 000 planets with life on them To visualize this number, take a beach of 50 meters wide and 1 km long. All the sand grains till 1 meter depth, 50 meter wide and 1 kilometer long, every grain represents a planet with life on it in our Universe.

How much life is there in the Universe Life on most other planets could be very basic, but on others very eveloved. There probably are planets with life way beyond our evolution. The most important reason why we didn’t find other life on planets or did not receive signals is because the Universe is so big! Most of the other galaxies are hundreds of million light years away.

How much life is there in the Universe In case an intelligent species on another planet sends a radio message into the Universe. Then that message can only travel at the speed of light. Imagine an intelligent creature sends today a nice message full of valuable information from a planet in the Sombrero Galaxy. Then we would receive that message in 29.3 million years! Or imagine that our intelligent creature was sending the message for a 1000 years but then would be gone because of a meteor collission.

How much life is there in the Universe If the message was send 29.4 million years ago for a thousand years, then we would have missed it by 99 thousand years. The width of the Universe is 44 billion light years across. We probably miss a lot of messages. There most be a lot of life in the Universe! The Universe is teeming with life. We can not prove it yet, because we can not see it. But 300 years ago we couldn’t prove there where bacteries, because we could not see them, this is a similar situation.

Time and humans in the Universe If we would place the age of the Universe (13.8 billion years) on 1 year. Then the first Homonids would appear on Earth 1 hour and a half ago. The average life span of a human life of 80 years would take in the Universal year only 0.2 seconds Show calculation

Calculation of the age of the universe to 1 year 13 800 000 000 / 365 =37 808 220 Y/24 hours = 1 575 342 y /60 min = 26 255 year per minute 26 255 /60 sec = 437 year per second So 80 years would take 80/437 = 0.18 seconds A life span of 80 years would take 0.18 sec on the Universal time scale of 1 year.