Why Aren't We Finding Aliens .... Scientists have a theory

Supernova

Scientists might have found why there are so few aliens .... in fact, why there may be less life than we hoped, in any form, out there in the cosmos.
Life as we know it on Earth could be far more unusual than we previously thought, according to a new study. The research suggests that the universe is substantially lacking in phosphorus. This element is essential for some of the most fundamental behaviours of life itself. It helps us store and move energy around our bodies, and forms the foundation of DNA.
But the new research suggests we have enough phosphorus on Earth, only because we were close enough to a supernova to receive phosphorus bearing rocks from the explosion. Phosphorus is formed as stars explode at the end of their lives. But not all supernovae have the right conditions to create it.
 Earth may be unusually lucky, because it happened to be situated close enough to the "right" kind of supernova.
Astronomer Dr Jane Greaves, from the University of Cardiff, said: "The route that carries phosphorus to  new-born planets is rather precarious and does not happen often in exactly the right conditions.
"We already think that only a few phosphorus-bearing minerals that came to the Earth, probably in meteorites, were reactive enough to get involved in making proto-biomolecules ( the building blocks of life ). The phosphorus must be the kind that reacts with the elements already present on the planet.
"If phosphorus is sourced from supernovae, and then travels across space in meteoritic rocks, I'm wondering if a young planet could find itself lacking in reactive phosphorus simply because of where it was born in relation to supernovae."
"That is, it started off near the wrong kind of supernova? In that case, life might really struggle to get started out of phosphorus-poor chemistry, on another world otherwise similar to our own."
The evidence comes from observations of two supernova "remnants", Cassiopeia A (Cas A) and the famous Crab Nebula.
The team used the UK's William Herschel Telescope on La Palma, Canary Islands, to look for signatures of phosphorus and iron from the Crab Nebula, the aftermath of a supernova explosion 6,500 light years away in the constellation of Taurus.
A previous study had searched for phosphorus from Cas A, 11,000 light years away. Comparing results from the two observations showed much less phosphorus from the Crab Nebula than Cas A, which came as a surprise.
Dr Phil Cigan, another of the Cardiff astronomers, said: "The two explosions seem to differ from each other, perhaps because Cas A results from the explosion of a rare super-massive star."
The findings were presented at the European Week of Astronomy and Space Science meeting in Liverpool. The scientists now plan to continue their search to see if other supernova remnants also lack phosphorus.
Theoretically, if all the complicated elements, conditions, environments and requirements for life do not exist on a planet, then life cannot exist. And it is a far more rare occurrence than we previously believed. I wonder if that is a good thing or not.