If you’re talking intelegent life, the great filter has to be explained.
Either humanity will survive the next couple hundred years and get to a point where we can build self sustaining space colonies, or we will regress and - having used all our fossil fuel - earth won’t produce another space faring civilisation for a long time.
if we do survive though, then those colonies will inevitably head to the stars. One we can launch one colony successfully to alpha centauri we will spread over the galaxy exponentially over the next 10 million years with no way of stopping it, short of a local supernova in the next 20,000 years. We won’t be a single civilisation - culturally or biologically, and may not even have history of where we started, but earth originated dna will be everywhere and it will be unstoppable.
With that in mind it seems unlikely that another space faring species is in this galaxy.
Howver there are answers to the great filter, just finished the Salvation trilogy by Peter F Hamilton, which is one answer to that.
Either humanity will survive the next couple hundred years and get to a point where we can build self sustaining space colonies, or we will regress and - having used all our fossil fuel - earth won’t produce another space faring civilisation for a long time.
if we do survive though, then those colonies will inevitably head to the stars. One we can launch one colony successfully to alpha centauri we will spread over the galaxy exponentially over the next 10 million years with no way of stopping it, short of a local supernova in the next 20,000 years. We won’t be a single civilisation - culturally or biologically, and may not even have history of where we started, but earth originated dna will be everywhere and it will be unstoppable.
With that in mind it seems unlikely that another space faring species is in this galaxy.
Howver there are answers to the great filter, just finished the Salvation trilogy by Peter F Hamilton, which is one answer to that.