Remember how people were excited about methane on Mars because it could
mean there was life? Phosphine, which they
found now on Venus is a much stronger marker for life than methane in
rocky planets. We know that methane can come from microbes, but it can
also come from volcanoes and other geological processes. So, on Mars there
are other known sources/processes to explain the amounts of methane. But
phosphine on rocky planets is different. Other than life, there is
no other process currently known that would explain the amounts of
phosphine the astronomers found on Venus. So, there are only two explanations for what they found: either there
is a new chemical/geological process out there that produces phosphine in
rocky planets that we don’t know about, or there is
life on Venus.
Watch David Kipping, an astronomer explain this finding
Read the scientific paper