I think I have read that the universe is or could be infinite. But that is not possible because we know that the Universe started from a Big Bang. And its size has been expanding ever since. At each point in the past through to the present, the Universe measures a finite size with 0 unit of size at t=0. Therefore the universe has always been and is to the present moment finite. The universe might expand forever but it does not matter because at each specific time, the universe will always be of finite size hence to speak of an infinite universe is nonsense in the Big Bang model. An infinite universe can only exist in a static, infinite universe where the universe has 'always been infinite'.