It looks like every star in the Milky Way has at least one planet. By looking at the exoplanets we’ve found so far, and taking into account factors like distance from the star, temperature, density, etc., it looks like there may be as many as 100,000,000 planets that may support complex life. We’re not talking about alien civilizations here. Just something more than a microbe. That’s only for our galaxy. Given the hundreds of billions of galaxies out there, we’re very likely not alone.