Bacteria Outnumber Stars in Universe

While the vastness of the cosmos often captures our imagination, an even more populous and ancient kingdom of life exists unseen all around us. The sheer scale of Earth's bacterial life is difficult to comprehend, with a total population estimated to be around 100 million times greater than all the stars in the observable universe. This invisible majority makes its home everywhere, from volcanic vents and the deepest oceans to the inside of our own digestive systems, where they are essential for our health.

This incredible abundance is possible due to bacteria's simplicity, rapid reproduction, and ancient lineage. As some of the earliest life forms, emerging over 3.5 billion years ago, they have had eons to diversify and colonize every conceivable niche. The world of these "animalcules," as they were first called, was discovered in the 17th century by Antonie van Leeuwenhoek, who used his