Just within our Galaxy the Milky Way, astronomers say there are at least 400 BILLION STARS—even though some believe stars in the milky way number the trillion, which means that the Milky Way alone is home to at least 100 BILLION planets.
Due to the fact that Astronomers are unable to take a peek at our galaxy from the outside, it’s nearly impossible to know the exact number of planets in our galaxy. This means that scientists are forced to make estimates of the number of worlds within the Milky Way.
To understand the number of planets hiding in our galaxy, scientists calculate the Milky Way’s mass, and estimate of how much of the mass is composed of Stars. Based on these mathematical calculations, scientists are confided that the Milky Way is home to roughly 400 BILLION STARS—even though some believe stars in the milky way number the trillion—which means that the Milky Way alone is home to at least 100 BILLION planets, although many astronomers agree that this number could rise as our observational techniques get better.
According to Universe Today, we can then say that the Milky Way galaxy has – on average – between 800 billion and 3.2 trillion planets, with some estimates placing that number as high as 8 trillion.
NASA indicates that there is likely to be at least 1,500 planets within just 50 light-years of Earth.
Based on a statistical analysis of all the Kepler observations, UC Berkeley and University of Hawaii, Manoa, astronomers now estimate that one in five stars like the sun have planets about the size of Earth and a surface temperature conducive to life.
Based on geometric-based methods, or measuring specific astronomical objects, our Sun is located around 25,000–28,000 ly (7.7–8.6 kpc) from the Galactic Center.
Check out NASA’s Exoplanets Archive to learn more about the exact number of confirmed exoplanets.
Now remember, we are talking about the Milky Way Galaxy alone. In comparison, the neighboring Andromeda Galaxy contains an estimated one trillion (1012) stars.
Jason Marshall, aka “The Math Dude,” has calculated that there are roughly 5 sextillion grains of sand on all our planet’s beaches combined. So take every grain of sand on every beach on Earth and you can begin to be able to actually visualize how many planets we’re talking about. Then you begin to wonder why we aren’t overrun with aliens. (source)
NASA’s Kepler space telescope has been one of the most important tools for discovering alien worlds.
Based on Kepler space mission data, astronomers believe there could be as many as 40 BILLION Earth-sized planets orbiting habitable zones of Sun-like stars and red dwarfs in the Milky Way alone. Interestingly, astronomers say that around 11 billion may be orbiting Sun-like Stars.
The nearest such planet may be 4.2 light-years away, according to a 2016 study.