Details. as.character and is.character are generic: you can write methods to handle specific classes of objects, see InternalMethods. Further, for as.character the default method calls as.vector, so dispatch is first on methods for as.character and then for methods for as.vector.
But this is the number of stars we can see from the entire Earth and we should remember that one hemisphere of Earth is always in daylight, so really only about 2500 to 5000 stars are visible at night from any given point on Earth.
There are very roughly 200 billion stars in the Milky Way, so that gives us 20 billion stars. If one of every five has an Earth-like planet, that means there are about four billion Earth-like planets in our galaxy alone! And mind you, thatâs only for stars like the Sun.