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.
By measuring the number and luminosity of observable galaxies, astronomers put current estimates of the total stellar population at roughly 70 billion trillion (7 x 1022). The number of stars you see in the night sky depends on several variables, including your locationâs light pollution and your own vision. In large, light-polluted cities, only a few dozen of the brightest stars may be visible - though that doesn't mean there's nothing to observe from a city.