What if Earth and the Sun were black holes?

What if Earth and the Sun were black holes?

To explore the sizes of black holes, let’s first start by looking at two objects that we’re more familiar with: Earth and the Sun.

Earth has a mass of some 6x1024 kilograms. And though that’s more massive than any human can truly comprehend, when it comes to black holes, Earth is puny.

To create a black hole, you need enough mass that the object’s gravity overcomes any outward forces preventing it from total collapse. This is why there are no known black holes as light as Earth — they just wouldn’t have enough mass to completely collapse. (However, some scientists think there could be a class of ancient primordial black holes. The recent black hole Hubble found is over 50,000 times the mass of the Sun. Discovered in a distant, dense star cluster on the outskirts of a larger galaxy, it was precisely where astronomers expected to find evidence for these “missing links.” At tens of thousands of solar masses, the intermediate-mass black hole candidate would still only have a radius one-fifth that of the Sun, or about twice the radius of Jupiter. 

forged in the first few moments after the big bang. These theoretical black holes could range from less massive than a paperclip to tens of thousands of times the mass of the Sun.) 

At the center of a black hole is believed to be an infinite gravitational well in the fabric of spacetime, called a gravitational singularity. This singularity is infinitely dense, and anything that reaches it is stuck there for good. The outer edge of the black hole, called the event horizon, is the boundary beyond which nothing can escape the gravitational pull of the black hole, including light. Where this event horizon starts depends on the mass of the black hole and was first calculated by German astronomer Karl Schwarzschild in 1916. 

Using the Schwarzschild radius calculation, a black hole the size of Earth would have a radius of less than one inch, making it about as big as a ping pong ball. The Sun, on the other hand, would have a radius of just under two miles.