> How big is the supermassive black hole S50014+81 compared to Earth?

To answer that, we divide the black hole's "size" by Earth's "size." And by "size," I think you mean something like diameter. So, the formula is H ÷ E.

This is a really simple formula, but we have to make sure we're using the same units for it to work.

• The diameter of Earth is 12,756.3 km.

• The black hole's diameter is 1,582 AU, which is a unit of length (like meters), but is still a different unit than kilometers.

So, we either have to convert Earth's size from km to AU, or convert the black hole's size from AU to km. (Let's do the latter.)

1 AU = 149,597,870.7 km

So, the size of the black hole is 1,582 × 149,597,870.7 = 236,663,831,447.4 km.

Now that both are in the same units, we can go back to the original formula and plug in our numbers:

H ÷ E becomes 236,663,831,447.4 km ÷ 12,756.3 km = 18,552,701.9 km.

Thus, the black hole is about 18.5 million times as big as Earth.