Given their mass would be, as the article says, the size of a large asteroid, the event horizon would be quite small. Ceres has a mass of 10^21kg, for example.

Given their mass would be, as the article says, the size of a large asteroid, the event horizon would be quite small. Ceres has a mass of 10^21kg, for example. This website[0] to calculate Schwartzchild radius estimates the event horizon for a black hole of that mass would be roughly 1 micro-meter (1 millionth of a meter). [0]https://www.omnicalculator.com/physics/schwarzschild-radius https://www.omnicalculator.com/physics/schwarzschild-radius