Black holes the size of an atom that contain the mass of an asteroid may fly through the inner solar system about once a decade, scientists say. Theoretically created just after the big bang, these examples of so-called primordial black holes could explain the missing dark matter thought to dominate our universe. And if they sneak by the moon or Mars, scientists should be able to detect them, a new study shows.
Weight in pounds isn’t the right unit here. Weight varies depending on the strength of the gravitational field you’re in, whereas mass does not. A kilogram here on earth weighs 2.2lbs but on the moon it only weighs 0.36lbs.
In the English Engineering System, the unit of mass is 1 pound mass (lbm), and is equivalent to the amount of matter that weighs 1lb at 1G. I won’t argue that EES is a good system, but it does at least have a kludged unit for mass. It has an equally kludged unit for force, too, called pounds force (lbf).
I called that out. It was the weight of the earth… on earth.