Scientists believe our universe has been expanding since the Big Bang. The Hubble constant is a number expressing the speed of expansion of the universe. There are several methods of measuring the Hubble constant, and each one leads to a substantially different value. Scientists don’t blame each other when the numbers don’t add up, they simply agree that they need to understand the universe better. We need to understand each other better, which is why we talk about vertigo, lying about your age, CBD oil, and whether old people smell or not.