The Earth is trying to give you more hours in your day… but it wasn’t always
As we gear up for our yearly fundraiser, I feel confident in saying that just about everyone on our team is wishing we could somehow cram more hours into every day. At a certain level, our world is happy to oblige, and every year our days get the smallest fraction of a second longer and the Moon gets a few centimeters farther away.
In science, we often find things related in the wildest of ways. In this case, conservation of momentum is trying to keep everything rotating with the same amount of energy: we have the Earth rotating about its axis, the moon rotating and revolving around the Earth, and the Earth and Moon going round and round the Sun. All things being constant, everything would stay exactly the same forever, but… things aren’t constant. Because our Earth isn’t perfectly spherical, the Moon’s gravity is pulling on mountains and others high-mass points a little bit harder, and in the process slowing our world’s rotation. As the Earth slows, the Moon moves outward. This is the same physics that describes how an ice skater can slow down by flinging their arms outward.
In this simple situation, everyday from here forward will get a little bit longer, and everyday — looking back through history — we thought the days would be getting a little bit shorter.
