Melting ice triggered by global warming may make Earth whirl faster than before and could shift the axis on which the planet spins, researchers say. This could also affect sunsettimes, as the length of Earth's day depends on the speed at which the planet rotates on its axis. Prior research found the rate at which Earth spins has changed over time. For instance, ancient Babylonian, Chinese, Arab and Greek astronomers often recorded when eclipses occurred and where these phenomena were seen. This knowledge, in combination with astronomical models that calculate what the positions of the Earth, sun and moon were on any given date and time, can help reveal how fast Earth must have been spinning. To do so, researchers calculate the speed necessary for the planet to face the sun and moon in ways that allowed those astronomers to observe the eclipses. In general, the gravitational pull of the moon and sun on Earth is relentlessly slowing the planet's rate of spin. However, in the short term,