The heart of our planet has been spinning unusually slowly for the past 14 years, new research confirms. If this mysterious trend continues, it could potentially lengthen Earth's days — though the effects would likely be imperceptible to us. Earth's inner core is a roughly moon-size chunk of solid iron and nickel that lies more than 3,000 miles (4,800 kilometers) below our … [Read more...] about Earth’s rotating inner core is starting to slow down — and it could alter the length of our days