46,000 Miles Per Hour, Orbiting Back Toward Earth

Scientists later calculated that this particular asteroid travels at roughly 46,000 miles per hour on an elliptical orbit around the sun, completing that orbit once a year, and on a path that regularly brings it back toward Earth. The size threshold matters enormously here. An object half a mile or more in diameter is right at the point where the consequences of an impact stop being regional and become global, and at that scale you are likely looking at a collapse of the global food supply, not because of the impact itself but because of what follows it. The fires and the dust injected into the atmosphere from an impact of that magnitude would take somewhere in the range of three to five years to clear, and during that window the disruption to sunlight, temperature, and growing seasons would be severe enough to threaten agricultural systems worldwide.