By the numbers

Random science

4,000: Distance in miles from the Earth’s surface to its center, a solid ball of iron the size of the moon

100,000: Number of traffic accidents per year caused by lack of sleep

30-40: Percentage of patients who report feeling better after taking placebos

5: Percentage of the universe that is not dark energy (72 percent) or dark matter (23 percent)

6: Feet of tightly cornrowed DNA in a typical human cell

Source: Wired magazine