On the morning of 10 August 1971, a fireball flew over several US states and Alberta before disappearing at the horizon. To be visible in broad daylight, the meteoroid had to be quite massive. Scientists have estimated that it measured over ten metres long. Luckily, the celestial body continued its race through space and left the atmosphere thousands of kilometres farther away. The rock came very close to our planet. If its angle of entry had been different, the meteoroid would have become a meteorite.