And it could ery well have happened, it was a matter of Earth rotation... it come close...
Truth is, had the meteor come two hours earlier, it would have passed close from Earth on its orbit around the Sun, but missed it. The only way would be to give the metor a slightly higher speed over the previous decades and centuries, so that is still slams into Earth, with Moscow having rotated with Earth and become a huge target in place of Tungska.
Another interesting whatif is Tambora and Krakatoa erupting, not 68 years apart (1815 and 1883) but the same year or only months apart. Dear God. You can kiss Indonesia goodbye, 92 000 + 36 000 death OTL, probably much more ITTL.
Those two ranks among the five biggest volcanic eruption in human recent history. They actually wrecked the climate for months and years at a time. Krakatoa explosion was heard 2000 miles away, loudest sound ever recorded.
Then, if you divide 68 by two, that's 34 years. 1815 + 34 or 1883 - 34 = 1849.
Kaboom go the Indonesian monster volcanoes, and down the drain goes the weather - the year without a summer happening the year after 1848, hell of a moment in Europe history, France included.
There will be blood.