The Tycho crater is thought to be the youngest major impact on the Moon, estimated at 108 million years ago. This puts it firmly in the reign of the dinosaurs, I find myself curious as to what our thunder-lizard brethren would have witnessed.

Tycho Crater by LRO

Roughly how bright would the initial flash have been? Would a glowing scar have been left on the Moon for days, weeks or months? Would the Earth have been subject to spectacular global meteor showers from ejected debris? Would any other effects have been felt on Earth? I'd guess that a simulation would be required to accurately answer these questions but I'm hoping that some reasonable estimates can be made by comparison of studies of other impacts.

Finally, was the Tycho impact of greater or smaller magnitude than the Shoemaker–Levy 9 impact in 1994?

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    $\begingroup$ Very nice question! I don't know, but I am greatly interested on the answers! :) +1 $\endgroup$
    – Max0815
    Mar 1, 2019 at 19:25
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    $\begingroup$ Had a quick play with an impact simulator site, it seems like the Tycho impact might have released 1.00x10^23 joules of energy which is more than any of the Shoemaker-Levi 9 fragments (G was about a quarter of that). $\endgroup$
    – MichaelB76
    Mar 5, 2019 at 9:20
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    $\begingroup$ For reference, fragment G of Shoemaker Levy 9 was estimated at being 100,000 times the energy of the Tsar Bomba. $\endgroup$
    – Ingolifs
    Mar 19, 2019 at 21:19
  • $\begingroup$ perhaps a tiny percentage of the impact would have been converted to friction based light, judging but the amount of glass and magma generated by asteroid impacts. The moon wouldn't glow for weeks unless there were swimming pools worth of molten rock. There must have been a flash of some kind. $\endgroup$ Mar 23, 2019 at 19:34

1 Answer 1


I found a partial answer in this article on the smaller and younger Giordano Bruno crater.

The impact creating the 22-km-wide crater would have kicked up 10 million tons of debris, triggering a week-long, blizzard-like meteor storm on Earth...

So the secondary effects of the Tycho impact would have been even more spectacular. However, I don't know whether the fragments would have been large enough to devastate the Earth's surface.

Experimenting with an online impact simulator it appears that the Tycho impact was somewhere in the order of 1.00x10^23 joules, judging by the size of the crater. This is about four times that of the G fragment impact of Shoemaker-Levy 9. When you consider all the fragments it would be fair to say humans have witnessed an impact of similar magnitude to Tycho.


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