What would happen if we blew up the Moon?

  The year is 2113. Humanity has spent the last 100 years stockpiling nuclear warheads. And not just a few – 600 billion of the largest, biggest, deadliest warheads they can build. Sort of like the Russian Tsar Bomba (the biggest nuclear bomb ever detonated) but, well, times 600 billion.

Why? Because we’ve decided to blow up the Moon, and to do so would require the equivalent of 30 trillion megatons of TNT.

When we say blow up, we don’t just mean slightly-blow-up. See, if you don’t completely obliterate the Moon, the remaining fragments will likely coalesce back together into a Moon-sized object. Sure, it won’t look as pretty or as spherical as our modern Moon, but it will be pretty similar in its gravitational effect on Earth.
No, what we (or, more specifically, our future selves) want to do is completely get rid of the Moon. So, with their multiple rockets ready and waiting to attack the Moon from all sides, they launch them towards our natural satellite and blow it to smithereens. Scientists around the world eagerly prepare for one of the greatest (and most idiotic) experiments of all time.
With the fragments of the Moon too small to gravitationally bond together, they begin to spread out. First, a large number of them head towards Earth, raining molten Moon rock down on our planet. Cities are destroyed, countries are wiped off the map, and we begin to wonder if blowing up the Moon was such a brilliant idea.
The remaining Moon material enters orbit around the world, forming a ring around our planet. But, like Saturn’s ring, it doesn’t just stay there. Periodically, for the rest of Earth’s life, meteorites break from the ring and slam into the surface. We’re now under constant bombardment from an apparently vengeful Moon.

“Now we have rings! Just like all the other cool planets…”

  But the Moon isn’t quite done getting even yet. Have you ever noticed that the Moon is covered in craters? Well, that’s because it gets pounded by meteorites, protecting Earth from some of the rocks that head our way. With the Moon annihilated, we’re now also more vulnerable to space rocks.
Of course, one of the Moon’s most noticeable effects is (or was) the tides. With the Moon no longer there, the oceans of the world become much calmer. The Sun still has an effect on them (known as solar tides), so surfers wouldn’t be completely devoid of waves. But the oceans would largely become serene.
This has a dire effect on life on Earth. When life first formed on Earth in tidal pools, it was thanks to the gravitational pull of the Moon that primordial life was able to traverse between different pools and generally spread across the planet. While we’re already here now, life that is currently in the oceans is no longer able to move so easily. The churning of the oceans, and thus the circulation of nutrients, ceases. Water-based life struggles to survive and, eventually, thousands (and probably millions) of species go extinct.
The Moon isn’t done yet, though. You see, it also accounted for about one-eightieth of the Earth-Moon mass system. The loss of the Moon directly affects the Earth’s orbit, rotation and wobble. Without the Moon to act as a stabiliser, the Earth begins to wobble more and more, sending our seasons into turmoil and changing our orbit around the Sun from slightly elliptical to massively elliptical. We now swing around the Sun in a wild, unstable, fluctuating orbit.
As the world regrets their ill-advised decision to destroy the Moon, it’s already too late to do anything. If humanity survives the constant bombardment from the remains of the Moon and other space rocks, the eradication of most other species from the globe, and finally the potentially catastrophic seasonal changes then, well, maybe blowing up the Moon wasn’t such a bad idea.