The Moon is the Tango to Earth's Cash, the Hall to our Oates, the Lennon to our McCartney before they hated each other. Simply put, our planet and the Moon are soul mates: Except, of course, if something were to happen to one of them. Like, I don't know, what if we just blew up the Moon?
Image: Jim Cooke/Gizmodo/Lucasfilm
For this week's Giz Asks, Gizmodo spoke to astronomers and planetary scientists about the ramifications of blowing up our beloved satellite. While the idea has been excellent fodder for sci-fi (hello, Neal Stephenson), it's worth understanding what would actually happen if some madman decided to destroy the Moon. Just... don't get any ideas, OK?
Image: Universe Sandbox/Roberto Póo Muñoz/Gizmodo
Astronomer, physicist, and PhD candidate in Space and Planetary Sciences at the University of Arkansas
Let's say we wanted to explode the Moon, just for fun. What are our options?
The moon is a spherical piece of rock with gravity. This means that all the rocks and grains are gravitationally bound with what is called "binding energy."
With a cute little mass of 7.3x10^22 kg and a radius of 1,737 km (oh, how adorable), we're going to blow it up.
Now, blowing it up won't come easy. Anything smaller than the binding energy, and the rocks will rearrange themselves back to a sphere. The binding energy of the Moon is 1.2x10^29 Joules.
So let's put this into perspective, with 3 possible weapons of choice:
1. Nuclear: the moon's binding energy converted to TNT energy equivalent is 2.86x10^13 Megatonne TNT. The most powerful bomb during the Cold War produced 50 megatonnes. You would need 572,000,000,000 of those bombs!
2. Laser: the amount of energy from the Sun every 6 minutes produces 3x10^13 Megatonnes. That's just enough light energy to cook and vaporise the moon! (Maybe even lesser chunks?)
3. Drilling: if we were to "cause a moon quake"(because why not), it would need to be higher than a 16.45 magnitude quake! (The largest earthquake [ever recorded] was at 9.5 Magnitude)
Astronomer, writer, and Director of Technology and Citizen Science at the Astronomical Society of the Pacific
How dangerous would it be for life on Earth if we exploded the moon?
There are times when we all say (jokingly), "And now, we are all going to die." I know this is how I feel trying to cross the rush hour streets of Jakarta. While death is a possibility in these situations, it's not certain or common.
If we were somehow to pump enough energy into the moon to make it explode, the correct response is a serious utterance of "And now, we are all going to die." The moon is held together globally by gravity and on smaller scales by the chemical bonds that hold together boulders, rocks, and even grains of sand. If the moon were made to go Ka-Boom, the needed forces would send chunks of Moon flying at high velocities. Larger chunks would crater our world, while smaller chunks would burn up in the atmosphere.
In a weird case where only big chunks are created, some chunks would hit Earth and generate massive shockwaves, potentially global tsunami, and would throw massive amounts of debris into the atmosphere. The impactors could leave boiling hot spots where bodies of water are involved.
While it may seem that debris (or smaller pieces of moon) falling through the atmosphere shouldn't be too deadly, this intuition is wrong. As high speed material slows down in the atmosphere, [and] its kinetic energy gets turned into heat energy. The more stuff (either debris splashed up and falling down, or small moon bits falling) that goes through our atmosphere, the more heat goes into our atmosphere. At a certain point, our planet becomes a convection oven, and life outside of the oceans and not burrowed beneath the soil will be baked.
This is a bad way to die.
How would the tides be impacted if the moon exploded?
Taken semi-literally, the tides would be splashed to kingdom come.
Taken as intended, whatever bodies of water reformed as the Earth recovered from this devastating event would potentially be shaped by non-tidal forces - which would mean their would be no tides. It's possible that some chunks of the exploded Moon and tossed up debris could reform into a new, smaller object, and this would in turn drive new tides that had times dictated by the new moon's orbital period, and heights dictated by that new moon's size and distance from Earth.
Astronomer and Assistant Professor of Planetary Sciences at Caltech
Would Earth look different if we blew up the Moon?
The moon is precious — it stabilizes the Earth's spin-axis. Without the moon, the Earth will tumble chaotically between zero and 85 degrees. Although the timescale on which such changes would unfold is exceedingly long (tens to hundreds of millions of years), chaotic variation of the Earth's obliquity can prove detrimental to the stability of our climate, and the overall habitability of our planet.
We might not have been here to ask the question of what would happen if the moon were not there, if not for the moon's existence!