During a battle between two extremely powerful space wizards, a beam of magical lightning has blasted a perfectly circular hole around 10 feet in diameter directly through an Earth-sized planet. In and out like a gunshot through paper. How would this impact life on the planet after this event, if at all?

NOTE: The incident occured about 150 miles south of the planet's north pole.

  • 3
    $\begingroup$ @user535733 no I was saying this thing goes smoothly in and out like a well-placed gunshot. In reality, expect this thing to be moving at about 560,000,000 mph (so VERY fast). Also the blasted mass is simply deleted from existence because magic. $\endgroup$ Sep 16, 2020 at 17:49
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    $\begingroup$ South of the North Pole actually says practically nothing about the actual location. A latitude and longitude would be useful. Everything can be said to south of the north pole. $\endgroup$ Sep 16, 2020 at 18:41
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    $\begingroup$ @StephenG - 150 miles south of the north pole (equivalent to "150 miles away from the north pole") is enough to determine the latitude. I doubt that longitude is relevant to the answer, aside from determining whether specific surface features are hit (but there are unlikely to be important features that close to the pole anyhow, if the climate is Earth-like). $\endgroup$ Sep 17, 2020 at 8:41
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    $\begingroup$ The existence of a 10 foot diameter hole is inconsequential compared to the method which created it. If it was bored then nobody would notice. If it was more of a laser disintegrating things in its path then it goes unnoticed. If it was a powerful bullet-like impact then the wizard must have harnessed and released enough energy to destroy themselves upon releasing the shot. See what-if.xkcd.com/1 $\endgroup$
    – MonkeyZeus
    Sep 17, 2020 at 12:37
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    $\begingroup$ That's probably a good question for what-if.xkcd.com $\endgroup$
    – Tom
    Sep 18, 2020 at 6:58

8 Answers 8


Depends on the side effects of the weapon.

  • If a 3 m wide, 12,750 km long plug through the center of the Earth simply disappears, at worst there will be two smallish volcanoes and a couple of earthquakes. The total material is roughly a cube 450 m to a side.
  • If sufficient force is applied to punch such a plug out of the Earth by conventional means like a bullet, the amount of energy that is imparted will cause major destruction.
  • $\begingroup$ I wonder if there could ever be a situation like some gunshot wounds, in which a faster bullet does less damage than a slower one because it overpenetrates. Probably not good for any Earthlings either way. $\endgroup$
    – Ryan_L
    Sep 17, 2020 at 4:35
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    $\begingroup$ @Ryan_L Another answer here already mentions it, but for non-relativistic speeds how fast something goes doesn't impact penetration depth much, as long as both objects are roughly the same density. Randall Munroe of xkcd fame discusses both what would happen at both relativistic and non-relativistic speeds on this what-if page. $\endgroup$
    – eirikdaude
    Sep 17, 2020 at 7:02
  • $\begingroup$ @eirikdaude OP has stated the bolt will be travelling at around 83.5% of the speed of light, although they've also said the material will simply disappear. $\endgroup$
    – JBentley
    Sep 17, 2020 at 9:34
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    $\begingroup$ @JBentley I was responding ryan though. The question in the OP is nonsensical if you want to deal with the real world, because what it describes has no basis in real physics. Anyway, unless the "bolt" is superdense it is unlikely to do more damage than what is found in Munroe's simulation which seems to be "barely break the crust". $\endgroup$
    – eirikdaude
    Sep 17, 2020 at 9:48
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    $\begingroup$ 90 million cubic meters, formed into a cube, would be 448 meters on a side. $\endgroup$ Sep 17, 2020 at 14:56

The first thing that occurs to me is that 10 feet in diameter is very, very, very etc. insignificant compared to the total surface area of the Earth (196,900,000 square miles).

The second thing that occurs to me is the location of the event -- 150 miles south of the north pole, or latitude 87.5 degrees north. It's very likely that's in the middle of the Arctic Ocean.

So even though this magical lightning bolt has the power to go "straight" through the Earth and out the other side (somewhere in Antarctica?), I can't see it as having much actual effect, or leaving any lasting sign.

First, water would rush into the hole, rapidly cooling it.

Deeper down, pressure would cause the tube to collapse in on itself, probably almost instantly, especially since I believe you wrote that there's no debris left behind.

The lack of debris makes me think this beam is more like a disintegrator rather than a projectile -- so it's not really like a bullet at all. It's magically removing the matter from existence.

So on the way out... perhaps a highly localized atmospheric disturbance, like a thunderclap, as air rushes to replace the missing matter... but that would be that.

The hole might last a bit longer down in arid Antarctica than up in the Arctic Circle, but it would be a curiosity, little more.

  • $\begingroup$ A tiny black old moving at a high velocity might remove a bit of matter from the earth like this, without magic. $\endgroup$
    – Tim Grant
    Sep 17, 2020 at 15:17
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    $\begingroup$ @TimGrant Assuming you mean "black hole", this was the beginning of the plot of Niel Stephenson's "Seveneves". Only it was the Moon instead of the Earth that was hit. Spoilers, the results were pretty catastrophic. Like Earth-uninhabitable-for-millennia catastrophic. And again, that was just from the Moon being hit by a mini black hole, not even the Earth itself. $\endgroup$ Sep 17, 2020 at 15:55
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    $\begingroup$ This is a magical matter-removing lightning bolt, though (so not even really a lightning bolt), not a tiny black hole. So no destructive gravitational effects. Bill DeSmedt wrote a novel about a micro black hole slowly mucking things up eleven years before Stephenson's book, in his "Singularity." $\endgroup$ Sep 17, 2020 at 16:36
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    $\begingroup$ Yeah, but in Hyperion, didn't it actually turn out to be REDACTED? $\endgroup$ Sep 18, 2020 at 3:43
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    $\begingroup$ Seveneves does not assume a black hole passing through the Moon. Seveneves posits that the Moon is split into seven (IIRC) fragment that are somewhat distanced from each other (else they'd simply join back to be the Moon). This requires a force that pushes the Moon fragments away from the common center of mass, which is pretty much the opposite of what a black hole would do. $\endgroup$
    – toolforger
    Sep 18, 2020 at 18:39

Other answers have addressed the qualitative details of what happens, I want to try and put some numbers to it.

If the hole is filled by material flowing in from the sides, then the amount of energy released by the expanding material is roughly equal to its pressure times the volume of expansion. Looking at the plot from this answer on Physics SE, the average pressure in the hole is, let's say, 200 GPa. Then the energy release is:

(π/4 × (10 feet)2 × 12 000 km) × 200 GPa = 1.7 × 1019 J

We can convert this energy to a value on the moment magnitude scale of about 7. Now since most of the energy release will happen deep in the core and mantle of the Earth, people on the surface nearby will experience less than the equivalent of a magnitude 7 earthquake.

I guess that only the energy release within the first few hundred kilometers of the surface significantly affects the perceived earthquake magnitude. Looking back at the same plot, the slope near the surface looks like around 30 GPa per 1000 km. Taking a wild guess and setting the cutoff of 500 km, the amount of energy released "near" the surface is roughly:

(π/4 × (10 feet)2 × 500 km) × (1/2 × 30 MPa/km × 500 km) = 2.7 × 1016 J

(The 1/2 accounts for the fact that the average pressure is equal to half the maximum pressure for a linearly increasing pressure.) This is an amount of energy equal to roughly 5 on the moment magnitude scale, which is not that big; globally, more than a thousand of magnitude 5 earthquakes happen every year.

  • $\begingroup$ Your first calculation was correct, you are not calculating a fraction of the work done by the earthquake but all of the work. 1.7 × 10^19 J, the planet has to close the hole entirely to stabilize. the earth is not good at dissipating energy it tends to just transmit it, this is why earthquakes are detectable on the opposite side of the planet. even the deep event will propagate just fine to the surface. the entire mass of the planet is going to shift by a few feet. $\endgroup$
    – John
    Sep 17, 2020 at 21:21
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    $\begingroup$ @John Even if the energy was not damped at all, it would still be spread out over a larger area. The center of energy release is 6000 km away, so compared to a more typical epicenter depth of say 6 km, the effects of energy released at that depth will be (6000/6)^2 = 1,000,000 times weaker at the surface. We may be able to detect earthquakes from the other side of the Earth but they don't feel like much! $\endgroup$ Sep 17, 2020 at 21:31
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    $\begingroup$ @John Also, the amount of movement far from the hole will be quite small. The volume in the hole is only 1/10^13 the volume of the Earth, so the average movement across the entire surface would be in the 100's of nanometers range. $\endgroup$ Sep 17, 2020 at 21:36
  • $\begingroup$ that dissipation is already accounted for in the moment equation scale. I think you are confused about how earthquake scales work, the depth of the quake is irrelevant for measuring its magnitude on the scale you are using. I am not saying the entire planet experiences a magnitude 7 quake, just that your attempted conversion is completely wrong. the amplitude of this quake is massive because the "fault" is a straight line, the fact it is vertical does not change that, if anything it makes it worse at the epicenter. You are trying to convert focus magnitude to epicenter magnitude. $\endgroup$
    – John
    Sep 17, 2020 at 22:19
  • $\begingroup$ the epicenter quake will be far above a magnitude 7, because the OP has created ideal conditions for reinforcing wave propagation. Basically they have created a cylindrical spike wave earthquake. it is not a normal earthquake but an earthquake based shaped charge. $\endgroup$
    – John
    Sep 17, 2020 at 22:38

In the dept of the Earth the hole would be filled in moments. In the surface two things may happen, depending on the state of the dynamic system that is going on beneath the crust:

  • some minor seismic activity happens because of a sudden (and quite little) lack of pressure, deep landslides block lava from coming out of the hole, but still a lot of heat would keep coming out of it (geothermal spot).
  • lava smashes out in a huge jet. I think it's unlikely that a volcano would set there permanently anyway.

If you want to know precisely (well, not 100% precisely) you have to tell the exact spot to a geologist. There are models of the activity of Earth's mantle that can predict what would happen more precisely.


I would assume this depends on how the Beam did its work. If it just "deleted" the matter in its way, just about nothing would happen excpet that some random Animal will have a pretty bad day.

If the Beam melts its way across you may see a pretty big explosion on both sides of the Planet. The first when the Beam enters and the 2nd when it goes out. So overall, a bunch of Animals would have a bad day. But not much more.

If it pushes everything to the side, like a Force Field. Well then still not a lot would happen. Except someone in the distant future will see a strange long diamond bolt going from one side of the Planet to the other. This is because at some point, or depth, the Beam pushes dense stuff into very dense stuff. Thus creating bling blings.

At the end of the day, 3 Meters just isnt that wide and the total amount of Energie blasted into the plant could be scrapt of as a Rounding Error.

For anything drastic to happen, you gonna need a wider beam. Making it more powerfull but keeping the diameter the same wouldnt do anything. Sure at some point the Impact spots would look like several nukes went down, but at some point it makes no difference anymore. You need to affect a bigger area at once.

Example, a Photon at Lightspeed dosnt hurt you. Even although it carries momentum. But let's say the Photon is 1 Meter across. Well then you are going to have a bad day.

The wider the beam is, the more stuff gets turned into dust and the bigger the Impact Explosion is.

Sorry for Misspellings , I am German.

  • $\begingroup$ diamonds need way more time to form, pressure isn't sufficient by itself, there is more than enough down there already $\endgroup$
    – carlo
    Sep 16, 2020 at 17:49
  • $\begingroup$ Really ? I just assumed the heat and Pressure would do the trick but i dont know that. $\endgroup$
    – Erik Hall
    Sep 16, 2020 at 17:51
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    $\begingroup$ well actually if you have the right elements ready in place you don't need much time, they managed to do it artificially $\endgroup$
    – carlo
    Sep 16, 2020 at 17:53
  • $\begingroup$ Did you really just say "Well actually" ? Dude.... I mean, i could see how Diamonds would form at certain spots but in a realistic sceneraio, you got a bunch of obsidian and similar stuff. $\endgroup$
    – Erik Hall
    Sep 16, 2020 at 17:56
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    $\begingroup$ lets say the Photon is 1 Meter across - What does that even mean? Photons have a wavelength, not a diameter. A 1 meter long wavelength is another name for radio waves. physics.stackexchange.com/questions/206772/… $\endgroup$ Sep 17, 2020 at 3:24

Immediate Effect

You're going to get a pair of volcanoes. They might turn out fairly small, but I think there is a good possibility of super-volcanic eruptions. Consider this: the pressure around the surface of the solid inner core[1] is estimated to be around 330GPa (3.3 million atmospheres).

A supervolcano[2] erupts when the gasses dissolved in the magma come out of solution and I think this is exactly what would happen when a 3m diameter cylinder of earth, going right through the core, simply ceases to exist. Maybe the magma will quickly plug such an "insignificant" hole but I wouldn't bet on it; I suspect it would be more like a water-main break, where the jet of magma would continue to erode the hole for a long time.

Long-term Effects

A typical supervolcano erupts with such force that large amounts of material (thousands of cubic km!) are launched into the atmosphere and disperse, to some extent, across the majority of the planet. The widespread particulate clouds can lead to a decrease in global average temperature. However, in this case such effects are likely to be more limited due to the type of eruption. I think of it inflating a balloon and then releasing the air from it rather than popping it... only the release of magma could continue for a rather long time. Instead of fizzling out with the hole plugging up, we might instead see the hole widen with magma flowing out for a Very Long Time (see Siberian Traps[3]). In this case, it could be nearly life-ending!


  • Probably (super?)volcanoes!
  • Effects could range from "ooh, another volcano" to "where have all the plants/animals/people gone?"

[1] https://en.wikipedia.org/wiki/Earth%27s_inner_core
[2] https://en.wikipedia.org/wiki/Supervolcano
[3] https://en.wikipedia.org/wiki/Siberian_Traps

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    $\begingroup$ 10ft is not wide enough to get many effect, the hole will be slammed shut be pressure as fast as it forms. gasses won't get a chance to separate in any quantity. It can't trigger a super volcano quickly but only decades or more in the future, it creates a path to the surface but magma will take quite a lot of time to fill it. it has to melt continental crust to get the gases it needs. Note that the shockwave of the hole closing will be the largest quake in earths history, there will not be a building left standing on the planet. $\endgroup$
    – John
    Sep 17, 2020 at 20:48
  • $\begingroup$ @John I assumed near-instant formation of the hole. Considering the viscosity and extreme pressure of magma, probability of at least some dissolved gasses, and rigidity of bedrock, I would expect at least a supersonic jet of hot gasses followed closely by a geyser of magma, short-lived though it might be. Of course, this is all semi-educated speculation on my part. :) $\endgroup$
    – Shadovv
    Sep 18, 2020 at 14:26

Soil doesn't behave like that when hit. We have craters, not cylindrical cavities all the way through when a meteor falls for example. In order to displace so much matter neatly, the amount of energy involved would probably be enough to turn the planet into plasma.

XKCD What If no. 20 is about how deep a 100-feet wide diamond meteor would penetrate the Earth. It has this quote:

Oddly, the speed that something is going doesn’t really affect how deeply it digs into the ground. Isaac Newton came up with a very clever idea for estimating how deeply projectiles will go in their targets before stopping. It turns out that no matter how fast a projectile is going, if it hits something that’s about the same density, it will only go about one body-length in.

So for an object to go through the Earth, it would need to be either as dense as a stellar core, or it would need to have a mass comparable to the Earth's. Even Mars-sized Theia, upon hitting Earth ~4 billion years ago didn't go all the way to the core of the Earth. An energy weapon (either using lasers, or electricity as in the question) would have to provide a similar amount of energy to obtain the same effect.

Let's assume that instead of smashing through the planet like that, the magic beam teleports away all matter in its path. This paragraph from L. Dutch's answer summarizes the result:

An end to end hole on Earth would not be stable, and would collapse under the gravitational force exerted by the planet. That would alone would release a large amount of energy which would surely evaporate the oceans if not even melt the crust.

The hole would not be stable exactly because of what gave the Earth its round shape. A prerequisite for a body to be a planet is for it to have enough self-gravity to overcome rigid body forces. In laysman terms, the magma/core material forming the walls of the hole won't be strong enough to keep the planet around it from collapsing into the hole. This collapse will dissipate vast amounts of energy.

I don't know how to calculate that energy, but I have an idea to approximate it. While the hole doesn't close, every point in the remaining Earth would have ~1.5m below it to fall onto. Of course they can't all fall 1.5m as they will crunch upon each other along the way, but the potential energy being turned into kinectic will be mostly the same.

That would be the equivalent to the mass of the Earth falling from a 3m height. So...

$$ mgh = (5.972 \times 10^{24}kg) \times (9.8m/s^2) \times (q.5m) = 8.8 \times 10^{25} j$$

Looking at this handy table tells us it's like the total energy output of the sun in half a second, or 50 times all the solar energy that Earth gets in one full year. It is also like being hit by the dinosaur killing asteroid five hundred times. You'll have that energy dissipated on the planet within a moment. That does not bode well to life.

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    $\begingroup$ I am pretty sure thats not how it works. Assuming the beam deletes the Matter away, all that would happen is that very viscous liquids such as Molten Metal would fill the hole. And remeber, Gravity isnt actually pulling anything anywhere near the center of the Planet. So the hole would slowly fill up. And by no means would that energie by so high. $\endgroup$
    – Erik Hall
    Sep 16, 2020 at 17:54
  • $\begingroup$ @ErikHall gravity may be small neart the core, but pressure from above is not. Also notice that gravity would only be small inside the cylindrical void close to its center - close to the poles, the gravitational pull would be that of Earth's surface. $\endgroup$ Sep 16, 2020 at 17:56
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    $\begingroup$ interesting. but your estimation is clearly many orders of magnitude over the real value. a hole that passes trough the earth is not like the whole planet falling. more like a 3m wide section of it $\endgroup$
    – carlo
    Sep 16, 2020 at 18:00
  • $\begingroup$ @carlo if you have a cylindrical hole on a planetary mass, all of the mass will collapse on that hole. $\endgroup$ Sep 16, 2020 at 18:02
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    $\begingroup$ The rest of the earth doesn't drop 3m. A 3m diameter hole through the earth removes 89.7M cubic meters of earth. Spread evenly over the 510M square km of earth surface area, this amounts to an average drop at the surface of only 17cm. I think you're overestimating the energy involved, as we're not moving the whole mass of the earth, the force of gravity starts to diminish deep inside the earth, and the drop is not 3m. We're using absolute worst-case figures for all of these estimates, so the actual result will certainly be lower. $\endgroup$ Sep 16, 2020 at 21:27

How would this impact life on the planet after this event, if at all?

Say good bye to life.

An end to end hole on Earth would not be stable, and would collapse under the gravitational force exerted by the planet. That would alone would release a large amount of energy which would surely evaporate the oceans if not even melt the crust.

Add to that also the kinetic energy dissipated by the projectile when crossing through the entire planet, and the picture gets only worst.

  • $\begingroup$ Would this all happen instantly or would there be time to evacuate some of the planet's population in the aftermath? $\endgroup$ Sep 16, 2020 at 17:45
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    $\begingroup$ This leads me to wonder how big of a hole would be catastrophic. I'd think a very small hole (<1mm) would have rather small effects, while the shockwave and seismic disturbance will grow with the size of the hole. I'm not convinced a 10 foot wide hole will have anywhere near a big enough effect to boil the oceans or melt the crust, though. Even dropping the entire mass of the earth from 1 earth radius up only yields enough energy to boil the oceans 100x over, and we are only moving a couple of millionths of a percent of that amount of material (and through a region of diminishing g). $\endgroup$ Sep 16, 2020 at 17:55
  • $\begingroup$ @nuclearwang drop an Earth on an Earth at point blank and both planets reform into a new one. $\endgroup$ Sep 19, 2020 at 2:05

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