<p><a href="https://iopscience.iop.org/article/10.3847/PSJ/abefda" rel="noreferrer">Robertson et al. (2021)</a> (note the <a href="https://iopscience.iop.org/article/10.3847/PSJ/aca1a7/pdf" rel="noreferrer">erratum</a>) provide a very comprehensive answer to your question.</p>
<p>Surprisingly (to me) the asteroidal flux (impacts per unit area) is slightly higher at the poles (by 8%) than at the equator.</p>
<p>However, the impact angles tend to be slightly shallower at the equator, which leads to airbursts that are more dangerous for smaller asteroids. Larger asteroids reach the ground whatever and so the lower flux at the equator means slightly less risk. Asteroid velocities are similar at all latitudes.</p>
<p>Note that asteroids would hit the Earth at greater than the Earth's escape velocity and have a similar density to the Earth. They are unlikely to be captured and unlikely to be broken up by tidal forces before entering the atmosphere unless they were so large they would end all life on Earth.</p>
<p>Your best bet is to always stay at the point on Earth that is antipodal to the direction of motion in its orbit around the Sun, since the flux will be higher from that direction and the incoming relative velocities larger. Of course, the Earth spins, so that is difficult...</p>
<p>EDIT: To address some comments on the question. The break up timescale of a gravitationally bound asteroid is going to be a small multiple of the freefall timescale of <span class="math-container">$\tau_{ff} \simeq (G\rho)^{-1/2}$</span>, where <span class="math-container">$\rho \sim 3000$</span> kg/m<span class="math-container">$^3$</span> for a typical asteroid density and <span class="math-container">$\tau_{ff} \sim 2000$</span> s.</p>
<p>At a minimum closing relative velocty of <span class="math-container">$\sim 11$</span> km/s, the asteroid will travel <span class="math-container">$&gt;20,000$</span> km during <span class="math-container">$\tau_{ff}$</span>, but given that the Roche radius will not be much larger than the Earth's radius, it will already have impacted before it has any chance to respond to tidal forces.</p>

CC BY-SA 4.0
2024-02-13T15:52:06.380Z
Re your last paragraph: This suggests flying in a jet that keeps you at the antipode? But if you're already in a jet you should be able to just fly away from the impact area (I assume astronomers can predict it in time).
Barmar
CC BY-SA 4.0
2024-02-13T16:54:04.747Z
And the thicker atmosphere at the equater would also likely help.
SoronelHaetir
CC BY-SA 4.0
2024-02-13T17:00:11.600Z
@Barmar you might find that tickets are quite expensive...
ProfRob
CC BY-SA 4.0
2024-02-13T20:06:52.100Z
Just keep that airplane flying into the evening sunset at all times at because the sunrise and the dawn is where the asteroids hit, it's like the front side and the back of a car driving into the rain, the dawn is the front side and the dusk is the back.
bandybabboon
CC BY-SA 4.0
2024-02-14T11:15:27.260Z
Please note there has been an erratum issued for this article. See https://iopscience.iop.org/article/10.3847/PSJ/aca1a7/pdf
Pierre Paquette
CC BY-SA 4.0
2024-02-14T12:29:16.460Z
@PierrePaquette thanks. I made an edit. The answer is qualitatively the same, but "slightly" becomes even more slightly.
ProfRob
CC BY-SA 4.0
2024-02-15T10:00:53.077Z
Now I'm imagining a Snowpiercer sequel where it's just a train trying to minimize the risk of getting hit by a meteor in an otherwise unchanged world.
Grooke
CC BY-SA 4.0
2024-03-03T18:14:16.610Z
@Grooke this is a good premise to a movie and a bullet train would be needed. With Earth rotating about 1000 mph a train rail at 600 mph circling the Earth would be needed about 54 degrees north or south of the equator. Cities in the North would be  Tromsø, Norway, Murmansk, Russia, Reykjavik, Iceland, Fairbanks, Alaska, USA,Rovaniemi, Finland, Anchorage, Alaska, USA, Kiruna, Sweden.
Nuuk, Greenland (Denmark), Yellowknife, Canada
Justintimeforfun
CC BY-SA 4.0
2024-02-13T07:20:22.663Z
2024-02-14T12:28:25.470Z
2024-02-14T12:28:25.470Z
ProfRob
<p>Where on Earth is statistically safer if an asteroid was to break up in the Roche limit and rain meteorites effectively resetting the Earth? I would imagine that a ring of falling meteors would form around the equator making the poles more safe?</p>

CC BY-SA 4.0
2024-02-13T07:16:24.210Z
You seem to suppose that an asteroid will get captured into an Earth orbit. The orbit will decay to the point that the roche limit is passed and the asteroid breaks up.  But that is the most unlikely scenario. Far more likely is that the asteroid just hits the Earth. And it could hit anywhere.
James K
CC BY-SA 4.0
2024-02-13T13:42:24.423Z
Most asteroids are not held together by gravity, but are simply solid chunks of rock. They won't be pulled apart at the Roche limit.
Nuclear Hoagie
CC BY-SA 4.0
2024-02-13T15:34:38.403Z
@NuclearHoagie I'm not sure we can say with clarity what the makeup of "most" asteroids is. Recent missions suggest that more asteroids are rubble-piles than previously thought.
Darth Pseudonym
CC BY-SA 4.0
2024-02-13T17:09:11.527Z
The asteroid can travel many Roche radii in the timescale on which it might fall apart. Therefore tidal break up can be neglected (see edit in my answer), even for rubble piles.
ProfRob
CC BY-SA 4.0
2024-02-13T23:30:31.697Z
The safest place is in a deep cave.
Mark
CC BY-SA 4.0
2024-02-14T01:11:28.987Z
What does "effectively resetting the Earth" mean?
PM 2Ring
CC BY-SA 4.0
2024-02-14T05:34:40.683Z
If you fear that the asteroid is big enough to be capable of "resetting the Earth" (aka leading to at least the collapse of modern civilization, if not extinguishing of life), then the best place to be would be directly at the site of impact, otherwise you will starve to death even if you somehow survived the impact itself. Unless you somehow have a self-sustaining bunker deep below the surface, with enough spare parts to sustain it until you die of old age, but it seems the question was more about a geographic location.
vsz
CC BY-SA 4.0
2024-02-15T00:33:05.043Z
@JamesK: (sorry for my bad nomenclature) I would assume that an asteroid is slightly more likely to hit us if its orbit aligns with our orbital plane compared to being orthogonal to it (for the same reason you're more likely to shoot someone who runs in a straight line at/away from you as opposed to someone who runs orthogonal to your shot). Doesn't that suggest that the poles are harder to hit than the equator? That being said, I'm not claiming that direct impacts are the sole source of danger, but if we ignore planetkillers (since they're "game over") is the impact less likely on the poles?
Flater
CC BY-SA 4.0
2024-02-15T10:35:36.560Z
Safest place would be a few hundred metres under the sea, right?  Only the biggest meteorites would be a threat, and the smaller ones would have their velocity reduced so much that it would be like a stone falling at a few cm/s by the time it came near to your underground lair, Mr Bond.
Neil
CC BY-SA 4.0
2024-02-15T15:20:47.917Z
Seated next to Elon Musk.
eshaya
<earth><meteorite><roche-limit><impact-probability>
Safest Place on Earth from Falling Meteorites
Justintimeforfun
# Safest Place on Earth from Falling Meteorites

(Asked by: username_0 on 2024-02-13)

Where on Earth is statistically safer if an asteroid was to break up in the Roche limit and rain meteorites effectively resetting the Earth? I would imagine that a ring of falling meteors would form around the equator making the poles more safe?

**Tags:** earth, meteorite, roche-limit, impact-probability

> **Comments:**
> **username_1**: You seem to suppose that an asteroid will get captured into an Earth orbit. The orbit will decay to the point that the roche limit is passed and the asteroid breaks up.  But that is the most unlikely scenario. Far more likely is that the asteroid just hits the Earth. And it could hit anywhere.  
> **username_2**: Most asteroids are not held together by gravity, but are simply solid chunks of rock. They won't be pulled apart at the Roche limit.  
> **username_3**: @username_2 I'm not sure we can say with clarity what the makeup of "most" asteroids is. Recent missions suggest that more asteroids are rubble-piles than previously thought.  
> **username_4**: The asteroid can travel many Roche radii in the timescale on which it might fall apart. Therefore tidal break up can be neglected (see edit in my answer), even for rubble piles.  
> **username_5**: The safest place is in a deep cave.  
> **username_6**: What does "effectively resetting the Earth" mean?  
> **username_7**: If you fear that the asteroid is big enough to be capable of "resetting the Earth" (aka leading to at least the collapse of modern civilization, if not extinguishing of life), then the best place to be would be directly at the site of impact, otherwise you will starve to death even if you somehow survived the impact itself. Unless you somehow have a self-sustaining bunker deep below the surface, with enough spare parts to sustain it until you die of old age, but it seems the question was more about a geographic location.  
> **username_8**: @username_1: (sorry for my bad nomenclature) I would assume that an asteroid is slightly more likely to hit us if its orbit aligns with our orbital plane compared to being orthogonal to it (for the same reason you're more likely to shoot someone who runs in a straight line at/away from you as opposed to someone who runs orthogonal to your shot). Doesn't that suggest that the poles are harder to hit than the equator? That being said, I'm not claiming that direct impacts are the sole source of danger, but if we ignore planetkillers (since they're "game over") is the impact less likely on the poles?  
> **username_9**: Safest place would be a few hundred metres under the sea, right?  Only the biggest meteorites would be a threat, and the smaller ones would have their velocity reduced so much that it would be like a stone falling at a few cm/s by the time it came near to your underground lair, Mr Bond.  
> **username_10**: Seated next to Elon Musk.  

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## 1 answers

### Answer by username_4 on 2024-02-13. Score: 29 | Accepted answer

[Robertson et al. (2021)](https://iopscience.iop.org/article/10.3847/PSJ/abefda) (note the [erratum](https://iopscience.iop.org/article/10.3847/PSJ/aca1a7/pdf)) provide a very comprehensive answer to your question.

Surprisingly (to me) the asteroidal flux (impacts per unit area) is slightly higher at the poles (by 8%) than at the equator.

However, the impact angles tend to be slightly shallower at the equator, which leads to airbursts that are more dangerous for smaller asteroids. Larger asteroids reach the ground whatever and so the lower flux at the equator means slightly less risk. Asteroid velocities are similar at all latitudes.

Note that asteroids would hit the Earth at greater than the Earth's escape velocity and have a similar density to the Earth. They are unlikely to be captured and unlikely to be broken up by tidal forces before entering the atmosphere unless they were so large they would end all life on Earth.

Your best bet is to always stay at the point on Earth that is antipodal to the direction of motion in its orbit around the Sun, since the flux will be higher from that direction and the incoming relative velocities larger. Of course, the Earth spins, so that is difficult...

EDIT: To address some comments on the question. The break up timescale of a gravitationally bound asteroid is going to be a small multiple of the freefall timescale of $\tau\_{ff} \simeq (G\rho)^{-1/2}$, where $\rho \sim 3000$ kg/m$^3$ for a typical asteroid density and $\tau\_{ff} \sim 2000$ s.

At a minimum closing relative velocty of $\sim 11$ km/s, the asteroid will travel $>20,000$ km during $\tau\_{ff}$, but given that the Roche radius will not be much larger than the Earth's radius, it will already have impacted before it has any chance to respond to tidal forces.

> **Comments:**
> **username_11**: Re your last paragraph: This suggests flying in a jet that keeps you at the antipode? But if you're already in a jet you should be able to just fly away from the impact area (I assume astronomers can predict it in time).  
> **username_12**: And the thicker atmosphere at the equater would also likely help.  
> **username_4**: @username_11 you might find that tickets are quite expensive...  
> **username_13**: Just keep that airplane flying into the evening sunset at all times at because the sunrise and the dawn is where the asteroids hit, it's like the front side and the back of a car driving into the rain, the dawn is the front side and the dusk is the back.  
> **username_14**: Please note there has been an erratum issued for this article. See https://iopscience.iop.org/article/10.3847/PSJ/aca1a7/pdf  
> **username_4**: @username_14 thanks. I made an edit. The answer is qualitatively the same, but "slightly" becomes even more slightly.  
> **username_15**: Now I'm imagining a Snowpiercer sequel where it's just a train trying to minimize the risk of getting hit by a meteor in an otherwise unchanged world.  
> **username_0**: @username_15 this is a good premise to a movie and a bullet train would be needed. With Earth rotating about 1000 mph a train rail at 600 mph circling the Earth would be needed about 54 degrees north or south of the equator. Cities in the North would be  Tromsø, Norway, Murmansk, Russia, Reykjavik, Iceland, Fairbanks, Alaska, USA,Rovaniemi, Finland, Anchorage, Alaska, USA, Kiruna, Sweden. Nuuk, Greenland (Denmark), Yellowknife, Canada  

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