Dreams are weird, especially when you fall from a cliff, jolting you out of your sleep. But ever wondered what would happen if you fell into a hole through the center of the Earth? It can happen only in dreams!
One of the great things about theoretical physics is that you can ask absurd questions and calculate equally weird answers. Like, a free fall through the center of the Earth!
If you want to consider it really, you can assume that you could dig a hole that was straight out to the other side of the Earth. If the hole has a strong wall, it won’t need to collapse or melt. What would happen if you fell into this hole?
Before jumping into the hypothesis of the situation, let’s discuss a few detrimental factors which need to be considered for the scenario. Let’s talk about all the possibilities that could happen if you fall through the center of the Earth.
Things To Consider While Falling Through The Centre Of The Earth
1. Layers of the Earth
- Crust: The crust is the topmost thin layer of rocks and soil that constitutes the continents and the ocean bed. The crust is not solid but is divided into several tectonic plates. These tectonic plates are not static but move relative to each other. The atmospheric pressure here is 1, and the surface temperature is normal.
- Mantle: Underneath the crust, the mantle can reach a thickness of 2900 km. It is made up of hot, dense, iron-rich solid rock rich in magnesium and iron. The lithosphere, divided into big and small plates, comprises the crust and the uppermost portion of the mantle.
- Core: The inner core is solid, while the outer core is liquid, making up the core, which is the planet’s center. Nickel, iron, and molten rock make up the outer core. Here, temperatures can rise as high as 50,000 C, and you can only imagine the pressure!
2. Earth’s Gravitational Force
Asteroids, planets, stars, galaxies, superclusters, and other objects with mass are drawn toward one another by the natural phenomenon known as gravity. An object’s gravitational pull on nearby objects increases with mass. As a result, when the distance between two objects increases, the gravitational force exerted on that object diminishes.
The Earth exerts a force of approximately 9.8 m/s² on each gram of matter towards its center. At the tiniest scales, gravity has little impact on the matter (i.e., subatomic particles). However, gravity is the main factor influencing matter interactions at the macroscopic level, including planets, stars, galaxies, etc.
The force doesn’t sound or feel much of a thing, but it becomes dramatic with large, heavy objects falling from huge heights. It would be a dominant factor while free falling through the Earth’s center.
Additionally, the gravitational pull varies depending on where you stand on Earth. The rotation of the Earth is the first explanation. It indicates that the Earth’s gravity is 9.789 m/s2 at the equator and 9.832 m/s2 at the poles. Therefore, the centripetal force causes you to weigh more at the poles than at the equator, but only slightly.
3. Extreme Conditions Human Bodies Can Withstand
- Temperatures: A human can survive at a maximum body temperature of 108.14 degrees Fahrenheit. The body becomes scrambled eggs at higher temperatures: proteins become denatured, and the brain gets irreparable damage.
- Cold Water: Body heat is lost when in cold water. An individual may last for a maximum of 30 minutes in a lake that is 39.2°F cold. The cause is a quick rise in the blood concentration of stress hormones, which stimulates the body’s ability to produce heat. Additionally, chilly shivering begins abruptly to generate heat through the muscles. However, shivering in cold water causes body heat to evaporate much more quickly than in cold air. The body supercools, and the muscles immediately become exhausted.
Shivering ends as soon as the body temperature drops to between 89.6 and 86 °F and energy reserves are used up. The cold paralyzes the nerve endings and causes muscles to stiffen. It explains why you can no longer experience cold or discomfort.
Even a rapid increase in temperature could be harmful too. The blood vessels in the skin and extremities dilate, and the blood pressure drops quickly. The circulatory system is at risk of collapsing when submerged in cold water.
- Hot Environment: The humidity has a major impact on how long you can endure the heat; the lower the humidity, the longer you can endure. Adults may survive for 3 to 4 minutes in a sauna at 230°F and up to 10 minutes in a burning house, provided they don’t pass out from the carbon monoxide.
Children succumb to high ambient temperatures much more quickly; for example, after a few minutes in a car that has been heated to 122°F.
- Extreme Heights: Altitude sickness often begins with headache and vertigo about 1.6 miles above sea level. Most individuals lose consciousness around 2.8 miles in altitude, and if you climb too rapidly, you might die from pulmonary edema. Blood with less oxygen makes the vessel membranes more porous, allowing more blood plasma to reach the tissue.
- Extreme Depths: If a person dives without a scuba tank deeper than 59 inches, they will at most lose consciousness after two minutes. The air is squeezed more, and your lung capacity is reduced the deeper you dive.
The lungs are squeezed to their maximum expiration depth at 82 to 114 feet due to intense pressure. Lung edema results from tissue fluid moving to the lungs as you dive deeper.
- Loss of Blood: A person may make up for a 30% reduction in blood volume. Blood loss causes death by acidosis, micro thrombosis, volume deficiency shock, and insufficient circulation. So it’s critical to replenish blood as soon as feasible. A transfusion, ideally with concentrated red cells, is necessary for blood loss of 40%.
- No Oxygen: A person usually passes out after two minutes of not having oxygen. Blood oxygen allows the human body to survive. Fitness level and other factors determine this from person to person.
Electric brain activity ends within 20 seconds without oxygen, and humans become comatose. After two to three minutes, the brain stem, which regulates respiration and blood circulation, and the cortex both suffer damage. After five minutes, irreparable brain damage occurs, and a person can only survive in a chronic vegetative condition.
A person is considered clinically dead after 10 minutes without oxygen. It’s hard to believe, but 22 minutes is the world record for breathing capacity.
Now that we know the limits of the human species, let’s attempt a free fall through the center of the Earth. Are you ready? Let’s go!
What Happens After You Fall Into A Hole Through The Centre Of The Earth?
Naturally, you would tumble and gain speed as you did so. The pull of gravity would weaken and finally stop as you got closer to the Earth’s center, but inertia would keep you moving. You would begin to slow down at the same rate you would accelerate once you were past the center.
But before you can reach the center, you’ll experience roughly 20 atmospheres of air pressure and pass out from hyperoxia after descending about 0.15 kilometers. Your body will be crushed further by the severe air pressure the further you fall. Remember that the air bearing down on you directly, not the rocks, is the source of this pressure. It is only 0.002% of the distance to the Earth’s center.
You will lose your eyesight and become less able to make decisions after about ten seconds, and the chilling impact of evaporation will cause your mouth and nose to become nearly frozen. A few seconds later, cyanosis (blue skin coloring) would become obvious, followed by unconsciousness and spasms.
You reach a temperature of around 320 Kelvin after descending 1.1 kilometers (0.02% of the distance to the Earth’s center), at which point you pass out from heat exhaustion. Your corpse reaches a temperature of around 400 Kelvin after falling a total distance of about 2.7 kilometers (0.04% of the way to the center of the Earth), at which point your body fluids start to boil away.
Your dried-up bones and flesh scraps meet a temperature of around 1200 Kelvin while plummeting to a depth of about 200 kilometers (3% of the way to the heart of the Earth), where they are entirely consumed into dust. The remainder of the 6200 kilometers, or 97% of your dust, will fall to the planet’s core.
Going deep underground is typically not a good idea, as should be evident. You don’t get very far in a pressure suit before being burned to death by the heat. You may feel the heat even if you are not touching the tunnel walls. These temperatures apply to the tunnel’s actual air.
What If You Wear A Futuristic Pressure Suit While Jumping Through The Centre of The Earth?
Assume for the moment that you can wear a futuristic pressure suit that can shield you from any pressure. In this pressure suit, let’s say you’ve been protected from pressure, heat, toxic gases, and radiation effects for the sake of argument. Then what happens?
Because of the Earth’s gravity, you gain speed as you descend. You arrive at a top speed of around 200 kilometers per hour after 10 seconds and have descended 0.5 kilometers (0.008% of the distance to the Earth’s center), which is about 120 mph.
You cannot accelerate further at this speed because of high air resistance. Since more of the mass of the Earth is above you, gravity becomes weaker as you fall further. By doing so, the gravitation from the other side of the planet is canceled.
Additionally, as you descend through the center of the Earth, the air pressure increases, increasing the resistance to your motion. Your speed slowly decreases as air resistance and gravity both become more powerful.
You ultimately arrive at the precise center of the Earth after falling for roughly a week (at a maximum speed of 200 km/h, it takes some time to cover the 6400 km to the center). Because there is an equal quantity of matter in every direction and each direction has an equal gravitational force, there is no gravitational attraction at the planet’s center.
At this point, the air inside the hole feels like soup. As you keep moving through the hole, you will overshoot the center of the Earth because of your small amount of momentum.
However, as you pass the Earth’s center, “down” is heading in the opposite direction. You keep falling back toward the Earth’s center, overshooting it due to your velocity, and then falling back oppositely. Therefore, you must slow down and change course before going very far beyond the center.
This motion resembles a yo-yo or a kid who keeps missing the bottom of a playground swing. You ultimately run out of velocity and cease spinning around the planet’s center in such dense air. You wind up floating helplessly at the planet’s center.
What If The Tunnel Is Completely Evacuated?
There wouldn’t be any air resistance if there weren’t air. As a result, you would accelerate as you fell, reaching a top speed of around tens of thousands of kilometers per hour. You will feel weightless, like an astronaut in space.
Instead of taking weeks, you may get to the planet’s center in minutes or hours. You are traveling so quickly that you entirely miss the center of the world. Just as you leave the hole and go to the opposite side of the planet, your speed has dwindled to nothing. Gravity is now working against you as you pass through the other end of the hole, slowing you down.
As far as energy conservation is concerned, this makes sense. Your starting point was on one side of the world, so your endpoint must be on the other side. It will be the case if air resistance doesn’t lose any energy.
In The End
All of the affairs mentioned above would happen within less than 45 minutes. The deepest dug by man is the Kola well in Russia, only 12 km deep. Even at the backside of this hole, humans are only about 0.3% closer to the core than to the surface. So, we understand that digging a hole through the Earth’s center is impossible.
An explosion would occur even if we drilled a hole as small as your palm straight through the Earth’s core. A catastrophe like this would entirely wipe out the entire surface of Earth and kill every living thing. Wouldn’t this be pretty selfish for a thrill-seeking experience?
What do you think about this theory? Comment down your questions and tell us if you want to see more of such hypothetical situations!