Gravity train – What if we dug a tunnel through the Earth?
Introduction – Gravity Train: If we dig a tunnel between any two points on Earth, We can take advantage of the Earth’s gravity. Instead of travelling between two antipodes, you could travel a much shorter distance without piercing so far down. This concept is called a Gravity Train. For example, you could build a shallow tunnel from London to Paris that only goes down about 55 kilometres. Evacuate the tunnel, and the gravity train is pulled down for half the journey, then decelerates naturally for the second half. And amazingly, the trip still only takes 42.2 minutes. No matter which two points you connect, the journey will only take 42 minutes.
Origin Of Gravity Train Project-
In the 17th century, British scientist Robert Hooke presented the idea of an object accelerating inside a planet in a letter to Isaac Newton. A gravity train project was seriously presented to the Paris Academy of Sciences in the 19th century.
What is a gravity train?
The Gravity Train proposes an alternative travel method allowing passengers to go from one end of the earth to the other in 42 minutes. The theory behind the gravity train is that it would work much like a rollercoaster. The train would require no fuel, using the sheer force of gravity to accelerate through a channel in the middle of the earth. During the first half of the trip, the downwards pull of gravity towards the centre would fire the train along towards its destination. During the second half, its inertia would go against gravity, causing the acceleration to reverse directions and slow the train down as it neared the end of its journey. The train would allow passengers to get to and from anywhere in the world in roughly 42 minutes. The reason shorter distances would be equal in time to longer ones is that the train’s maximum speed would be increased exactly enough to make up the difference.
Problems of Converting Gravity Train Idea into Reality
Of course, there are some obvious problems with the gravity train idea.
- First of all, the train’s transit tunnel would bore through the earth’s mantle, crossing a region where no known materials have been able to endure the incredible heat, pressure, and melted rock.
- Secondly, friction losses would be extreme, which means the train would have to somehow develop enough horsepower to compensate.
- The biggest problem of all, we need a huge amount of money, Although the gravity train is far from becoming a reality at this stage, scientists have not yet closed the book on this idea, and it is quite possible that some day we will have the technology necessary to bring it to life.
Conclusion: Yes. A gravity train is theoretically possible. It does not violate any known laws of physics, and it is not logically impossible. And from the calculation, we see that it will take a fixed time approx. 42 minutes to travel from any two points of the earth’s surface.
Why Gravity Train is nearly impossible?
The train itself would work, no question. (Though we would need to maintain vacuum in the tunnel.) The trouble is that, even if we could drill the tunnel (and we can’t), we have no way to keep it from collapsing. Much of the length of the tunnel would be subject to pressures of tens of millions of pounds per square inch and temperatures at which no known substance could stay solid (unless subjected to those tens of millions psi uniformly all around. The best we can do without force fields or unobtainium tubes is probably to run chords through the outer crust, no deeper than 20 km (much deeper than that, and any empty metal tube we drop there would be squished like an empty soda can.) At 20 km depth in the middle, that gives us a maximum range of about 1000 km. The whole thing is basically a stupid version of Hyperloop. We still have to run tubes; we still have to evacuate them and do some sort of maglev and low friction rails as backup, and we still need motors because the capsule will not travel 100% for free, there will be _some_ friction, and it will need to be helped for the last portion of the climb. However, instead of laying tubes on Earth’s surface, we go to the insane expenses of boring a 1000 km tunnel through bedrock. So, for our future, we should invest in a hyperloop instead of a gravity train.
