Understanding General Relativity: Gravity Warping Space-Time

In summary: The premise doesn't make sense and the general relativity effects would be negligible. The heavier the locomotive, the more energy is required to maintain its speed.
  • #1
Bobbyam
3
0
Hi, I was an armchair student of physics some time ago, so I appreciate your patience with me. I was on a tour of the lost Atlantic Avenue tunnel in Brooklyn and I'm hoping someone can give me more insight, perhaps an analogy, to help me imagine this better. If I understood him right, this was mind blowing to me because for the first time I could glimpse actually understanding something of general relativity. The tour guide said that the heavier a locomotive is, the less energy is required to maintain its speed. This is because gravity is warping space time, like a bowling ball in a mattress, and the heavier locomotive, having more mass and more gravity, is actually "falling" through a space-time hole. Is this right? Can anyone add to it? Thank you.
 
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  • #2
None of that is true, or even vaguely accurate. Sorry.

Most blatantly, the overall premise doesn't make any sense: the more massive a locomotive is, the more energy is required to keep it going---even neglecting high order effects (i.e. the details of the wheels, engine, air-resistance, wheel-track interface, etc).

For instance: how much energy does it take to keep a model train going? Is that more or less than a full size locomotive?

Now, as far as the general relativity: any GR effects for a locomotive staying on the surface of Earth would be extremely negligible. Like, extremely, extremely. Even more importantly, if---for some reason---GR effects were important, they would still make it harder to maintain a given speed for a larger mass.
 
  • #3
Thank you!
 
  • #4
Bobbyam said:
Hi, I was an armchair student of physics some time ago, so I appreciate your patience with me. I was on a tour of the lost Atlantic Avenue tunnel in Brooklyn and I'm hoping someone can give me more insight, perhaps an analogy, to help me imagine this better. If I understood him right, this was mind blowing to me because for the first time I could glimpse actually understanding something of general relativity. The tour guide said that the heavier a locomotive is, the less energy is required to maintain its speed. This is because gravity is warping space time, like a bowling ball in a mattress, and the heavier locomotive, having more mass and more gravity, is actually "falling" through a space-time hole. Is this right? Can anyone add to it? Thank you.
So, not knowing the situation, is this locomotive going down in a tunnel or traveling flat in a tunnel?
 
  • #5
It's supposedly on a perfectly flat grade.
 
  • #6
Bobbyam said:
It's supposedly on a perfectly flat grade.
In that case I fully agree with zhermes
 

FAQ: Understanding General Relativity: Gravity Warping Space-Time

1. What is general relativity?

General relativity is a theory of gravity developed by Albert Einstein in the early 20th century. It explains how gravity works by describing the relationship between mass, space, and time. According to general relativity, gravity is not a force between masses, but rather the effect of objects with mass curving the fabric of space-time.

2. How does general relativity explain gravity?

General relativity states that the presence of mass and energy warps the fabric of space-time, causing objects to follow curved paths. The more massive an object, the more it warps space-time, and the stronger its gravitational pull. This explains why objects with mass are attracted to each other, as they are simply following the curvature of space-time created by their mass.

3. What is the significance of general relativity?

General relativity revolutionized our understanding of gravity and space-time, and it has been confirmed by numerous experiments and observations. It is essential for understanding the behavior of large-scale objects, such as planets, stars, and galaxies. It also plays a crucial role in modern technologies, such as GPS and satellite communications.

4. How does general relativity differ from Newton's theory of gravity?

Newton's theory of gravity, also known as classical mechanics, describes gravity as a force between masses and does not consider the curvature of space-time. General relativity, on the other hand, describes gravity as the curvature of space-time caused by the presence of mass. While Newton's theory is accurate for everyday situations, general relativity is required for understanding the behavior of massive objects or objects moving at high speeds.

5. Is general relativity still a valid theory today?

Yes, general relativity is still a valid and widely accepted theory today. It has been extensively tested and confirmed by experiments and observations, and it has not been disproven or replaced by any other theory. However, it is always possible that future discoveries may lead to a better understanding of gravity and space-time.

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