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Anujkumar
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When the universe is expanding then why not we are expanding along with it
Because expansion is so incredibly weak that gravitationally bound systems, and systems (such you you and me) bound by additional forces are not affected. Things as large as galactic clusters, and anything smaller, do not expandAnujkumar said:When the universe is expanding then why not we are expanding along with it
Well, if you don't like my answer don't accept it. I do suggest you do some research (which will show you that I have given you the correct answer). And by the way, "fabric" is a TERRIBLE way to describe the universe. Yes, I know Einstein used it, but he knew what he was talking about. For most people, it just leads to confusion.Anujkumar said:But according to the general relativity of Einstein the whole universe is a fabric of space and time and when this fabric of the space time is expanding then the effect must also occur in such a large structure because universe has a homogeneous entropy of space and time
But strong forces are short range forces ,and they only effective up to Fermi of distancerajaverma said:Take Earth ,not only gravitational but there are electromagnetic and strong nuclear forces so it might be compensating the effect
Anujkumar said:But strong forces are short range forces ,and they only effective up to Fermi of distance
Yes, but my understanding is that the issue is NOT that it is hard to detect, the issue is that it just doesn't happen. It's like an ant pushing on a house. It's not that the ant moves the house such a small amount that it's undetectable, it's that the ant doesn't move the house at all. The ant simply can't exert enough force to change the balance of the rest of the forcesPeroK said:The expansion is too small to notice in any case. For example:
The lifetime (80 years) expansion per meter is about ##6 \times 10^{-9}m##. Which would be hard to detect.
And, for the Earth's orbit round the Sun. The expansion of space would amount to about ##1km## in a lifetime. That would also be hard to detect, even if gravity didn't counteract it.
Expansion at the atomic level would also be undetectable and counteracted by other forces in any case.
Khashishi said:The solar system is very much smaller, so the fluid approximation is not at all valid.
As I said in my previous post, gravitational orbits are different than electromagnetic orbits. What do you mean by "binding forces" for a gravitational geodesic orbit? Expansion could conceivably make planetary orbits get larger over time. At the same time, the orbital velocity of the planets would decrease due to cosmological redshift consistent with the increase in radius from the Sun.PeterDonis said:it's just way too small to overcome the binding forces between those objects (let alone the binding forces between their atoms).
Khashishi said:What do you mean by "binding forces" for a gravitational geodesic orbit?
Khashishi said:Expansion could conceivably make planetary orbits get larger over time.
Khashishi said:the presence of dark energy means that the orbital velocity needs to be a very tiny bit less for a given radius than expected just from the gravity of the Sun to execute a stable circular orbit. There's no "accumulation over time" effect
How do you know we are not?Anujkumar said:When the universe is expanding then why not we are expanding along with it
petm1 said:Because we do not measure it, except with our accelerators.
petm1 said:We measure an accelerated expanding Earth at the surface, we do not measure this with our ruler, but we do measure it with our accelerators.
The term is accelerometer.petm1 said:We measure an accelerated expanding Earth at the surface, we do not measure this with our ruler, but we do measure it with our accelerators.
jbriggs444 said:The term is accelerometer.
Spacetime relativity is a scientific theory that explains the relationship between space and time. It was first proposed by Albert Einstein in his theory of general relativity. According to this theory, space and time are not separate entities but are connected and can be affected by gravity and the motion of objects.
The expansion of the universe is a key concept in spacetime relativity. According to the theory, the fabric of spacetime itself is expanding, causing galaxies and other objects to move away from each other. This expansion is also responsible for the observed redshift of light from distant galaxies.
The theory of universe expansion is supported by several pieces of evidence, including the observation of the redshift of light from distant galaxies, the cosmic microwave background radiation, and the abundance of light elements in the universe. Additionally, the predictions made by general relativity, such as the bending of light by massive objects, have been confirmed by numerous experiments.
Our understanding of spacetime relativity has greatly expanded our knowledge of the universe and our place in it. It has helped us to understand the origins of the universe, the behavior of objects in space, and the nature of gravity. It has also allowed us to make accurate predictions about the movement of objects in the cosmos.
Yes, there are several practical applications of spacetime relativity. One of the most well-known is the Global Positioning System (GPS), which uses the principles of general relativity to accurately calculate the position of objects on Earth. Additionally, general relativity has also been used to develop technologies such as gravitational wave detectors and time dilation correction in satellite communication systems.