Space expansion on smaller scales

In summary, the expanding space carries objects along with it on larger scales, but the effects on smaller scales are minimal due to the large timescales and the gravity holding galaxies together. The expansion does not cause objects within galaxies to pull apart. The fact that galaxies are moving with the expansion is due to their initial momentum from the big bang, rather than a direct causation. The current understanding is that the universe expands only over vast intergalactic distances, with nearby galaxies remaining relatively unaffected. This has been a topic of discussion and study, with more information available through researching Hubble expansion and gravity's role in the expansion.
  • #1
Galap
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0
Space is expanding. This is evident from the redshift of distant objects.

My question is what effect does it have on smaller scales? Since the expansion of space carries objects along with it (necessary for the objects to be farther) wouldn't the expansion within galaxies slowly pull them apart? wouldn't the expansion on planets exert a minute outward pressure? on smaller objects?

Of course due to the small distances involved (since the stretching of space is cumulative over distance i.e. that unit of length expands x, as does the next one) and the large timescales required, these effects would be miniscule, but they would be present, right?

Or is the fact that the galaxies are moving with the expansion not due to causation but due to a root common cause: i.e. space is expanding, but it does not carry objects with it. The reason galaxies move along with the expanding space is only due to their initial outward momentum from the big bang.

Which (if either) seems to be the correct model as to our current understanding? I'm a little bit confused...
 
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  • #2
You should do a search..this has been discussed many,many times. Or search Hubble expansion...here or Wikipedia.

The gravity holding galaxies together prevents expansion within galaxies...the universe expands only over vast intergalatic distances...adjacent galaxies are essentially not affected...for example, our Milky Way galaxy is going to collide with our nearest neighbor galaxy, the Andromeda galaxy
 

FAQ: Space expansion on smaller scales

What is space expansion on smaller scales?

Space expansion on smaller scales refers to the phenomenon of the universe expanding at a faster rate on smaller, local scales compared to larger scales. This is due to the presence of dark energy, a mysterious force that is causing the universe to accelerate its expansion.

How is space expansion on smaller scales measured?

Space expansion on smaller scales is measured using a variety of methods, including observations of the cosmic microwave background radiation, galaxy redshift surveys, and the use of standard candles like type Ia supernovae. These measurements allow scientists to track the expansion rate of the universe over time.

Why is space expansion on smaller scales important?

Understanding space expansion on smaller scales is important because it helps us to better understand the overall structure and evolution of the universe. It also has implications for the fate of the universe, as the rate of expansion will determine whether the universe will continue to expand forever or eventually collapse.

How does space expansion on smaller scales affect objects in the universe?

On a smaller scale, space expansion does not have a noticeable effect on objects like planets and stars. However, on larger scales, it can affect the distribution and movement of galaxies and other objects in the universe. As space expands, the distance between objects increases, causing them to drift farther apart.

Can space expansion on smaller scales be reversed?

Currently, there is no known way to reverse space expansion on smaller scales. However, there are theories that suggest the expansion rate may slow down or even reverse in the distant future due to the effects of dark energy. Further research and observations are needed to better understand the nature of dark energy and its impact on space expansion.

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