Linked Questions

12
votes
3answers
2k views

Height Issues of the Time Traveler [duplicate]

A person from the year 2250 goes back in time. They go back 60 Million years, because they want to observe dinosaurs. Imagine their surprise when they see T-Rex's running around like little chickens!...
1
vote
1answer
2k views

Do atoms expand with universe? [duplicate]

Possible Duplicate: Why space expansion affects matter? Why does space expansion not expand matter? As we know, the universe is expanding, galaxies are away from each other. But what about ...
1
vote
2answers
1k views

What is the implication of an expanding universe on a small scale? [duplicate]

As a layman I am struggling to understand what effects the fact that the universe itself expands has on distance, density etc. If the universe expands by a factor $k$, does that mean that the ...
1
vote
2answers
484 views

Expansion of the space-time metric [duplicate]

If the space-time metric is expanding with the expansion of the universe, if I could travel back in time, would I be less dense than the matter in that previous era?
1
vote
1answer
929 views

How do we know space is expanding when we are part of space? [duplicate]

From what I understand space itself is expanding, and the Big Bang attempts to describe this expansion at the very early stages of the universe. This is usually described in a visual way as 2 dots on ...
1
vote
1answer
847 views

What exactly is expanding when they say universe is expanding? [duplicate]

We know that universe is expanding and galaxies are moving away from each other. Does this mean the galaxies are also expanding in itself and therefore I guess growing larger in volume? Depending on ...
4
votes
4answers
226 views

Are atoms getting weaker? [duplicate]

If the universe is expanding, it would make sense that the spaces between particles are getting bigger. If this is so, then the particles which make up atoms are also affected. Does that imply the ...
0
votes
3answers
221 views

why isn't all space expanding? [duplicate]

Examining the metric tensor used to explain expansion, I see no reason why the expansion should not occur everywhere, i.e. between molecules, between the planets, between the stars in a galaxy, etc. ...
1
vote
1answer
150 views

Expanding metre sticks [duplicate]

Given the Universe is expanding. Therefore everything within the U is expanding, in all dimensions, subatomic to cosmic. Then all metre sticks are expanding. The question: How can we measure U ...
3
votes
1answer
463 views

What is the difference between matter & spacetime? [duplicate]

If the universe is expanding why doesn't the matter in it expand proportionally making it seem as if the universe is static? Alternatively, as spacetime expands why does it not just slide past matter ...
2
votes
2answers
267 views

Expanding universe and the speed of light [duplicate]

When physicists talk about the expanding universe they often say that the distant galaxies are not really "moving" away but instead the space itself between us and them is expanding. If this is true ...
3
votes
2answers
264 views

How does the gravity well change as space expands? [duplicate]

How does the gravity well change as space expands? If we assume that the Earth's gravitational field curves flat space to create a gravity well then how does the gravity well change as space expands ...
0
votes
1answer
129 views

Expansion of the universe in “everyday live” [duplicate]

According to space.com the universe is expanding with 75km/1Mpc/1s (megaparsec), which comes down to $\beta=2.43\times10^{-18}/s$, a relative rate per second. To put this in perspective: The average ...
-2
votes
2answers
161 views

Why should I believe that matter does not expand along with the space between it [duplicate]

This question has been asked before under other guises. I am not a scientific profesional however i have some schooling in pyhsics and mathematics and have a keen interest in these subjects. It seems ...
4
votes
2answers
258 views

Why doesn't everything expand when the universe expands? [duplicate]

Everybody has been taught at one point, "oh the universe expands, but that doesn't mean that everything is expanding uniformly, since that means we can't detect the expansion, but only that huge ...
1
vote
1answer
218 views

Does Red shift affect electron waves? [duplicate]

According to the De-Broglie Wave Hypothesis an electron can be considered to be a wave. Red Shift occurs due to the expansion of space(Cosmological red shift), which must expand even on the scale of ...
0
votes
2answers
214 views

Don't rulers expand at the same rate as the universe they measure? [duplicate]

If you placed a giant ruler between the sun and our nearest star for example, wouldn't the divisions on the ruler expand at the same rate as the universe - therefore maintaining a constant distance? ...
0
votes
2answers
77 views

We stretch as the universe does [duplicate]

Here's an idea I thought about; more of a thought experiment than anything: The universe is essentially the same as the universe 14 billion years ago, just stretched. However, all matter stretches ...
0
votes
1answer
180 views

Effect of Cosmological Expansion at the Atomic Level [duplicate]

Possible Duplicate: Why does space expansion not expand matter? Does cosmological expansion have any effects at the atomic level?
0
votes
2answers
163 views

Expansion of spacetime and matter [duplicate]

When space expands, light is said to be stretched or red-shifted. In fact, Penzias and Wilson discovered this in 1965 and were awarded the Nobel prize in Physics for this discovery. Now, what I am ...
1
vote
2answers
68 views

Is the “expansion of space” limited to intersteller space only? [duplicate]

Does the expansion of space (that started from BigBang) limited to expansion of intersteller space only (as observed by Hubble) or does it happen even in the local observable universe? Specifically, ...
0
votes
1answer
100 views

does space-time expansion affect on fundamental particle? [duplicate]

does space-time expansion affect on fundamental particle or point particle?
0
votes
1answer
67 views

As space expands does the density of matter remain same or increase? [duplicate]

I learned that space is always expanding. Even between sun and earth, it's just gravity is stronger. Imagine space as graph paper and there is a square object that fills it. Space expands, 1x1 cell ...
1
vote
2answers
100 views

If the universe is constantly expanding, shouldn't we go away from other planets? [duplicate]

I also saw that every point in the universe is the center. So what does it mean that the universe is expanding? It depends on the repository?
0
votes
1answer
65 views

Why redshift of light occurs between galaxies only? [duplicate]

Edwin Hubble discovery of redshift of distant galaxies make me wonder why is this phenomenon only occurs when object is further away, is it possible that redshift happens in short distance too such as ...
0
votes
1answer
60 views

What is meant by “space is expanding”? [duplicate]

Is it just the distance between galaxies that increases? Or is the distance increasing between the molecules in my body? Does expansion affect universal constants? Various sources I have heard on the ...
1
vote
1answer
77 views

According to some theories space is constantly expanding but at what granularity? [duplicate]

One idea from cosmology is that galaxies are all moving away from each other. Naively this could be taken to mean that they are expanding into something. Popularly this could be seen as them moving ...
1
vote
0answers
72 views

How is it possible to measure expansion of universe [duplicate]

Possible Duplicate: Why does space expansion not expand matter? If according to Hubble's law space the expanding then shouldn't everything else along with the space expand and we should not be ...
1
vote
1answer
54 views

If space expands, why does a liter of water stay a liter? [duplicate]

From observing the universe, we know that space expands. I see what that means on cosmic scales. But what does it mean on smaller scales? If I have a graduated beaker of 2 liter, and 1 liter of ...
0
votes
1answer
68 views

Universe expanding - Interstellar space, Intergalactic space or Intersupercluster space? [duplicate]

When we say that the universe is expanding, the space between everything is not. The space between atoms, the space between my house and school, and the space between Earth and Sun remains the same, ...

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