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Question on the expanding universe?
Since the universe is expanding after the big bang, galaxies are moving away from each other as first determined by Hubble. But, our solar system and our galaxy (and any galaxy we look at) is not expanding. To bring the point down even further, the earth and its parts (down to atoms and sub atomic particles) are not expanding either. If everything was expanding at the same rate, we could not detect the expansion.
How can the universe be expanding but the individule parts not be?
17 Answers
- gp4rtsLv 71 decade agoFavorite Answer
I just attended a course in modern physics in which the expansion of the universe was discussed. It just happens that I asked almost the same question of the instructor. The answer he gave was that the expansion applied to objects within space-time, but not to the structure of objects. This applies not only to atoms and physical objects made of atoms but even to galaxies and galactic clusters, which also do not expand with the universe. Unfortunately, he could not explain further except to say that he called Brian Greene (author of "The Fabric of the Cosmos") and confirmed that fact. It apparently has something to do with the forces holding the structures together; atomic/molecular forces for objects and gravitational forces for galaxies.
I think part of the answer is that the concept of the expansion of the universe is embodied in the solution of Einstein's equation of General Relativity, and I thought that the solution to those equations for uniformly distributed matter meant that space-time itself is expanding. What I think now is that the solution represents the behaviour of uniformly distributed isolated particles interacting. The solution describes the motion of physical units, not space-time. Apparently physical objects, galaxies and galactic clusters behave as independent physical units, while their components do not.
- Chug-a-LugLv 71 decade ago
The simple way to understand the reason you're not expanding is that you are held together by electromagnetic forces. These
electromagnetic forces are strong enough to overpower the expansion of the Universe. So you do not expand. Similarly, the Earth is held together by a combination of electromagnetic and gravitational forces, which again are strong enough to overpower the Universe's expansion.
On even larger scales---those of the Solar System, the Milky Way, even the Local Supercluster of galaxies (also known as the Virgo Supercluster)---gravity alone is still strong enough hold these objects together and prevent the expansion. Only on the v
ery largest scales does gravity become weak enough that the expansion can win
- Anonymous1 decade ago
The universe is not expanding. It has its own cycle just as the mass of the Sun moves up to the surface, emits energy then boils down to the core of the Sun; just as the earth's water has a cycle of under currents from poles to equator and then to the other pole to keep its temprture constant; just as every galaxy has black holes to rotate the mass/energy stars to control everything in the galaxy....in a similar fashion everything in this universe has a cycle of its own. Everything is changing and yet everything is in equilibrium with the other. This everything is the physical universe which is only 20% of the dark unseen universe. The physical universe has energy, mass, space and time which are again in equilibrium with each other. The dark unseen universe has energy only called dark energy. This is dark because it can not be detected by our senses as our senses are
made to detect only change in energy because we are born in the changing universe called physical universe. To conclude I can say the universe is not expanding but changing. It is also exchanging energy to keep the identity just as small ripples, bubbles, waves, sunami waves in an ocean. For the little twig floating on these waves , the waves and the ocean will be expanding so we as well as our small home called the Earth is a small twig in the ocean of Energy - Called the universe. So the universe is not expanding but completing its cycle. It seems to be expanding but it is an illusion and nothing more.
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- Anonymous1 decade ago
The individual parts are bound by their gravitational attraction to each other. To measure true Hubble Flow, you have to look at least several 100 million light years out. For example, our local group of about 12 galaxies is gravitationally locked together. Our next door neighbor, the Andromeda Galaxy, is actually moving towards us on a collision course. But on even larger scales (megaparsecs) everything is moving away from everything else. Our local group of galaxies is being gravitationally attracted to an even bigger group of galaxies called the Virgo Cluster (because the cluster is in the constellation Virgo). That group of 1000's of galaxies is attracted to the Virgo Supercluster (tens of thousands of galaxies). The Virgo Supercluster is attracted to a wall of hundreds of thousands of galaxies, aptly named the "Great Wall." It doesn't stop there. To answer your question, though: Empty space itself is expanding, and everthing in it is moving apart from everything else because these "individual parts" are all in the same ever-expanding volume of empty space (i.e., our Universe). It's a pretty complex subject to wrap your mind around. I can recommend some good cosmology books below:
Source(s): Tim Ferris -- The Whole Shebang Brian Greene (MIT professor and particle physicist) - The Elegant Universe Brian Greene - The Fabric of the Cosmos - How do you think about the answers? You can sign in to vote the answer.
- wacky_racerLv 51 decade ago
The natural reaction is in the situation of the sub atomic particles! Heat expands them, colds shrinks them together.
So, I may say that the two or more atomic particles have collided in the first place, which brings us into the Big Bang of the Universe.
Source(s): I was not absent on this one. - Anonymous1 decade ago
The galaxies are expanding from the point of origin, the singularity that preceeded the big bang. If you throw a baseball the atoms don't expand (at least in any measurable context )
- 1 decade ago
you will get all stupid answers, balloon swelling. red shift, bla bla. Even a child will laugh at these explanations. Adults should make some sense when they write something.
no body will explain you how is it possible for universe to expand but not solar system.
believe me, it is impossible for the universe to expand without solar system expanding too. no balloon or any other analogy can explain it.
another point; big bang and stupid red shift etc tells us that all galaxies are moving away from each other, then we also read news like our galaxy is going to collide with andromedia galaxy; how is it possible; if everything moving away from each other how can galaxies collide;
aren't these scientists contradicting themselves??
- brainiacLv 41 decade ago
we detect the expansion by the red shift in light that comes from stars. stars look redder than they are because they are moving away from us.
the big bang was not an explosion of matter in the middle of empty space...it IS space istself that is expanding.
the empty space between galaxies is getting bigger.
besides if atoms were getting bigger, how could you tell?
if you measure something, then measure the same thing later it would measure the same even if it is getting bigger because your ruler is expanding at the same rate! and so are you!
- ?Lv 44 years ago
The very premise of your question is wrong. area is a actual components of the universe - it replaced into created on the 2d of the huge bang. in the previous the BB, it only did no longer exist. that is basic to image the singularity that went growth putting in a great darkish void waiting for some thing to set it off, yet that's totally incorrect. There wasn't everywhere for it to be - there replaced into no area. you in basic terms could desire to settle for that that's the case extremely than attempt and image it as that's so a methods out of human adventure we only can no longer think of it. Now, as a results of fact the universe maintains to enhance, that is not "eating" empty area - outdoors the universe there is none to devour. extremely, that is springing up that is own area because it is going. Your lonely planet isn't in basic terms sitting available waiting for the end results of the huge bang to get closer it - it replaced into created via the huge bang. each and every thing that exists interior the universe replaced into. look, this could look rude and that i apologise, yet you seem to have not the smallest weeniest clue approximately how the universe actual works - even in spite of the indisputable fact which you look involved to be conscious of. am i able to desire to advise you study invoice Bryson's a short background of almost each and every thing. rather trouble-free, relaxing and informative, and it explains all those products.
- visionaryLv 41 decade ago
think of it like a balloon with the pressure outside it being lowered. the "balloon-iverse" expnads, but the atoms inside it don't expand. the space between the various components (atoms) just increases. likewise, in the real universe, the space between galaxies etc. increases but they stay the same size (due to *gravity*)
so, my answer is: gravity holds the galaxies etc. together while the universe itself expands