What is Expanding: Definition and 634 Discussions

The expanding Earth or growing Earth hypothesis asserts that the position and relative movement of continents is at least partially due to the volume of Earth increasing. Conversely, geophysical global cooling was the hypothesis that various features could be explained by Earth contracting.
Although it was suggested historically, since the recognition of plate tectonics in the 1970s, scientific consensus has rejected any significant expansion or contraction of Earth.

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  1. O

    Why is the Sun Expanding Beyond Earth in Seconds?

    Alright. Now, I understand that the Sun is 1/2 way through its complete H-He fusion cycle, and I realize that after this fusion cycle, it will pass through all the elements until Fe, (i don't know whether it passes through each element in 7 seconds, or it takes 7 seconds for each element). My...
  2. M

    How Do I Expand Composite Functions in Mathematics?

    Expanding Composite Functions(urgent help needed) I had to solve an assignment question, we are asked to find the formula for g^-1, except once i plug n do everything, i come up with x=f(g^-1(x)+c), which is x=f(g^-1(x)) + f(c), now i m suppose to put the formula in terms of g^-1=..., but i...
  3. M

    Universe is expanding faster than the speed of light

    I always thought that the universe is expanding faster than the speed of light. Am i wrong, or is that only during the proposed period of "inflation" in the early universe.
  4. R

    Expanding Plasma: Equation Governing Gas Expansion

    Hi, When air is heated to a point where it turns into a plasma, is there any equation which governs how much the gas expands in the explosion? Thanks
  5. arivero

    Exploring Pi Square Lads: Latest Developments in Integer Pythagorean Triples

    Lads, I'd be glad if you were able to take a view of the last developments in the thread https://www.physicsforums.com/showthread.php?t=46055 and see if you can do some suggestion, as we have a pi^2 expresion which should somehow be related to integer pythagorean triples.
  6. T

    Is a Cosmological Constant necessary to explain the Universe's expansion rate?

    How perception affect understanding Taking a basic physics discovery, in this case “the Universe is expanding”. Do you think that mankind existence in this relatively young stage of the Universe “colours” our perception of what we observe as expansion? Does the static Universe have any...
  7. C

    Space Expansion: Earth-Sun, Nucleus-Electron?

    If all space is expanding, does this include the space between the Earth and the Sun and perhaps. the space between a nucleus and an electron.
  8. G

    What is meant by expanding space

    Hi, Cosmologists, starting perhaps with Hubble, say that our galaxy is expanding like a sponge, or a raisin bread. Now if I take only two raisins of this bread which are on its x-axis, am I to understand that : 1. the distance d = x2 - x1 is getting greater, or 2. the x-axis...
  9. S

    The Universe is expanding Right?

    I was just listening to 'The galaxy song' by monty python and I got thinking. The general belief (i think) is that its relatively early after the big bang and the universe is expanding, but what proof is there that we're not compressing? that we're already in the second stage of the universe...
  10. O

    Does Entropy in 5-D dipict an Expanding or Contracting Universe?

    If the Arrow of Time move's upwards from 'our' perceived 3-D +1 spacetime (expansive Entropy), then in this model:http://arxiv.org/PS_cache/hep-th/pdf/0408/0408217.pdf Has the implications that the Arrow (Thermodynamic Time) predicts that from a 5-D Space, relays an arrow of Time converging...
  11. R

    Question about expanding black holes

    Somewhere on the web I read that as new matter is captured by a black hole, the event horizon expands. But as it expands it does not engulf the matter that previously accumulated close to the horizon. Instead all that matter is carried outward along with the expanding event horizon. But...
  12. N

    Older faster if the universe wouldn't be expanding?

    Would we be getting older faster if the universe wouldn't be expanding?
  13. S

    Expanding Universe - weakening gravity?

    Please excuse the simplistic approach to the following question. If one accepts that the universe is indeed expanding could this not be simply because the relative strength of gravity has or is diminishing? Instead of suggestions of dark energy and or dark matter to make equations make...
  14. Chronos

    WMAP has conclusively proven an expanding universe.

    WMAP has conclusively proven an expanding universe. anyone care argue?
  15. O

    Why does Expanding Space have a 2 to 1 Ratio with Contracting Space?

    Can anyone explain howcome the ratio of expansive space always has the above Ratio? If there is a backgound of space that is expanding exponentially, then any Space that is Contracting with a photon pressure seems to always be 2 to 1. For the ignition of Stars, this would correspond to a...
  16. Zefram

    Exploring the Expansion of the Universe

    The question of what the universe is expanding into seems to come up all the time and the answer is always the same--here's an example from one of the many FAQs around the internet on the subject that all say the same thing: In other words, the universe isn't expanding into anything because...
  17. P

    How is the Formula (1+x+x^2+...+x^n^-^2+x^n^-^1)^2 Expanded?

    Can you tell me what the following formula will be after it gets expanded ? (1+x+x^2+...+x^n^-^2+x^n^-^1)^2 = ? Thanks a lot,
  18. M

    Expanding universe and absolute zero

    hi every one. i was on my way out of my astronomy class today and i hit my self with an odd question. The universe is expanding and as a result it is cooling, now i was wondering if the universe expands infinitly then would it be possible for it to cool infinitly as well. eventualy reaching...
  19. K

    Gzk paradox and expanding universe

    If the universe were divided into two mass zones, and one zone repelled the other,supernovae would not only accelerate away from us but the zone in which we are living would accelerate away from the supernovae.Also cosmic rays could be repelled by one zone and pushed through another.Could...
  20. A

    Expanding Universe: Matter Growing?

    Hello all, I am from Amsterdam, the Netherlands. I am an super-amature on this topic but I have a question. Is it not possible that the universe is expanding because the amount of matter is growing? See it like a bucket filled with water(universe), throw a rock(matter) in the bucket and...
  21. M

    Expanding manifold with constant boundary

    OK. Suppose you have a surface with a closed curve as a boundary. Then suppose that surface grows like a soap bubble but the boundary is stationary like the orifice through which air passes to make the bubble grow. It would seem that the 2D surface grows in both dimensions in the middle of the...
  22. holly

    Expanding Steel, Can't Follow Equation

    Gosh, I can't stand the new look. Q. Place a 1 kg block of iron at 40 degrees C into a kg of water at 20 degrees C and the final temp will be: More than 30 degrees C, Less than 30 degrees C, At or Around 30 degrees C. I felt it would be At or Around 30 degrees C, because I tried to do an...
  23. D

    Exploring the Expanding Universe and Robertson Walker Metric

    There is some discussion about the expansion "of space" in a thread that actually belongs to a different topic so I thought I'd start a thread about that with my input here. Consider the Robertson Walker metric in the following form ds^2 = dct^2 - \frac{R^2}{R_{0}^2}\frac{d\rho ^2 + \rho^2...
  24. V

    Expanding people in an expanding universe?

    Help me please! do'nt know if I'm right here, but any hint leading to a simple answer of the following question would be appreciated: if the universe is expanding, are we expanding as well? does my hand expand at the moment? what about a center of expansion? what about our point of...
  25. V

    Expanding people in an expanding universe?

    Help me please! do'nt know if I'm right here, but any hint leading to a simple answer of the following question would be appreciated: if the universe is expanding, are we expanding as well? does my hand expand at the moment? what about a center of expansion? what about our point of...
  26. G

    Exploring the Expansion and Convergence of the Universe: A Scientific Discussion

    Hi, I have read a bit about open, closed, and flat universes, Hubbles Constant, the accellerating universe, big bag, big cruch, etc... Is it possible that the expansion rate (+ or -) of the universe might be independant of the expansion rate (+ or -) of the matter within it? Is it...
  27. A

    What is the relationship between inflation and dark energy?

    the universe is expanding, ok. but what is causing this? the big bang? in that case, what causes the expansion to accelerate or decelerate? and what is beyond the boundaries of the universe?
  28. Adrian Baker

    Photon energy in an expanding Universe

    We are told that as the Universe expands, the 'temp' of it cools and we now have the microwave background radiation as a remnant. Fine. Considering the energy density of the universe, energy is indeed conserved as it expands and cools. However, what about an individual photon, who's...
  29. wolram

    If space is expanding how can the electrical properties stay constant?

    edit. if space is expanding how can the electrical properties stay constant?
  30. Hydr0matic

    Opinions on the Expanding Earth Hypothesis

    What is your opinion on this hypothesis ? http://www.wincom.net/earthexp/n/navback.htm http://users.indigo.net.au/don/ee/nav.html http://www.expanding-earth.org/ http://www.geocities.com/CapeCanaveral/Campus/2730/...
  31. J

    Why is the Universe expanding at an accelerated rate?

    I may be out of touch, but I don't think I've ever read it for sure so what are your theories on this? I mean the big bang theory may provide the inertia to expand but why at an accelerated rate? What force is being added if any to accelerate this expansion and where does it come from?
  32. wolram

    Is the Universe Really Not Expanding?

    http://www.Newtonphysics.on.ca/faq/flat-universe.html this may be old news to some of you but it does show a differant side of the coin
  33. A

    Light Years And Expanding Universe

    How is it that we are able to see galaxies that are billions of light years away considering that we are presumably traveling from the same origin? Would that somehow mean that the distance between the two galaxies was growing at a rate greater than the speed of light? If not, why not? The...
  34. S

    Acceleration of expanding space

    What's the reason for it? Is there a mechanism already existing in physics to explain it, such as virtual particle energy density, to account for the anomalous acceleration? Will such an explanation solve the mystery of the acceleration of the Pioneer spacecraft ? To know we've got to solve...
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