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How insignificant we are

  1. Jun 7, 2009 #1
    So I wanted to take a break from my term paper (which I pretty much got the skeletal draft of it done) to do a quick calculation.

    One of the articles I was reading in science mag. was talking about the dark ages of the universe and the birth of the first star what have you.

    One of the things he mentioned was "I learn about the great things in the universe and then in the morning I open my newspaper to find out about war and drama, and I just feel so stupid".

    Note I'm paraphrasing, that's not how he said it.

    Well that sort of hit me since my mom was talking to me about both good things and bad. I didn't know whether this should go into the physics section or not, and then I realized the message is a bit more existential so.

    Anyways getting to the point. I decided to make an order of magnitude estimate as to how insignificant we actually are.

    So, what are the parameters?

    Well the mass of the earth is [tex]M_{Earth} \sim 6x10^{24} kg[/tex], and for the sun is [tex]M_{Sun} \sim 2x10^{30} kg[/tex]. The mass of the milky way is estimated to be ~[tex]5x10^{11} M_{Sun}[/tex]

    Let's assume that every galaxy in the universe has the same mass as the milky way (order of magnitude so who cares about being off by a small factor). There are 125 billion galaxies (according to HST), so the percentage that the Earth is compared to all the galaxies and stars is given by

    [tex] \frac{M_{Earth} * 100}{M_{Sun} * 5x10^{11} * 125,000,000,000} \sim 4.8x10^{-27} \% = 0.0000000000000000000000000048 \%[/tex]

    But that's not all. Not even close. Let's say the average person weighs 150 lbs or ~68 kg (doesn't matter, google calculator converts everything).

    Then the average person, relative to the visible universe is:

    [tex] \frac{150 lbs * 100}{M_{Sun} * 5x10^{11} * 125,000,000,000} \sim 5.5x10^{-50} \% = 0.000000000000000000000000000000000000000000000000055 \%[/tex]

    Oh but we don't stop there folks. According to the Wilkinson Microwave Anisotropy Probe (WMAP) and other instruments, the density distribution is given as 74% dark energy, 22% dark matter, and 4% matter, where 0.4% is all the stars and galaxies. (Yes I know it's density but density is a function of mass and this is order of magnitude so who cares)

    So the Earth relative to what we know as everything in the universe (visible and invisible):

    [tex] \frac{M_{Earth} * 100}{(M_{Sun} * 5x10^{11} * 125,000,000,000)/0.004} \sim 2x10^{-29} \% = 0.00000000000000000000000000002 \%[/tex]

    And so a man or woman, relative to the whole universe:

    [tex] \frac{150 lbs * 100}{(M_{Sun} * 5x10^{11} * 125,000,000,000)/0.004} \sim 2.2x10^{-52} \% = 0.00000000000000000000000000000000000000000000000000022 \%[/tex]

    Why do we still have wars and other petty BS?
  2. jcsd
  3. Jun 7, 2009 #2
    Because I'm the most significant thing, to me.
  4. Jun 8, 2009 #3


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    The kilogram is not a unit of significance. :wink:
  5. Jun 8, 2009 #4


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    So fat people are more significant than thin people?
  6. Jun 8, 2009 #5
    There used to be a time, when ALL of your constituent particles were in the Singularity which appears to have been much much smaller than an atom. Common-sense views of reality are unfortunately often wrong.
  7. Jun 8, 2009 #6

    Ivan Seeking

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    I didn't think that was "a time". :biggrin:
  8. Jun 8, 2009 #7

    ooops :blushing:
  9. Jun 8, 2009 #8


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    I don't see how our significance (measured in mass fraction or in any other way) relates to our propensity for war.
  10. Jun 8, 2009 #9
    I would take it more as we are quite lucky to be one of those, 0.00000000000000000000000000000000000000000000000000022% significant in relation to mass, people. We should probably not risk it by wars etc. I'm not saying we are special or anything but we don't know if we aren't special so why risk it...

    I guess we're all gonna end up dying anyways. and heck. 6.7 billion people is quite a lot of people relative to the area we are inhabiting. IMO
  11. Jun 8, 2009 #10
    Imagine that the universe is the size of your living room. Would you be happy that you were more significant?
  12. Jun 8, 2009 #11

    It's worthy of a new topic, but you should know that we feel we must be lucky to be here not because the world is beautiful or a wonderful place to be in, but because natural selection has weeded out the genes that were causing people to commit suicide because they disliked the world as it is. Those genes are now gone, because the people who didn't like our world diasappeared without leaving offspring. Thus, the world as we perceive it is beautiful, but not because it's intrinsically beautiful, but because of how we were designed by natural selection. To someone less biased by their genes at birth(as we all are), this place might be a true living Hell. It's all a perception in our heads(kind of reminds you about the illusion of free will; i get a freaking headache when i think of how beautiful this place is only because i am a robot-machine designed to perceive it that way by a random or not process).
    Last edited: Jun 8, 2009
  13. Jun 9, 2009 #12
    It is a confusion of two different levels of analysis, the here-and-now, and the history of eventual fate of our universe.
  14. Jun 23, 2009 #13
    Or maybe we are special, contrary to some assumptions by overly secular physicists. Although I don't know this to be a Fact, there is no way to disprove it either(and Occam's razor is in favour that we seem to be special).

    It's about the Cosmological and Copernican principle. The Copernican principle has never been confirmed as a whole and as Albert Stebbins of Fermilab puts it - "it is the cornerstone of most of astronomy, it is assumed without question, and plays an important role in many statistical tests for the viability of cosmological models. It is also a necessary consequence of the stronger assumption of the Cosmological Principle: namely, that "not only do we not live in a special part of the universe, but there are no special parts of the universe."

    In a few words - in 1929 Edwin Hubble observed for the first time the red-shift of light coming from distant galaxies. Every direction he pointed his antenna, he got the same result, light was red-shifted. He saw that the farthest galaxies were receding the fastest, this observation becoming what is now known as the Hubble Law. He initially inferred from these observations that the Earth must be at the centre of the universe. Then he and other physicists rejected this model based on their belief that this cannot be and mustn't be so, making an even wilder model of metric expansion of space(FLRW universe):

    "…Such a condition would imply that we occupy a unique position in the universe, analogous, in a sense, to the ancient conception of a central Earth...This hypothesis cannot be disproved, but it is unwelcome and would only be accepted as a last resort in order to save the phenomena. Therefore we disregard this possibility.... the unwelcome position of a favored location must be avoided at all costs.... such a favored position is intolerable...Therefore, in order to restore homogeneity, and to escape the horror of a unique position…must be compensated by spatial curvature. There seems to be no other escape."

    This quote by Michael Rowan-Robinson is telling of the importance of the Copernican principle to somewhat overly secular scientists:

    "It is evident that in the post-Copernican era of human history, no well-informed and rational person can imagine that the Earth occupies a unique position in the universe."

    Here is what Stephen Hawking says about the CMBR "...all this evidence that the universe looks the same whichever direction we look in might seem to suggest there is something special about our place in the universe. In particular, it might seem that if we observe all other galaxies to be moving away from us, then we must be at the center of the universe.

    There is, however, an alternate explanation: the universe might look the same in every direction as seen from any other galaxy, too. This, as we have seen, was Friedmann’s second assumption. We have no scientific evidence for, or against, this assumption. We believe it only on grounds of modesty: it would be most remarkable if the universe looked the same in every direction around us, but not around other points in the universe."



    A general test of the Copernican Principle by Chris Clarkson, Bruce A. Bassett, Teresa Hui-Ching Lu

    The principle that we are not at or very near the the centre of a spherically symmetric universe(as uniform CMBR from every direction suggests) is an assumption. While it relieves us from the burden of explaining such a weird occurence(>100 billion galaxies), this assumption is not proven yet, i think it should be printed in the form of a disclaimer in textbooks for objectivity's sake.
    Last edited: Jun 23, 2009
  15. Aug 21, 2009 #14


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    I've always wondered who decided that mass or amount determined significance...
  16. Sep 14, 2009 #15


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    haha physics jokes are always so funny but they make me feel so geeky, good one though :P

    Also your picture kind of looks like Joe Biden lol
  17. Sep 14, 2009 #16


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    Rocky Kolb. He generally prefaces his presentations with a pie chart that...well I won't spoil it for you. Just Google on him and pick a video presentation about high-energy physics.
  18. Sep 14, 2009 #17


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    Where have you been the last 250 000 years? It`s all about us! And if it is about something else, then the most important thing is how we percieve it. We are significant because we are ourselves! The size of the universe is not a reasonable factor considering our proposed insignificance.
  19. Sep 14, 2009 #18


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    I actually couldnt find one, could you maybe send me a link?
  20. Sep 15, 2009 #19

    It could be about life in general, but why would it be strictly about us?
  21. Sep 15, 2009 #20


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  22. Sep 15, 2009 #21


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    thanks a lot man
  23. Sep 15, 2009 #22


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    And who or what do you propose would or could decide a thing like that? It would only make sense if we decided life in general is the most important thing. Meaning always originates in ourselves. It is us that decide what is meaningful and what is not, and thus we are our own most significant thing in any reasonable definition of the word significance. That is if you don`t believe in God, or something similar to that.

    By the way, "It`s all about us" was a manner of speaking.
    Last edited: Sep 15, 2009
  24. Sep 15, 2009 #23


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    You're welcome. Rocky is really tongue-in-cheek a lot of the time, but when he shows this pie chart and argues that high-energy physics shouldn't get more than 95% of the total science budget because the theoretical "dark" entities seem to make up no more than 95% of the mass-energy budget of the universe, I always get a laugh. It's an old routine, but it plays well with popular audiences.
  25. Sep 15, 2009 #24


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    Theres something to what your saying here lol, actually makes lots of sense.
  26. Sep 30, 2009 #25
    lol so... because we're so small compared to the rest of the universe, we shouldn't fight each other?... That makes no sense... there are many reasons to be peaceful, but that is not one of them.
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