Science stories of the week

Discussion in 'General Science & Technology' started by wegs, Jan 31, 2021.

  1. wegs Matter and Pixie Dust Valued Senior Member

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    No apologies needed.

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    Is it safe to say that gravity seems stronger than it's given credit for, because it's always attractive?

    I guess what stumps me a bit is suppose you're laying down under an apple tree, and apples begin falling from the tree, landing on your head. Wouldn't it seem that gravity (at that very moment) isn't weak at all? We tend to take gravity for granted in every day life, because we don't ''feel it.'' I guess what I'm asking is how can gravity be such a fundamental force, yet weak?
     
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  3. Seattle Valued Senior Member

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    A fly can walk across the ceiling without being pulled off.

    The Earth is huge and is pulling your arm down but it doesn't take much effort/energy on your part to simply bend your elbow and counteract all that gravity.
     
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  5. exchemist Valued Senior Member

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    Being fundamental isn't a question of strength, it's a question of whether something can be explained in terms of something else or not. And gravitation can't. It just is what it is, so far as we know at the moment. That's what we mean by fundamental.
     
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  7. geordief Valued Senior Member

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    Maybe it is weak but it is everywhere.

    Tortoise and the hare ?
     
  8. James R Just this guy, you know? Staff Member

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    One way to compare the relative strengths of forces is to see how different forces act on the same objects.

    Consider, for example, the electric force between two electrons, separated by 1 metre. The force is $2.3\times 10^{-28}$ Newton, which is a small force.

    But compare the force of gravity between the two electrons at the same separation. That force is $5.5 \times 10^{-71}$ Newton.

    In other words, for this example, the electric force is about $10^{42}$ times strong than the gravitational force.

    That's 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000 times stronger.
     
  9. geordief Valued Senior Member

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    Yeah, but gravity says to electro -magnetism "Is that all you got? See you around"

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  10. wegs Matter and Pixie Dust Valued Senior Member

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    Okay, when you compare the math equations, it's the weakest, but in terms of importance (because of its incredible range/reach), it should be considered the strongest, no? It's the most strongly present force in our lives, every single day. (Even though we can't detect it.)
    And all things considered, gravity is inevitable.
     
  11. exchemist Valued Senior Member

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    Actually the reach of the electromagnetic force is the same as that of gravitation. Both obey inverse square laws, i.e. if you double the separation between objects, the force falls to 1/2², i.e to 1/4 of what it was before.

    The reason for the effect of gravity at vast distance is that, unlike the electrostatic force, it does not get neutralised when objects attracted because of it come together. So it becomes cumulative.

    If you could somehow get a mass of electrons together, on their own, that had the same mass as the earth, the electrostatic force they would exert on charged objects in space would be immense, far greater than gravity. But you can't do that, because such a collection of electrons would firstly fly apart under their colossal mutual repulsion, and even if that could be prevented, it would strip protons from everywhere around in space until it was largely neutralised by them. The same sort of thing applies to the other fundamental interactions too.

    But not to gravity, which is why it alone can accumulate large amounts of matter together and thereby magnify its "weak" influence until it outstrips everything else.
     
  12. Michael 345 New year. PRESENT is 71 years old Valued Senior Member

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    I get that

    But somewhere out there the inverse square law breaks down to a Planck Length

    Soooo do you speculate there is a space (I'm thinking middleish between galaxies) where there is no Gravity

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  13. exchemist Valued Senior Member

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    Planck length remains a speculative theoretical concept, so far as I am aware, with no observable effects.
     
  14. wegs Matter and Pixie Dust Valued Senior Member

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    Thank you for explaining further. I guess what I'm getting at is that it just seems comparing gravity to the other forces, is like comparing apples to watermelons. I'm now understanding why gravity is considered the weakest of the forces, but the forces themselves don't seem entirely comparable?
     
  15. wegs Matter and Pixie Dust Valued Senior Member

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  16. Seattle Valued Senior Member

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    They don't need to be comparable. They need to be forces and they need to be describable and when two are called the strong force and the weak force this brings forth the comment that gravity is the weakest especially in that it has a small role to play in particle physics where the standard model of the 4 fundamental forces comes from in the first place.
     
  17. RainbowSingularity Valued Senior Member

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    feeding-seaweed-cattle-could-help-curb-climate-change

    im not sure seaweed can properly digest cattle

    it would be more beneficial to feed humans seaweed & allow cattle to die out as a domesticated stock animal

    if we look at the carbon transfer
    you still need to grow the seaweed that will be eaten by th cattle
    what happens to the paddocks of grass where the cattle live ?
    over nitrating the cattle which then poops into the ground, then rns off
    you would still need to have capture process i to re-capture the excess nitrates

    the beef industry need to be reduced in size
    did we see the beef industry out campaigning to block driver less taxis ?
    nope
    what about bio-fuel ?
    did they campaign against that ? nope

    beef farming has seen its day
    meat eating is old world
    birds no problem
    cattle = huge problem
    like driving old cars that are wasteful on fuel and produce lots of pollution
    red meat farming is too high in methane & excess resources to produce it

    it would be fine if they were open grazing o massively huge pastures hundreds and thousands of square kilometers wide
    but hats not how money works
    and thats not how greed drives human economics

    its just a fact of human evolution and the terrible pollution and climate change human civilization has cast upon the world

    cattle farmers should switch to mushrooms and turkeys & small beef production organic etc
     
    Last edited: Mar 18, 2021
  18. exchemist Valued Senior Member

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    This is very interesting. I see from the article that CHBr₃ does however have potential to be an ozone-depleting compound, so they will need to assure themselves about that before implementing this commercially. However since it seems to be short-lived in the atmosphere, it may not be an issue. The great thing about this is that it makes the animals convert food more efficiently as well, so there is a commercial incentive for the farmer to use it, apart from its beneficial effect on methane emissions.

    One just hopes there is enough red seaweed to go round.
     
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  19. wegs Matter and Pixie Dust Valued Senior Member

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  20. Seattle Valued Senior Member

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  21. wegs Matter and Pixie Dust Valued Senior Member

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    lol Oh you.

    Well, at least you learned something about moths, today.

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  22. Seattle Valued Senior Member

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    That's true!
     
  23. wegs Matter and Pixie Dust Valued Senior Member

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    Last edited: Apr 24, 2021

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