Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The source of all energy is the Sun?

  1. Mar 19, 2015 #1

    Duz

    User Avatar

    I've recently been told by my mentor that the source for all energy is the Sun, which makes sense if were talking about chemical energy in photosynthesis, solar energy, etc. However, if we think about a meteorite which is due to hit the earth, surely we cannot say it got its energy from the Sun :nb)???

    Can somebody help clarify my confusion?

    Thanks in advance.:cool:
     
  2. jcsd
  3. Mar 19, 2015 #2

    mfb

    User Avatar
    2016 Award

    Staff: Mentor

    The source of most of the power sources we use is the sun - but not everything. The meteorite is a counterexample (but this is not energy we can use), geothermal energy is a counterexample.
     
  4. Mar 19, 2015 #3

    Duz

    User Avatar

    Thanks for that!
     
  5. Mar 19, 2015 #4

    Duz

    User Avatar

    Help will be appreciated.

    Mentor note -- OP's follow up question was "Does the heat in the Earth's core come from the Sun?"
     
    Last edited by a moderator: Mar 19, 2015
  6. Mar 19, 2015 #5

    A.T.

    User Avatar
    Science Advisor
    Gold Member

    No.
     
  7. Mar 19, 2015 #6
    It's heat left over from the formation of the Earth and to a very much lesser extent heat produced from radioactive decays.

    In some bodies such as the moons of Jupiter heat is also generated internally from the tidal effect of the large planet's gravity, but there is no such significant heating of that type for Earth.
     
    Last edited: Mar 19, 2015
  8. Mar 19, 2015 #7

    sophiecentaur

    User Avatar
    Science Advisor
    Gold Member

    OTOH, if the Sun were not there, the meteorite would not be in orbit around it (with Gravitational Potential Energy due to the Sun) so, maybe not nuclear energy but still energy 'from' the Sun.
     
  9. Mar 19, 2015 #8
    The OP might be interested to note that the energy received from the decay of Earth's radioactive content ultimately comes from other earlier stars that created those radioactive elements.
     
  10. Mar 19, 2015 #9
    Sure, almost every atom the Earth is made of would have at some point in it's history been inside a star, possibly several.
    So it's fair to say that everything in Earth all matter and all energy is a result of solar processes one way or another.
    Possibly I have replied to the wrong topic here, I thought the question had been about the source of geothermal energy in particular.
     
  11. Mar 19, 2015 #10

    Duz

    User Avatar

    Thank you for the response. I thought the Milky Way was born as a result of collisions within a Nebula (I may be wrong). If so, both the sun and thereafter, the earth (with its core) should have also originated from this Nebula?

    Thus, this doesn't make sense: "almost every atom the Earth is made of would have at some point in it's history been inside a star".o_Oo_O:frown:
     
  12. Mar 19, 2015 #11

    phyzguy

    User Avatar
    Science Advisor

    I hate to nitpick, rootone, but I have to take issue with your "to a very much lesser extent". Studies of this, such as http://www.nature.com/ngeo/journal/v4/n9/full/ngeo1205.html, have shown that the contribution from radioactive decay is slightly larger than the primordial heat left over from the formation of the Earth.
     
    Last edited by a moderator: May 7, 2017
  13. Mar 19, 2015 #12
    Fair enough,I'm happy to be corrected, I guess my understanding of that had become outdated.
     
  14. Mar 19, 2015 #13

    Bandersnatch

    User Avatar
    Science Advisor

    The current best theory for the early universe at one point has matter coalescing from radiation. Such matter included mostly hydrogen, some helium, and a tiny amount of lithium. If you were to look at the periodic table of elements, you'll notice that these are the three lightest elements in existence.
    These floating clouds of primordial matter collapsed under mutual gravitational attraction to form 'clumps'. On a small scale, these clumps became stars, and the collections of stars became first galaxies.

    As the proto-stars collapsed enough to start fusion, the first step towards enriching the universe in heavier elements begun. Stars fuse hydrogen into helium, heavier stars take it further to the neighbourhood of oxygen, silicon and carbon, and the heaviest stars manage to fuse elements as heavy as iron and nickel. Fusion of heavier elements cannot produce energy, so it only happens when the heaviest stars explode in a supernova - the process releases excess energy that is partially consumed in fusing all the remaining (natural) elements of the periodic table.

    The death of a star, be it as a supernova, or a less-violent expulsion of outer layers (like what our Sun will do), is the step where the heavier elements formed by the star are released back into space, where they get mixed with the primordial hydrogen and helium.

    Over time, more and more heavier elements are produced, enriching the interstellar medium.

    Since you, me, and the rest of the Earth are made from stuff that is not only hydrogen (helium never 'makes' anything - it's a noble gas, so it doesn't react with other elements), it means that most of the atoms we're made of were once made in the furnace of one or more dying stars.
     
  15. Mar 19, 2015 #14

    Duz

    User Avatar

    Legendary. Thank you.
     
  16. Mar 19, 2015 #15

    mfb

    User Avatar
    2016 Award

    Staff: Mentor

    I'm not so sure about that "most" estimate. We contain mainly water, where 2/3 of the atoms are hydrogen. Which fraction of hydrogen has been in a star at least once? I don't know, but if that fraction is small about 50% of our atoms have never been in a star, but for sure all those hydrogen nuclei (protons) were not made in stars.
     
  17. Mar 19, 2015 #16

    Bandersnatch

    User Avatar
    Science Advisor

    You're right, of course. I shall hastily defend the sloppy wording by insisting that I meant to say 'most by mass' or 'most kinds', rather than 'most by number'.
     
  18. Mar 19, 2015 #17
    Just for a sense of scale (sourced using a search engine, yielding sites/data believed but not guaranteed to be credible), the current distribution of atomic matter in the observable universe is estimated to be H - 73%, He - 25%, All Other - 2%.

    diogenesNY
     
  19. Mar 19, 2015 #18
    Energy of tides as result of Earth-Moon gravitational binding is another counterexample
     
  20. Mar 22, 2015 #19
    A very small part of the earth’s heat budget comes from non-solar sources. These include the steady flow of heat from the earth’s molten interior to the surface of the planet and radiation from parts of the universe other than the sun. Heat flux from the interior is the next largest source of energy after insolation, but is still less than twenty thousandths of one percent of the solar energy input. The total energy from the rest of the universe is even less. The energy that mankind releases to the atmosphere in an entire year is less than the Earth gets from the Sun in ten minutes. All non-solar sources put together are—for all intents and purposes—insignificant in devising heat budgets for the earth and its components and in understanding climatic changes.
     
  21. Mar 22, 2015 #20

    Suraj M

    User Avatar
    Gold Member

    what happens when we master fusion, any part of that process, solar(in origin)?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: The source of all energy is the Sun?
  1. Energy is all ? (Replies: 3)

  2. Source of all motion (Replies: 5)

Loading...