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Relation Between Areas of Astronomy

  1. Apr 27, 2006 #1
    NOTE by SpaceTiger: Split from the "Nasa" thread started by wolram. Here, we'll explore the question of the relation between seemingly disconnected areas of astronomical research.

    I respectfully suggest these are actually interrelated ideas. By better understanding what the planets are made of, we can gain insights into how our universe came to be. Exploration is part of human nature. We're a curious lot. Furthermore, most of the real estate of the universe is beyond planet earth. :)
     
    Last edited by a moderator: Apr 27, 2006
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  3. Apr 27, 2006 #2

    SpaceTiger

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    Not to a great extent. Planetary science contributes much less to cosmology than fields like physics, mathematics, and statistics. In the long run, all fields are related, but the planets won't be telling us much about the universe at large for quite some time.
     
  4. Apr 27, 2006 #3
    Hmm. That seems like a topic that warrants a new thread. :) The study of our planet and it's mass allowed us to make predictions about our sun, and then about our galaxy. The study of aurora led Birkeland to realize that the sun and the earth are electrically connected. It seems to me that planetary exploration can tell us a great deal about our universe.
     
  5. Apr 27, 2006 #4

    SpaceTiger

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    Well, technically, classical physics was all worked out in earth-based laboratories, but that's not what we usually consider "planetary science".


    What does this have to do with cosmology?
     
  6. Apr 27, 2006 #5
    Almost every are in phyiscs which once seemed "united" has now been divided into tinier bits. There was a time when there were people who contributed to many areas of mathematics, physics(well, the terrestrial version) and astronomy.

    Similarly, when astronomy was confined to the Solar System, studies of the planets and the rocks on Earth put a lower limit to the age of the Sun and such. But today, things are vastly different. Knowing whether a form of iron exists/existed on Mars will not tell you anything about the CMB. Of course, both the knowledge of Mars and CMB are very important to get a complete picture (from the Beginning to the present), but I doubt if one could influence the other in any way. (Just my 0.02 units of currency)
     
  7. Apr 27, 2006 #6

    Nereid

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    One important aspect is the great depth of interlocking consistency that is oft all but invisible ... we have today's cosmology, planetary science, astrophysics, ... in large part because 'it all hangs together'.

    For example, the oldest rocks are dated to be ~billions of years old, and the Sun ~billions of years old (stellar evolution models, etc), so cosmological results that are ~10 billion years are clearly consistent.

    It was not always thus; before the discovery of what powers the Sun, things like the age of the Earth (derived from geological studies) seemed inconsistent with the mere existence of a constant powered Sun.

    Another example is GR: the anomalous advance of the perihelion of Mercury is one observational result consistent with GR; GR is, in turn, where all modern cosmology starts.

    It can be fascinating to follow the threads; there are so many, and the inter-connectedness and mutual consistencies are very large in number.

    Oh, and to bring it back to PF, the glue is physics.
     
  8. Apr 27, 2006 #7

    SpaceTiger

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    Actually, I wouldn't call either of those things "planetary science" (in the modern sense) either, but let's project this into the bigger picture. The first question we're asking ourselves is, "What are we interested in?" If we can agree on an answer to that question (at least partially), then we want to ask, "How can we most efficiently answer the questions we're interested in?" Ultimately, the correlations that are being discussed here are indirect and hard to predict. It would seem to me rather inefficient to attempt to address cosmological questions with probes to Jupiter or Saturn when virtually all of our current knowledge about cosmology comes from dedicated missions (COBE, WMAP, HST, etc.) or surveys (SDSS, 2dF, etc.).

    So Michael's original statement:

    is probably true in the long run, I wouldn't deny that. However, if wolram is most interested in cosmology, is it in his interest to support diversion of funds from cosmology probes to planetary ones?

    This question is generally relevant to astronomy because we grapple with it every time we submit suggestions for money allocation at NASA.
     
  9. Apr 27, 2006 #8
    Electirical

    That's not really what I meant. I find myself in general agreement to what Nereid said. They are all interrelated, and they can be studyied through physics and mathmatical models, but only if we fully understand the event well enough to model it properly.

    You are essentially asking me what electricity has to do with cosmology. First let me ask you what role do you believe that electricity plays in cosmology?
     
  10. Apr 27, 2006 #9
    Well, try looking at it this way. We know that electricity plays "some" role in the "big picture". By studying the aurora on Mars and Jupiter, we can better understand what to look for when looking for planets around other solar systems. Perhaps we will be able to image the aurora before we can image the whole planet properly, or pick out planets based on their aurora. It's the interrelated areas of science that can come together to for new ways of studying the universe that fascinate me. I'm willing to let a little splintering to occur in the short term so that we can be better prepared in the future to interpret what we see in future Spitzer and Hubble images.

    I hear that. I suppose my attitude is that there is room for all sorts of new ideas and different exploration missions, provided that we continue to improve our technology and drive down the costs over the long haul. I also think it's a good idea to look at our universe from all sorts of angles so we don't miss anything important.
     
  11. Apr 27, 2006 #10

    SpaceTiger

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    ...no. You said that Birkeland realized that the sun and earth were electrically connected. What does this fact have to do with cosmology?


    That's correct, planetary science is useful in our study of extrasolar planetary systems, but extrasolar planets are all observed within a small portion of the galaxy and are not generally considered to be in the realm of cosmology. Many years from now, we may be able to explore planets outside of our galaxy and, at that point, local explorations may become important for cosmology, but this is a long way off.


    I can't speak for wolram, but my personal opinion is that we should be exploring all accessible areas of astronomy, but I would like to see more focus on cosmology and less on planetary science.
     
  12. Apr 27, 2006 #11
    It has everything to do with cosmology since it's a cosmological phenomenon, not just between the sun and the earth but between the sun and every planet as far as we know. We know that planets and suns exchange charged particles. That is a known fact of cosmology.

    Today that may seem true from your perspective, but as you rightfully note, future generations with more advanced telescopes won't necessarily agree with that statement. I'm not sure that time is such a "long" way off. The moon landings seem a "long" way off to some, but I'm old enough to remember seeing the landings live on TV. With the adaptive optics that are coming online, I don't think it will be all that long before we are peering into other solar systems. Understanding how our own solar system functions will help us to understand what we should be looking for in other solar systems.

    I guess the difference between us is that I don't really think of planetary science as being separate from "cosmology". As Neried suggested, we date the age of our sun by the ages we find in the crust of our own planet. We derive a host of mathematical relationship between the sun and other bodies in our solar system based on what we've learned here on earth. I tend to see our solar system as a method to begin to comprehend what we see when we look at distant stars. Once we understand how our whole solar system works and how it ties into the whole, then we can begin to make sense of what we observe in Spitzer, Chandra and Hubble images.
     
    Last edited: Apr 27, 2006
  13. Apr 27, 2006 #12

    SpaceTiger

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    Aside from being something you should point out before participating in a debate about "planetary science as compared to cosmology", this kinda misses the point of the whole thread. The question of how different areas of astronomy effect one another yields a trivial answer if you just lump everything into the same discipline.

    By the way, your definition of "cosmology" fell out of use at the beginning of the 20th century. Our concept of the "universe" has grown a lot since then.


    No, we've been studying cosmology (in the modern sense of the word) for almost a century now, but still don't understand in detail how the solar system formed. The latter is not necessary to understand the former. There are certainly things to be learned from the solar system that can be applied to cosmology (Nereid mentioned a few), but science is not done in the stepwise method that you're suggesting.


    So you're predicting the detection of planets in other galaxies on what timescale, exactly?
     
  14. Apr 28, 2006 #13

    Chronos

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    Why attempt to fine tune the very serviceable Newtonian physics that work so very well within our solar system? Granted, a few things, like the orbit of Mercury require some GR tweaks, but the rest is . . . history. There is little left to discover about the solar system that is worthy of any appreciable funding. I grant that the pioneer anomaly is still interesting enough to explore, but only as a piggy back mission.
     
  15. Apr 28, 2006 #14

    wolram

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    I may be wrong, i have have not seen any figures from nasa, but guesstimates put a mission to mars at between half and one
    TRILLION $ over a 30yr period, i would expect one heck of a lot
    of science for that outlay, but i think in reality we will end up with
    some of the most expensive bits of rock ever.

    ADDED, other than the existance of planets, i can see no real roll for them in the big picture.
     
    Last edited: Apr 28, 2006
  16. Apr 28, 2006 #15
    I guess I'm having a tough time wrapping my head around your definition of "cosmology". Planets are the primary objects that allow life forms, as we understand them, to flourish. It seems to me that life, and the distribution of life in the universe is an important part of the "big picture". You and I couldn't even have this discussion were it not for the existence of planets.

    I can only assume by "big picture", you personally are more interested in trying to get a handle of the "total mass layout" of the universe, and what forces created this layout and what forces continue to make it tick. Even in that scenario however, planets have a role and makeup some percentage of "big picture".

    For instance, what role might electricity play in the "big picture"? By studying planetary phenomenon, we might start to understand it's role in solar system formation, and cosmology as a whole. I'm just not sure we can even answer these kinds of questions properly without first understanding the "smaller pictures" first.

    I hear your point about the money that being spent, but frankly I'd rather spend that kind of money exploring Mars than in Iraq. Governments are never "cost efficient" to begin with, which is part of the reason I will be glad to see private industry start to get more actively involved. I suspect the motives behind these actions will have a lot to do with taking people (and charging them accordingly) to other "planets". :)
     
  17. Apr 28, 2006 #16
    Well, for one thing Newtonian physics, without consideration of Birkeland currents, may not work as well outside of this particular solar system. In fact, we are still finding planets in different regions and different orbital planes of our own solar system, so it's not altogether clear that simple Newtonian physics will fully explain the layout of our solar system. Why did we include GR into Newtonian physics? As you noted, by including that greater understanding into our equations, we were better able to model the orbits of planets in our solar system. Fine tuning is accepted part of all areas of science, and the computer you are using today is a remarkable example of the value of "fine tuning" theory over time.

    I completely disagree with your assessment that exploration *inside* our solar system is not worthy of appreciable funding. I think there is still a great deal to learn and to understand about our own solar system, and the things we we learn from continued exploration will forever change our views of cosmology.
     
  18. Apr 28, 2006 #17
    I think different areas of astronomy affect one another by giving us a greater understanding of how the whole "system" functions. We get a more rounded and a more complete picture that way, and we are in a better position to understand then what we can only see from a very great distance.

    It seems pretty "stepwise" from my perspective. We "measured" the gravity of the earth and the distance from the sun to the earth and then we used these numbers to calculate the mass of the sun and the moon. We used these numbers to and methods calculate the mass of the other planets as well. We then created models based on the mass of a solar system to build models of how a galaxy might function. Without a starting point (in this case earth), we wouldn't be able to make progressive steps toward understanding the cosmos.

    I'm not predicting the detection of planets in other galaxies in my physical lifetime, but I am predicting the detection of smaller and smaller planets in our own galaxy as our "methods" get more refined over time.

    If course if we recieved an intelligent "signal" from another galaxy, we might have good cause to believe there is a "planet" in that galaxy as well. :)
     
  19. Apr 28, 2006 #18

    SpaceTiger

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    I think everyone is already agreed on that. What I (and presumably wolram) don't agree with is your seeming assertion that we'll learn just as much about cosmology from planetary probes as we will from cosmological ones.


    These aren't steps from field to field, as you were suggesting, they're steps in solving a particular problem. Research is done concurrently in a variety of fields, you don't have to completely solve one to study another.


    Obviously, but that's not what we were discussing. Review the previous posts a little more carefully.
     
  20. Apr 28, 2006 #19
    But I did not assert that to begin with. I personally favor more solar satellite systems over planetary probes, but I'm convinced it all has merit and will help us to better understand and interpret what we are looking at in Hubble, Spitzer and Chandra satellite images. I'm fascinated by the Hubble and Spitzer images just like you, but I'm also fascinated in the images from Mars. It's simply "all good" from my perspective.
     
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