Postcard from Cassini

Discussion in 'Astronomy, Exobiology, & Cosmology' started by Tiassa, Nov 28, 2012.

  1. Tiassa Let us not launch the boat ... Staff Member

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    Postcard from Cassini

    Taken yesterday:

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    Saturn Santa? At the North Pole of Saturn, via Cassini; Nov. 27, 2012.
    (NASA/JPL/SSI)

    I mean, come on. That's just so damn cool.

    Under ten hours from now, about 00:56 Pacific Time, Cassini will fly by Titan at a range of 630 miles (1,014 km).
    ____________________

    Notes:

    Cassini Solstice Mission. NASA Jet Propulsion Labortatory. http://saturn.jpl.nasa.gov/
     
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  3. RoccoR Registered Senior Member

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    Taissa, et al,

    Yes, that is cool, and --- as you elude to --- more to come.

    (COMMENT)

    I think that this type of science is easier for most of humanity to understand than the concepts dealing in the bogus Dark Energy and Dark Matter.

    Most Respectfully,
    R
     
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  5. prometheus viva voce! Registered Senior Member

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    What does this have to do with the thread topic, and what makes you think dark matter and dark energy are "bogus?"
     
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  7. RoccoR Registered Senior Member

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    prometheus, et al,

    I was merely commenting on the "WOW" factor of the science, and the tangible results of "Cassini." I, as a taxpayer, would further and promote this type of endeavor.

    (COMMENT)

    I, as a layman, was trying to make a distinction between the two types of research. One that I find productive and one I find rather dubious. I was not trying to tie the two together; much the opposite.

    For many of us who are just trying to understand, scientist - especially physicist and cosmologist, make some leaps and assumptions that make laymen skeptical.

    Most Respectfully,
    R
     
  8. rpenner Fully Wired Valued Senior Member

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    Laymen who assume that dark matter and dark energy are assumptions rather than inferences are probably not in the best position to judge the value of astrophysical research.
     
  9. orcot Valued Senior Member

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    Those are some fine pictures thank you for sharing them tiassa
     
  10. arauca Banned Banned

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    Can you get me one Kg of dark matter , or get me 10 Jouls of dark energy , the it is some thing real otherwise what you have
     
  11. rpenner Fully Wired Valued Senior Member

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    4,833
    An unreasonable request since the best estimates of local dark matter density is about 1 kg in a cube 11,000 to 14,000 km on a side and all conventional matter is powerless to constrain it so you can't build a dark matter pump or concentrator. Such "show-me" brand pseudo-skepicism is no substitute for scholarship, or you would put the assassination of Lincoln and the Taj Mahal in the same putative category of unknowables.
     
  12. RoccoR Registered Senior Member

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    144
    rpenner, et al,

    Yes, of course. While I did not make this mistake (this time), let's say - I'm not beyond making such a mistake.

    Noting, that I seldom write a dissenting view, rather opting to read an learn.

    (COMMENT)

    Laymen are they ones that fund research (all kinds).

    I not so sure that science has a complete handle on the fabric of space, gravity, and the impact of a an object as big as a galaxy that is spinning, that science knows what electromagnetic fields are being generated at the outer edge of the galaxy.

    As for the gravitational lensing effect, wouldn't you already expect light to bend around a galaxy that is distorting the fabric of space on such a huge scale? If the Sun can bend light, just imagine the effect a galaxy would have.

    The assumptions I was alluding to were not "dark matter or dark energy" themselves; but, the way we come to those inferences. As if we understand the accumulative effect of all the various forces involved, and not just the gravity. What is so amazing is the difference --- 4% (light matter and energy) of the universe versus 96% (dark M&E) of the universe. That is such a huge difference, that it doesn't even pass the smell test. I suggests that (as a laymen) something is being interpreted wrong.

    Most Respectfully,
    R
     
  13. Tiassa Let us not launch the boat ... Staff Member

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    37,225
    Brief note

    For what it's worth, I got your point.

    This is where I disagree. I wish I could understand the mathematics involved. We "know" that this is what we are supposed to be seeing. We know what we are seeing. The difference is explained by that cumulative effect of undiscovered origin. The question of that cumulative effect is the whole principle of "dark matter".

    The validity of dark matter is its necessity. The question marks are the physical properties describing this range of events in the Universe, and the specific pathways—relationship values of those physical properties—by which those events interact with and affect more "mundane", such as it is, events.

    And we move steadily closer to the answers.

    In the long run, it's not because it's dubious, but, rather, because the dark matter discussion is obscure, that it slips by the general public. Eventually, the answers will begin to emerge and thread into the culture, and people will start to wrap their heads around the importance of dark matter, but also its fascinating significance in human understanding.

    For now, though, people need really cool pictures, like that set from Cassini.
    ____________________

    Notes:

    Bayliss, Rachael. "Scientists see dark matter web between galaxies". Cosmos. July 5, 2012. CosmosMagazine.com. November 30, 2012. http://www.cosmosmagazine.com/news/5765/scientists-shine-light-dark-matter
     
  14. Janus58 Valued Senior Member

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    2,309
    You would expect it to bend light by a degree that corresponds to it mass. And that's just the point; the galaxies bend the light more than what you would expect for the visible mass. But it is not only by how much the light is bent, but how it is bent. Just like you can determine the shape of a lens by the way it bends light, you can determine how the mass of a galaxy is distributed by the way it bends light. The manner in which light bends around galaxies matches what which would be produced if dark matter halo existed
     
  15. youreyes amorphous ocean Valued Senior Member

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    2,830
    OMG the clarity...it is mind buggling to conceive the size of this event being larger than Earth itself...

    The Planet itself is a world in itself...

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  16. RoccoR Registered Senior Member

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    youreyes,

    Yes, it is most amazing and breathtaking.

    (COMMENT)

    It opens an entirely new perspective on the way it all comes together. Wonder!

    Most Respectfully,
    R
     
  17. RoccoR Registered Senior Member

    Messages:
    144
    Janus58, et al,

    I have to say that, there is much of this I don't understand. There are, clearly, observations that suggest that something is causing the expansion of the "fabric of space." That the "fabric of space" is not "nothingness" - but real. That the mass of stelar object can twist and wrap both space and (by extension) time. Certainly the Gravity Probe B make a very convincing case for the Earth's mass dragging the "fabric of space" around with it as it rotates; twisting it as it goes. So, it is becoming a convincing argument that the motion of a mass through space alters the path of light, as well as the movement (spin and velocity) alter the shape of the "fabric of space."

    (COMMENT)

    I agree, that a mysterious energy and matter could account for the observation. Yes, I agree. All the brilliant minds of the day essential support the idea. Just as they all agree that using Super Nova measurements (Dr Saul Perlmutter), the universe is expanding, as if the "fabric of space" (instead of being just elastic to give the impression of gravity as a force) was growing, giving the impression of an expanding universe.

    Einstein may not have been able to unity gravity with the other forces, because it is not a force at all. But Einstein did make a very convincing argument that space and time work together. So if space, in the fabric of space, is both elastic and expanding, then it is also creating a change in time.

    As you say, for which I cannot argue against, the consensus is that Dark Energy is the dominate "force" in the universe. But I tend to think differently. I think there are a lot of little pieces that have been observed, but are not put together correctly. We know that some galaxies spin, and we cannot begin to compute the effect that has, when we put it together with the orchestra of galaxies in its neighborhood that are also spinning and accelerating away from each other; as we observe the other galaxies from our own which is, itself spinning and accelerating. The combination of all these actions, like the little geek magnet toy on my desk that makes the various pieces spin and dance, takes a series of calculations that would choke a super computer.

    Yes, I agree there is something unexplained. I don't necessarily believe that it is some new and exotic energy or particle. If we understand the Solar System, the local "fabric of space" and how the system with revolving parts that spin within, which itself is system that is spinning, then we might be able to extrapolate all the associated fields (how they interact and affect each other) to something greater (like a galaxy). The reason we call it Dark Energy is because (as near as this layman can make-out) neither Quantum Mechanics or Relativity can explain it. So why suppose it is there? (Occam's Razor)

    But then, what do I know? (Nothing)

    Most Respectfully,
    R
     
  18. Janus58 Valued Senior Member

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    2,309
    You seem to be clumping dark matter and dark energy together. They are not related to each other and the only thing they share is the word "dark" in their names. "Dark" matter got its name by virtue of the fact that it apparently does not give off EM radiation. "Dark" energy got its name simply because we had already coined the phrase dark matter, so let's just make it easy on ourselves and call it dark energy.

    The evidence that dark matter is indeed some type of particle keeps growing. On the other hand, the nature of "dark energy" is still up in the air. Right now it is merely a placeholder term for whatever seems to cause the apparent acceleration of the universe's expansion.

    I also have to take issue with your implication that DM is an "exotic" particle. I think that this is indicative of what I call baryo-centrism. The idea that baryonic matter is somehow "normal" and non-baryonic matter is abnormal. By what criteria? Maybe we are the ones that are made from "exotic" particles and DM is the norm. This would seem to be bolstered by the apparent abundance of DM compared to baryonic matter, and DM does seem to be much simpler (none of that complicated electromagnetic interaction that allows for all those different elements and compounds to form.).
     
  19. Tiassa Let us not launch the boat ... Staff Member

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    Homeward View

    A Homeward View

    I posted this image here once before.

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    The color is obviously enhanced in this image, but here's the thing: There is a little blue dot to Saturn's left, just inside the G ring at about the ten o'clock position. That dot is Earth, from a billion miles away.

    You know, just one of those really cool things.
     
  20. RoccoR Registered Senior Member

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    144
    Tiassa,

    This is an amazing image. Thanks for pointing out Earth. That is something special in itself.

    (QUESTION)

    Coming off the outer ring area, there is this halo looking shadow and several outcroppings that look like jets. Do you know what they are?

    Most Respectfully,
    R
     
  21. RoccoR Registered Senior Member

    Messages:
    144
    Tiassa,

    This is an amazing image. Thanks for pointing out Earth. That is something special in itself.

    (QUESTION)

    Coming off the outer ring area, there is this halo looking shadow and several outcroppings that look like jets. Do you know what they are?

    Most Respectfully,
    R
     
  22. Tiassa Let us not launch the boat ... Staff Member

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    37,225
    Effect of Enhancement?

    Honestly, I think they're just artifacts of the color enhancement. That is, perhaps to a naked eye a million miles off Saturn, they wouldn't be visible, or, at least, nearly as prominent. The APOD caption for the picture:

    In the shadow of Saturn, unexpected wonders appear. The robotic Cassini spacecraft now orbiting Saturn recently drifted in giant planet's shadow for about 12 hours and looked back toward the eclipsed Sun. Cassini saw a view unlike any other. First, the night side of Saturn is seen to be partly lit by light reflected from its own majestic ring system. Next, the rings themselves appear dark when silhouetted against Saturn, but quite bright when viewed away from Saturn, slightly scattering sunlight, in this exaggerated color image. Saturn's rings light up so much that new rings were discovered, although they are hard to see in the image. Seen in spectacular detail, however, is Saturn's E ring, the ring created by the newly discovered ice-fountains of the moon Enceladus and the outermost ring visible above. Far in the distance, at the left, just above the bright main rings, is the almost ignorable pale blue dot of Earth.

    (Boldface and bold-italic accents added)

    What you're seeing is basically a diffusive effect of the rings themselves, especially the E ring, which is essentially made of ice crystals blown off Enceladus by cryovolcanic processes. So you're looking at a nebulous ring of swirling ice crystals that will have refractive and diffusive effects. The color enhancement for the image probably makes them stand out more than they otherwise would. It would take a better physicist than I—you know, like, someone who actually studies astronomy and physics—to describe the behavior of the crystals in the E-ring in such a manner as to reasonably assert the differences in density that might account for the apparent flare effect. But, barring a dirty lens or resolution issue with the CCD, I would expect diffusion of light to explain the phenomenon you note.

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    Ice geysers: Cassini image of cryovolcanic venting on Enceladus is the suspected origin of Saturn's E-ring.
    (NASA/JPL/SSI)
    ____________________

    Notes:

    Nemiroff, Robert and Jerry Bonnell. "In the Shadow of Saturn". Astronomy Picture of the Day. January 11, 2009. APOD.NASA.gov. December 3, 2012. http://apod.nasa.gov/apod/ap090111.html

    —————. "Cassini Flyby Shows Enceladus Venting". Astronomy Picture of the Day. November 24, 2009. APOD.NASA.gov. December 3, 2012. http://apod.nasa.gov/apod/ap091124.html
     
  23. RoccoR Registered Senior Member

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    144
    Tiassa

    Many thanks, brilliant photos.

    I especially liked the Ice Geysers. Who would have thought? Beautiful!

    v/r
    R
     

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