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Featured Science continues to implode the "Big Bang" and billions of years!

Discussion in 'Creation & Theistic Evolution' started by nolidad, May 16, 2019 at 12:47 PM.

  1. nolidad

    nolidad Well-Known Member

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    1. Galaxies wind too fast!

    Our galaxy is a spiral galaxy! The inner stars are moving faster than the outer stars. If our galaxy was more than a few hundred million years- it would be just a featureless disc. One theory that was popular and then failed was called density wave theory. It was abolished when they discovered what has been dubbed the spiral whirpool galaxy.

    2. Too few supernovae.

    According to astronomical observations, galaxies like ours experience a supernova about every 25 years. But all available galaxies we observe only show gas and dust remnants from supernovae that are consistent with a 7,000 year universe.

    3. Comets disintegrate too quickly.

    Secular astronomers theorize that comets are the same age as our universe, c. 5 billion years.

    But as comets pass near the sun, they lose so much mass that they could only be 100,000 years at most. The bb'ers have advanced that new comets from an unproven, unseen, un verifiable "oort" cloud so thus renewing comets often. But that is fantasy solving a problem.

    4. time and distance problem.

    If the big bang occurred c. 14 billion years ago as hypothesized, there is an enormous problem We have seen galaxies 13.2 bly distant from us! That means under standard bb cosmology, the light we are seeing from that distant galaxy took 13.2 billion years at light speed to reach us! This poses an unsolvable problem for the big bang. The universe is hypothesized to be 13.8 billion years ols from the time of the big bang. this means that the 13.2 billion light year distant galaxy had to travel at 20X the speed of light to reach that point in space time (and form itself from energy to matter to clumps to planets and stars at waRP 20) in 600 million years to shine the light as a fully formed galaxy with millions of stars that is reaching us now!

    The most scientific statement about the universe is still Genesis 1:1

    In the beginning God created the heaven and the earth.
     
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  2. crossnote

    crossnote Berean Supporter

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    Oh NO!, Does this mean I am going to age another few Billion years in the next 10 years? LOL
     
  3. nolidad

    nolidad Well-Known Member

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    Only if you travel at warp 20! LOL
     
  4. myst33

    myst33 Well-Known Member

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    You have been reading icr.org again? :)
     
  5. nolidad

    nolidad Well-Known Member

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    I love reading that scientific web site.

    Not just teh acts and facts blurbs, but the research and technical; papers that go into great depth showing their research! I respect it more than AIG and far more than talkorigins.:ebil:
     
  6. myst33

    myst33 Well-Known Member

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    Try to google the issues outside of creationist webpages and you will see that the BBT is still there.
     
  7. The Barbarian

    The Barbarian Crabby Old White Guy

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    And the Gish Gallop continues...


    Spiral galaxies, such as the one above (M101), are generally medium- to large-sized congregations of stars. They have either a bulge in the center or a bar in the center. The bulk of the galaxy is a disk (much wider than it is thick) that contains spiral arms. For more basic information on galaxies, see this link.


    The feature in question in creationist circles is these subjectively beautiful spiral arms themselves. The trick is that these arms are not “solid.” It is not the case that stars either always exist within a spiral arm or they always exist outside of an arm. Rather, the arms are constantly picking up stars and losing others. What the arms represent are just density waves.


    The common analogy to think of is cars on a highway. You may be driving along with many dozens or hundreds of meters between you and the car in front of you. Then, for no apparent reason, you start to get much closer to the car in front of you. And then, for the next several kilometers, there are only maybe five to ten meters between you and the car ahead of you. Afterwards, traffic seems to thin out again and there’s a large distance between you and the next car.


    What you have just experienced is a density wave. You are a star, traveling the road that is an orbit around the galaxy, and every now-and-then you find yourself in a density wave where you have to slow down.


    The mechanism that perpetuates the density waves – why they don’t just dissipate – is that as a star approaches a density wave, it will speed up slightly due to the gravity of the stars there. And as a star is about to leave a density wave, it will slow down a little, again because of the higher gravity there. So they won’t just smooth out over time.


    How did the spiral arms get there in the first place? The main idea here is that all you need is a disk of stars. Stars closest to the center of the disk will need to rotate around it faster than those near the edge, just like planets in our solar system (Mercury’s velocity around the sun is much faster than Earth’s). This can easily set up the initial differential rotation needed to start them.


    In addition to this, stars do not orbit on circular paths, rather on elliptical ones (Kepler’s first law). When farthest from the center, their velocity will be at its slowest (Kepler’s second law). When you have just a few extra stars traveling a little slower in some parts of a differentially rotating disk, then you will get spiral patterns.
    Creationist Claim: Spiral Galaxies “Wind Up” Too Fast for an Old Universe

    The Whirlpool’s most striking feature is its two curving arms, a hallmark of so-calledgrand-design spiral galaxies. Many spiral galaxies possess numerous, loosely shaped arms which make their spiral structure less pronounced. These arms serve an important purpose in spiral galaxies. They are star-formation factories, compressing hydrogen gas and creating clusters of new stars. In the Whirlpool, the assembly line begins with the dark clouds of gas on the inner edge, then moves to bright pink star-forming regions, and ends with the brilliant blue star clusters along the outer edge. Some astronomers believe that the Whirlpool’s arms are so prominent because of the effects of a close encounter with NGC 5195, the small, yellowish galaxy at the outermost tip of one of the Whirlpool’s arms. At first glance, the compact galaxy appears to be tugging on the arm. Hubble’s clear view, however, shows that NGC 5195 is passing behind the Whirlpool. The small galaxy has been gliding past the Whirlpool for hundreds of millions of years. As NGC 5195 drifts by, its gravitational muscle pumps up waves within the Whirlpool’s pancake-shaped disk. The waves are like ripples in a pond generated when a rock is thrown in the water. When the waves pass through orbiting gas clouds within the disk, they squeeze the gaseous material along each arm’s inner edge. The dark dusty material looks like gathering storm clouds. These dense clouds collapse, creating a wake of star birth, as seen in the bright pink star-forming regions. The largest stars eventually sweep away the dusty cocoons with a torrent of radiation, hurricane-like stellar winds, and shock waves from supernova blasts. Bright blue star clusters emerge from the mayhem, illuminating the Whirlpool’s arms like city street lights. The Whirlpool is one of astronomy's galactic darlings. Its beautiful face-on view and closeness to Earth allow astronomers to study a classic spiral galaxy’s structure and star-forming processes.
    http://amazingspace.org/uploads/pdf/name/14/lp_the_whirlpool_galaxy_and_companion_galaxy.pdf

    [​IMG]

    Obviously the small galaxy nearby, is distorting the shape of the whirlpool galaxy. No one is puzzled about this; creationists hide the facts to make a convincing story.

    I'm going to break up this mishmash of unrelated claims into single posts...
     
  8. The Barbarian

    The Barbarian Crabby Old White Guy

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    Next scam up. This is a really interesting one, because it evolves an especially egregious attempt to deceive on the part of a major creationist group.

    There is a young-Earth creationism argument that goes as follows: Stars that are much more massive than the Sun end their lives by exploding their outer layers into space in a process called a “supernova.” These outer layers of stellar debris are heated and lit up by the energy from the supernova event. The claim then goes that there is a certain expected rate of these (this particular article claims 1 every 25 years in our Milky Way galaxy). Then, if you take the number of observed remnants (around 200) and multiply by the rate of occurrence, you get an age of our galaxy of around 5000 years.


    Seems pretty bad for a 13.7-billion-year-old Universe, right? Well sure it does when you’re fed half-truths.


    The real story is a little more complicated, though I’m going to work a little backwards through this problem. First, almost no astronomer says that a supernova should occur in our galaxy once every 25 years. Rather, the canonical number is about 1 every 100 years (in fact, this was featured in an episode of Star Trek Voyager, “The Q and the Gray”). Revisions over the past few years have pinned it down more at once every 50 years.


    So now, if we do straight multiplication, we have about 50 * 200 = 10,000 years. Isn’t that exactly what creationists say (more or less) the age of the Universe should be? Yep, but there’s more.


    We cannot observe supernova remnants across our entire galaxy – basically nebulae. Supernova events we can see across the visible universe, but the actual gaseous remnants are much fainter because they are more diffuse. Because of dust and gas in the way, we cannot see all the objects in our own Galaxy. Probably the farthest we can see into the galaxy is maybe to a distance of 10,000 light-years. The galaxy is about 100,000 light-years across. Doing a simple calculation of the area of a disk 10,000 light-years vs. 100,000 light-years (but 50,000 light-years in radius) yields an area of our galaxy about 25 times larger that we can NOT survey for supernova remnants vs. what we can.


    So now, we need to multiply our 10,000 years by 25, giving us 250,000 years for the age of the galaxy.


    The next part is that supernova remnants don’t just form out of nothing, they form from the explosions of dying stars. The stars that live and die the fastest still take about 10,000,000 years before they “go nova” and release a cloud of debris that will later become what we observe. That’s pretty much the minimum time a star can “live” during the current epoch of the Universe. Only after that will we see a supernova form.


    So, add that to our estimate of the age by the number of stars and we have 10,250,000 years, or 10.25 million years for the age of the galaxy. You should note at this point I’ve been saying “age of the galaxy.” That’s because this would only be used to date our galaxy, not the Universe as a whole. So you need to add in the time for galaxy formation … which is still a number that’s hotly debated, but no respected astronomer will say happens instantaneously.


    BUT, there’s another complication to this situation which shows why this apparent “method” for dating our galaxy isn’t valid: Supernova remnants fade! They only are visible for a few tens of thousands of years. What does this mean for our estimate of 1,000,000 years for the age of our galaxy? Well, by the time the “oldest” supernova is fading, we starting to observe supernova 200! We should only expect to see in the neighborhood of a few hundred supernova remnants in our vicinity, regardless of how old our galaxy actually is.
    Why Few Supernova Remnants Do NOT Indicate a Young Universe


    The interesting part of this is that among various astronomers who have determined the number of SNRs we should be able to see are D.H. Clark and J. Caswell, who authored a paper about it. "Answers in Genesis" cited the paper, saying that Clark and Caswell claimed that the number of remnants was a "mystery." However...

    Jonathan Sarfati, another frequent contributor to your creationist perspective website, is no better. In his article “Exploding Stars Point to a Young Universe: Where Are All The Supernova Remnants?” first published in Creation Ex Nihilo 19:46-48 and later online at Astronomy, Sarfati tries to claim that the absence of Type III supernovas suggests that the universe is young, perhaps a few thousand years old, not billions of years as evolutionary scientists claim. He offers the following quote from Clark and Caswell in Monthly Notices of the Royal Astronomical Society, 1976, 174:267:

    "As the evolutionist astronomers Clark and Caswell say, ‘Why have the large number of expected remnants not been detected?’ and these authors refer to ‘The mystery of the missing remnants’."

    Sarfati conveniently forgot to finish the last sentence, which actually appears on page 301. In its entirety, it reads

    "…and the mystery of the missing remnants is also solved."
    Answers in Genesis BUSTED!: The Deception of True.Origin


    On to the next scam...
     
  9. The Barbarian

    The Barbarian Crabby Old White Guy

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    This one is particularly irrational, since even someone completely ignorant of astronomy would see the holes in it with a little thought...

    First, the solar system, not the universe, is about 4.5 billion years old. Notice, that our enthusiastic Gish Galloper seems to not have even read the stuff he's throwing up here; the next scam, he's posting stuff saying the universe is thought to be 14 billion years old. such are the hazards of thoughtless cut and paste.

    But let's look at this one and see what else is faulty...

    1. Short-period comets come from the Kuiper Belt, not the Oort cloud. We know it exists, and that new comets come from that belt, because orbiting telescopes and planetary probes have visually identified objects there. We knew it was there and that it was a belt, because Kepler's laws allow us to find the period and aphelion of comets by observing a portion of their orbits. And because short-period comets always come in along the plane of the solar system. And yes, from time to time, new short period comets show up. How do we know they are new? Because we have thousands of years of data from astronomers, including three hundred years of telescope data.

    Long-period comets have orbital periods up to a million years. So again, by Kepler's laws, we know where the aphelia of these comets are. And they come in from all directions, so we know it's not a belt, but a cloud of comet-like objects surrounding the solar system.

    The other obvious question is:"how, if the universe is 6,000 years old, do we see comets with orbital periods of a million years? They would (Newton's laws) have to have started at their aphelion, and that would mean at least 500,000 years to get to the perheilion when they round the sun and head back out.

    Of all the claims, this one seems the most obviously bone-headed.

    On to the next...
     
  10. The Barbarian

    The Barbarian Crabby Old White Guy

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    In Petit's VSL model, the variation of the speed of light c accompanies the joint variations of all physical constants combined to space and time scale factors changes, so that all equations and measurements of these constants remain unchanged through the evolution of the universe. The Einstein field equations remain invariant through convenient joint variations of c and G in Einstein's constant. According to this model, the cosmological horizon grows like R, the space scale, which ensures the homogeneity of the primeval universe, which fits the observational data. Late-model restricts the variation of constants to the higher energy density of the early universe, at the very beginning of the radiation-dominated era where spacetime is identified to space-entropy with a metric conformally flat.
    Horizon problem - Wikipedia

    And that ends our latest gallop.

    Nope. All scientific theories must be at least conceivably falsible. And since this can't be scientifically tested, it's a religious belief, not science. It'strue, though.

    You see, it's O.K. to be unscienfic when the situation calls for it. I am often unscientific myself.
     
  11. nolidad

    nolidad Well-Known Member

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    All the verbage to prove nothing.

    And your little ad-hom about Dwane Gish just debases most of what you have to say!

    Facts:

    Spiral galaxies are winding- that is empirical! Based on observed speeds of winding up- they cannot have existed for billions of years. Fact.

    Astronomy cannot prove anything they have not observed- they can only hypothesize! Fact.

    But I will give you a shot here.

    Please explain this:

    1. We are now seeing light from 13.2 billion years in the past from distant galaxies. Now we know that the galaxy is no longer in that place in space time.

    2. These are declared very ancient galaxies that were in that place in space time 13.2 billion light years ago to shine the light we are seeing now!

    3. The universe is 13.78 (lets call it 13.8 for ease sake) billion years old from when the alleged singularity blew up! Or whatever they may now call it! I prefer a quantum flatulence!

    4. So how did that galaxy get to that quadrant of space time in 600 million years after teh Big Bang to shine light that took 13.2 billion light years to reach us?

    5. Did it travel at 20X the speed of light (it had to) and at the same time gather the alleged dust and particles and matter required to form millions or billions of starts all while travelling at 3,720,000 miles per second? Now I know space is expanding, but it does not expand faster than light! As of now, there is nothing known that travels faster than light!
     
  12. The Barbarian

    The Barbarian Crabby Old White Guy

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    I'm just showing you that the one exception you thought would save your idea, turns out to be due to the gravitational effects of neighboring dwarf galaxy.

    As you learned, astronomers have found why it appears so. But not the reason you thought.

    You now know that they only appear to be winding.

    They observe those effects in countless galaxies.

    There was no explosion. "Big Bang" was a scoffing nickname given to the theory by an atheist, who was put out by the Christian who formed it. Mostly because it implied a created universe, not an eternal one.

    You do realize that the expansion was an expansion of space, not an explosion, right?

    In Petit's VSL model, the variation of the speed of light c accompanies the joint variations of all physical constants combined to space and time scale factors changes, so that all equations and measurements of these constants remain unchanged through the evolution of the universe. The Einstein field equations remain invariant through convenient joint variations of c and G in Einstein's constant. According to this model, the cosmological horizon grows like R, the space scale, which ensures the homogeneity of the primeval universe, which fits the observational data. Late-model restricts the variation of constants to the higher energy density of the early universe, at the very beginning of the radiation-dominated era where spacetime is identified to space-entropy with a metric conformally flat.
    Horizon problem - Wikipedia
     
  13. nolidad

    nolidad Well-Known Member

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    Well for a scoffing response- the term Big Bang has found its way in legions of science textbooks, articles, seminars ans tv shows by folks like De-Grasse who is not a scoffer. So if teh evolutionary cosmologists use it we shall also!

    Well if we had an eternal universe- then it would have been a dead universe- 2nd law is a b****! Can't be broken- all energy goes from kinetic to entropic in a closed system and the universe is a closed system.

    Petit presents a model. Models are not facts but ideas. If one believes it- they believe it not proven it!~

    Petit still doesn't answer how a galaxy can travel 13.2 billion light years in 600 million years after the quantum Fart!

    It was Sir Fred Hoyle a very famous scientist who coined the term big bang! LeMaitre may have been a priest, but being a priest does not make one a Christian anymore than living in a garage makes one a car!

    No spiral galaxies are winding.

    1. Galaxies wind themselves up too fast.

    The stars of our own galaxy, the Milky Way, rotate about the galactic center with different speeds, the inner ones rotating faster than the outer ones. The observed rotation speeds are so fast that if our galaxy were more than a few hundred million years old, it would be a featureless disc of stars instead of its present spiral shape.1 Yet our galaxy is supposed to be at least 10 billion years old. Evolutionists call this "the winding-up dilemma," which they have known about for fifty years. They have devised many theories to try to explain it, each one failing after a brief period of popularity. The same "winding-up" dilemma also applies to other galaxies. For the last few decades the favored attempt to resolve the puzzle has been a complex theory called "density waves."1 The theory has conceptual problems, has to be arbitrarily and very finely tuned, and has been called into serious question by the Hubble Space Telescope's discovery of very detailed spiral structure in the central hub of the "Whirlpool" galaxy, M51.2

    1. Scheffler, H. and Elsasser, H., Physics of the Galaxy and Interstellar Matter, Springer-Verlag (1987) Berlin, pp. 352-353, 401-413.
    2. D. Zaritsky, H-W. Rix, and M. Rieke, Inner spiral structure of the galaxy M51, Nature 364:313-315 (July 22, 1993
    All non YEC folk

    New Galaxy Model Leaves Old Questions Unanswered
    Distant Galaxies Look Too Mature for Big Bang

    And the density wave hypothesis to answer this problem has been roundly rejected by both sides of teh aisle!
     
  14. The Barbarian

    The Barbarian Crabby Old White Guy

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    The scoffer who disagreed with the Christian who proposed the Big Bang theory was an atheist.

    You still don't get it. There wouldn't be an eternal universe. God is eternal; everything else is created.

    Not all energy is kinetic. And if you're like most creationists, you have no idea what the 2nd law of thermodynamics actually involves. What do you think the second law says?

    And because it account for so much of the observable universe, it's well-accepted.

    It was Sir Fred Hoyle a very famous scientist who coined the term big bang! LeMaitre may have been a priest, but being a priest does not make one a Christian anymore than living in a garage makes one a car!

    No spiral galaxies are winding.

    Radiating out from the central nucleus come any number of spiral arms -- usually between two and four -- that wrap around the galaxy as they spiral outward. One of the fantastic discoveries we made in the 1970s, quite contrary to our expectations, is that the stars don't move slower in their orbital speed around the galaxy as you move outward, the way planets orbit our central star more slowly the farther out you go. Instead, the speed remains constant, which is another way of saying that the galactic rotation curves have flat profiles.
    Ask Ethan: Why Aren't Spiral Galaxies More Wound Up?

    [​IMG]
    Figure 1 - The predicted (A) and observed (B) rotation curve of a galaxy (the orbital velocity as a function of distance from the center of a galaxy).
    The Age of the Earth - Spiral Galaxies as a Creationist Clock: Mike Janssen


    No, they don't. See above.

    You've been misled, yet again. The existence of density waves, and the mechanisms for them have been repeatedly demonstrated:

    Journal reference: Nature Astronomy (2019)

    DOI: 10.1038/s41550-018-0627-5

    Astrophysics > Astrophysics of Galaxies

    A direct test of density wave theory in a grand-design spiral galaxy


    Thomas Peterken, Michael Merrifield, Alfonso Aragon-Salamanca, Niv Drory, Coleman Krawczyk, Karen Masters, Anne-Marie Weijmans, Kyle Westfall

    (Submitted on 21 Sep 2018 (v1), last revised 13 May 2019 (this version, v3))
    The exact nature of the arms of spiral galaxies is still an open question. It has been widely assumed that spiral arms in galaxies with two distinct symmetrical arms are the products of density waves that propagate around the disk, with the spiral arms being visibly enhanced by the star formation that is triggered as the passing wave compresses gas in the galaxy disk. Such a persistent wave would propagate with an approximately constant angular speed, its pattern speed Op. The quasi-stationary density wave theory can be tested by measuring this quantity and showing that it does not vary with radius in the galaxy. Unfortunately, this measurement is difficult because Op is only indirectly connected to observables such as the stellar rotation speed. Here, we use the detailed information on stellar populations of the grand-design spiral galaxy UGC 3825, extracted from spectral mapping, to measure the offset between young stars of a known age and the spiral arm in which they formed, allowing the first direct measure of Op at a range of radii. The offset in this galaxy is found to be as expected for a pattern speed that varies little with radius, indicating consistency with a quasi-stationary density wave, and lending credence to this new method.

    Note the date.
     
  15. nolidad

    nolidad Well-Known Member

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    Hoyle was more an ID kind of guy!

    Oh I do get it!

    But the ones you rely on more than the Words of God have proposed either an eternal universe or nothing creating everything.

    all energy is moving from kinetic (active) to entropic( expended) that is the 2nd law.

    The Second Law of Thermodynamics states that the state of entropy of the entire universe, as an isolated system, will always increase over time. The second law also states that the changes in the entropy in the universe can never be negative.

    Well that 1970's discovery was negated by the 1980's study that the core of spiral galaxies move faster than the arms!

    1. Scheffler, H. and Elsasser, H., Physics of the Galaxy and Interstellar Matter, Springer-Verlag (1987) Berlin, pp. 352-353, 401-413.
    No I have not been misled- they still are only speculating! And the article even says so!

    They speculate that the arms are immaterial !

    "Originally, astronomers had the idea that the arms of a spiral galaxy were material. However, if this were the case, then the arms would become more and more tightly wound, since the matter nearer to the center of the galaxy rotates faster than the matter at the edge of the galaxy.[6] The arms would become indistinguishable from the rest of the galaxy after only a few orbits. This is called the winding problem.[7]

    Lin and Shu proposed in 1964 that the arms were not material in nature, but instead made up of areas of greater density, similar to a traffic jam on a highway. The cars move through the traffic jam: the density of cars increases in the middle of it. The traffic jam itself, however, moves more slowly.[1] In the galaxy, stars, gas, dust, and other components move through the density waves, are compressed, and then move out of them."

    This is foolishness at its height.!
     
  16. The Barbarian

    The Barbarian Crabby Old White Guy

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    Why do you think this universe is a closed system?


    You've been misled...
    Journal reference: Nature Astronomy (2019)
    DOI: 10.1038/s41550-018-0627-5
    Astrophysics > Astrophysics of Galaxies
    A direct test of density wave theory in a grand-design spiral galaxy
    Thomas Peterken, Michael Merrifield, Alfonso Aragon-Salamanca, Niv Drory, Coleman Krawczyk, Karen Masters, Anne-Marie Weijmans, Kyle Westfall
    (Submitted on 21 Sep 2018 (v1), last revised 13 May 2019 (this version, v3))
    The exact nature of the arms of spiral galaxies is still an open question. It has been widely assumed that spiral arms in galaxies with two distinct symmetrical arms are the products of density waves that propagate around the disk, with the spiral arms being visibly enhanced by the star formation that is triggered as the passing wave compresses gas in the galaxy disk. Such a persistent wave would propagate with an approximately constant angular speed, its pattern speed Op. The quasi-stationary density wave theory can be tested by measuring this quantity and showing that it does not vary with radius in the galaxy. Unfortunately, this measurement is difficult because Op is only indirectly connected to observables such as the stellar rotation speed. Here, we use the detailed information on stellar populations of the grand-design spiral galaxy UGC 3825, extracted from spectral mapping, to measure the offset between young stars of a known age and the spiral arm in which they formed, allowing the first direct measure of Op at a range of radii. The offset in this galaxy is found to be as expected for a pattern speed that varies little with radius, indicating consistency with a quasi-stationary density wave, and lending credence to this new method.

    Note the date.

    You've been snookered. Even your galaxy exception turns out to be an artifact of the gravitational pull of nearby galaxy. It's really clear. If the speed of rotation varies little from the edge to the center (and we can measure it, and is doesn't vary much) then it can't be winding.

    No excuses for you.
     
  17. nolidad

    nolidad Well-Known Member

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    Because it is a UNIVERSE! Not a biverse or triverse or string dimensions or we are one of trillions of universes!

    But it has been empirically demonstrated that the centers are spinning faster than the outer arms. Sorry but you are just being disingenuous.

    Your whole quote is filled with supposition and untested conclusions. It may lend credence- but it is still not past the hypothesis stage.

    Some on your side have even suggested that these spiral arms are not even made of matter!

    It seems we can choose 1 from column A 1 from Column B 1 from Column C etc.etc.etc.
     
    Last edited: May 19, 2019 at 3:27 PM
  18. The Barbarian

    The Barbarian Crabby Old White Guy

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    Nope. In fact, astronomers have found that the centers turn about the same speed as the edges. I already showed you that, twice.

    Journal reference: Nature Astronomy (2019)
    DOI: 10.1038/s41550-018-0627-5
    Astrophysics > Astrophysics of Galaxies
    A direct test of density wave theory in a grand-design spiral galaxy
    Thomas Peterken, Michael Merrifield, Alfonso Aragon-Salamanca, Niv Drory, Coleman Krawczyk, Karen Masters, Anne-Marie Weijmans, Kyle Westfall
    (Submitted on 21 Sep 2018 (v1), last revised 13 May 2019 (this version, v3))
    The exact nature of the arms of spiral galaxies is still an open question. It has been widely assumed that spiral arms in galaxies with two distinct symmetrical arms are the products of density waves that propagate around the disk, with the spiral arms being visibly enhanced by the star formation that is triggered as the passing wave compresses gas in the galaxy disk. Such a persistent wave would propagate with an approximately constant angular speed, its pattern speed Op. The quasi-stationary density wave theory can be tested by measuring this quantity and showing that it does not vary with radius in the galaxy. Unfortunately, this measurement is difficult because Op is only indirectly connected to observables such as the stellar rotation speed. Here, we use the detailed information on stellar populations of the grand-design spiral galaxy UGC 3825, extracted from spectral mapping, to measure the offset between young stars of a known age and the spiral arm in which they formed, allowing the first direct measure of Op at a range of radii. The offset in this galaxy is found to be as expected for a pattern speed that varies little with radius, indicating consistency with a quasi-stationary density wave, and lending credence to this new method.


    Note the date.

    The truth isn't going to change for you.
     
  19. The Barbarian

    The Barbarian Crabby Old White Guy

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    Show us your evidence for that.

    Nope. I showed you twice that they aren't. One more time...

    The quasi-stationary density wave theory can be tested by measuring this quantity and showing that it does not vary with radius in the galaxy. Unfortunately, this measurement is difficult because Op is only indirectly connected to observables such as the stellar rotation speed. Here, we use the detailed information on stellar populations of the grand-design spiral galaxy UGC 3825, extracted from spectral mapping, to measure the offset between young stars of a known age and the spiral arm in which they formed, allowing the first direct measure of Op at a range of radii. The offset in this galaxy is found to be as expected for a pattern speed that varies little with radius, indicating consistency with a quasi-stationary density wave, and lending credence to this new method.

    Everyone can see how they tested their hypotheses. And notice that results of the tests confirm the hypotheses. No point in denying it.
     
  20. The Barbarian

    The Barbarian Crabby Old White Guy

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