APOD: The Galactic Center in Infrared (2016 Jan 17)

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Expand view Topic review: APOD: The Galactic Center in Infrared (2016 Jan 17)

Re: APOD: The Galactic Center in Infrared (2016 Jan 17)

by Ron-Astro Pharmacist » Fri Jan 29, 2016 4:59 pm

If size is a separate dimension the force carrier between the scalar Higgs field and the vector graviton field should called a "demon"? :twisted:

I was attempted to suggest a "rovon" but that might be too self-satisfying. :wink: Fun but need to learn more about physics too. Been listening to chapters 7 and 8 and my imagination went crazy. :yes:

Re: APOD: The Galactic Center in Infrared (2016 Jan 17)

by Ron-Astro Pharmacist » Tue Jan 19, 2016 7:02 pm

I hate to beat a dead horse. :?

Any chance it's a dark horse? :ssmile:

Yes I know. Now I'm beating a dead dark horse. :bang:

Re: APOD: The Galactic Center in Infrared (2016 Jan 17)

by Ron-Astro Pharmacist » Mon Jan 18, 2016 6:05 pm

Chris Peterson wrote:
Ron-Astro Pharmacist wrote:
Chris Peterson wrote: Well, the problem is, the premise is inconsistent with any theory based on observation. So that kind of makes the rest of the conjecture fall apart.
And that's fine if you would choose to educate me on "why it's inconsistent" so I would learn of my error. That was another point in my post.
Because everything points to dark matter being some kind of non-baryonic particle that will fit into the Standard Model. And we don't find any such particles surrounding other matter. Particles that interact gravitationally and possibly via the weak nuclear force have no binding mechanism to link them to other matter in the ubiquitous manner you suggest. We'd expect large scale clumping due to gravity (which we observe, of course), and a low density of free particles zipping around, unbound, which is what current experiments are attempting to detect. Some new particle bound to all other particles would throw the Standard Model into disarray, and that's a theory that is very well supported.
Thanks for your reply Chris. Another useful purpose that lay people may serve in the scientific process is that we can claim ignorance and get away with crazy ideas. Someone with a formal education might get drummed right out of their profession... Not that it would even cross their minds. I just risk the wrath of Geck . :ohno: I do take that seriously let's say . :D

Re: APOD: The Galactic Center in Infrared (2016 Jan 17)

by Chris Peterson » Mon Jan 18, 2016 4:52 pm

Ron-Astro Pharmacist wrote:
Chris Peterson wrote:
Ron-Astro Pharmacist wrote:Let's say I suggest that dark matter surrounds all matter from the smallest quantum bit to the largest clusters of galaxies.
Well, the problem is, the premise is inconsistent with any theory based on observation. So that kind of makes the rest of the conjecture fall apart.
And that's fine if you would choose to educate me on "why it's inconsistent" so I would learn of my error. That was another point in my post.
Because everything points to dark matter being some kind of non-baryonic particle that will fit into the Standard Model. And we don't find any such particles surrounding other matter. Particles that interact gravitationally and possibly via the weak nuclear force have no binding mechanism to link them to other matter in the ubiquitous manner you suggest. We'd expect large scale clumping due to gravity (which we observe, of course), and a low density of free particles zipping around, unbound, which is what current experiments are attempting to detect. Some new particle bound to all other particles would throw the Standard Model into disarray, and that's a theory that is very well supported.

Re: APOD: The Galactic Center in Infrared (2016 Jan 17)

by Ron-Astro Pharmacist » Mon Jan 18, 2016 4:42 pm

Chris Peterson wrote:
Ron-Astro Pharmacist wrote:Let's say I suggest that dark matter surrounds all matter from the smallest quantum bit to the largest clusters of galaxies.
Well, the problem is, the premise is inconsistent with any theory based on observation. So that kind of makes the rest of the conjecture fall apart.
And that's fine if you would choose to educate me on "why it's inconsistent" so I would learn of my error. That was another point in my post.

I don't expect that every question be answered; sometimes that's too big an effort for which I would be rude to expect. After all we are all here just for the purpose of communication and enjoyment. :)

Re: APOD: The Galactic Center in Infrared (2016 Jan 17)

by Chris Peterson » Mon Jan 18, 2016 4:19 pm

Ron-Astro Pharmacist wrote:Let's say I suggest that dark matter surrounds all matter from the smallest quantum bit to the largest clusters of galaxies.
Well, the problem is, the premise is inconsistent with any theory based on observation. So that kind of makes the rest of the conjecture fall apart.

Re: APOD: The Galactic Center in Infrared (2016 Jan 17)

by Ron-Astro Pharmacist » Mon Jan 18, 2016 4:16 pm

Let's say I suggest dark matter surrounds all matter from the smallest quantum bit to the largest clusters of galaxies. It is functional in ways unique to each size dimension. In the atom's nucleus it functions to separate charge and spin forcing electrons to exist in shells and the nucleons to separate from the electrons.

In our galaxy its purpose is to confine and reuse matter internally making it a functionally separate yet still capable of combining with other galaxies similarly to the way smaller atoms can become more complex and complicated.

In the universe, clusters of galaxies and voids operate similarly providing integrity and a mechanism to prevent expansion to the point of a Big Rip.

The main theory being that dark matter functions such to allow mass to exist (possible in dimensions where imaginary numbers make sense?) with size providing a flow from small to large.

As a layman I may be functionally capable to present a grand theory but it would likely breakdown as professionals would critic. The main point being that a scientific method may have two purposes; it could drive layman to learn more as their theories are debunked while simultaneously stimulating the curiosity of the most educated if the thought happens to be profound.

That's why I like this site- it's a composite of both.

Who knows – as independent pieces of matter we could all be surrounded by an aura of dark matter that connects us to a universe we use daily in our unconscious mind but that's a theory for another day. :wink:

Re: APOD: The Galactic Center in Infrared (2016 Jan 17)

by geckzilla » Mon Jan 18, 2016 1:42 am

Jim Leff wrote:
Chris Peterson wrote: scientific thinking begins with an observation that suggests a question. That makes much more sense to them than the idea that it somehow starts with a hypothesis, and also makes it much easier for them to apply.
That's a distinction without a difference. Even if a hypothesis seemingly springs from deep within the recesses of a person's mind/imagination/intuition, it always stems from observation of some sort at some level. There is no such thing as a purely hermetic hypothesis.
I've got a few nutters around who seem to be able to pull hypotheses seemingly out of nowhere, based on nothing apparently based in reality.

Re: APOD: The Galactic Center in Infrared (2016 Jan 17)

by Jim Leff » Mon Jan 18, 2016 1:25 am

heehaw wrote: "I would not agree that there ever was a 'first' member," said the Cloud. McNeil did not understand this remark, but Kingsley and Marlowe exchanged a glance, as if to say 'Oh-ho, there we go. That's one in the eyes for the exploding universe boys.'

Way to nail it with the perfect, super-obscure quote!

Re: APOD: The Galactic Center in Infrared (2016 Jan 17)

by heehaw » Sun Jan 17, 2016 11:28 pm

Boomer12k wrote:. Fred Hoyle STILL does not accept the Expanding Universe. *
Fred Hoyle's universe has contracted severely, as will yours (and mine) in due course. I just re-read Fred's sci-fi novel "The Black Cloud," in which an intelligent interstellar cloud arrives at the Sun. Kingsley [Hoyle] communicates with it: page 156, "But it must have happened when the first member of your species arose," suggested McNeil. "I would not agree that there ever was a 'first' member," said the Cloud. McNeil did not understand this remark, but Kingsley and Marlowe exchanged a glance, as if to say 'Oh-ho, there we go. That's one in the eyes for the exploding universe boys.'

"look around for something interesting that inspires you to ask yourself how that happens"

by neufer » Sun Jan 17, 2016 7:56 pm

Chris Peterson wrote:
<<Once you understand things, the idea that you must first make an observation seems obvious, but I assure you, it is not obvious to most students. Framing it as "look around for something interesting that inspires you to ask yourself how that happens" takes the abstraction out of hypothesizing. The idea that all scientific inquiry begins with observation really is key to understanding.>>
https://en.wikipedia.org/wiki/Joseph_Plateau wrote:
<<Joseph Antoine Ferdinand Plateau (14 October 1801 – 15 September 1883) was a Belgian physicist. Fascinated by the persistence of luminous impressions on the retina, he performed an experiment in which he gazed directly into the sun for 25 seconds. He lost his eyesight later in his life, and attributed the loss to this experiment. However, this may not be the case, and he may have instead suffered from chronic uveitis.

Plateau studied the phenomena of capillary action and surface tension (Statique expérimentale et théorique des liquides soumis aux seules forces moléculaires, 1873). The mathematical problem of existence of a minimal surface with a given boundary is named after him. He conducted extensive studies of soap films and formulated Plateau's laws which describe the structures formed by such films in foams.>>

Re: APOD: The Galactic Center in Infrared (2016 Jan 17)

by neufer » Sun Jan 17, 2016 7:40 pm

Chris Peterson wrote:
There are actually a few papers on the subject of Bussard ramjets (which aren't current technology, of course) that consider how big the scoops would need to be, how much power would be required to sustain them, and how much thrust could be produced given different assumptions about ISM density and different possible fusion reactions.
One neat thing about Bussard ramjets is that they would probably need to use carbon as a catalyst in order to efficiently burn hydrogen via the CNO cycle. Hence, we could make good use of our obsolete fossil fuels (and/or excess population).
https://en.wikipedia.org/wiki/Bussard_ramjet#Feasibility wrote:
<<Since the time of Bussard's original proposal, it has been discovered that the region surrounding the sun has a much lower density of interstellar hydrogen than was believed at that time. T. A. Heppenheimer analyzed Bussard's original suggestion of fusing protons, but found the bremsstrahlung losses from compressing protons to fusion densities was greater than the power that could be produced by a factor of about 1 billion, thus indicating that the proposed version of the Bussard ramjet was infeasible. However Daniel P. Whitmire's 1975 analysis indicates that a ramjet may achieve net power via the CNO cycle, which produces fusion at a much higher rate (~1016 times higher) than the proton-proton chain.>>

Re: APOD: The Galactic Center in Infrared (2016 Jan 17)

by Chris Peterson » Sun Jan 17, 2016 7:33 pm

Jim Leff wrote:
Chris Peterson wrote: scientific thinking begins with an observation that suggests a question. That makes much more sense to them than the idea that it somehow starts with a hypothesis, and also makes it much easier for them to apply.
That's a distinction without a difference. Even if a hypothesis seemingly springs from deep within the recesses of a person's mind/imagination/intuition, it always stems from observation of some sort at some level. There is no such thing as a purely hermetic hypothesis.
I agree in principle, but if you try to explain the scientific method to middle school students, you'll immediately recognize the value of starting with observation, followed by questioning and then hypothesizing. Year after year I deal with students coming into the class who learned the classic "hypothesis is the first step" trope and are completely clueless about how to apply the scientific method. Once you understand things, the idea that you must first make an observation seems obvious, but I assure you, it is not obvious to most students. Framing it as "look around for something interesting that inspires you to ask yourself how that happens" takes the abstraction out of hypothesizing. The idea that all scientific inquiry begins with observation really is key to understanding.

Re: APOD: The Galactic Center in Infrared (2016 Jan 17)

by neufer » Sun Jan 17, 2016 7:25 pm

Jim Leff wrote:
Chris Peterson wrote:
scientific thinking begins with an observation that suggests a question. That makes much more sense to them than the idea that it somehow starts with a hypothesis, and also makes it much easier for them to apply.
That's a distinction without a difference. Even if a hypothesis seemingly springs from deep within the recesses of a person's mind/imagination/intuition, it always stems from observation of some sort at some level. There is no such thing as a purely hermetic hypothesis.
There are hermetically sealed Gedankenexperiments; e.g., Schrödinger's cat, Einstein's spaceship or elevator.

Re: APOD: The Galactic Center in Infrared (2016 Jan 17)

by Jim Leff » Sun Jan 17, 2016 7:22 pm

PS - I'd imagine there'd be some serious inefficiency involved in transferring errant H2 molecules from the "scoop" and into actual use...

Re: APOD: The Galactic Center in Infrared (2016 Jan 17)

by Chris Peterson » Sun Jan 17, 2016 7:21 pm

Jim Leff wrote:
Chris Peterson wrote: I think it's still uncertain if a Bussard ramjet or similar system could work in most interstellar space, where the ISM is very tenuous. It almost certainly could work in regions where the gas density is higher.
Oh, I wouldn't imagine that current ramjet tech would apply. Just wondering what the total volume of H2 scooped up at such speeds (from a reasonably-sized "scoop".... say <1km in width) might be....in typical space. To compute it from higher density areas would be cheating - I'd think it unlikely that most flight plans could include significant travel through such areas.
There are actually a few papers on the subject of Bussard ramjets (which aren't current technology, of course) that consider how big the scoops would need to be, how much power would be required to sustain them, and how much thrust could be produced given different assumptions about ISM density and different possible fusion reactions.

Re: APOD: The Galactic Center in Infrared (2016 Jan 17)

by neufer » Sun Jan 17, 2016 7:19 pm

Chris Peterson wrote:
neufer wrote:
Chris Peterson wrote:
(And I'd argue that the scientific method starts with making an observation, not making a hypothesis.)
The Scientific method STARTS with hypotheses (right or wrong) that are compatible with all well established observations...and which are often (but not always) stimulated by some new (though less well established) observations.
Suit yourself. There is no THE scientific method. I always teach my students that scientific thinking begins with an observation that suggests a question. That makes much more sense to them than the idea that it somehow starts with a hypothesis, and also makes it much easier for them to apply.
The important point is that BOTH observations & the making of (often crazy seeming) hypotheses are vitally important for science.

Hypotheses should be dismissed out of hand ONLY if they are INcompatible with well established observations, IMO.

(It is certainly permissible, however, for hypotheses to be dismissed by experimental scientists if they are untestable.)

Re: APOD: The Galactic Center in Infrared (2016 Jan 17)

by Jim Leff » Sun Jan 17, 2016 7:19 pm

Chris Peterson wrote: I think it's still uncertain if a Bussard ramjet or similar system could work in most interstellar space, where the ISM is very tenuous. It almost certainly could work in regions where the gas density is higher.
Oh, I wouldn't imagine that current ramjet tech would apply. Just wondering what the total volume of H2 scooped up at such speeds (from a reasonably-sized "scoop".... say <1km in width) might be....in typical space. To compute it from higher density areas would be cheating - I'd think it unlikely that most flight plans could include significant travel through such areas.

Re: APOD: The Galactic Center in Infrared (2016 Jan 17)

by Jim Leff » Sun Jan 17, 2016 7:15 pm

Chris Peterson wrote: scientific thinking begins with an observation that suggests a question. That makes much more sense to them than the idea that it somehow starts with a hypothesis, and also makes it much easier for them to apply.

That's a distinction without a difference. Even if a hypothesis seemingly springs from deep within the recesses of a person's mind/imagination/intuition, it always stems from observation of some sort at some level. There is no such thing as a purely hermetic hypothesis.

Re: APOD: The Galactic Center in Infrared (2016 Jan 17)

by Chris Peterson » Sun Jan 17, 2016 7:11 pm

Jim Leff wrote:I hope this isn't too much of a tangent, but all the talk of dust made me think about how unbelievably sparse even "thick" interstellar dust is.

Per this link in today's APOD, the most abundant interstellar molecule is H2. So I wonder whether even at this extreme sparseness, if a spacecraft going extremely fast - perhaps 50k-100k mph - might gather and use enough H2 to significantly boost its velocity? Or is it still a trivial amount even at those speeds (or an order of magnitude higher)?
I think it's still uncertain if a Bussard ramjet or similar system could work in most interstellar space, where the ISM is very tenuous. It almost certainly could work in regions where the gas density is higher.

Re: APOD: The Galactic Center in Infrared (2016 Jan 17)

by Jim Leff » Sun Jan 17, 2016 7:04 pm

I hope this isn't too much of a tangent, but all the talk of dust made me think about how unbelievably sparse even "thick" interstellar dust is.

Per this link in today's APOD, the most abundant interstellar molecule is H2. So I wonder whether even at this extreme sparseness, if a spacecraft going extremely fast - perhaps 50k-100k mph - might gather and use enough H2 to significantly boost its velocity? Or is it still a trivial amount even at those speeds (or an order of magnitude higher)?

Re: APOD: The Galactic Center in Infrared (2016 Jan 17)

by Chris Peterson » Sun Jan 17, 2016 7:01 pm

starsurfer wrote:
APOD Robot wrote:The Galactic Center itself appears on the left and is located about 30,000 light years away towards the constellation of the Archer (Sagittarius).
I thought the centre of the Milky Way was 26,000 light years from Earth?
When it comes to astronomical distances, 26,000 ly is probably well described as "about 30,000 ly", given that the likely uncertainty is greater than the difference. Or was when this APOD first ran. Actual estimates range from less than 24,000 to nearly 29,000, and may change yet again if we figure out better ways of determining this hard to measure value.

Re: APOD: The Galactic Center in Infrared (2016 Jan 17)

by starsurfer » Sun Jan 17, 2016 6:50 pm

Boomer12k wrote:
heehaw wrote:The American Astronomical Society met in Toronto, Canada, in August 1959, when I was 19 and already an astronomer. At the meeting, Ambartsumian suggested the presence of a blackhole at the center of our Galaxy, and I thought that was the stupidest idea I'd ever heard in my life!
They laughed in the early 70's when I said there were other planets around stars... I hope you were not one of those who laughed. But don't feel bad... Fred Hoyle STILL does not accept the Expanding Universe.
So we are all in good company... :lol2:

They nearly KILLED Galileo... :x


:---[===] *
Don't forget Nicolaus Copernicus as well. Truth is often stranger than fiction.

Re: APOD: The Galactic Center in Infrared (2016 Jan 17)

by starsurfer » Sun Jan 17, 2016 6:48 pm

APOD Robot wrote:The Galactic Center itself appears on the left and is located about 30,000 light years away towards the constellation of the Archer (Sagittarius).
I thought the centre of the Milky Way was 26,000 light years from Earth?

Re: APOD: The Galactic Center in Infrared (2016 Jan 17)

by Chris Peterson » Sun Jan 17, 2016 6:08 pm

neufer wrote:
Chris Peterson wrote:(And I'd argue that the scientific method starts with making an observation, not making a hypothesis.)
The Scientific method STARTS with hypotheses (right or wrong) that are compatible with all well established observations[/size]...and which are often (but not always) stimulated by some new (though less well established) observations.
Suit yourself. There is no THE scientific method. I always teach my students that scientific thinking begins with an observation that suggests a question. That makes much more sense to them than the idea that it somehow starts with a hypothesis, and also makes it much easier for them to apply.

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