APOD 15/04/06

Post a reply


This question is a means of preventing automated form submissions by spambots.
Smilies
:D :) :ssmile: :( :o :shock: :? 8-) :lol2: :x :P :oops: :cry: :evil: :roll: :wink: :!: :?: :idea: :arrow: :| :mrgreen:
View more smilies

BBCode is ON
[img] is ON
[url] is ON
Smilies are ON

Topic review
   

Expand view Topic review: APOD 15/04/06

by l3p3r » Wed Apr 19, 2006 2:41 am

Thanks Qev! I follow now :)

by BMAONE23 » Tue Apr 18, 2006 1:57 pm

Gravity can be considered to be similar to Love in thet it can be a mutual attraction between two bodies. If the attraction is mutual and the mass is similar, they might lock in a symbiotic relationship of a permanent (?) binary pair. If the mass is too dissimilar and the attractive force is greater in one then it might eventually consume the other or cast it out.


Sounds like a few relationships I know of.

by harry » Tue Apr 18, 2006 1:06 pm

Hello all

Has anybody seen a bush fire.

I have seen a fire ball jump over 500 meters looking for dry organic matter.

What makes this attraction? How does it know? Is it the dry organic matter attracting the fire ball or is the fire making the action, or is it both.

Similar with gravity who does the pulling or is it both.

by Qev » Mon Apr 17, 2006 6:00 pm

l3p3r wrote:
Wouldn't it be either a field or a geometry, and always a force?
can you explain what you mean?
Gravity is one of what we call the 'fundamental forces'. How this force is actually manifest in the universe, however, is open to theorizing. Einstein considered the gravitational force to be a product of space-time curvature, ie. geometry. Quantum mechanical explanations usually consider gravity a field of potential, much like a magnetic field (with obvious differences).

So, gravity is always a 'force' (the 'force of gravity'), but whether it's a field or product of curvature is still open to debate. :)

by l3p3r » Mon Apr 17, 2006 5:12 am

Wouldn't it be either a field or a geometry, and always a force?
can you explain what you mean?

by astroton » Sun Apr 16, 2006 9:10 am

Qev,

Your corrections noted. Yep, afterall it's about the geometory.

I think, there has to be another law. "Entities with better geometory has better power."

That explains woman power too. :lol:

by Qev » Sun Apr 16, 2006 7:52 am

astroton wrote:Yup, Gravity is both a force and a field. Depends which theory you invoke to explain what behavior.
Wouldn't it be either a field or a geometry, and always a force? :)
M82 is a galaxy under turmoil; it's another thing that it appears, like a vulnerable woman fearful of seemingly tranquil but mighty man in M81, in APOD picture. :roll: :lol:
Isn't it usually the guy who's tearing himself apart over the seemingly serene woman? :lol:

by astroton » Sun Apr 16, 2006 4:59 am

Yup, Gravity is both a force and a field. Depends which theory you invoke to explain what behavior.

M82 has a black hole. Interestingly, M82 has been under scrutiny for a long period of time. I was recently reading a book written in 70's, which describes black holes with lots of skepticism and describes early debate on quasars as radio stars. The book has a picture of M82 as an active galaxy.

M82 is a galaxy under turmoil; it's another thing that it appears, like a vulnerable woman fearful of seemingly tranquil but mighty man in M81, in APOD picture. :roll: :lol:

by Qev » Sun Apr 16, 2006 4:14 am

The disruptions caused by close encounters between galaxies are due to tidal effects, pretty much as l3p3r described. Galaxies, being extended objects, will often encounter situations where one part of them will be interacting more strongly with a neighbor galaxy than a more distant part of them. This causes things to get rather 'stirred up'.

In regards to the Magellanic Clouds, the Milky Way is slowly disrupting its closes satellite galaxies, and eventually they'll be consumed and made part of their larger neighbor. It'll take a while. :lol: The Milky Way's gravity certainly has an effect on its neighbors; one of the most intense-known star forming regions, 30-Doradus, is located in the Large Magellanic Cloud.

Gravity affects all matter, regardless of spin, depending solely on the masses involved. All fermions, by the way (including quarks, protons, neutrons, and electrons), are spin-1/2 particles; but spin-1 particles (known as bosons) are equally affected. Gravity will most certainly deflect the path of a beam of light, comprised of 'massless', spin-1 photons. The term 'spin' was most certainly chosen since the term is referring to a particle's quantum angular momentum; however, I honestly don't understand what quantum angular momentum really means, since it's not quite the same thing as the angular momentum a macroscopic spinning object possesses; at least, not as far as I know.

Gravity is the least-well understood of the 'fundamental forces', as they're often termed. Under General Relativity, gravity is simply the curvature of spacetime itself, as caused by the presence of matter. Under quantum theories, gravity is a field of some sort, and therefore also has a corresponding boson particle, known as the graviton.

by harry » Sun Apr 16, 2006 2:46 am

Hello All


Gravity is both a force and a field.


Both galaxies have black holes

pushing on a string theory

by kovil » Sun Apr 16, 2006 2:18 am

Gravity is the concept of the Undivided showing thru into this universe we perceive.
It primarily acts on matter, which has a full unit of spin, as the physicists call it.
It doesn't act on energy in the pure sense that the electromagnetic spectrum represents.
It's not a force nor a field, it's a tendency, the way in which matter is ert and sentient, it knows where the other matter is, and moves toward it in a desire to be Undivided again.

As gravity doesn't really effect things with a 1/2 unit of spin, but does strongly effect things with a full unit of spin, that is why when an electron and a proton combine, a neutrino is emitted. The neutrino carrys away that 1/2 unit of spin from the electron, so that the electron can now remain in one place, not constantly moving as in hydrogen. It is it's angular momentum component if you will, and must depart to maintain conservation, or unity or parity, whatever is the right way to say that. So that the electron can combine with the proton's full unit of spin harmoniously; as a unit and a half would get things out of phase in a way and be unstable.
It has to do with the Wheeler Feynman: Absorber as the Mechanism for Radiation Theory. The wave from the border of the universe coming backward thru time and the wave from the electron here, going to the border of the universe forward thru time. Where they meet at the electron, the 1/2 unit of spin "pinches" the waves to be 1/2 out of step with each other; previously they were in exact opposition of wave and canceled each other out and that is why no electron showed up anywhere along the wave, between here and the border. That's why the electron shows up here, the spin component pinches the waves by 1/2 and the wave amplitudes double, oppositely, in respect to each other and that high/low is what we see or detect, as the electron's presence, or energy density. Take away the 1/2 unit of spin and the electron is now free to not be moving, and will sit comfortably in one place with the proton to make a neutron. That's what neutrinos are explaining, but conventional physics describes it differently.

If a neutron is left on its own and not part of a neuclus, it will revert back into an electron and a proton, in about 15 minutes. What happens is it picks up a passing neutrino and with that incompatable 1/2 unit of spin the electron gets restless and has to move around and jumps off. To use an anthropomorphic metaphore.

My question is what's the difference between a 1/2 unit of spin and a whole unit of spin?

My suspicion is that spin is how momentum attaches to matter. It is just an accident that the word spin conotates angular momentum, or maybe that is why physicists chose that for the term of description.

After finishing painting the house yesterday all this added up in a new way, especially after going to Dr. Pogge's nova website and pondering it for a while. It's all kindergarten stuff to the pros in this biz, but I wonder if I'm on any kind of a right track here.

And when that tidal wave of 1/2 units of spin come roaring out of the collapsing under gravity iron sphere at the stars core, the incoming material has all sorts of new options for combining into new and exotic elements and isotopes, all the combinations and permutations that those building blocks can produce.

As any neutrons in the several elements above the iron core, will now have the option of becoming protons and electrons very easily; especially with the temperature soaring and all neucli tending to disassociate.

by astroton » Sun Apr 16, 2006 12:21 am

I think relationship between M81 & M82 is a good research topic in relation to gravity.

Is gravity a force or a field?

by orin stepanek » Sat Apr 15, 2006 6:00 pm

I think M81 has a black hole but I'M not so sure about M82. What a beautiful galaxi M81 is.
Orin

by l3p3r » Sat Apr 15, 2006 7:57 am

With such a strong gravity how come a smaller companions can remain intact and the larger galaxies show dramatic effect?
I expect that the gravity 'gradient' would play an important role, for large galaxies the side closer to the companion galaxy would feel a greater force than the far side, whereas the effects are not so obvious for smaller star clusters. The example that springs to mind is falling into a black hole, where (if approaching feet first, say) the gravity pulling on your legs would be significantly greater than the gravity pulling on your head and you are stretched... spaghettification? Maybe an extreme case but I think the concept is the same.

by harry » Sat Apr 15, 2006 6:41 am

Hello astroton


The active Black Hole plays an important role in the activity and shape of a galaxy

The spin will also determine the direction of the shape

APOD 15/04/06

by astroton » Sat Apr 15, 2006 5:40 am

http://antwrp.gsfc.nasa.gov/apod/image/ ... er_c80.jpg

I don't know how far is M82 from M81 but one thing I don't understand is the effect of gravity or the field at vast distances.

With such a strong gravity how come a smaller companions can remain intact and the larger galaxies show dramatic effect?

Examples or questions,

What happens to the smaller cloud in the picture, at 5 to 12 from M81?

What is the effect of Milky Way on Magellan’s clouds?

Has anyone seen or heard about such vast star forming regions in companion clouds?

Top