how did we get gravity so wrong?

this thread is about how we underestimated the gravitational lensing potential of individual galaxies.
it is not intended as a challenge to e=mc2 or einstien or relitivity, but instead asks why did we not suspect individual galaxies were capable of gravitational lensing.
the effects of underestimating the potential of gravitational lenses has a major influence on galaxay surveys in the distant past.
if a small percentage of the entire universe was only there for us to view directly because without these lenses we would not see them, then this would effect the location and amount of mass in a given area.
recently i read that the cosmic microwave backround survey has been able to be used to show gravitational lensing of the cosmic microwave backround from their data alone....
but if gravitational lensing is effecting how we "view" the cosmic microwave backround, how do we know the temperature variation is not simply due to the different lensing potentials?
why does the temperature of the cosmic microwave backround matter?
we deduce alot of information about the big bang from the temperature variations we detect.
and if lensing by foreground objects can skew the data enough to be noticable in the raw data then any conclusion drawn from the temperature variations are now questionable.

a list of objects that have been suspected of gravitational lensing by type
planets and stars in our local environment (micro lensing) + (corona lensing)
heliospheres (bubble density/gravity lens)
super nova (density/gravity/velocity)
individual galaxies (density/gravity lens)
quasar (gravity) (einstiens)
Active galaxy neclus AGN galaxay (density/gravity)
galaxy cluster (gravity/density)

and the effects of this lensing on the cosmic microwave backround are able to be detected in the raw data.
so how did we underestimate the ability for smaller mass and smaller galaxies to act as gravitational lenses?

and an even bigger question,
why is the light shifted into the infra-red and subb MM wavelengths when observed through these lenses?

According to the position of the submillimeter galaxies in the H-ATLAS map data, investigations can
be made to identify their nature in order to study gas, dust and stars formation in far galaxies. These
properties are obtained using ground instruments.
For the present study, one fundamental question is why are the observations done in infrared and sub MM wavelengths
12
Section 2.2. Redshift Page 13
submillimeter wavelengths regime? One way to answer this is not only to consider the fact that galaxies
are too distant, but it becomes easier for scientists to learn about the properties and how objects are
formed in the universe. Some galaxies may contain a lot of gas and dust which obscure stellar light,
making the optical and near-infrared techniques dicult for observations. In addition, the incoming light
rays may or not be absorbed, according to the atmosphere level. We mean in the case of ambient and
low levels where the water vapour content is more important, that the incoming rays are absorbed at
submillimeter wavelengths: this complicates observations. In the case of a high altitude, the content of
water vapour is considerably reduced, which makes the space more transparent, facilitating observations.
That otherwise explains why observations are made in space rather than on Earth.

source pdf

why is the light in the sub mm range?
how can we know how much wavelength shift is distence from the point we detect it(foreground galaxy)?
without knowing how far away the light travelled before being lensed?

we are working with the model that redshift equals distence, and that this holds true for light weather it passes through empty space or a gravitational lens?

by definition the lens must effect the light or it would not be focused or collected,
a light collecting and focusing medium could be slightly reflective when viewed from outside,
how can no loss occour (no reflected or difused light) while traveling throught the lens?.

how could we underestimate gravitys ability to magnify and distort our universe?
we used to look for the most massive collections of mass in the universe, (galaxy clusters and super clusters)
for the effects of gravitationallly lensed back round galaxies to study,

we can now use individual galaxies as lenses,
there is a huge difference in scale there,

the question still remains,
why do the lenses all shine in sub mm light?
and is the source of that light an early star forming galaxy,
or is the lens distorting the light to look like a far off dusty star forming galaxy?

because if we find the lenses are creating "some" redshift it would effect distence and age of these early galaxies
and weather they were acually star forming or just "appar" to be

light is expected (by me) to be modulated by the lens, which explains why the light is shifted to sub mm wavelengths.

xploder

xploder

Yea, using light to get it's interaction with gravity and how gravity works through that observation is tricky. Light being extremely low mass (massless), can loop on it self, possibly endless limit in wavelengths both high and low (although that's entirely relative).

Distortions, reflections, lensing, diffraction, interaction with dark energy/matter, ?????

In effect, 3 dimensional space could be like endless amounts of two dimensional holographic planes that are shifting around like tectonic plates?!

reply to post by xacto


we have massivly underestimated the number of objects that can be lenses,
this could effect alot of studies
dark matter
dark energy
CMB
redshift "cosmological"
the amount of mass in the universe and where it acually is
galaxy surveys

us use light to "weight" objects in space,
but if the distortions can be galaxy sized instead of cluster sized,
then mabey we need less dark matter to explain lights paths

xploder

Because people look at Gravity as though it's a force - much like magnetism.

However, I tend to look at gravity as a sort of viscous state or a density gradient. Light and matter tend to interact with gravitational fields in a manner much more consistent with refraction than anything else.

To me, gravity as a force (or, at least a force that acts upon known particulate constructs) has always been something of a handicapped expression. We don't really know what it is, but treat it like it is a force in the classical sense.

While rational... it's not exactly scientific to jump to such conclusions.

When you consider that gravity, instead, affects the 'fabric' of space (speed of light remaining constant means that an altering of spatial properties alters the -perception- of time) - or what we perceive as space (things get really weird when you consider holographic principle and other such information equivalency concepts)... then light - and even the odd behavior of observed matter in certain areas, becomes much more sensible.

But, essentially - most people consider gravity to be a force that acts on things. I contend that it's actually 'space' (another handicapped term, in my opinion) that acts upon all energies passing through it in a manner consistent with the mass distribution affecting it (exactly how that is accomplished is just left to mystery at this point).

Perhaps, in this sense, we've been missing the forest for the trees. It would surprise me if I were the first person to think about looking more closely at how, exactly, particles/energy interact with space, itself to gain clues to the nature of gravity as opposed to searching for mysterious gravitons and other bogeymen of the physics universe.

What bothers me most is that no matter which direction we look, the background radiation is statistically constant, thus the implication we are at the center. How could you otherwise explain the same temperature at 180 degrees of separation?
Only thing that would make sense to me is that even if things are "hotter" in one direction than its opposite, things are less dense in one direction and more dense in the other (which would require the "farther" to be more dense than it appears thus appear warmer).
Or maybe matter really is distributed evenly throughout even though it doesn't look that way...?

reply to post by XPLodER

I'd say the problem is largely a dark matter problem. Since we can't see it, so it may exist in places we aren't aware of and may be lensing things we don't even know are lensed.

So if we can ever solve the dark matter problem I think that solves a lot of this. It's not so much that we got it wrong, but we have a big gap in our knowledge...we make observations we can't explain, so we presume dark matter is responsible. Until that's confirmed, I'd characterize the problem as "we don't know" rather than "we're wrong". I think we could be right or wrong about what we claim to know, I don't know about that. But we admit ignorance about dark matter so when we say we don't know what it is, it's hard to say we're wrong, rather, we just don't know what dark matter is (or if it really exists).

reply to post by abecedarian

There is some conflicting literature on this. Some sources say it's isotropic to one part in 100000, but some other sources claim to have discovered some anisotropy:

blogs.discovermagazine.com...

One of the important features of the universe around us is that, on sufficiently large scales, it looks pretty much the same in every direction — “isotropy,” in cosmology lingo....

A tiny effect could be lurking there, and be hard to see; or we could see a hint of it, and it would be hard to be sure it wasn’t just a statistical fluke.

In fact, at least three such instances of apparent large-scale anisotropies have been claimed.

reply to post by Arbitrageur

Rethinking equilibrium: In nature, large energy fluctuations may rile even 'relaxed' systems

source

The research appeared online Oct. 21 in Physical Review E.

In their study, the scientists used computer simulations to model the behavior of a closed, granular system comprising a chain of equal-sized spheres that touch one another and are sandwiched between two walls. Energy travels through this system as solitary waves, also known as non-dispersive energy bundles.

When the system was disturbed by multiple energy perturbations -- imagine someone tapping on each of the walls -- the energy spread unevenly through the system.

Distinct hot and cold spots with an energy much higher and lower than the average energy per sphere persisted over short periods of time, and some regions remained cold over extended times. This held true even in simulations that lasted for several days, demonstrating that the system's eventual state was something very different from what is traditionally thought of as equilibrium.

the fundimental idea of what equalibrium is and how it works is being investigated.............

Like many systems in nature, the system the scientists simulated is subject to strong, nonlinear forces, which vary sharply as a system evolves.

Nature's laws may vary across the Universe

source

One of the most cherished principles in science - the constancy of physics - may not be true, according to research carried out at the University of New South Wales (UNSW), Swinburne University of Technology and the University of Cambridge.

The study found that one of the four known fundamental forces, electromagnetism - measured by the so-called fine-structure constant and denoted by the symbol ‘alpha' - seems to vary across the Universe.

another study showing a change in alpha with a specific direction of change......
i wounder with the galaxy rotational axis study and the electromagnitism studies
and the metal spectra study

is the homogeneous nature of the universe in question?

xploder

If things were hotter in one direction or less dense like in our atmosphere then gravity could BE density as seen by means of buoyant force, nothing more. Everything settles to its place according to the density of the atmosphere( with regard to vaporized matter, followed by liquid and solid as pressure increases) with the more dense being 'pushed ' away from the less dense hotter upper atmosphere, rather than being 'pulled' by a mysterious force called gravity. -Just a thought. Is density by means of buoyant force, gravity?

a reply to: XPLodER

How did we do this? Because when things are first theorized about our collection of evidence for it isn't as high as it would be 100 years afterwards. You can only discard the bad once you've figured out that it is bad. Ah crap... just noticed this was a necro post...