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Comment Re:The dark matter between their ears (Score 1) 157

The way it varies though - mapping out the "dark matter" - suggests interactions with common matter both ways. So it's not like "the underlying fabric varies" - it really behaves like matter, forming clouds, strands, that "hair" - it's not a generic field or a generalized property of space "resulting in galaxies".

MOND suggests some unknown as of yet function mu(a/a0). If that function was to fit the observational data, it would be incredibly complex; nothing as elegant and common as common [something]/r^2 or sqrt(v^2/c^2). It would be more like a function to describe shapes of clouds basing on air flow, temperature and humidity.

We don't know any other physical entity that would behave that way - move, flow, gather - than matter. And while still some predictions are defied and we can't say for sure it's matter, if we compare the effects to known behaviors of various physical entities - waves, fields, energies - this one has strong similarities to matter and very few to others.

For example, space expansion is uniform; about all of cosmos expands at the same, flat rate that slowly changes over time, but is independent of location. Its source is described as "dark energy" but you can have justified doubts if it's really energy because its interaction with reality seems really unidirectional: it affects space, but the space and its contents don't seem to affect it. In case of dark matter though, the similarities are striking.

And if you think about difficulties of detecting it - it doesn't interact with electromagnetism... What percentage of our observation methods are not based on electromagnetism? All known matter keeps its structure - solid, gas, structure of atoms - due to electromagnetic forces. Bindings between atoms are all about electrons and protons interacting electromagnetically. All of light is EM wave. Most of non-electromagnetic observations like neutrina or collisions of neutrons - boil down to interactions that *eventually* produce some EM influence; be it an emitted photon, a neutron decaying into a proton and an electron, and so on - we observe them indirectly. If Dark Matter doesn't interact electromagnetically, it could sit right in front of our noses and we'd be unable to spot it. A solid chunk of dark matter could directly phase through a solid chunk of steel, because there's a lot of room between electrons and the nuclei and no force (electromagnetic!) that would prevent particles of the dark matter occupying locations in between; it could even phase through the nuclei because who says it needs to follow Pauli's Exclusion Principle? It's enough that it interacts gravitationally, and so your chunk of steel would exhibit 30% higher gravitational pull - but since its original gravitational pull is piconewtons, the change would be undetectable.

Comment Re:It probably comes down to ... (Score 3, Insightful) 90

The difference in the way of thinking is simple.

Mathematician: "This is too complex for my brain. I can grasp the outer layer of the problem, but the underlying thing is beyond any human's capacity."

CompSci guy: "Oh, I can write a program that handles the outer layer of this problem; I have no clue what that underlying thing is but I bet it can be brute-forced."

Comment Re:Ockhams's razor (Score 2) 157

Yes, it would - given a theory fully consistent with the observation without the "god-like" dark matter. Which we don't have.

So until either a workable alternate theory is developed, or we manage to disprove Dark Matter through other means (e.g. discovering it's not actually matter) it's there to stay.

Comment Re:Terrible summary (Score 1) 206

aaaand quite a few of them don't even contain metadata that says what camera they were taken with so you have to pull down the right one from a menu, and in certain cases guess what camera the photographer used.

I could understand an editor who wouldn't want to deal with this crap.

But in this case it's a bit different. The photographer sends you a nice JPEG. And you say "nope, it was made from RAW with Lightroom, we don't want it. Send us the JPEG your camera created directly."

Comment Re:Terrible summary (Score 1) 206

Interesting idea but faulty like hell. The photographer took some important photos in poor lighting condition. The JPEGs came out unreadable but he was able to restore the content by processing the RAWs. Nope, don't wanna.

The photographer spent three days in war zone, evenings in the bunker spent developing RAWs of what he took during the day. Finally he gets a courier to deliver the SD card to his contact out of the war zone and send it to Reuters. Nope, these were obtained from RAWs, we don't want them.

Someone finds a camera near the body of a dead climber, the contents are RAWs the climber took. Not kosher though, no original JPEGs, GTFO.

Comment Re: Is a JPEG at 0% compression a RAW image? (Score 2) 206

To answer in a more technical way (than "use ImageMagick").

JPEG encoding inherently can be completely lossless. 8x8 pixel squares of pixel values are converted to 8x8 matrices of frequency components - transforming the representation of data as a superposition of specific sine waves of fixed set of frequencies and parametrized amplitudes. Due to small area and range of values being covered, this mapping is lossless - the data is sufficient to recreate the exact image, errors of the "floating point nature" of sine waves being less than 1 bit of value representation.

Then, depending on the settings of the software - the "compression rate", the parameters of lowest values and of highest frequencies are replaced by zeros. The "quality" parameter decides how many, and how significant ones. Unlike with direct value function which would leave black pixels, with sine waves this leaves the characteristic "artifacts" of JPEG, a kind of wavy imprecision along any sharp edges, some colors being misrepresented etc. This is not very visible to human eye, and you can get away with zeroing half and more of the parameters without significantly altering the perceived image.

And then this is compressed using a standard lossless data compression.

The gain comes from the fact that strings of zeros, repeating zeros and such compress very well - much better than "random" data of standard image.

Of course if you don't strip any zeros and keep all the values, JPEG will be lossless and you won't gain anything size-wise, the compression being equivalent to standard lossless ones. And still you can lose relative to RAW, because the original (input) data uses 8-bit color channels, so 3 8x8 matrices of bytes per one "block". RAW can keep much more bits per pixel.

We're here to give you a computer, not a religion. - attributed to Bob Pariseau, at the introduction of the Amiga