From Dark To Invisible
Names and attributes must be accommodated to the essence of things, and not the essence to the names, since things come first and names afterwardsGalileo Galilei
We remember Nick Lucid's video Dark Matter isn't Dark. It's Invisible. In it he proved exactly why the name "dark matter" is inappropriate for the cosmic web - the only form of dark matter he is aware of. His reasoning is sound and beyond debate:
Based on our evidence of dark matter, it has a few properties that we can say conclusively about it. Now we call it dark matter, but it should really be called Invisible Matter. It's actually legit, invisible. It doesn't interact with light, at all! ... And if it doesn't interact with light, it's not electromagnetic - at all! That means we can't put it in a container either." Nick Lucid
In our search for the most appropriate name for dark matter, we will initially concentrate on the first part of Galileo's logical quote: we will first identify all the known attributes of "dark matter." This will give us an Evidence Profile, we will then search for any matching Evidence Profiles. If we find any, we will immediately know the true identity of dark matter. Only then will we know "the essence of" dark matter, and be rightly confident in giving it a fitting scientific name!
DARK MATTER: Detectable by its Affects on the MOTION of Baryonic Matter
Invisible
Already, from the above quote, we know two things: the evidence tells us that dark matter is invisible and non-physical. This of course, we have already confirmed for ourselves. We are not merely taking Lucid's word for it. The evidence we have already presented is overwhelming. The argument for dark matter being invisible is straightforward. Since it does not interact at all with electromagnetic radiation, no one can "see" it. It not a matter of scale as is the case with our inability to see objects that like bacteria. They interact with light, but their scale is too small for use to see with the naked eye. Humans face a similar problem of scale when it comes to seeing all the stars in the universe. Most are so far away from us that we can only see around 7 000 with the naked eye. So for microbial life and far away galaxies we need equipment to bring them to within reach of our eyes and then we can indeed see them! This is not the case with dark matter. There is no instrument which can give us a direct view of dark matter. If that is the case, then how can humans map out its distribution throughout the universe? Through how it causes visible matter to move counter to the laws of nature.
We CANNOT Call it "Dark"
Newton told us that objects without a force acting upon them will continue in the current state - forever. If they were at rest, they will continue to be so. If they were moving, they will maintain their movement in said direction without stopping - also forever. What happens when dark matter is involved? Objects move with energy that is way above the visible baryonic forces acting upon them. This - as Vera Rubin so rightly concluded - means there is an "unseen" force or mass that is acting upon them - dark matter. Since Vera Rubin declared her finding so many decades ago, other ways of confirming her insights have been discovered, and used to great effect to corroborate her intuition. These include methods such as measuring the Tully-Fisher Relation, and gravitational lensing at the galactic and super-cluster galactic scales. In fact, it is this method that is responsible for the actual mapping of the distribution of dark matter throughout the universe, making possible illustrations such as Figure 77. Our take-away: dark matter cannot be detected directly because it does not interact with electromagnetic radiation "at all!" However, dark matter has profound effects on the motion of baryonic matter throughout the universe! This is especially true of light. Don't be surprised or confused. Dark matter does not interact with light at all, but it does have the effect of affecting the motion of light. (More on that later). To say: "Interesting" would be an understatement! We conclude: DARK MATTER IS NOT "DARK" BUT INVISIBLE. FOR THIS REASON WE WILL CALL IT INVISIBLE MATTER FROM NOW ON.
EXPLANATORY NOTE
Every piece of what we now understand to be Invisible Zint - and not dark matter - has been mapped by detecting how it changes the path of light traveling through the universe. These techniques of detection mean it could verified as an entity in the universe, despite being invisible. Thus, scientists have managed to map it, cataloguing its features and components - including the fact that it is a one-piece structure that spans the whole universe, Called the "scaffolding of the universe," for its role in determining where the galaxies are (through the Tully-Fisher Relation), and giving them angular momentum, that is, their spin, it has been determined to have three interconnected parts: halos, that house the galaxies; long filaments that connect the halos into a one-piece structure; and vast voids, where there are no halos or filaments. Since it determines the placement of all galaxies throughout the universe, the whole Cosmos, the visible realm of the universe exists inside this one-piece, networked structure that is called the cosmic web for that reason!
Non-Physical
The second notable property dark matter possesses is also a direct result of its non-electromagnetic nature - it is non-physical. That is what Lucid meant when he said we "can't put it in container." Electron repulsion is what makes things solid. You are not falling through the chair you are sitting on right now because the electrons in your body are repelling the electrons in the chair. This mutual repulsion between the electrons is what makes you and the chair "solid!" Since dark matter does not have electrons, is does not behave in this way, hence scientists say it is "non-interfering." That phrase means non-electron-repulsing, as per our earlier explanation. We don't yet have a fitting term to label something that is non-electron-repulsing (what a mouthful). So for now "non-physical," is the term that will have to do as a placeholder. Nonetheless, we appreciate understanding the why and how non-electromagnetism creates this affect. This non-physical feature of Invisible Matter however has an immediate follow on ...
How do you "see" the truly invisible? By detecting any movement it creates in visible matter. In the case of dark matter, it does not interact with light, but it does bend it. It is the bending of light that allows us to know each place where dark matter is present throughout the whole universe. In the figure to the left, what was happening where dark matter blobs appear, and what's different between that region and where there are no dark matter blobs? The direction of light rays changes wherever there is dark matter. So that means any region where light rays continue straight forward, there is no dark matter. Wherever, they are bent, dark matter is present.
We CANNOT Call it "Matter"
It is true that Invisible matter is a something! After all, it is the "scaffolding of the universe." It could hardly play that role if it wasn't a real object somehow. So while it is a "thing," we cannot say it is matter: for that term is used exclusively for material - i.e., baryonic electromagnetic - objects. So our last correction for the information we have now, is to stop calling it Invisible Matter and start calling it by a more appropriate name INVISIBLE ZINT. If you are South African and you cannot figure out how I came up with that name, you need to broaden your circle of friends. It may not be perfectly obvious at first, but once you identify the root word, you will never forget the meaning behind it, or fail to recognize why it is appropriate - remember:
Names and attributes must be accommodated to the essence of things, and not the essence to the names, since things come first and names afterwards" Galileo Galilei
So it is, that having come to understand the "essence" of dark matter more clearly, we give it the name that accommodates its true nature: INVISIBLE ZINT! This name is not an identifying label for the vast, one-piece structure that spans the entire universe. We will only be able to positively identify that structure in the next section. The term "Invisible Zint" is merely a label for the invisible, non-physical, non-material "thing" from which it is made! "Thing" in this case is not meant in any way to be derogatory. It just means an 'object' of some sort. Just like your heart and brain are things - but are highly valuable. We now move on to the exciting, event filled - Day 4!