Why does it … matter?
A work for SFMOMA?Standing on Earth and looking out into space, it’s easy to assume that you have it figured out. There are stars, gases, metals– all ‘normal matter’ that we can see, made up of electrons and protons. From this vantage point, there is no reason to believe that there is anything else out there. At least this is what astronomers used to believe.
Let’s begin by reviewing the hierarchy of objects that are found in the universe. On the small end are solar systems, with a series of planets orbiting around a central star. Galaxies like the Milky Way define the second level. At the highest level are galaxy clusters which are a collection of thousands of galaxies much like a galaxy is made up of billions of stars.
Stepping back to 1933, an astronomer from the California Institute of Technology named Fritz Zwicki was observing the motion of galaxies in the Coma Cluster. Coma is one of our nearest neighbor galaxy clusters, being only 100 million light years away and containing more than 1,000 galaxies. Zwicki observed that the galaxies in the Coma Cluster were moving much faster than predicted. When counting up all the light from the galaxies, he saw that there is not nearly enough mass to create the gravitational attraction responsible for the speed of these galaxies. To account for the missing mass, he postulated the idea of dark matter, which would be invisible to us here on Earth. Invisible matter??? He was ridiculed for his ideas that defied common sense.
Not much else was said about this invisible matter until the 1970’s when Vera Rubin, an astronomer from the Carnegie Institution of Washington, started to observe the rotation of nearby galaxies (see figure below*). Much like Zwicki and the Coma Cluster, she saw that the mass from all of the stars did not account for nearly the gravity required to describe the speed at which the galaxies were spinning. To account for the missing matter, she again invoked the dark matter scenario, and again, no one believed her.
Fortunately, technology has finally caught up to the intuition of Rubin and Zwicki. Astronomers now routinely see indirect evidence of this invisible matter at work. It is now generally accepted that dark matter exists, and actually dominates the composition of galaxies. We now believe the universe to be only 4 percent normal matter and 22 percent dark matter.
Now, for those of you who are keeping score, you probably noticed that I only accounted for 26 percent of the materials that make up the universe. Where are the other 74 percent? I hate to keep you on the edge of your seat, but here’s a hint. Stay tuned…
* Figure 1
Rotation curve of an average galaxy. The X-axis represents distance from the center of the galaxy while the Y-axis represents the speed at which the galaxy is spinning. Curve “A”shows the expected rotation curve for a galaxy which is composed solely of it luminous matter. Curve “B” is what is actually observed. The presence of dark matter is currently the best explanation for the difference between the two curves.
Kyle S. Dawson is engaged in post-doctorate studies of distant supernovae and
development of a proposed space-based telescope at Lawrence Berkeley National Laboratory.
Sure, go ahead and leave us in the dark!
Ask can WIMP dark matter exist really? How could particles that need to have significant mass - ie much more massive than neutrinos that have been directly detected - and to comprise at least 90% of all matter in the cosmos, and at the same time evade direct detection after some two decades of experimentation?
And if not, what else could explain the galaxy rotation curves, the behaviour of galaxies in clusters and cosmic lensing?
So there have been serious thoughts about modifying the action of gravity but there are observations of galactic behaviour indicating that such a theory wouldn’t work.
But I haven’t heard of any scientist suggesting that a cause could act universally in addition to the forces.
Yet, despite the spectacular success of the standard model of quantum and particle physics, one can still agree with Richard Feynman, Nobel prize winning physicist extraordinaire, and insist that nobody understands quantum mechanics.
And hence, also, there are still quantum mechanical interpretation as various and conflicting as the Copenhagen, many worlds and de Broglie-Bohm accounts. And the last of these interpretations is a systematic nathematically worked out caount with its own mechanics that does describe a distnct cause acting in addition to the forces, called the quantum potential.
So could all the problems in theoretical physics including those in cosmology boil down to the fact that physics is still stuck with the push or pull causes that can’t, by themselves, be described to explain how the universe is naturally organised either on the smallest or the cosmic scale?
I’ve outlined a theory on my blog that gives quite deatiledreasons to consider that this is so, to find it google> foranewageofreason
[...] hour exposure of star trails above the Keck Telescopes taken by yours trulyThe dark matter that I discussed in my last post is quite bizarre, but makes up only a small fraction of the universe. The dominant material in the [...]