When I was growing up, my best friend's grandfather was a physicist. One day we were visiting his home on the East Bench in Salt Lake City, and while we were swimming in his pool on a hot summer day, my friend's older brother yelled out to their grandfather who was sitting in a at patio table quietly engrossed in something, "whatcha doing grandpa?" Their grandfather coyly replied, "I am calculating the amount of dark matter in the universe." If I remember, that had to occur sometime in the late 80's before my friend''s father left Utah to serve as a mission presidents in Fort Lauderdale. Hurricane Hugo hit while they were there which would make it before 1989. Anyways, That's how a few of the conversations went over at their house.
Even before Einstein, many scientists conceived of some kind of ether throughout the universe. This kind of thinking fell out of vogue until more recently astronomers just couldn't make the numbers add up when it came to galaxies. After calculating the masses of galaxies based on the number and weight of all their stars, the combined mass just didn't account for the high speed of galactic rotation. That is when scientists began looking for what is known as "Dark Matter" which is currently believed to make up nearly 90% of the mass of the Universe. Dark Matter cannot be observed directly, but is inferred based on its effect on regular matter. We are not just talking about dark clouds of hydrogen or other elements. When clouds of gases pass in front of other stars, the gas absorbs certain light and emits certain other wavelengths of light. It is this kind of astro-spectroscopy that allows scientists to directly measure regular matter in space. On the other hand, Dark matter does not interact with light the way regular matter does.
There is another problem with the universe. It turns out that as we build larger and higher resolution telescopes that can look further and further into the past. Observations of galaxies by gravitational lensing and other observations of super-massive gamma ray bursts have been calculated to be about 13 billion light years away. The universe is only calculated to be about 14 billion years old. In looking out at the universe, scientists have observed by red-shift observations that the universe appears not to just be expanding away, but also accelerating. To provide the energy necessary to explain the acceleration, scientists have proposed the existence of "dark energy" which would comprise 74% of the total mass-energy of the universe. Together with dark matter which comprises an additional 22% of the mass-energy of the universe, this means that man has no idea what is going on with 96% of the universe. And even the 4 % we can see we can't explain well.
The visible universe that we see is comprised of stars, gases, and planets. As I said above, we really can't explain very well how the stuff we can see works let alone the stuff we can't see. One example of the mystery of stars centers around our own sun. Our sun is theorized to be a gigantic fusion reactor. However, the combining of hydrogen to produce helium should give off a certain number of neutrinos. The problem is that when scientists go to measure neutrinos, 2/3rds of them are missing. Now some theorize that there can be 3 types of neutrinos and they are constantly fluctuating between neutrino flavors. But again, that is the current theory.
Back when I was a boy, I remember by friend's father saying that maybe electromagnetism and gravity were the same thing. The equations for gravitational bodies compared to charge carrying particles do look similar. Also, he said that the reason for the missing neutrinos was because the sun was absorbing dark matter coming from outside the solar system. This dark matter possibly coming from a binary star was generating the intense heat of the corona and a majority of the energy of the sun.
Now scientists are claiming something similar. Space.com is featuring an article that claims the sun might be generating dark matter. Theoretic particles called Axions may be forming inside the sun. As the axions travel outward and are subjected to a gravitational field, they turn into photons of light. The scientists claim that these axion conversions may be the reason why the corona of the sun is hotter than the sun's surface. Scientists are currently trying to detect axions by pointing large cold superconducting magnets at the sun and x-ray detectors at the magnet hoping that they will observe the conversion of an escaped solar axion into an x-ray as it passes through their magnetic field. If my friend's father is correct, the axions would be coming from outside the solar system and attracted by the sun. As the axions interact with the sun's powerful magnetic field they then convert into photons in the photosphere. The sun's magnetic field is only 1 Gauss and 4000 Gauss at sun spots. A 1 Telsa magnet equals 10,000 Gauss. Neutron stars and magnetars can generate a magnetic field of 10^12 -10^17 Gauss. I'll have to ask is the xray film is being exposed if it sits next door to the MRI room. WIMPS are theoretic supersymmetry particles that are also being proposed as a candidate for dark energy.