Visible matter, the objects we can see and the sources of energy that emit radio waves, comprise but 5% of all the matter in the universe. There is so little visible matter, in fact, that astrophysicists explain that the gravity that holds galaxies together is not that of visible matter, but is instead gravity produced by what they now call dark matter.
Dark matter is matter we cannot see, the composition of which is at present mostly unknown. Some dark matter is not comprised of the protons, electrons, neutrons and other particles we have become accustomed to; it is something else yet again. It exhibits gravity and therefore must have mass, but beyond that we know nothing.
WIMPS, or Weakly Interacting Massive Particles, is dark matter we cannot see, and are suspected to be some type of high mass particle matter, a form of “cold” dark matter emitting no energy of any kind; no heat, no light, and no measurable signature we can record. Forming part of a massive invisible matrix or scaffolding into which ordinary matter is irrevocably infused, its presence is betrayed by its gravitational effect on visible matter.
MACHOS, or Massive Astrophysical Compact Halo Objects, are ordinary matter generally too dark to see, such as very faint stars, white dwarf stars, or planets within a galaxy. Given this character, it is currently impossible to determine what percentage of the universe’s matter MACHOS represent.
Calculations indicate that MACHOS and WIMPS together account for at least 23% of the matter in the universe; accordingly, its gravity effects are great. Even though dark matter is poorly understood at present, it has nonetheless become a powerful tool in gathering information about the universe and its history. This tool is called gravitational galactic lensing, and it was predicted by Albert Einstein around 1911.
I cannot possibly cover Einstein’s discoveries in a 550 word essay, but gravitational lensing was a by-product of his prediction that like a glass lens, the gravity of massive celestial structures would bend and magnify the visible light of objects at a distance, even many light years in the distance. He did not envision the Hubble Space Telescope or other sophisticated computerized imaging systems; he thought his theory would never be verified through direct observation. He was wrong.
Today, galactic gravitational lensing is providing us with information about celestial objects nearly 13 billion light years away. MACHOS and WIMPS, dark matter, play a role in this because their mass within and surrounding clusters of galaxies generates substantial gravitational effects on the surrounding space, and intensifies the lensing effect. In other words, though we cannot see most dark matter, we can use it to see visible matter light sources beyond it. We can even somewhat determine size, shape and chemical components.
If one day we discover that a species of beetle had developed television, or if a colony of ants invented the radio, we would rightly be astonished. We would frankly, consider it a miracle. Human beings are in evolutionary terms a recent species inhabiting a little planet in a backwater solar system within an average galaxy, one among uncountable billions. Yet here we are, using super-sensitive instruments to view galaxies 13 billion light years away using galactic lensing predicted by a remarkable genius nearly 100 years ago. Talk about astonishing!
