- Astronomers and physicists are trying hard to find Dark Matter. Astronomers have convincing evidence that the entire Universe is made up of matter and energy, time and space with 73% of the energy being used to fill space and expand the Universe at 47,000 miles per hour for every million lightyears of space. Residing in the space is concentrated energy called matter, 23% of which we can not see. 4% of matter-energy we can see. The 4% is all that we know and love, the rest is all “ Dark”.
-
- When astronomers use light to detect what is in the Universe they come up far short, only 4% of what they find interacts with electromagnetic energy. So, astronomers are trying to use gravity to detect what is out there. Dark Matter and Dark Energy do interact with gravity.
-
- So, just looking at matter alone 85% is Dark Matter, 23% out or 27%. You would think with that much out there we should be able to find it. Astronomers think that Dark Matter is made up of particles that we have yet to discover. We have discovered the fundamental particles like electrons and quarks that make up protons and neutrons. We have discovered neutrinos and the force carrying particles like gluons and bosons. Dark Matter must be another one of these fundamental particles. To make up so much of the matter out there they must be massive particles. They must be weakly interactive because they do not interact with electromagnetic energy. Call them “ WIMPS” for weakly interactive massive particles.
-
- WIMPS due interact with gravity. We should still be able to detect them. One way they are detected is in studying the rotation of galaxies. Something is holding galaxies together and that is gravity. The center of galaxies are the most dense and therefore provide the strongest source of gravity. Stars rotating around the center with a shorter radius should be traveling faster than the stars out at the edge of the galaxy with a radius of thousands of lightyears distance.
-
- Our Solar System for example contains the Sun with 99% of the mass and planets like Mercury that has rotational velocity at 48 kilometers / second versus Saturn that has a rotational velocity of 10 kilometers per second. Orbital velocities are directly proportional to mass and inversely proportional to radius of their orbit , v^2 = G*M / r. The outer stars should be orbiting at a slower velocity than the inner stars. However, that is not the case. The orbiting velocities seem to be constant out to the edge of the galaxy.
-
- In order to explain this with our physics we conclude that there is no central mass. There must be a halo of invisible mass that completely surrounds the galaxy. Let’s try to find it around the Milky Way. Astronomers have explored out to 13,000 lightyears and have found no evidence that Dark Matter is there.
-
- Astronomers ought to be able to detect the gravitational effects of Dark Matter mass. Light passing from a distant star should be warped or bent as it passes by this mass. It is called gravitational micro-lensing. Distant stars should vary in brightness as the lensing effect passes in front of the traveling light beam. So far, no effect of Dark Matter has been detected.
-
- Astronomers have also studied over 400 red giant stars that hover above the galactic plane supposedly in the Dark Matter halo. Again, the effects of gravity from Dark Matter has not been detected.
-
- The microlensing effect is a difficult measurement to make and there could be other explanations as to why we do not see the results expected. For one, the calculations assume the Dark Matter halo is spherical. If it were cigar shaped, or squashed beach ball shaped, the Dark Matter could still exist inside the calculations. We can not tell for sure because we do not know the Dark Matter distribution.
-
- The Earth is orbiting the Milky Way center every 225 million years. We should be passing through the Dark Matter particles. Physicists are trying to detect these fleeting particles by putting measurements deep underground. The mass of Earth around the measurements is to separate surface noise and random particles that are buzzing around the surface. Here are some of the experiments in process. Google them to learn more:
-
------------------- CDMS, is the Cryogenic Dark Matter Search using germanium / silicon detectors in an old mine shaft in Soudan, Minnesota
-
------------------ CoGeNT is a wedge germanium detector that is in the same mine. The hope is that these detectors should capture a WIMP as it is passing through the Earth. Remember the WIMP is unaffected by the electromagnetic forces that hold the atoms together. It must collide with another fundamental particle to be detected.
-
------------------ XENON 100 is a detector using liquid xenon beneath Gans Sasso Mountain in Italy.
-
----------------- CRESST is in the same location using calcium Tung state crystals as detectors.
-
----------------- DAMA is still another detector using sodium iodide.
-
- Detections have occurred but confirmation remains illusive. Dark Matter is still eluding us. An announcement will be made shortly, stay tuned.
-
----------------------- ------------------------------------------------------------------
RSVP, please reply with a number to rate this review: #1- learned something new. #2 - Didn’t read it. #3- very interesting. #4- Send another review #___ from the index. #5- Keep em coming. #6- I forwarded copies to some friends. #7- Don‘t send me these anymore! #8- I am forwarding you some questions? Index is available with email and with requested reviews at http://jdetrick.blogspot.com/ Please send feedback, corrections, or recommended improvements to: jamesdetrick@comcast.net.
or, use: “Jim Detrick” www.facebook.com, or , www.twitter.com.
707-536-3272, Monday, June 4, 2012
No comments:
Post a Comment