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Dark matter

            
             Astronomers have wondered for ages about the existence of dark matter. The truth is astronomers aren't sure what dark matter is made of, but they think that it does exist in space. Dark matter is thought to exist as large black rings surrounding galaxies. The space between planets and stars isn't just nothing, it's probably matter of some sort. The consensus seems to be that it's made up of small subatomic particles called MACHOs (MAssive Compact Halo Objects) and WIMPs (Weakly Interacting Massive Particles). They aren't as big as atoms, but they're made of the same materials as atoms are. Astronomers think that WIMPs are between 10 to 100 times the size of protons, and that they may account for much of dark matter. So dark matter is full of WIMPs! .
             The first evidence of dark matter was found in clusters of galaxies in 1933. Astronomer Fritz Zwicky discovered that the "mass of luminous material in a cluster of galaxies was much less than the total mass of the cluster implied by the velocities of the galaxies.".
             Later in the 1970's astronomer Vera Rubin conducted a study on the rotation of galaxies. The velocity of the stars in a galaxy was measured using a radio telescope. If you look at a spiral galaxy, some stars will be moving toward you and some will be moving away because of the rotation of the disk. By plotting the velocity in these stars he realized the stars near the edge of the galaxy were moving at the same speed as stars in the middle.
             In the year 2000 using the NSF Cerro Tololo Inter-American Observatory in Chile and a method known as "weak gravitational lensing", a group of scientists from Bell Labs, were the first to map the distribution of dark matter over large portions of the sky. The team analyzed the light from 145,000 very distant galaxies for evidence of distortions produced by the gravitational pull of dark matter that lay in their paths. To observers, the light from distant objects is distorted by this gravitational pull into elliptical shapes, an effect known as "cosmic shear".


Essays Related to Dark matter

1. Dark Matter

There is perhaps no current problem of greater importance to astrophysics and cosmology than that of "dark matter". ... Hence we infer that there is non-luminous matter in the Universe, i.e. there is dark matter. Dark matter has important consequences for the evolution of the Universe. ... Then, under non-baryonic, hot dark matter (HDM) and cold dark matter (CDM) are its types. ... The ever-so important question what is dark matter will not be answered tomorrow. ...

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2. Dark Matter

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3. The Dark Snow by Brendan DuBois

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4. Heart Of Darkness

Kurtz is definitely a disturbing symbol in Heart of Darkness, embodying the gloom, the despair, the "impenetrable darkness" of the unknown jungle, the darkness inherent in all men's hearts but he does not dominate the novel. It is Marlow's perception, his ever changing understanding of the darkness and its many elements from afar and up close, that fills the novel, creates its many layers. It is his indeed this intense journey to Kurtz, Marlow's journey of discovery on all levels that dominates Joseph Conrad's novella, Heart of Darkness. ... It is Conrad's subtly...

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5. Heart of darkness

In Chinua Achebe's essay, "An Image of Africa: Racism in Conrad's Heart of Darkness,"" Achebe contends that Joseph Conrad's portrayal of Africa, and the African people, in his book Heart of Darkness, is that of a racist. ... However, Conrad wrote Heart of Darkness at the beginning of the 20th Century. ... The Heart of Darkness is something that one takes into himself, and can pass it from person to person. ... No matter who or you are, and why you think you are here, this truth will come out. ... However, after all the riches he found, he still could not escape the Heart of ...

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6. The Dark Side of ADD

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7. Heart of darkness

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8. Dark Lady

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9. Heinrich Himmler

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