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The Ultimate Fate of The Universe - Again the Focus of Scientists' AttentionDark Matter |
By Gabriel Gache, Science News Editor
26th of October 2007, 12:45 GMT
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The dark matter is supposed to be one of the forms of energy present in our universe, besides ordinary matter, out of which everything we know is composed, and pure energy. It is called dark matter because it was not actually observed, but its effects can be seen in all the visible galaxies. According to observations, there is not enough visible matter in a galaxy to keep its stars from escaping its gravitational field. So there must be something else to account for the extra gravitational pull of a particular galaxy. Dark matter.
Astronomers at the University of Michigan
have found that, dwarf spheroidal galaxies behave in way that suggests that they are dominated by dark matter.
Newton's law of gravity says that a star farther away form the galaxy's core will move slower than a star closer to the core. New observations from professor Mario Mateo and researcher Matthew Walker, who have observed and measured the velocity of about 7,000 stars in seven dwarf galaxies of the Milky Way, contradict Newton's law. The speed with which the stars farther to the core of a galaxy move does not decrease, but it actually remains the same as the speed of those closer to the core. "These galaxies show a problem right from the center," Mateo said. "The velocity doesn't get smaller. It just stays the same, which is eerie."
Spiral galaxies, such as the Milky Way, behave in a similar way, the information collected from smaller galaxies implying that the distribution of mass inside a galaxy is not the same as the distribution of light.
Though the dark matter may never be observed, the scientists cannot hide the fact that there is something out there. One of the examples being the discovery of planet Neptune, which was predicted based on the anomalies in the orbit of Uranus, and after a few calculations, they pinpointed its exact location, therefore the discovery of Neptune.
Dark matter could take the form of dwarf stars and planets, elementary particles including neutrinos, or hypothetical and yet undetected particles that don't interact with visible light or other parts of the electromagnetic spectrum.
Dark matter has a more profound implication, and could hide the ultimate fate of our universe. Galaxies can not exist forever, therefore in a long period of time, they will break down and dissipate in the infinite vacuum that is our universe. Depending on how much dark matter there is in the universe, we might live in: a closed universe, an open universe of a flat universe, every one of which will ultimately destroy all life.
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