Brain Makeover #11: The Universe.
The universe was born at a specific time in the past, and it has been expanding ever since.
The American astronomer Edwin Hubble discovered two important facts about the universe. First, he showed that matter is clumped together into large collections of stars called galaxies, and, second, he showed that galaxies are moving apart from each other. If you think of “running the film backward,” you see that the Hubble expansion implies that the universe began at a specific time in the past—a little more than 14 billion years ago, in fact. The idea that the universe began in a hot, dense state and has been expanding and cooling ever since is the main tenet of the Big Bang picture of the universe.
We now know that visible matter is actually only a small part of what the universe contains. Over 90% of the mass of a galaxy is made of dark matter. We do not yet know what it is, but we can see its gravitational effect of stars. Furthermore, we now know that the expansion of the universe is accelerating rather than slowing down. This means that there is another kind of material in the universe, dubbed dark energy, that is capable of exerting a force that overcomes the attraction of gravity. Understanding dark matter and dark energy are the primary goals of cosmology.
Today, scientists can trace the history of the universe back to within a tiny fraction of a second of the beginning, both through experiment and theory. Understanding the beginning of the universe is another goal of cosmology.
Tags: dark matter, galaxies, Hubble, universe
June 25th, 2009 at 2:48 pm
[...] Brain Makeover #11: The Universe. The universe was born at a specific time in the past, and it has been expanding ever science. The American astronomer Edwin Hubble discovered two important facts about the universe. First, he showed that matter is clumped together into large collections of stars called galaxies, and, second, he showed that galaxies are moving apart from each [...] [...]
August 5th, 2009 at 8:36 pm
I have an idea about how this might be possible. If every particle and every charge in the universe has an equal and opposite particle or charge somewhere else to balance it out, then the net total of the universe is still zero, the same as prior to the Big Bang. The Big Bang separated opposite charges on a very large scale, probably with each pair splitting in opposite directions. Think of how a sine wave is zero at the origin, then has a positive peak in one direction and a negative peak in the opposite direction.
Most of the visible universe is matter, not antimatter. Perhaps the explanation for this is that the antimatter went into other dimensions that are not visible to us. In any event, I suspect that it all balances out in the end.
January 13th, 2010 at 2:50 am
How come hypothesis on Theoric Physics do not require actual experiments. They just require an interpretation of what we are limited to observe from this distant point and then a bunch of brain power, and sweat goes into mathematics to validate that. C p.annf erby- i.y cyv (Bry. naoy lapy. ,pcyy.b cb Ekrpat)