Our Expanding Universe
Tim's Blog Entry
When Edwin Hubble discovered that the universe is expanding in 1920s, topics such as “big bang”, “born of universe” and “expanding of universe” became very popular for astronomers debating. This blog is written based on “Our expanding universe: Age, history & other facts” written by Charles Q. Choi, Ailsa Harvey on Space.com Website.
Born of the Universe
We all known from our class that the Universe was born with the big bang. During the big bang, the space has an extremely rapid expansion (faster than speed of light) that double in size at least 90 times. After the big bang, the universe continues expanding with a slower rate, the mild expanding allows the universe cooled and formed matters in the space. According to the article, one second after the Big Bang, the universe was filled with neutrons, protons electrons and anti-electrons, photons, and neutrinos.
In the past, people believed that universe contains entirely with ordinary atoms which is called baryonic matter. However, NASA corrected this misinterpretation by stating “most of the ingredients making up the universe come in forms that we cannot see’. Only 4.6 % of universe is composed with the atom that we have seen before. 23 % percent is made up of dark matter, and 72% is made of dark energy.
The shape of the universe is also a very interesting topic. Since the universe is shifting away from us. According to the ancient stars and the relic radiation leftover from the Big Bang. the Universe is roughly 13.8 billion years old, and the shape of the Universe has three different conclusions based on its density.
If the density of the universe exceeds a specific critical value:
We will expect to see a “closed” universe. This sphere liked universe will make the parallel eventually converse and cross each other and return to its starting point. The Universe will eventually stop expanding and start collapsing in on itself. This is called “Big Crunch”
If the density of the universe is less than the critical value:
We will expect to see a negative curve, like a shape of saddle. In this case, the universe will expand forever, without bounds.
If the density of the universe is equal to the critical value:
NASA says, in this condition, the universe will be expanding in a horizontal line, like a “flat” or “sheet of paper”. In this case, the universe also will expand forever, but the expansion rate will gradually approach to zero.
Conclusion:
Our Universe is an infinite space that scientists only has very limited time of studying on it. Based on the technology and scientist’s analysis. We have discovered the forming of the universe, its expansion, and its future. This is the first step for understanding our universe. With more of more astrophysics students like us entering the field of astronomy, it’s very likely that one day we will reveal the “true face” of the universe.
It is mesmerizing that astrophysicists are in the beginning phases of comprehending the universe's expansion. So much is still unexplored about our universe, and I wonder what will be the subsequent discovery that will solidify itself in astronomy.
ReplyDeleteIt is absolutely astonishing that scientists are about to detect the origin of the space.Does the singularity contain all the matters that we are having right now in the form of energies? So when the universe is expanding, it does not create new energy but lowers its density by "stretching". If the universe is homogeneous and every cluster of galaxies is red shifting, then based on that, can we find where the location of where the big bang happened? Based on the research I did, it seems like it was not a "bang" but rather expanding. If it is a bang, would there be a spot where it is hotter than anywhere else in the universe?
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