The Expanding Universe 03/05/2019 – Posted in: Daily News
The expanding Universe
For: Mains
News Flash
A newly published paper in ‘The Astrophysical Journal’ is suggesting that the universe is expanding faster than it was believed, by about 9%.
| When scientists talk about the expanding universe, they mean that it has been growing ever since its beginning with the Big Bang. |
Our universe is Expanding
The expansion of the universe is the increase of the distance between two distant parts of the universe with time. It is an intrinsic expansion whereby the scale of space itself changes. The universe does not expand “into” anything and does not require space to exist “outside” it.
The galaxies in our universe are moving farther and farther apart with time. As we move farther away on an expanding universe, the speed with which the objects fly apart also increases.
Scientists describe the rate of this increase using a parameter called the Hubble constant. The higher the Hubble constant, the higher the rate of expansion.
Different groups have yielded the estimated values for the Hubble constant that fall into two sets. One set bunched the Hubble constant around 67 km a second per megaparsec, and another set around 74 km a second per megaparsec (one megaparsec is a distance approximately equal to 3.3 million light years).
It has been unclear whether the discrepancy in the two estimates for the Hubble constant are due to differences in measurement technique or, quite simply, errors. The latest paper lowers the possibility that this discrepancy could be a fluke to a factor of 1 in 100,000, according to a press release issued by NASA. If the discrepancy is not a fluke, it can only mean that our understanding of the physics is incomplete, and that we need a theory that can yield the correct value of the Hubble constant. This throws open an interesting puzzle in cosmology.
Expanding Universe Theory
The American astronomer Edwin Hubble made the observations in 1925 and was the first to prove that the universe is expanding. He proved that there is a direct relationship between the speeds of distant galaxies and their distances from Earth. This is now known as Hubble’s Law. The Hubble Space Telescope was named after him, and the single number that describes the rate of the cosmic expansion, relating the apparent recession velocities of external galaxies to their distance, is called the Hubble Constant.
Dark Energy
In physical cosmology and astronomy, dark energy is an unknown form of energy which is hypothesized to permeate all of space, tending to accelerate the expansion of the universe.
Source: The Hindu
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