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The two methods used to measure the size and expansion of the universe give different results. Therefore, a third was added.
The third meode was edited by the human physicist David Harvey. He adapted a third independent measurement method using Einstein’s predicted properties of light-distorting galaxies. He published his findings in the Royal Astronomical Society’s monthly reports.
We have known the expansion of the universe for nearly a century. Astronomers observed that light from distant galaxies has a shorter wavelength than galaxies in their vicinity. Light waves are in the red spectrum, which means galaxies are moving away from us. Conversely, when light waves are in the blue spectrum, galaxies are getting closer to us, like in the M31 galaxy in the Andromeda constellation.
The first way to measure the rate of expansion is called the Hubble constant. Some supernovae or exploding stars have a well-measured brightness, which makes it possible to estimate their distance from Earth and associate that distance with their redshift or speed. For every megaparsec of distance (the parsec is 3.3 light years), the speed at which galaxies move away from us increases by 73 kilometers per second. The second method of measurement is more and more accurate. However, measuring the cosmic microwave background of the rest of the light in the early universe produced a different Hubble constant: about 67 kilometers per second.
Albert Einstein’s general relativity predicts that the concentration of matter, such as a galaxy, can bend the path of light, just as a lens does. When a galaxy is faced with a bright light source, the light is bent around it and can reach Earth through various paths that provide two, and sometimes even four, images of the same source.
Therefore, physicist David Harvey decided to try another method and that is gravitational lenses, where in his work shows that in this approach, the error in the threshold of the Hubble constant reaches 2% as it approaches thousands of quasars.
Zdroj: Phys,
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