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Expansion of the Universe

18 July 2019

At https://phys.org/news/2019-07-fast-radio-field-astronomy.html … we have mysterious radio bursts – first discovered in 2007. Since then 100 or so have been announced – fast and bright flashes of radio waves issuing from space. What they are has yet to be determined.

At https://phys.org/news/2019-07-small-fragments-carbon-rich-asteroids-frag… … a new theory on why chondritic meteors are not as common on Earth as chondritic asteroids are in space. The claim is that small fragments of carbon rich asteroids are too fragile and break up on entry into our atmosphere. In other words, they are destroyed before they can reach the surface. The current Japanese mission to asteroid Ryugu has revealed a surface that is porous and carbon rich.

At https://phys.org/news/2019-07-hubble-constant-mystery-universe-expansion… … a new Hubble constant measurement has just been published. It pertains to how fast the universe is expanding and uses different stars than on previous attempts. It falls short of a previous calculation. NASAs Hubble Space Telescope was used and they compared the brightness of giant red stars in several galaxies on the basis it is thought that red giants reach the same peak of brightness in their late evolution. Hence, it should be able to use them to calculate distance and speed of expansion. Mind you, that depends if the giant red stars are really what they say they are.

We are told that scientists have known for a century that the universe is expanding and the distance between galaxies is becoming ever more vast every second. How fast the rate might be has remained elusive. A new study by Wendy Freeman et al claims the new measurement rate of 70km a second per megaparsec (km/sec/mpc). One parse is equivalent of 3.2 light years distance. This is slightly smaller that the Hubble SHJoES team made. They used Cephoid Variables (which are stars that pulsate at regular intervals corresponding to their peak brightness. This worked out somewhere close to 74km a second per megaparse. Another, third, study used the rippling structure of light left over from Big Bang which is known as the Cosmic Microwave Background. A rate of 67.4 km/sec/mpc was calculated. So, we have three different measurements and three different results. One may wonder what exactly was it they were really measuring. In spite of this researchers are hopeful the next round of results won't be so contradictory. They aim to take advantage of the NASA Wide Field Infrared Array Telescope which will be launced in the 2020s. Will this lead to a better handle on what is happening via a wider view of the stars in space. Does this automatically translate into better measurements. The downside might be that they still intend to measure rate via cepheid variables and red giants.

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