HUBBLE’S MAGICAL OBSERVATION THAT CHANGED COSMOLOGY:

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THE EXPANDING UNIVERSE: 



Wherever we gaze into the night sky ,it all looks the same,doesn’t it?
Some may be wondering we may be at the centre of the universe for which it’s happening.Well,that’s a big no. Ya,it’s true that the universe looks identical in whichever direction we look ,but it’s also true that this thing occurs if we were observing the universe from anywhere else.These were the two ideas alone from which Physicist Alexander Friedmann showed that  we shouldn’t expect the large universe to be static or not expanding.
Actually ,it was Edwin Hubble who confirmed the same when he observed some redshift in the galaxies.It was a surprise back then to have seen the galaxies appearing red-shifted as most were wondering that the galaxies were moving around quite randomly,which was obviously not the case.

RED-SHIFT:


 The question is what the red-shift has to do anything with all this.Well,let’s understand first what red-shift actually means.
You know that our human eyes see different frequencies of light as different colours;the one with the lowest frequency appearing at the red end of the spectrum and the ones with highest frequencies appearing at the blue end of the spectrum.So when we see light emitted by a star moving towards us ,the time taken by the wave crests of the light will be less as it’s approaching us(Like in Doppler Effect),so the frequency will be ultimately high.Hence the light appears blue-shifted.So the exact opposite happens in case of light of star receding from us(or going away from us).The wave crests will take more time to reach ,making the frequency lower,which make the light appear red-shifted.
Well ,Edwin Hubble observed the same phenomenon when he sneaked into the vast realm of space through his Hubble telescope.He observed the light from the galaxies being red-shifted.Hubble spent time calculating their distances and observing their spectra.He concluded that the farther the galaxy is,the faster it’s moving away! It means the distance between the galaxies is always increasing.

ROLE OF DARK ENERGY:

You would have heard about this mysterious thing that controls a lots of things in our universe.Dark energy is currently responsible for 68 per cent of all the mass-energy in the universe;dark matter comprises 27 per cent and baryonic matter 5 per cent.Dark energy is an unknown form of energy hypothesized to permeate all of space ,believed to be the reason behind acceleration of the universe.

CONSEQUENCES:

It’s believed that the acceleration with which the universe is expanding will ultimately lead to increase in distance between planets and their stars and other galxies to such an extent that the stars won’t get their required fuel from other stars as they’d be far away .This will ultimately lead to the destruction of planets which is termed as “The Big Rip”.
Well,what do you think about the expanding universe ?Let me know in the comments below.

Author: Som Abhishek

2 thoughts on “HUBBLE’S MAGICAL OBSERVATION THAT CHANGED COSMOLOGY:

  • July 13, 2019 at 2:44 pm
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    Understood little bit.. but it's good to see discovery of such powerful things🙃

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  • July 14, 2019 at 3:48 am
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    Observation & vigorous patience – those two things I admire The most about scientists ..well I've several questions in my mind bt I'll ask only two -in the above diagram why there were no light radiations in dark ages while it happened next to afterglow incident, was it only constitution of atomic particle ? Other is what will happen if there will be fluctuation of dark matter (hypothetically)? Will it trigger the expansion rate or lead to another supermassive celestial incident? I want to know….

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