The Expanding Universe

The Expanding Universe

From, BringMeKnowledge

Some physicists and mathematicians were working on Einstein's theory of gravity that described an expanding universe. In these solutions, the light coming from far objects would be red-shifted as it traveled through the expanding universe. In 1912, Vesto Slipher, was able to find out that lights from remote galaxies was red-shifted. The red-shift would increase with increasing distance to the object. 

Red-shift and speed:

Astronomers see red-shift in virtually all galaxies. It is a result of the space between the Earth and the galaxies expanding. This expansion stretches out the light waves during their journey to us, shifting them towards the red end of the spectrum. The more red-shifted the light from a galaxy is, the faster the galaxy is moving away from Earth.

How fast is it expanding?

The universe has been expanding since it was created or the time of the Big Bang, about 13.8 billion years ago. What is new, and what I’ll talk about at Northwestern, is evidence that the expansion of the universe has actually been speeding up.., and that the more recent history of cosmic expansion shows galaxies zooming away from each other faster than the galaxies were receding from one another in the past. This expansion stretches out the light waves through their journey to us, shifting them towards the red end of the spectrum. The more red-shifted the light from a galaxy is, the faster the galaxy is moving apart from Earth.The most reasonable explanation for the discrepancy is that the light from the supernovae, which exploded billions of years ago, traveled a greater distance than theorists had calculated, and this explanation, in turn, led to the conclusion that the expansion of the universe is actually speeding up, not slowing down. Wendy Freedman was able to find out the expansion rate of the universe. He calculated that the expansion rate of the universe is 72 km/h. 

Would it stop its expansion?

There are so many theories about it. Some says it'll keep expanding, some says it will stop expanding and some says it'll contrast. For this basis, this future scenario once popularly called "Heat Death" is now known as the Big Chill or Big Freeze.

#Bonus information:

During the inflationary epoch about 10^−32 of a second after the Big Bang, the universe suddenly expanded, and its volume increased by a factor of roughly at 10^78 (an expansion of distance by a factor of at least 10^26 in each of the three dimensions), equivalent to expanding an object 1 nano-meter in length to one approximately 10.6 light-years (about 10^17 m or 62 trillion miles) long. A much slower and steady expansion of space continued after this, until at around 9.8 billion years after the Big Bang (4 billion years ago) it began to gradually expand more quickly, and is still doing so.