Ride the Wave(s),
Previously I touched on the expansion of the universe and thought it would be a good idea to expand on the underlying mechanics that allowed us to reach that conclusion.
Red-shift and blue-shift is a phenomenon where light changes as objects in space move closer or farther away from us. For example when a police car drives past a stationary observer and the siren appears to increase and decrease in pitch. This is the Doppler Effect and can be applied to light as well.
Visible light is a spectrum of colors and when an object moves away from us the light is shifted to the red end of the spectrum. If an object moves closer the light moves to the blue end of the spectrum as its wavelengths get shorter and more compacted.
This effect was first theorized by Christian Andreas Doppler and is called the Doppler effect. Since light is a wavelength this means the wavelengths can stretch or squish together depending on the position of objects relative to one another. However we don't notice it during our daily lives because light travels much faster than the speed of sound.
Proof of Expansion,
American astronomer Edwin Hubble was the first to describe the red-shift phenomenon and tie it to an expanding universe. His observations, showed that nearly all galaxies he observed are moving away.
"This phenomenon was observed as a red-shift of a galaxy's spectrum. This red-shift appeared to be larger for faint, presumably further, galaxies. Hence, the farther a galaxy, the faster it is receding from Earth." - Quote from NASA.
The galaxies are moving away from Earth because the fabric of space itself is expanding. While galaxies themselves are on the move, with some moving closer together and some further apart. There is an overall phenomenon of red-shift happening as the universe gets bigger.
Not just Light,
The terms red-shift and blue-shift can be applied to any part of the electromagnetic spectrum, including Infrared, Radio waves, X-rays and Gamma rays.
If radio waves are pushed into the ultraviolet part of the spectrum they are said to be red-shifted, as in shifted toward the lower frequencies.
The red-shift of an object is measured by examining the absorption or emission lines in its spectrum. These lines are unique for each element and always have the same spacing.
When an object in space moves toward or away from us, the lines can be found at different wavelengths than where they would be if the object were not moving.
Red-shift is the change in the wavelength of the light compared against the wavelength that the light would have if the source was not moving.
Different ways to Shift,
At least three types of red-shift occur in the universe. From the universe's expansion. From the movement of galaxies relative to one other and from gravitational red-shift. Which happens when light is shifted due to the sheer bulk of matter inside of a galaxy.
This latter red-shift was the most difficult to track down of the three. however in 2011 scientists were able to identify it on a universal scale.
Astronomers did an analysis of a large data-set known as the Sloan Digital Sky Survey, and found that gravitational red-shift does happen, perfectly in line with Einstein's theory of general relativity.
The first detection of gravitational red-shift came after scientists detected it occurring in gamma-ray light emanating from an Earth-based lab.
We talked a lot about red-shift in this post, but the inverse is true for blue-shift. It's just the phenomenon of waves being compressed together increasing the perceived wavelength by us relative to the original wave.
While not being as common in the galactic playground it is definitely something to 'watch out for' as it represents an object accelerating as it approaches us.
Perhaps an alien visitor accelerating hard at the beginning of a very long journey?
Thanks for taking the time to read through this dearest readers. I hope you have a fantastic day, much love. <3
Sourcing and further information here and here
Outstandingly informational and kickass, as always! I love it when you blog about this kind of stuff and make it easier to digest and understand!
Please keeping doing this forever.
Hahahaha, that is a great gif, love it. Thanks for dropping by. <3
I learned a lot of these concepts from Sci-Fi reading as a kid, and then in my Fuck Math, Physics Sucks, and other shitty classes I took in HS and university ;)
The expansion of the universe is not infinite, one day it will end and end up contracting to the origin and if it is infinite then it will expand so much that then it will cool and everything in it will perish.
It sounds rather tragic.
Anyway, good post!
See you.
Yes, I went over this in a previous post called cycles within cycles or something.
Lemme dig up the link. Glad you found it enjoyable, hope you have a great day. Oh and that perish thing won't happen for many many many many many many deep breath many many many millennia.
meep
https://steemit.com/technology/@sammosk/the-heartbeat-of-the-universe-shells-inside-shells-the-grandest-cycle
Thank you, I will read it soon.
Hasta luego
As I understand it then, the Universe keeps expanding? Rather cool but also very abstract for me. I keep wonder what is it expanding in, what is surrounding our Universe? Lol this gets to big to think about. But anyway great article!
Well space is space because something is in it/ between it, so the universe is pretty much expanding and creating more space as it expands.
What is surrounding our universe?! EMPTY SPACE!
It does indeed get rather big to think about, I remember spending hours and hours trying to wrap my mind around these things and just going.. arrrgh!! brainmelt
Thanks for stopping by and taking the time to read and comment kerlund. much love <3
Yes I can feel that brain melting now:-) But it's interesting facts!
I've never been able to wrap my brain around the concept of what the universe is expanding into. It's quite beyond my capacity to think logically about that.
Well there is a possibility there are multiple universes all moving away from each other at the speed of light or beyond, thus providing a never ending expanse of 'space' for us to expand into. if that helps you conceptualize it a bit better.
God, it all just got even worse in my brain :D Need to look at the flowers in my garden to calm my brain down a bit.
I think they worked out to be like a bubble - in another bubble (and after that on the outside is God).
Let's hope and pray!
Very nice. Things about Space fascinate me. Time travel is more what I'm into, but this is interesting and maybe we will be seeing an advancing blue light soon.
I'm not too sure I would want to see something that is blue shifted to any extent, because that means that object is very big. In order to see it from any appreciable distance, even from 1 light year away, it would have to be very big. If it's that big, and coming toward this solar system, it's not going to be good when it gets here.
Either very big, or highly energetic.. either way it'll be something VERY EXCITING!! :D
Quite true!
That would be very interesting. :)
Awesome post. This expansion is trippy because it seems like the expansion is relative to the observers position. From any point it seems the expansion is outward, but there might be hidden variables, well of course there are. We are limited by our brains haha. Anyways, great post :)
Thanks for taking the time to check it out soundwaves. I love me some expansion! ;) <3
Where is it expanding out from?? Have we found the center? Is it steemit?
Great post!
Would that mean that at some point, a visible star/galaxy's light would be so red-shifted that it moves out of the visible spectrum? So basically, would the night sky be darker for the naked eye in the future?
Yes, that can happen. Frightening thought that eventually in the far far far future it is possible that we will have no stars. :(
Wow, I feel my brain about to burst into flames after reading this - however, this was a great read and now I learned something new! You helped me achieve my daily goal of learning at least 1 new thing a day, so thank you!
Keep up the great work bro. I followed you as well!
Winning! learning is amazing. much joy I am feeling. thanks for taking the time to comment. <3
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It's always satisfying to read something well written even if the information presented is well known. Very good post.
Geeky! These are the kind of stuff I want to talk about and my dad will really feel he got premium service for the cost of my upkeep all those years. Lol. I nominate you to represent us when we're negotiating for this space with aliens. 😁
Love the awesome reads from you Sammo!
Fascinating and all new information for me (apart from just hearing the term Doppler Effect). I enjoyed learning about this intricate process. 😊
my VP sucks (~68%) but I shot you some SP ;)
Great article, I learned most of this thru Sci-Fi reading :D
Legend!!
... so sayeth Professor Sammo ;)
Wow Sammo that is a really brilliant post dude.
I love it when a post gets me thinking it in the way this has, it's rare.
Cracking work dude.
When we first saw redshift of distant galaxies, the only two mechanisms at the time were Doppler shift and gravitational redshift. Initially, Doppler shift was assumed and so the redshift was attributed to the result of motion.
Then, we noticed redshifts were greater than the value of 1 and so we took the correlation known as Hubble's Law and extracted it from the redshift observations so that nothing had a redshift greater than 1.
Then we took Hubble's Law and said "this is due to expansion of space." This is a huge assumption to make, that there is a new cause just because of the observation of a correlation of redshift per distance. In fact, using Occam's Razor, both expansion of space and dark energy stem from the assumption that motion is the cause. This indicates that, logically, gravitational redshift is the real cause. The question is just a matter of how.
As gravity also can bend light through gravitational lensing, if masses were to be able to be ever larger, then some masses would be so large that they could influence light in our entire observable universe so as to cause it to bend. If that light bent into a Figure-8 pattern as a result, centered on such an object, then it would produce gravitational redshift per distance as well as show how electromagnetic fields are produced by gravity. This view drastically reduces physics by showing electromagnetism as the result of gravity and removing the added concepts of expansion of space and dark energy from the model. The goal of physics, after all, is to find the simplest understanding rather than the most complex explanation.
Just my two cents. :)