cosmos background This is a topic that many people are looking for. star-trek-voyager.net is a channel providing useful information about learning, life, digital marketing and online courses …. it will help you have an overview and solid multi-faceted knowledge . Today, star-trek-voyager.net would like to introduce to you Cosmic Microwave Background Explained Space Time PBS Digital Studios. Following along are instructions in the video below:
“Space looks black nbut the entire universe used to be this color. How s that that possible let s find out stars and galaxies. Nnotwithstanding space is pitch black so a dark spot in the sky nand point an analog satellite dish at it you might expect to get nnothing. But you don t you get static pick another point nand more static move your dish nyet again static.
Even accounting for all npossible types of interference. No matter how you norient your dish there s this constant nunderlying microwave band static. That s just always there in nthe darkness of space. Emitting.
The same pattern over and over now since we pick up nthis mysterious static from every direction. Nwe look. It would seem to be coming from a nsource that exists literally everywhere on the sky problem is we don t nknow of any source anywhere that would emit this nobserved pattern of microwave emission. So where s nit coming from aliens no it s not aliens.
It s never aliens. But what if i told you that the nsource of static. Which we call the cosmic microwave nbackground or cmb was the process that formed nthe first atoms in the universe. Almost 13 and 1 2.
Nbillion years ago. And what if i also told you nthat. The source of the cmb also caused all of space to look norange for millions of years that s right the universe nused to be orange to understand how nthis could be true we first need to take a brief ndetour into your toaster turn on your toaster..
The heating elements. Glow na. Pale. Reddish color that glow isn t ambient light nreflecting off the toaster.
It s light being emitted nby. The toaster itself. If you were to analyze nthat glow with instruments less limited than nhuman eyes. You would realize that the ntoaster isn t just emitting.
Pale red light. It s emitting electromagnetic nwaves of all wavelengths moreover. The intensity nat. Different wavelength is in very specific nproportions that trace out a graph very close to this that emission pattern nrepresented by the graph is called the toaster s nthermal spectrum or really an idealization of a thermal nspectrum called a black body spectrum now everything nhas a temperature.
So everything has na thermal spectrum. And it emits all nelectromagnetic wavelengths you a taco the nsun everything in fact it s called na thermal spectrum. Because the light is generated nby. The random motions of particles in the material.
And those random motions nare themselves a reflection of. Temperature now if you go really nlow in temperature down to 27 degrees nabove absolute zero the peak shifts way into nmicrowave wavelengths and lo and behold nexactly matches the cmb and i mean exactly the cnb is one of nthe closest things to a mathematically perfect nthermal spectrum. That has ever been observed problem is space is npretty much empty..
There s nothing really nin there to have a temperature much less the nvery specific temperature of 27. Kelvin so why does the cmb look like na thermal spectrum at all to answer that and to see nwhy space used to be. Orange we need to turn the clock nback to about 400000 years. After the big nbang.
Give or take during that era. A nsupercharged particle with a temperature of nseveral thousand degrees permeated all of space at this temperature. It s too nhot for electrons and protons to even coalesce into atoms nlet alone stars planets or galaxies. This ionized soup nis called a plasma and just like toasters npeople and tacos.
It was emitting a nthermal distribution of electromagnetic waves. But because there were nno neutral atoms yet the light the nplasma emitted just couldn t travel nvery far before it would run into an electron nand ricochet. Like in a pinball game. So.
If you took the ntardis back to this era and could somehow nkeep it from melting. You wouldn t be able to see very nfar on the viewscreen maybe a few thousand lightyears nwhich sounds like a lot. But it s basically nzero visibility in astronomical terms. So at this moment.
It was as nif flash bulbs were constantly going off everywhere nin space. But the light was being snuffed out by a fog now as this plasma cooled nits temperature eventually dropped below the 3000. Nor so degree mark where neutral atoms ncould finally form with no more free electrons nto redirect..
The light. The universe became for the nvery first time. Transparent. The light that the nplasma had emitted then just before neutralized was one nlast hurrah.
One final flash of an infinite number of norange bulbs going off at every point in the universe. Nmore or less simultaneously and now that light could free nstream through the universe forever. Before during and after this nevent space was expanding that s what thinned nout the plasma and made it cool down nin. The first place.
But as we talked about nin a prior episode that you can revisit nhere. Expanding space stretches the wavelength nof free streaming light through a process called ncosmological redshift. So over the course of na. Few million years.
That orangey thermal nspectrum of light was redshifted to longer nand longer wavelengths becoming toaster read nand eventually infra red. So that to human eyes. The nsky eventually turned dark. If you throw in another n13 plus billion years of space expansion nall that light has redshifted into nthe microwave band to become what we today nperceive as the cmb and all those atoms nfrom that plasma well they managed to clump nbecome stars galaxies and through a complicated nprocess of cosmic recycling us so the cmb or nmore specifically the shape of its nthermal spectrum is pretty compelling nevidence that when it comes to the color of nspace black is the new orange.
Now the cmb is ninteresting for a lot of other reasons. Besides nits thermal character so i m sure you guys will nhave questions about i ll tackle as many as i can non the next episode of time last week. I challenged you to nstabilize a gyro driven star fox barrel roll a lot of you emailed in nresponses..
And a lot of you got it right the first five of you nwho emailed correct answers and i napologize in advance if i mispronounce nyour name were markus kesselring cameron nmoran mattias. Olla thomas hsu and jacob stueck good work the rest of your names nwill be scrolling below. As i explain the answer nwe were looking for the trick was to cancel out nall the intermediate angular momentum vectors nproduced as a flywheel with forward pointing nangular momentum rotates to end up with nbackward pointing angular momentum. And the solution is nto have two flywheels both with forward pointing nangular momentum that you rotate into the reverse norientation in opposite senses.
That way any sideways. Nintermediate angular momentum that gets produced nis canceled out the short youtube nvideo here shows. A demo of this principle in action. An answer that some of you nsubmitted that technically isn t wrong.
But wasn t nwe were going for is to take the already spinning nflywheel just one of them and slow down its spin in response. The ship would have nto be torqued the other way and technically nthat works. But you don t get nearly as much ntorque application or leverage as you do from actually rotating na gyroscope. Without changing its spin.
A few of you asked wouldn t nthe extra mass of the gyroscopes weigh just as much as nextra mass from fuel answer not necessarily if some fictitious really nlight. But really strong material could be spun nsufficiently fast you could store up a nlot of angular momentum with very little mass and to everyone who pointed out nthat. We got the aileron flap directions wrong in nthe video. Noted annotation added and thanks nfor keeping us accurate.
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