User:Kd2889

matter as we know it atoms stars and galaxies, planets and trees ,rocks and us this matter account for less than 5/100 of the known universe about 24/100 is dark matter and 71/100 is dark energy both of which are invisible this is kind of strange because it suggests that everything we experience is really only a tiny fraction of reality but it gets worse we really have no clue that what dark matter and dark energy are or how they work we are pretty sure they exist though so what do we know ? dark matter is the stuff that makes it possible for galaxies to exist when we calculated why the universe is structured the way it is it quickly became clear that there is just not enough normal matter the gravity of the visible matter is not strong enough to form galaxies and complex structures the stars would more likely be scattered all over the place and not form galaxies so we know there is something else inside and around them something that does not emit or reflect light something dark.... but besides being able to calculate the existence of dark matter we can see it ...kind of. places whit a high concentration of dark matter bend light passing nearby so we know there is something there that interacts with gravity right now we have more ideas about what dark energy is not than what it is we know that dark matter is not just clouds of normal matter without stars because it would emit particles we could detect dark matter is not anti-matter because anti-matter produces unique gamma rays when it reacts with normal matter dark matter is not also made out of black holes very compact objects that violently effect their surroundings while dark matter seems to be scattered all over the place basically we only know 3 things for sure 1 something is out there 2 it interacts with gravity 3 there is a lot of it dark matter is probably made up of a complicated exotic particle that does not interact with light and matter in way we expect but right now, we just don't know dark energy is even more strange and mysterious we cannot detect it ,we cannot measure it and we cannot taste it but we do see its effects very clearly in 1929,Edward Hubble examined how the wavelength of light emitted by galaxies ,shifts towards the red end of the electromagnetic spectrum as it travels the space he found that fainter more distant galaxies showed a large degree of red shift closer galaxies ..not so much Hubble determined that this was because the universe itself is expanding the red shift occurs because the wavelengths of light are starched as the universe expands more recent discoveries have shown that the universe is accelerating before that ,it was thought that the pull of gravity would cause the expansion to either slow down or even retract and collapse in on itself at some point space does not change its properties as it expands ; there is just more of it new space is constantly created everywhere galaxies are tight bound clusters of stuff held together by gravity so we do not experience this expansion in our daily lives but we see it everywhere around us wherever there is empty space in the universe, more is forming every second so , dark energy seems to be some kind of energy intrinsic to empty space energy that is stronger than anything else we know and it keeps getting stronger and stronger as time passes by empty space has more energy than everything in the universe combined we have multiple ideas about what dark energy might be one idea is that dark energy is not a thing ,but just a property of space; empty space is not nothing ,it has it’s own energy it can generate more space and is quite active so as the universe expands it could be that just more and more space appears to fill the gaps and this leads to a faster expanding universe ; this idea is close to an idea that Einstein had back in 1917 of a concept of a cosmological constant  a force that counteracted the force of gravity the only problem is when we try tied to calculate the amount of this energy the result was so wrong and weird that it only add to the confusion another idea is that empty space is actually full of temporary, virtual particles that spontaneously and continually form from nothing and then disappear into nothing again the energy from those particles could be dark energy or maybe dark energy is an unknown kind of dynamic energy fluid or field which permeates the entire universe, but somehow has the opposite effect on the universe than the normal energy and matter but if it exists, we do not know how and where or how we could detect it so there are still a lot of questions to answer the theories about dark matter and dark energy are still just that;...theories on the one hand this is kind of frustrating, on the other hand this is frontier science making it very exciting it shows us on matter how much we feel we are on the top of things, we are still very much apes with smartphones, on a tiny fragile island in space looking into the sky wondering how our universe works there is so much more to learn about and that is awesome