{"id":465109,"date":"2026-02-10T04:32:08","date_gmt":"2026-02-10T04:32:08","guid":{"rendered":"https:\/\/www.newsbeep.com\/ca\/465109\/"},"modified":"2026-02-10T04:32:08","modified_gmt":"2026-02-10T04:32:08","slug":"are-there-hidden-dimensions-to-the-universe-part-3-the-graviton-tower","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/ca\/465109\/","title":{"rendered":"Are there Hidden Dimensions to the Universe? Part 3: The Graviton Tower"},"content":{"rendered":"

This is Part 3 of a series on large extra dimensions. Read Parts 1<\/a> and 2<\/a>.<\/p>\n

To test it, I want you to imagine rolling up a piece of paper into a tight cylinder. Or, if you happen to be near a source of paper, doing it in real life. The analogy works either way.<\/p>\n

The long length of the tube is one of our real, usual dimensions. The stuff where the cosmos\u2026happens. The rolled up side is one of the extra, large dimensions, maybe as big as a millimeter, which for our purposes is absolutely gigantic.<\/p>\n

Now imagine sending a particle down the length of the paper. Make it something massless, like a photon. If the tube only had one dimension, then that photon would travel down its length at the speed of light, which photons are wont to do.<\/p>\n

But if that photon had access to the extra dimension, if it could experience it and travel through it, then its path along the rolled up tube would be different. It wouldn\u2019t just travel down its length. That\u2019s way too boring. It would also circulate around and around the extra dimension. It would still travel at the speed of light, but its motion would include the extra, hidden dimensions.<\/p>\n

But from our perspective, the extra dimensions are so tightly curled up (maybe you\u2019re really, really good at rolling up paper) that we can\u2019t see the full motion of the photon as it spirals around. We only see the motion down the length. From our perspective, the photon would now travel less than the speed of light, because some of its motion is getting tucked away into dimensions that we can\u2019t perceive.<\/p>\n

Any particle that travels slower than light must have mass. So if photons could access extra dimensions, they would appear to be more normal, massive particles. But the photon appears to be massless, so we can conclude that it can\u2019t access extra dimensions.<\/p>\n

But what about gravity? We don\u2019t have a quantum theory of gravity, but if we did we strongly suspect that we would view the gravitational force to be carried by a massless particle called the graviton. But if the graviton leaked into extra dimensions, it would appear to be so massless anymore. Because of the geometry of the situation, it would look to us like it had mass.<\/p>\n

And what\u2019s more, we have to include quantum mechanics in the mix, because of course we do when we take our wild ideas seriously. And quantum mechanics says that every particle has a wave associated with it. In the long dimension of the tube (which in our very rough analogy are the usual dimensions of reality), that little graviton can have any wavelength it wants. There\u2019s nothing to stop it. But in the compact, rolled-up dimension, the wavelengths have to fit. You can have either one whole wavelength, or two, or three, and so on.<\/p>\n

The action of rolling up one of the dimensions of the universe creates a quantum effect on any particles that can access it. What it does is this really crazy thing where the single massless particle that just wants to live its life and travel freely through all the extra dimensions gets effectively split into a number of different massive particles, one particle for each wavelength that can fit around the rolled-up dimension, like notes on a guitar string.<\/p>\n

(I used string as an analogy here, just want to make sure I am NOT talking about string theory!)<\/p>\n

And not just a few particles. An INFINITE number of particles, each one with a different wavelength and different mass. Keep in mind there\u2019s still only one single massless particle, but because we have a severely restricted point of view (we don\u2019t get to follow the particle in its travels through the extra dimensions), what we see instead appears to be an infinite number of massive particles.<\/p>\n

This is known as the graviton tower, or the Kaluza Klein tower, or just the tower if you\u2019re in a hurry.<\/p>\n

What this means is that we now have a tool to peer into the extra dimensions of the universe. Not directly, sorry, we\u2019re still little ants crawling on the floor looking for scraps. But these extra gravitons can now\u2026exist. As real particles. They have mass, they have range, they have speeds, they have lifetimes. They have properties in the real world.<\/p>\n

And most crucially, these gravitons get to slip away into the extra dimensions, just like you imagine a bad guy doing in a bad sci-fi movie as a cheap plot device. Oh we\u2019re about to get the evil mastermind and\u2026there he goes, slipping into another dimension.<\/p>\n

By the way there\u2019s an extra bit of jargon here that I need to divulge. For various nerdy reasons sponsored by string theory, our usual universe is sometimes called \u201cthe brane\u201d (as in membrane, not thinking brain), and the extra dimensions are called \u201cthe bulk\u201d. But I\u2019m not a big fan of this jargon because it leads to a lot of confusion and extra bookkeeping to keep track of the bulky bits and braney bits, so that\u2019s all I\u2019m going to say about that.<\/p>\n

We don\u2019t get to follow the gravitons into the extra dimensions, but if we keep careful accounting, we can see if we\u2019re missing anything. If we run a high-energy particle collider experiment (and trust me, this is something we absolutely love doing), then some of those reactions will create this tower of gravitons (which sounds like something out of Lord of the Rings, but I digress). These gravitons will have mass and energy and momentum, and then they\u2019ll slip away, because that\u2019s what they do.<\/p>\n

So when we run our experiments we\u2019ll know there\u2019s a certain amount of mass and energy and momentum going in, because we designed our experiment to know these sorts of things, and then at the end we\u2019ll find missing mass and energy and momentum, also because we designed our experiments to know these kinds of things.<\/p>\n

If the numbers don\u2019t math up, then we have evidence that the tower of gravitons is stealing away some momentum and taking it into extra dimensions.<\/p>\n

To be continued\u2026<\/p>\n","protected":false},"excerpt":{"rendered":"This is Part 3 of a series on large extra dimensions. Read Parts 1 and 2. To test…\n","protected":false},"author":2,"featured_media":465110,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[24],"tags":[49,48,314,66],"class_list":{"0":"post-465109","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-physics","8":"tag-ca","9":"tag-canada","10":"tag-physics","11":"tag-science"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/465109","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/comments?post=465109"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/465109\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media\/465110"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media?parent=465109"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/categories?post=465109"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/tags?post=465109"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}