a general audience but is still jokingly referred to as the most unread book of all time now this thesis was not written for a general audience but instead for experts in cosmology so it is not easy to understand and there are a lot of calculations but i'll do my best to share the main ideas with you i myself am not an expert in this topic so it's just what i've been able to pick up i would like to quickly thank galaxy lamps for sponsoring this video the amazing background that you see today is from their galaxy projector NUMBER_TOKEN which is something that you can easily point at the walls or ceiling to turn any room into a kind of planetarium it is really quite mesmerizing and i'd love to keep using it as a backdrop for future videos it integrates with an app to change color options speed and to set a timer but you can also just use the six inbuilt modes if you don't want to use your phone you can also set it up with amazon alexa or google assistant it has a three stand system which is really easy to set up or rotate and it doesn't make any noise it has a laser feature which makes the stars or you can just have the nebula lights if you would like to get one for yourself or maybe as a gift perhaps for christmas then you can head to galaxy lamps dot co slash tibbies and get a NUMBER_TOKEN discount that link will only work for NUMBER_TOKEN people and you can find it down in the description as well so looking at the thesis it is all about the expansion of the universe and the first line of the introduction is that the idea that the universe is expanding is of recent origin he talks about how all of the early cosmologies were essentially stationary including einsteins but he says there are grave difficulties associated with this including the fact that if the stars had been radiating energy at their present rates for an infinite time they would need an infinite supply of energy and there's a mention of the fact that not long before this thesis was written that the discovery of the recession of the nebulae by hubble had led to the abandonment of static models in favor of ones which were expanding so this expansion is a relatively new idea and hawking goes on to say there are a few possibilities one is that the universe may have expanded from a highly dense state a finite time ago which is the big bang model or there's the bouncing or oscillating model where the universe is going through periods of expansion and contraction finally hawking says it is possible that the expansion may have been proceeding at much the same rate for an infinite time for this it would be necessary to postulate some form of continual creation of matter in order to prevent the expansion from reducing the density to zero this is what is called the steady state model now hawking will go on to talk a lot more about that it's also important to establish that a lot of this thesis relates to einstein's general theory of relativity the idea that space and time are related in this kind of fabric called space-time where massive objects can warp space-time explaining things like planetary orbits or a gravitational pull einstein himself had been so sure that the universe was static and not expanding that he had added the cosmological constant to his equations in order to keep it that way which he would famously go on to call his
START_SPONSOR_TOKEN i would like to quickly thank galaxy lamps for sponsoring this video the amazing background that you see today is from their galaxy projector NUMBER_TOKEN which is something that you can easily point at the walls or ceiling to turn any room into a kind of planetarium it is really quite mesmerizing and i'd love to keep using it as a backdrop for future videos it integrates with an app to change color options speed and to set a timer but you can also just use the six inbuilt modes if you don't want to use your phone you can also set it up with amazon alexa or google assistant it has a three stand system which is really easy to set up or rotate and it doesn't make any noise it has a laser feature which makes the stars or you can just have the nebula lights if you would like to get one for yourself or maybe as a gift perhaps for christmas then you can head to galaxy lamps dot co slash tibbies and get a NUMBER_TOKEN discount that link will only work for NUMBER_TOKEN people and you can find it down in the description as END_SPONSOR_TOKEN