Airbrush

Sure, I'm on board with all that. I'm not here to get celebrated. I'm here to get an expert to explain to me how an infinite big bang happens. And if they can't do that, I'd rather they stop saying that an infinite big bang is just as plausible as a FINITE one. If that is a possible outcome of the big bang, then why do cosmologists avoid even discussing it? They go into great detail about the mechanics of what happened in a FINITE big bang...after it got started, of course. Where Does This Discussion End? It Must End Somewhere.

I disagree about the plausibility of an infinite universe. Infinite is very different from finite (infinitely different) and infinite is the least plausible. That infinite is "no more plausible" than finite seems a flimsy supposition. EDIT: Sorry I didn't see your last post before I posted this one, so please disregard. Any other takers? I don't believe my questions are about the "moment" of creation of an infinite universe, just about what happened after the infinite universe began.

I appreciate your attempt to answer my questions above. My post has 4 question marks and I don't think you have specifically addressed any of them except to repeat what I already stated about our observable portion not being the entire universe. We already know that. How would you answer my 4 questions? It is ok for you to say you don't know to each of them. "Nobody knows". Can anyone answer any of my 4 questions? #1 When does an infinite universe achieve an infinite size? #2 Was it before the first Planck Time? #3 Does infinite in size imply a universe infinite in mass? #4 An isotropic, homogenious, INFINITE big bang would spread out evenly to infinity in all directions, right? Thank you.

Yes it sounds strange. Because for an infinite-sized universe to pop out of the big bang, the universe would be infinite in size at the earliest moment, right? (At what moment, the first Planck time?) Cosmologists talk about the observable portion of the universe to have originally been smaller than a proton, but that does not make much sense in the creation of an infinite-sized universe. Infinite-sized implies our big bang would also be infinite mass, right? An isotropic, homogenious, INFINITE big bang would spread out evenly to infinity in all directions, right?

"...On 28 August 2013, it was thought that "a $1-billion high-powered spy satellite capable of snapping pictures detailed enough to distinguish the make and model of an automobile hundreds of miles below"[6] was launched from California's Vandenberg Air Force Base..." https://en.wikipedia.org/wiki/Spy_satellites If this is true then maybe, if the newstand is facing the perfect direction with good lighting for the spy satellite, and the headlines are very big, then it may be possible.

It depends on how big the headlines are. Spy satelites can read license plates from space, right? That is about as large of print as huge, one-word headlines in a newspaper.

How are these concepts related? Correct me if I'm wrong but I seem to remember something like for spacetime to exist, there must first be matter/energy. At the big bang, energy (not matter quite yet) expanded from a point (why not a giant rip?) outward rapidly. That was the beginning of time as we know it. We call it spacetime. That energy cooled and finally congealed into hydrogen and helium. There was no dust until the first generation of stars exploded millions of years after the big bang, just gas. So for spacetime to exist there must first be matterenergy. The next thing I wonder is before the big bang there may have been something like empty space, but it was not "spacetime". Right? There was something called "space" and that was not "spacetime" because matterenergy didn't appear yet. This "space" (not spacetime) could also be the infinite medium between big bangs. Could this "space" could be a region that has no virtual particle pairs appearing and annihilating?

Very interesting. Thanks for posting that which is a good explanation. Why does the big bang theory never mention the possibility of other big bangs that are far away from our big bang? This is just because it is much easier for me to visualize multiple, FINITE big bangs going off anywhere within a multiverse of big bangs, than to visualize one INFINITE big bang.

Blocking electromagnetic radiation from a planet may be a strategy of an advanced ET civilization that has realized that they have nothing to gain my announcing their location in space to all listeners. The reason is they don't want their nice, habitable planet to be taken over by a more advanced civilization that is predatory. I mean "predatory" not in the sense the more advanced civilization would want to EAT inhabitants on a certain planet, just wipe them out and take custody of their planet. Like what Stephen Hawking said that when Europeans discovered America, that was a disaster for the native Americans. For a predatory, more advanced ET civilization, looking for a planet to inhabit, and such habitable planets are very rare, they would probably not hesitate to destroy the inhabitants on the planet they desire.

Yes, that's a better example, thank you. But still something about this infinitely long ruler bothers me. It reminds me of the light speed limit on the universe. Infinity could be the distance limit on the universe. To say you can have infinity times 2 or 3 means the same as infinity. I have this suspicion that when it comes to distance, infinities of all sorts are equivalent. For example, it may be that if: INF = Infinity and N = Any Number, then INF x N = INF. I've never heard this before so it's pure speculation and thanks for listening.

Very interesting about the Grand Hotel Paradox. Thanks for posting that. Too bad it doesn't mention a universe that has an infinite diameter and how it can grow any larger. Can anyone think of another model comparable to the Grand Hotel Paradox to explain how the big bang could produce a universe that has an infinite diameter and yet keeps growing? That is beyond my ability to grasp using geometry of 3 dimensions: x, y, and z axes. Are you saying infinity is a quantity that you can add numbers to? That seems like cheating to me, infinity is already infinite. Adding a finite number to infinity is comparable to dividing a real number by zero. "...Choosing a Cartesian coordinate system for a three-dimensional space means choosing an ordered triplet of lines (axes) that are pair-wise perpendicular, have a single unit of length for all three axes and have an orientation for each axis. As in the two-dimensional case, each axis becomes a number line." https://en.wikipedia.org/wiki/Axis_(mathematics)

You know more about this subject than I do. Most of what I know about cosmology just comes from documentaries on TV. So I'd like to hear how something infinite in size can increase in size.

"Almost certainly many times larger"? There is no such certainty. The entire universe could be exactly as large as the observable universe, by coincidence. It could be 50% larger than the observable universe. But it is almost certainly larger, and we don't have ANY clue how much larger. Explain HOW the universe can be infinite in size before saying "it could by infinite". A finite universe can NEVER grow to an infinite size. For the universe to be infinite in size (and/or infinite in mass) it would have to ALREADY have been infinite in size at the first moment of the big bang. That is hard to imagine. If the entire universe ever had a finite size, it could never grow to an infinite size at any finite rate. Even cosmic inflation was a finite rate of expansion. The difference between finite and infinite is so great that the difference is infinite.

It makes sense, but how can we say what (or what nothing) the universe is expanding into if we can never know what's beyond our observable horizon? Our observable universe is too small a sample to make claims about what lies beyond, it seems to me. There could have been a pre-existing universe and our big bang happened inside that universe.

Only when the ape guesses correctly. On second thought the universe does NOT have much variation that we can see. I take back what I said. My new argument is that what we can see, which is homogenious and isotropic, is too small a sample to reach any conclusions. Beyond the observable universe is probably a lot more on the scale of infinity.

True the universe we can see is isotropic and homogenious in every direction, but on the scale of infinity our observable universe amounts to a tiny bubble. It is about 240,000 miles to the moon, much further to the Sun, much further to the nearest star, much further to the next galaxy, and so on. Beyond our observable bubble of the universe is probably much more of the same until you go far enough away. "Much further" to the next large stucture which could be another big bang, or big whatever.

"The is no edge" but what is intuitive is that the universe has variation. Once you travel far beyond the edge of our observable universe you will probably encounter regions that we never dreamed of. The image I keep visualizing is a finite-sized, finite-mass big bang beyond which there stretches vast space Trillions or Quadrillions of light years before you reach something interesting, which might be the edge of another big bang expanding in our direction, or a region of flying pink elephants.

Maybe we miss seeing most of them because most of our galaxy is obscurred by dust clouds.

OK, I got it now, thanks. Good perspective, the destruction of Saddam's regime created ISIS because all those Baathist military commanders were out of a job. When you have nothing, you have nothing to lose. So in desperation these military people "got religious". The leaders are like zombies who returned from the dead. They were as good as dead after the oppressed Shiites went on a rampage against the Sunis in Iraq. Maybe the leaders even convinced themselves that their cause is righteous and consistent with Islam. They got religious to make amends for their evil deeds. Their recruits are witless of what's going on. When new recruits are oriented do you think their programmers harp upon the goals of ISIS? The recruits may not be very informed about Islam, nor about the goals of ISIS. But they must be broken down like any cult breaks down its' recruits through isolation and indoctrination. Or like military boot camp. Your drill sargent is very hard on you to toughen you up to be fit for battle. Then many of the recruits become disillusioned and want to quit but they are stuck and must obey or be executed.

"Since at least 2004, a significant goal of the group has been the foundation of a Sunni Islamic state. Specifically, ISIL has sought to establish itself as a caliphate, an Islamic state led by a group of religious authorities under a supreme leader—the caliph—who is believed to be the successor to Prophet Muhammad. In June 2014, ISIL published a document in which it claimed to have traced the lineage of its leader al-Baghdadi back to Muhammad, and upon proclaiming a new caliphate on 29 June, the group appointed al-Baghdadi as its caliph. As caliph, he demands the allegiance of all devout Muslims worldwide, according to Islamic jurisprudence. ISIL has detailed its goals in its Dabiq magazine, saying it will continue to seize land and take over the entire Earth until its: “Blessed flag...covers all eastern and western extents of the Earth, filling the world with the truth and justice of Islam and putting an end to the falsehood and tyranny of [ignorance], even if America and its coalition despise such.”— 5th edition of Dabiq, the Islamic State’s English-language magazine. According to German journalist Jürgen Todenhöfer, who spent ten days embedded with ISIL in Mosul, the view that he kept hearing was that ISIL wants to “conquer the world” and all who do not believe in the group’s interpretation of the Koran will be killed. Todenhöfer was struck by the ISIL fighters' belief that “all religions who agree with democracy have to die, and by their "incredible enthusiasm"—including enthusiasm for killing "hundreds of millions" of people. When the caliphate was proclaimed, ISIL stated: "The legality of all emirates, groups, states and organisations becomes null by the expansion of the caliphate's authority and arrival of its troops to their areas.” According to Jason Burke, a journalist writing on Jihadi Salafism, ISIL's goal is to "terrorize, mobilize, polarize". Terrorize to intimidate civilian populations and force governments of the target enemy "to make rash decisions that they otherwise would not choose". Mobilize its supporters by motivating them with, for example, spectacular deadly attacks on enemy soil such as the November 2015 Paris attacks. Polarize by driving Muslim populations—particularly in the West—away from their governments, thus increasing the appeal of the ISIS caliphate among them. "Eliminate neutral parties through either absorption or elimination." https://en.wikipedia.org/wiki/Islamic_State_of_Iraq_and_the_Levant#Goals If these are the true goals of ISIS, then how delusional can anyone be to believe they can "take over the entire Earth" by violent means? The leaders of ISIS are devious delusional and their suicide robots are stupid delusional. And they propose to end the "tyranny of ignorance"? Maybe the goals and strategy of ISIS should be repeated more often so new recruits understand what they are getting into before they take the leap.

Yes indeed. Let's meet here again in about 50 years and discuss this issue. Because of the problems of such high speeds it now seems the way to interstellar travel is by generational ships. Get used to the idea of traveling at modest speeds, but be able to live comfortably in space in artificial one g gravity and able to make repairs, grow food, stopping at asteroids or rogue planets to pick up water and metals. Sending probes to the nearest stars through the interstellar medium at such high speeds may not be practicable. We may send out 100 of them and never hear from any of them again due to unknown mishaps. So we need to walk there at a leisure pace and have fun along the way. The ultimate destination, the habitable planet, is tens of thousands of years travel time.

"...A Medusa spacecraft would deploy a large “spinnaker” sail ahead of it, attached by separate independent cables, and then launch nuclear explosives forward to detonate between itself and its sail. The sail would be accelerated by the plasma and photonic impulse, running out the tethers as when a fish flees the fisherman, and generating electricity at the “reel”. The spacecraft would then use some of the generated electricity to reel itself up towards the sail, constantly smoothly accelerating as it goes.[10] In the original design, multiple tethers connected to multiple motor generators. The advantage over the single tether is to increase the distance between the explosion and the tethers, thus reducing damage to the tethers. Medusa performs better than the classical Orion design because its sail intercepts more of the explosive impulse, its shock-absorber stroke is much longer, and all its major structures are in tension and hence can be quite lightweight. Medusa-type ships would be capable of a specific impulse between 50,000 and 100,000 seconds (500 to 1000 kN·s/kg)." https://en.wikipedia.org/wiki/Nuclear_pulse_propulsion#MEDUSA Can such a spacecraft be built within the next 200 years? Assuming we don't return to a pre-industrial age due to human stupidity through nuclear war or extreme climate change, or supervolcano eruption. Could such a spacecraft reach 10%c? If so then could a habitable planet (for us) be studied up close and the results of the study beamed back to Earth within the next 500 years?

The next generation of space telescopes will certainly find plenty of interesting stars within 100 light years that have habitable zone planets. What are the current probability estimates of how far away is the nearest Earth-like planet or Superearth? I vaguely recall info based on Kepler's findings of a high probability of such a planet within about 13 light years. I suggested launching in 100 years or more to use better propulsion methods we don't even know about yet. Also you want such a probe to carry lots of bells and whistles, such as a number of landing craft and surveying devices we haven't even thought about, but also keep it light-weight so you can reach higher speeds for a shorter travel time. Is it unreasonable to speculate that in 100 years from now we should be able to send a probe at about 10%C? If the planet is 15 light years away it could get there in about 150 years travel time. Who cares about habitable planets over 1000 light years distant?

Does anyone know about how long it will take for the human race to build unmanned interstellar probes to be sent at the highest speeds possible to nearby stars? These would be sent to stars we find with nice Earth-like planets. Easier to build a craft for a one-way trip and there are no humans to support. There is no mention in this wiki article about interstellar probes using multiple methods of propulsion. Such a craft could be built in Earth orbit. It should be as small as possible so less mass needs to be accelerated. How about start it off using conventional rockets to get away from Earth. Ion thrusters can help. Then kick in the nuclear pulse propulsion to get it up to a high initial speed. Use gravity kicks from the outer planets. Outside the solar system spread a giant solar sail or some kind of Medusa propulsion. It will also have to slow down using the same means. Then it gets into orbit around an Earth-like planet of interest and studies it for a few years, then transmit its findings back to Earth. How about launching it a hundred years from now? Could it reach an interesting planet in a hundred years travel time? Could we know up-close details about another Earth within 250 years from now? https://en.wikipedia.org/wiki/Interstellar_probe

"...the universe was probably nothing more than a giant cloud everywhere. Everything stated, prior to that beginning point, can only be postulated or speculated. Corroborating evidence doesn't exist." What does "everywhere" mean? Why not other big bangs far away from us? If one big bang then why not an infinite number?