Register a SA Forums Account here!
JOINING THE SA FORUMS WILL REMOVE THIS BIG AD, THE ANNOYING UNDERLINED ADS, AND STUPID INTERSTITIAL ADS!!!

You can: log in, read the tech support FAQ, or request your lost password. This dumb message (and those ads) will appear on every screen until you register! Get rid of this crap by registering your own SA Forums Account and joining roughly 150,000 Goons, for the one-time price of $9.95! We charge money because it costs us money per month for bills, and since we don't believe in showing ads to our users, we try to make the money back through forum registrations.
 
  • Post
  • Reply
Ratios and Tendency
Apr 23, 2010

:swoon: MURALI :swoon:


Ftl doesn't make sense as a concept logically. You're still thinking of it in the classical sense as a big number on your speedometer that you can just add 1 to beep boop, rather than something inextricably linked to space and time and mass.

Adbot
ADBOT LOVES YOU

Heck Yes! Loam!
Nov 15, 2004

a rich, friable soil containing a relatively equal mixture of sand and silt and a somewhat smaller proportion of clay.

Raenir Salazar posted:

I'm not sure what you're talking about here, never said anything about observing the other universe, only about solving the part of the puzzle where there's time travel implications if you were to travel at FTL. I.e you go from A to B, at B you can look back at A and see you never left yet. Not being able to observe the universe you just left is the point, because you're not observing your past self, but from what is from your perspective a clone (the version of you that hasn't traveled FTL yet, but presumably soon will), ergo no more time travel. Interacting with it has no bearing with your own light cone.


I'm not exactly sure what you're considering as "making things up" relative to most peoples attempts at trying to do thought experiments to get FTL. Isn't the existence of parallel realities something that people think exists?

I'm not sure is a hell of a launching pad for whatever bullshit you're trying to push out of your rear end.

You're trying to do things that don't make sense with words that you don't know what they mean.

You're basically asking a question that is so flawed that it cannot be answered with anything other than a loving wet fart.

Conspiratiorist
Nov 12, 2015

17th Separate Kryvyi Rih Tank Brigade named after Konstantin Pestushko
Look to my coming on the first light of the fifth sixth some day

Raenir Salazar posted:

So I have an idea about FTL, so I'd be curious what would also make it impossible.

The idea that occurred to me when I was sleeping is, what if instead of traveling FTL in our universe, you just popped out of existence in our universe, but then popped into existence in a identical parallel universe in a different location?

Then if you pointed a telescope at your origin and saw yourself back in the past, there's no time travel because the "you" that pops out of existence in this universe is the "you" that replaces you in your old universe! No more time travel.

Yes there would need to be identical parallel universes and a means of getting there but my understanding is that that is a much lesser hurdle than going back to the drawing board for violating causality, so would this still violate causality?

Setting aside the nature of whatever magic you're using to find an entirely identical universe and then transport yourself to an arbitrary set of timespace coordinates in it, what stops you from jumping back from *that* universe to your original universe at the destination you originally intended to travel to?

America Inc.
Nov 22, 2013

I plan to live forever, of course, but barring that I'd settle for a couple thousand years. Even 500 would be pretty nice.

DrSunshine posted:

I'm leery of the proximity meaning it's tidally locked (though that's not really as huge a deal as one might imagine when it comes to habitability)

Hmm, my understanding was that tidal locking can make habitable planets really unfriendly places for life. Basically, the side of planet facing the host star would be super-hot and dry, while the side opposite would be frozen. The best part of the planet for life would be the meridian between both sides, where liquid water could form. The problem is that the meridian would also have extreme weather as hot and cold air from the two sides interact.

None of that makes life impossible nor makes it impossible to colonize, but it's a pretty raw deal compared to Earth.

E: A trend I've noticed too is that habitable planets orbiting red dwarfs are often tidally locked - basically these stars are so cold that planets have to get very close to be habitable compared to our solar system. Lucky us that red dwarfs are the most common type of star in our galaxy :v:

America Inc. fucked around with this message at 02:15 on Jun 6, 2020

Raenir Salazar
Nov 5, 2010

College Slice

Conspiratiorist posted:

Setting aside the nature of whatever magic you're using to find an entirely identical universe and then transport yourself to an arbitrary set of timespace coordinates in it, what stops you from jumping back from *that* universe to your original universe at the destination you originally intended to travel to?

I'm not exactly sure how that's important beyond establishing if the first part works, because if the first part solves light cone/causality violations then that implies there's probably solutions to later steps.


Heck Yes! Loam! posted:

I'm not sure is a hell of a launching pad for whatever bullshit you're trying to push out of your rear end.

You're trying to do things that don't make sense with words that you don't know what they mean.

You're basically asking a question that is so flawed that it cannot be answered with anything other than a loving wet fart.

You're being excessively angry about this. This was the explanation I got like 10 pages ago, I thought of a follow up question to that earlier conversation, maybe find better things to do than trying your best to mimic having your face flash the same colour as a sun exploding?

Ratios and Tendency posted:

Ftl doesn't make sense as a concept logically. You're still thinking of it in the classical sense as a big number on your speedometer that you can just add 1 to beep boop, rather than something inextricably linked to space and time and mass.


Uh pretty sure nothing about my post implies I am thinking of it in that sense, I'm well aware of what it is.

Heck Yes! Loam!
Nov 15, 2004

a rich, friable soil containing a relatively equal mixture of sand and silt and a somewhat smaller proportion of clay.

Raenir Salazar posted:

I'm not exactly sure how that's important beyond establishing if the first part works, because if the first part solves light cone/causality violations then that implies there's probably solutions to later steps.


You're being excessively angry about this. This was the explanation I got like 10 pages ago, I thought of a follow up question to that earlier conversation, maybe find better things to do than trying your best to mimic having your face flash the same colour as a sun exploding?



Uh pretty sure nothing about my post implies I am thinking of it in that sense, I'm well aware of what it is.

But you haven't established anything other than asking a question that equates to an underwear gnome level of comprehension. You know that step 3 is FTL, step one is, alternate universes, and you're asking us what step 2 is. You even worked in that order.

The answer is no. None of that stuff is how anything works.

We don't even know if other universes exist let alone if you could interact with them. Traversal is completely out of the question.

DrSunshine
Mar 23, 2009

Did I just say that out loud~~?!!!

WOWEE ZOWEE posted:

Hmm, my understanding was that tidal locking can make habitable planets really unfriendly places for life. Basically, the side of planet facing the host star would be super-hot and dry, while the side opposite would be frozen. The best part of the planet for life would be the meridian between both sides, where liquid water could form. The problem is that the meridian would also have extreme weather as hot and cold air from the two sides interact.

None of that makes life impossible nor makes it impossible to colonize, but it's a pretty raw deal compared to Earth.

E: A trend I've noticed too is that habitable planets orbiting red dwarfs are often tidally locked - basically these stars are so cold that planets have to get very close to be habitable compared to our solar system. Lucky us that red dwarfs are the most common type of star in our galaxy :v:

I've read about some simulations that indicate that the presence of water would heavily influence just how friendly / hostile to life tidal locking would be. Basically, if you have a big ocean on the sun-facing side, the evaporation from water helps circulate the excessive heat and moderates the planet. So, instead of a system with multiple convection cells split up along bands of latitude like we have on Earth (Hadley cells) due to the rotation of the planet, the whole planet would essentially be home to one big Hadley cell, with a single uniform direction of circulation from the "eye" to the night side and back.

EDIT: That means that if we're able to do some spectroscopic imaging on the planet and see a big "window" in infrared where the planet's not emitting because of H2O in the atmosphere, signs would be extremely good that we've got a great habitability candidate on our hands.

DrSunshine fucked around with this message at 03:55 on Jun 6, 2020

Conspiratiorist
Nov 12, 2015

17th Separate Kryvyi Rih Tank Brigade named after Konstantin Pestushko
Look to my coming on the first light of the fifth sixth some day

Raenir Salazar posted:

I'm not exactly sure how that's important beyond establishing if the first part works, because if the first part solves light cone/causality violations then that implies there's probably solutions to later steps.

Because if you can just jump back, then that's effectively the ability of making a FTL jump within your own universe (with an irrelevant extra step). You're arbitrarily injecting yourself into frames of reference.

And if you've got a method to relocate FTL within your universe, then you're free to violate causality as much as you want.

Ratios and Tendency
Apr 23, 2010

:swoon: MURALI :swoon:


Raenir Salazar posted:

Uh pretty sure nothing about my post implies I am thinking of it in that sense, I'm well aware of what it is.

If this were true you wouldn't be positing ftl.

Raenir Salazar
Nov 5, 2010

College Slice

Ratios and Tendency posted:

If this were true you wouldn't be positing ftl.

Don't think so. First, I am not positing FTL. That isn't what my post is doing. I am asking why the thought experiment I am asking wouldn't work.

Secondly, someone can understand a general idea as to why FTL is impossible and what relativity is; asking about why some particular version of FTL doesn't work doesn't require some specific (mis)understanding of it erroneously projected onto them. And it's just wasting your time to bark up that tree.


Conspiratiorist posted:

Because if you can just jump back, then that's effectively the ability of making a FTL jump within your own universe (with an irrelevant extra step). You're arbitrarily injecting yourself into frames of reference.

And if you've got a method to relocate FTL within your universe, then you're free to violate causality as much as you want.

The implication here is that you never get back to your original universe.

Heck Yes! Loam! posted:

But you haven't established anything other than asking a question that equates to an underwear gnome level of comprehension. You know that step 3 is FTL, step one is, alternate universes, and you're asking us what step 2 is. You even worked in that order.

The answer is no. None of that stuff is how anything works.

We don't even know if other universes exist let alone if you could interact with them. Traversal is completely out of the question.

I don't think that's what I'm asking. Feel free to skip over this, I don't think either of us want to waste time trying to figure out what the other person is saying. But I think that if its true we don't in fact conclusively know if alternate/parallel universes exist, or if interaction is possible, its fair to think what does that do, how does it interact if we assume you can. If you could traverse to a parallel reality where the laws of physics are the same, is there a way of not violating causality? Or would traversal to another parallel universe even if the math could be worked out to make it happen, also have issues with causality?

Raenir Salazar fucked around with this message at 05:27 on Jun 6, 2020

Heck Yes! Loam!
Nov 15, 2004

a rich, friable soil containing a relatively equal mixture of sand and silt and a somewhat smaller proportion of clay.

Raenir Salazar posted:

Don't think so. First, I am not positing FTL. That isn't what my post is doing. I am asking why the thought experiment I am asking wouldn't work.

Secondly, someone can understand a general idea as to why FTL is impossible and what relativity is; asking about why some particular version of FTL doesn't work doesn't require some specific (mis)understanding of it erroneously projected onto them. And it's just wasting your time to bark up that tree.


The implication here is that you never get back to your original universe.


I don't think that's what I'm asking. Feel free to skip over this, I don't think either of us want to waste time trying to figure out what the other person is saying. But I think that if its true we don't in fact conclusively know if alternate/parallel universes exist, or if interaction is possible, its fair to think what does that do, how does it interact if we assume you can. If you could traverse to a parallel reality where the laws of physics are the same, is there a way of not violating causality? Or would traversal to another parallel universe even if the math could be worked out to make it happen, also have issues with causality?

The best I can do for you is some hypotheticals derived from mathematical principles.

https://www.youtube.com/watch?v=4v9A9hQUcBQ

Rappaport
Oct 2, 2013

Raenir Salazar posted:

Don't think so. First, I am not positing FTL. That isn't what my post is doing. I am asking why the thought experiment I am asking wouldn't work.

It's not really so much a gedankenexperiment and just "whoa, dude, wouldn't this be really awesome and cool" when you're starting out with alternate universes to somehow jump into, for reasons, and then FTL.

Conspiratiorist
Nov 12, 2015

17th Separate Kryvyi Rih Tank Brigade named after Konstantin Pestushko
Look to my coming on the first light of the fifth sixth some day

Raenir Salazar posted:

The implication here is that you never get back to your original universe.

Why not?

stringless
Dec 28, 2005

keyboard ⌨️​ :clint: cowboy

So I have an idea about FTL, so I'd be curious what would also make it impossible.

The idea that occurred to me when I was sleeping is, what if the universe is a simulation and thus there technically is an objective observer? Is FTL signaling still a problem?

A GIANT PARSNIP
Apr 13, 2010

Too much fuckin' eggnog


Raenir Salazar posted:

Don't think so. First, I am not positing FTL. That isn't what my post is doing. I am asking why the thought experiment I am asking wouldn't work.

I think the most obvious issue is that the relationship of your speed vs your energy input is asymptotic to the speed of light, so you'd have to plug "infinity" energy into your propulsion to reach the point where your thought experiment could happen.

Rappaport
Oct 2, 2013

FFT posted:

So I have an idea about FTL, so I'd be curious what would also make it impossible.

The idea that occurred to me when I was sleeping is, what if the universe is a simulation

I will get the hose, and I will turn it on you, young man, don't test me

Also, if the universe were a simulation, it'd just turn out like all those youtube videos of people torturing their sims and oh my God

D-Pad
Jun 28, 2006

Some of the people in this thread are major assholes. There are plenty of thought expirements in science that involve impossible elements that are used to get a discussion going. Yes, the feasibility of the idea is dumb because it is impossible, but calling the guy an idiot makes you an rear end in a top hat.

Some of you are also misunderstanding what he is asking, although it is still impossible even if you understand the question correctly. Let me try to rephrase (knowing it's impossible, oh poo poo I must be an idiot child).

I want to travel from point a to point b at faster than the speed of light. I cannot because ending up at point b faster than light could travel between the two points would violate causality. What if there was an identical universe to ours and I could travel to arbitrary space/time coordinates in it (we know this is impossible I say as I drool and babble to my mama). You could then travel to point B and would end up where you wanted to go in a universe identical to you the observer but without having violated causality in the new universe you inhabit as you came from outside it.

What he is trying to get at, I believe, is that we've shown him why you could never travel faster than light within our own universe. That it isn't just a matter of physics we haven't discovered yet. The idea being that FTL is not just a matter of we don't know what we don't know and it could actually be possible in future, which is the conception many laymen have. He knows travel between universes is impossible, if identical universes even exist in the first place, but is asking what if that impossibility is actually physics we haven't discovered yet.

I'm making no claims as to the possibility, I don't think it will ever be possible myself, but jumping down someone's throat who is actually contemplating things like this in a world where most people never have an original thought in their life makes you a giant rear end in a top hat. Just say no and move on of you can't engage without being a superior dickhead.

D-Pad fucked around with this message at 16:31 on Jun 6, 2020

DrSunshine
Mar 23, 2009

Did I just say that out loud~~?!!!
Maybe that's what demonstrates that parallel universes (if they exist) aren't reachable. Because then, yes, what Raenir Salazar proposes - to travel 'sideways' as it were into another universe, and then back again to a point that would be unreachable at slower-than-light speeds in our universe - would be possible. In that case, I think it would be possible to sometimes observe objects disappearing out of existence and then reappearing immediately having been displaced light years. Since we do not observe such activity, it must mean that parallel universes can't be accessed.

EDIT:

I think it kind of depends on what you might think of as a "parallel universe". The pop-culture idea of universes as being these bubbles that are adjacent to each other, floating in some kind of white void, is probably not the case. Rather, there might only be one single universe, of which we happen to inhabit only one observable part, which happens to be about 46 billion light years in radius. Some "other universe" might very well exist beyond the cosmic event horizon, and it would probably have the same cosmic constants and so on, and to an observer, our universe would be just as unreachable as theirs to ours.

DrSunshine fucked around with this message at 16:39 on Jun 6, 2020

Rappaport
Oct 2, 2013

D-Pad posted:

Some of the people in this thread are major assholes. There are plenty of thought expirements in science that involve impossible elements that are used to get a discussion going. Yes, the feasibility of the idea is dumb because it is impossible, but calling the guy an idiot makes you an rear end in a top hat.

Some of you are also misunderstanding what he is asking, although it is still impossible even if you understand the question correctly. Let me try to rephrase (knowing it's impossible, oh poo poo I must be an idiot child).

I want to travel from point a to point b at faster than the speed of light. I cannot because ending up at point b faster than light could travel between the two points would violate causality. What if there was an identical universe to ours and I could travel to arbitrary space/time coordinates in it (we know this is impossible I say as I drool and babble to my mama). You could then travel to point B and would end up where you wanted to go in a universe identical to you the observer but without having violated causality in the new universe you inhabit as you came from outside it.

What he is trying to get at, I believe, is that we've shown him why you could never travel faster than light within our own universe. That it isn't just a matter of physics we haven't discovered yet. The idea being that FTL is not just a matter of we don't know what we don't know and it could actually be possible in future, which is the conception many laymen have. He knows travel between universes is impossible, if identical universes even exist in the first place, but is asking what if that impossibility is actually physics we haven't discovered yet.

I'm making no claims as to the possibility, I don't think it will ever be possible myself, but jumping down someone's throat who is actually contemplating things like this in a world where most people never have an original thought in their life makes you a giant rear end in a top hat. Just say no and move on of you can't engage without being a superior dickhead.

I didn't mean to jump at anyone's throat, and I apologize if I came off that way. But what you're saying here could just as well be "what if we made the Delorean go past 88 miles per hour?" Nothing wrong with that, it makes for good movies in fact, but it has very little to do with understanding how our reality works. Picking apart "well, what if alternative universes" might make for a good Arxiv paper or three, but that's about it.

D-Pad
Jun 28, 2006

He can clarify, but I don't think he is proposing coming back the original universe. I think he is saying now you live in the new universe. Since it is identical who cares, it's all the same to you. You didn't violate causality in your new universe because your starting point wasn't within the new universe, but you are at your intended destination at faster than the speed of light from your frame of reference.

Rappaport
Oct 2, 2013

D-Pad posted:

He can clarify, but I don't think he is proposing coming back the original universe. I think he is saying now you live in the new universe. Since it is identical who cares, it's all the same to you. You didn't violate causality in your new universe because your starting point wasn't within the new universe, but you are at your intended destination at faster than the speed of light from your frame of reference.

Okay, in an effort to be less of a bag of dicks, I'll try engaging with this.

"What if we went to an alternate universe" instead is, to put it mildly, still worlds apart (pun intended) from what we know is technologically feasible. Our best idea for decent-speed space travel at the moment involves blowing up nukes from the butt-end of your space ship, and even that still gets you close to c, not beyond it. The way extra-universal (?) travel works in fiction, like in The Man in the High Castle, does seem to violate things like the conservation of mass-energy and other pesky things, and simply saying "what if, you guys" doesn't really cut it.

Although this is the UFO thread, so my expectations are probably a bit high.

A GIANT PARSNIP
Apr 13, 2010

Too much fuckin' eggnog


D-Pad posted:

He can clarify, but I don't think he is proposing coming back the original universe. I think he is saying now you live in the new universe. Since it is identical who cares, it's all the same to you. You didn't violate causality in your new universe because your starting point wasn't within the new universe, but you are at your intended destination at faster than the speed of light from your frame of reference.

I think some people would take issue with the concept of dooming your spouse/friends/family to a lifetime without you, even if you personally get to spend your life with exact duplicates of them.

D-Pad
Jun 28, 2006

Rappaport posted:

Okay, in an effort to be less of a bag of dicks, I'll try engaging with this.

"What if we went to an alternate universe" instead is, to put it mildly, still worlds apart (pun intended) from what we know is technologically feasible. Our best idea for decent-speed space travel at the moment involves blowing up nukes from the butt-end of your space ship, and even that still gets you close to c, not beyond it. The way extra-universal (?) travel works in fiction, like in The Man in the High Castle, does seem to violate things like the conservation of mass-energy and other pesky things, and simply saying "what if, you guys" doesn't really cut it.

Although this is the UFO thread, so my expectations are probably a bit high.

I agree with all this. I am defending him because I know when I first started exploring these topics when I was young and just getting into physics I had what if ideas just like what he proposed. Engaging and giving an answer like you just gave (or not giving one if you can't engage in good faith) encourages him to keep thinking and exploring. Whereas if I had people jumping down my throat I probably would have never picked up another physics book. All of this is an incredibly hard subject. Most people will never get to the level of understanding some in this thread have. Let's cut people some slack. I know it gets old having the thread repeat itself when someone new comes in and says "but what if warp bubbles!" but we should be glad they even got interested in the first place.

DrSunshine
Mar 23, 2009

Did I just say that out loud~~?!!!

D-Pad posted:

I agree with all this. I am defending him because I know when I first started exploring these topics when I was young and just getting into physics I had what if ideas just like what he proposed. Engaging and giving an answer like you just gave (or not giving one if you can't engage in good faith) encourages him to keep thinking and exploring. Whereas if I had people jumping down my throat I probably would have never picked up another physics book. All of this is an incredibly hard subject. Most people will never get to the level of understanding some in this thread have. Let's cut people some slack. I know it gets old having the thread repeat itself when someone new comes in and says "but what if warp bubbles!" but we should be glad they even got interested in the first place.

Raenir's been with us from the start though (sorry Raenir, I haven't fully thought out my reply to your point about capitalism vs space), but yeah, tone matters if thread regulars shout down anyone and drive all new people away and leave just a few nerds to nerd out about General Relativity and stuff. We don't want to become the Spaceflight thread in SAL where all they talk about is just watching livestreams of satellite launches.

I AM GRANDO
Aug 20, 2006

About our particle horizon and the visible universe: if there were a civilization closer than we are to the edge of our observable universe but still visible to us, could we not in theory get information from them about the non-overlapping portion of their visible universe and vice versa?

Owlofcreamcheese
May 22, 2005
Probation
Can't post for 9 years!
Buglord

Antifa Turkeesian posted:

About our particle horizon and the visible universe: if there were a civilization closer than we are to the edge of our observable universe but still visible to us, could we not in theory get information from them about the non-overlapping portion of their visible universe and vice versa?

I mean, you can do that with a guy standing a couple feet to the side of you. But he can't tell you any faster than you could have just looked at the light now reaching you as well would have.

Heck Yes! Loam!
Nov 15, 2004

a rich, friable soil containing a relatively equal mixture of sand and silt and a somewhat smaller proportion of clay.

Antifa Turkeesian posted:

About our particle horizon and the visible universe: if there were a civilization closer than we are to the edge of our observable universe but still visible to us, could we not in theory get information from them about the non-overlapping portion of their visible universe and vice versa?

No because the transfer of that information is limited to the speed of light. By the time their message about the place beyond our horizon reached us, we would also see that place on our light sphere.

Information cannot travel faster than C.

I AM GRANDO
Aug 20, 2006

Heck Yes! Loam! posted:

No because the transfer of that information is limited to the speed of light. By the time their message about the place beyond our horizon reached us, we would also see that place on our light sphere.

Information cannot travel faster than C.

But wouldn’t it arrive eventually if it were sent before the transmitter passed over our light horizon? My understanding is that we will see incrementally less of the universe rather than more because of the rate of expansion, or is this a trivial issue in that context?

DrSunshine
Mar 23, 2009

Did I just say that out loud~~?!!!

Heck Yes! Loam! posted:

No because the transfer of that information is limited to the speed of light. By the time their message about the place beyond our horizon reached us, we would also see that place on our light sphere.

Information cannot travel faster than C.



Basically, kind of like this. You can't daisy-chain information because by the time something gets from the left side to the center, it's already out of reach of the center of the right side.

Heck Yes! Loam!
Nov 15, 2004

a rich, friable soil containing a relatively equal mixture of sand and silt and a somewhat smaller proportion of clay.

Antifa Turkeesian posted:

But wouldn’t it arrive eventually if it were sent before the transmitter passed over our light horizon? My understanding is that we will see incrementally less of the universe rather than more because of the rate of expansion, or is this a trivial issue in that context?

While expansion will theoretically push most of the current observable universe past our horizon, our local group will always be visible.

Let's say we take a person in our galaxy and one in Andromeda. They see a different observable universe that is essentially shifted by the distance between us. They see something that is past our horizon and immediately send a light pulse containing that info.

The light containing the info would actually be behind the original light source. As it had already reached Andromeda persons detectors and travelled beyond. By the time both sources of light reach us, we see it on our detectors and thus there is no point in sending the message.

Rappaport
Oct 2, 2013

D-Pad posted:

I agree with all this. I am defending him because I know when I first started exploring these topics when I was young and just getting into physics I had what if ideas just like what he proposed. Engaging and giving an answer like you just gave (or not giving one if you can't engage in good faith) encourages him to keep thinking and exploring. Whereas if I had people jumping down my throat I probably would have never picked up another physics book. All of this is an incredibly hard subject. Most people will never get to the level of understanding some in this thread have. Let's cut people some slack. I know it gets old having the thread repeat itself when someone new comes in and says "but what if warp bubbles!" but we should be glad they even got interested in the first place.

That's fair, and again I would like to apologize for being rude or dismissive. I remember my undergrad years. The problem with some of these questions, no matter how well-intentioned or earnest, still don't really have any answer besides "well no". That sucks, but also kind of how science operates.

Of course once in a while someone comes up with a novel idea where the response is also that "well no" until it no longer is, but these days it's all buried in publishing and only the interested geeks see it. I will simply say that, in my opinion, it isn't likely that someone will come up with a way to travel to other universes any day soon, or if they do, they'll get hired by the CIA or some poo poo and the end result for the rest of us is much the same.

Trainee PornStar
Jul 20, 2006

I'm just an inbetweener

Raenir Salazar posted:

Secondly, someone can understand a general idea as to why FTL is impossible and what relativity is; asking about why some particular version of FTL doesn't work doesn't require some specific (mis)understanding of it erroneously projected onto them. And it's just wasting your time to bark up that tree.

I think your asking why cant we travel at the speed of light?

The way it got explained to me (I think but happy to be corrected) is that your always travelling at the speed of light. Because space & time are kinda the same thing, the faster you move through space the slower you move through time & vice versa.

I AM GRANDO
Aug 20, 2006

DrSunshine posted:



Basically, kind of like this. You can't daisy-chain information because by the time something gets from the left side to the center, it's already out of reach of the center of the right side.

This helps a lot. Thank you.

ashpanash
Apr 9, 2008

I can see when you are lying.

Trainee PornStar posted:

I think your asking why cant we travel at the speed of light?

The way it got explained to me (I think but happy to be corrected) is that your always travelling at the speed of light. Because space & time are kinda the same thing, the faster you move through space the slower you move through time & vice versa.

This is pretty much true, but the concept of 'travel' here should be considered more generalized. The magnitude of your four-velocity is always c2. That's not quite the same as saying that you're travelling through spacetime at c at all times, but it's close enough that I won't belabour the point further.

D-Pad posted:

Some of the people in this thread are major assholes. There are plenty of thought expirements in science that involve impossible elements that are used to get a discussion going.

I get it, I really do. More than you might think. But I see a world currently where 'truthiness' has become the standard, where loving flat earth is making a comeback, and... gently caress, man. I don't know what to tell ya - reality can be a major buzzkill. Just ask the string theorists.

Heck Yes! Loam!
Nov 15, 2004

a rich, friable soil containing a relatively equal mixture of sand and silt and a somewhat smaller proportion of clay.

ashpanash posted:

reality can be a major buzzkill. Just ask the string theorists.

Can I still hold out for super symmetry

Trainee PornStar
Jul 20, 2006

I'm just an inbetweener

ashpanash posted:

This is pretty much true, but the concept of 'travel' here should be considered more generalized. The magnitude of your four-velocity is always c2. That's not quite the same as saying that you're travelling through spacetime at c at all times, but it's close enough that I won't belabour the point further.

The guy that explained to me did mention that but I wanted to keep it to the very basics.

ashpanash
Apr 9, 2008

I can see when you are lying.

Heck Yes! Loam! posted:

Can I still hold out for super symmetry

Sure, it's easy to hold out for things that can't be disproven ;)

That said, the MSSM is out the window, and that was the version of SUSY that gave people hope for a dark matter explanation and a path to a GUT. If SUSY is out there, it'll probably be strongly broken on some crazy energy scale. But those neutralinos ain't gonna find themselves!

Libluini
May 18, 2012

I gravitated towards the Greens, eventually even joining the party itself.

The Linke is a party I grudgingly accept exists, but I've learned enough about DDR-history I can't bring myself to trust a party that was once the SED, a party leading the corrupt state apparatus ...
Grimey Drawer

WAR CRIME GIGOLO posted:

Just imagine finding a loving house on Mars. A regular house. We have no clue what's under the sands of Mars.

We know that for some reason, the surface of Mars is covered by some dumb organic molecules that would be toxic to us. No-one so far has any idea why they are there. That they could be a precursor to life that was left there when the atmosphere of Mars went bye-bye ages ago is the best hypothesis I've seen so far.

Anyway, ironically it now presents an additional hurdle to colonization, as we would need to dome and then very carefully detoxify every piece of land we want to grow food on. :v:

The real question is: What is under the sands of Venus?


Sodomy Hussein posted:

If God did not exist, it would be necessary to invent him.

No, not really


Re: Simulation theory and many-worlds-hypothesis: They're both dumb garbage because nothing about this poo poo can be tested. My suggestion is to think about it as really esoteric science-fiction some people deluded themselves into thinking it's actually real.

And this harsh opinion of mine will stand until we find a way to open a gate to another universe. :colbert:


Zesty posted:

In other fun new science news, 'Oumuamua may be a hydrogen iceberg.

https://www.wired.com/story/oumuamua-might-be-a-giant-interstellar-hydrogen-iceberg/

and here's an interview with one of the people working on this theory.

https://www.youtube.com/watch?v=TwYAiSAmurM&t=60s

The idea that there are possibly many of those Death Cloud Nebulae out there which failed to become even a brown dwarf is kind of spooky, but I like it. Hopefully we can catch some more of those visitors to test this theory.

DrSunshine
Mar 23, 2009

Did I just say that out loud~~?!!!
Space Thread: Tickets to DEATH CLOUD NEBULA on sale now!

Adbot
ADBOT LOVES YOU

Raenir Salazar
Nov 5, 2010

College Slice

A GIANT PARSNIP posted:

I think the most obvious issue is that the relationship of your speed vs your energy input is asymptotic to the speed of light, so you'd have to plug "infinity" energy into your propulsion to reach the point where your thought experiment could happen.

I can't make heads or tails of this non-sequitor or how it relates to anything I said.

Trainee PornStar posted:

I think your asking why cant we travel at the speed of light?

The way it got explained to me (I think but happy to be corrected) is that your always travelling at the speed of light. Because space & time are kinda the same thing, the faster you move through space the slower you move through time & vice versa.

Most definitely is not what I'm asking no. Never in the original point am I actually suggesting you ever actually accelerate. The actual method is not important. Only that you were at A, and then you are at B, and B is nontrivially far enough from A that the light from A hasn't yet reached B from your perspective.

D-Pad posted:

Some of the people in this thread are major assholes. There are plenty of thought expirements in science that involve impossible elements that are used to get a discussion going. Yes, the feasibility of the idea is dumb because it is impossible, but calling the guy an idiot makes you an rear end in a top hat.

Some of you are also misunderstanding what he is asking, although it is still impossible even if you understand the question correctly. Let me try to rephrase (knowing it's impossible, oh poo poo I must be an idiot child).

I want to travel from point a to point b at faster than the speed of light. I cannot because ending up at point b faster than light could travel between the two points would violate causality. What if there was an identical universe to ours and I could travel to arbitrary space/time coordinates in it (we know this is impossible I say as I drool and babble to my mama). You could then travel to point B and would end up where you wanted to go in a universe identical to you the observer but without having violated causality in the new universe you inhabit as you came from outside it.

What he is trying to get at, I believe, is that we've shown him why you could never travel faster than light within our own universe. That it isn't just a matter of physics we haven't discovered yet. The idea being that FTL is not just a matter of we don't know what we don't know and it could actually be possible in future, which is the conception many laymen have. He knows travel between universes is impossible, if identical universes even exist in the first place, but is asking what if that impossibility is actually physics we haven't discovered yet.

I'm making no claims as to the possibility, I don't think it will ever be possible myself, but jumping down someone's throat who is actually contemplating things like this in a world where most people never have an original thought in their life makes you a giant rear end in a top hat. Just say no and move on of you can't engage without being a superior dickhead.

This.

DrSunshine posted:

Maybe that's what demonstrates that parallel universes (if they exist) aren't reachable. Because then, yes, what Raenir Salazar proposes - to travel 'sideways' as it were into another universe, and then back again to a point that would be unreachable at slower-than-light speeds in our universe - would be possible. In that case, I think it would be possible to sometimes observe objects disappearing out of existence and then reappearing immediately having been displaced light years. Since we do not observe such activity, it must mean that parallel universes can't be accessed.


I mean, doesn't this same argument apply to the Fermi Paradox? ;) Maybe we're the first space faring civilization to exist, and thus the first to discover some viable FTL? :)

Although one side note is, because reappearing back in your original universe probably still violates causality, because the possibility exists you appear somewhere while still being able to see your past self not having left point A yet, so one solution to that is you never actually return to your original universe, it's just an infinite stack of turtles all the way down swapping identical universes to travel around.

quote:

I think some people would take issue with the concept of dooming your spouse/friends/family to a lifetime without you, even if you personally get to spend your life with exact duplicates of them.

I feel like this gets into the ethics of teleportation as being magic 3D printers that disintegrate the old you to make a new you with the same information of the original. A society can very well come to exist that accepts it as fine, because there's no meaningful practical difference.

DrSunshine posted:

Raenir's been with us from the start though (sorry Raenir, I haven't fully thought out my reply to your point about capitalism vs space), but yeah, tone matters if thread regulars shout down anyone and drive all new people away and leave just a few nerds to nerd out about General Relativity and stuff. We don't want to become the Spaceflight thread in SAL where all they talk about is just watching livestreams of satellite launches.


It's all good. Take your time. :) I think like, it's definitely surprising at how not only negative some of the initial responses were, but also how most of them also just plain misunderstood my post (which D-Pad understood what I was getting at). So not only am I dealing with negativity but also gotta try to figure out how to unpack the misunderstanding just to have the conversation I wanted to have.

e to add: Obviously I don't wanna be the guy here: https://xkcd.com/675/ which was why I restrained myself until I got struck by what seems to me like an interesting idea, ignoring the issue of parallel universes, whether they are interactable, or traversable; if we for the sake of the thought experiment enable it to be allowable, could this resolve the issue of causality?

Raenir Salazar fucked around with this message at 21:56 on Jun 6, 2020

  • 1
  • 2
  • 3
  • 4
  • 5
  • Post
  • Reply