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Vampyromaniac
Joined: 08 Feb 2008
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 Posted: Thu Jul 19, 2012 11:51 pm Post subject: |
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| Sarg338 wrote: | | Vampyromaniac wrote: | | and Susskind's arguments even suggest that the shape of the singularity might not be constant, as baffling as it seems. |
Isn't the Singularity infinitely small, taking up exactly no space, and infinitely heavy? How something that literally takes up nothing can have a shape is baffling in and of itself  |
I'm with you, mate.
From Susskind's paper:
"An observer can cross the conventional horizon and migrate to
the region behind the firewall. Moreover that observer would see the origin of the firewall as a naked singularity."
He then describes the firewall as an "extension of the singularity," whereas Polchinski and friends described it as a different horizon, though semantics play some role in the difference in this case. 
My impression is that the firewall becomes basically a spherical plane surface, possibly 2-dimensional. In 3 spatial dimensions, this still results in infinities, and if I'm correct in assuming the term "singularity" was originally used for describing topological spaces, I believe the firewall would still be considered a singularity. So basically the zero-dimensional central point gets replaced by a 2-dimensional sphere.
I still have lots of questions, namely: Is it that the central point slowly goes away as the firewall forms, as a gradual process? (I think so) And surely if it's gradual, it can't be perfectly uniform... meaning that the black hole would have "hair." (meaning it's not perfectly symmetrical, so the event horizon is not perfectly spherical)
But most importantly, I still don't know what exactly causes this to begin with. I guess I'll try to wade through Polchinski and folks' article 
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Sarg338
Joined: 07 Feb 2008
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| Posted: Thu Aug 16, 2012 3:59 am Post subject: |
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So, theoretical question for someone who knows more than me: I was watching The Science Channel's How the Universe Works and they talked about comets and how that if a 6-7 mile long comet would hit Earth, life as we know it would cease to exist, etcetc
My question is, let's say that same comet hit Venus or Mars (The 2 closest planets to us) And either obliterated them or knocked them off their usual orbit (Closer or further from the sun, again, either or). Assuming that no debris collides with us, how would this affect life on Earth or Earth itself, if at all? Would losing a planet close to us like that and losing that little gravitational pull that the Earth feels from them affect us majorly?
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bclare
Joined: 21 Jun 2008
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Location: Boston
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| Posted: Thu Aug 16, 2012 4:26 am Post subject: |
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| Sarg338 wrote: | So, theoretical question for someone who knows more than me: I was watching The Science Channel's How the Universe Works and they talked about comets and how that if a 6-7 mile long comet would hit Earth, life as we know it would cease to exist, etcetc
My question is, let's say that same comet hit Venus or Mars (The 2 closest planets to us) And either obliterated them or knocked them off their usual orbit (Closer or further from the sun, again, either or). Assuming that no debris collides with us, how would this affect life on Earth or Earth itself, if at all? Would losing a planet close to us like that and losing that little gravitational pull that the Earth feels from them affect us majorly? |
The moon affects Earth's tides primarily; other planets are so much farther away that even with their greater mass, they have minimal effects on things like tides, but if Venus or Mars disappeared there wouldn't be much of a difference noticeable on Earth.
Heck, even a 7-mile comet that would end life on Earth wouldn't destroy the fucking planet. You'd need a pretty huge fucking impact to destroy Venus or Mars, and then it probably would create enough debris to at least cause concern for our satellites, if not have a small effect on global climate or something.
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youhas 
Joined: 21 Jul 2006
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Location: Santa Clara, CA
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| Posted: Thu Aug 16, 2012 9:42 am Post subject: |
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| bclare wrote: | | The moon affects Earth's tides primarily; other planets are so much farther away that even with their greater mass, they have minimal effects on things like tides |
Yeah, that whole "square of the distance" part of the gravitational equation really kicks things in the teeth. If I recall correctly, at the time of your birth, the doctor delivering you has a greater gravitational pull on you than the planet Jupiter does. I don't remember whether I crunched the numbers myself to verify this, but that seemed ballpark-correct. Accounting for other planets or lack thereof: tiny little rounding errors when it comes to calculating tidal equations.
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inv4der
Joined: 16 Sep 2007
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Location: Meridian, ID
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| Posted: Thu Aug 16, 2012 9:53 am Post subject: |
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More fun hypotheticals:
Time travel is achieved, but you can only observe past events incorporeally and are unable to affect outcomes of events. It is also incapable of going off-planet or before Earth was human habitable. It's also very expensive and a power hog so only one machine exists and it can only send one group of observers at a time.
What is the most important thing to learn about given these restrictions? (Or a top three if you wish, the machine is unlikely to explode early on. :p)
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bclare
Joined: 21 Jun 2008
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| Posted: Thu Aug 16, 2012 4:33 pm Post subject: |
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| inv4der wrote: | More fun hypotheticals:
Time travel is achieved, but you can only observe past events incorporeally and are unable to affect outcomes of events. It is also incapable of going off-planet or before Earth was human habitable. It's also very expensive and a power hog so only one machine exists and it can only send one group of observers at a time.
What is the most important thing to learn about given these restrictions? (Or a top three if you wish, the machine is unlikely to explode early on. :p) |
Incidentally, of course if the time machine couldn't move in space then it if you go even a few hours backward you would be thousands of miles away from the Earth in space, but let's ignore that. Let's say that it can't leave the path of Earth's gravity and pretend that just makes sense.
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Yewb 
Joined: 10 Jan 2008
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| Posted: Thu Aug 16, 2012 5:07 pm Post subject: |
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He did say that it would remain on Earth at all times. And anyway, there's no reason to assume it couldn't move in space; for example I assume we can visit any of Europe, North America or Asia, and aren't confined to witnessing whatever happened to occupy the space we're currently in thirty thousand years ago, because that removes almost all of the question from the question.
I was going to say we should go back and gather data on the last common ancestor of humans and chimpanzees, but it's not like that would really convince anyone because evolution is already observable within our lifetimes.
We could at least go back sixty thousand years and kick Young Earth creationism in the teeth, though. But I wouldn't say that's the most important thing. That said, I'm having trouble thinking of anything that would be truly ground-breaking in science; humanities, of course, and even literature, but not science. I'm probably just not that imaginative, though.
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| expertwin wrote: | | ShadoWolf wrote: | | expertwin wrote: | | I just want to, you know, get my name out there. BTW, it updates every Thursday, Friday, and Saturday. Was just the first two, decided to do Saturdays as well. |
Serious advice now: No-one likes indecision in their work, so find what you like that you're even remotely good at, and stick with it. Don't flit from one thing to another, because that just smacks of a large lack of determination and drive. And people don't like you for that, and won't remember you for it. I mean, I get that you have a plucky spirit and a willingness to try new things, but there's a limit, man. |
I might knock it down to just Thursday and Friday. |
| JOE2210 wrote: | | Leave me alone, I have been drinking and your made up words mean nothing to me. |
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PiemanLK
Joined: 03 Dec 2007
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| Posted: Thu Aug 16, 2012 5:41 pm Post subject: |
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| inv4der wrote: | | What is the most important thing to learn about given these restrictions? |
Go back in time to watch your parents have sex
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[quote=''Otend'']Id come up with a long post, but Pieman said what we are all thinking, as usual[/quote]
[quote=''youhas'']EDIT TO ADD: Hey, post #3000! Neat! I will eagerly anticipate my set of ScoreHero-branded steak knives within six to eight weeks.[/quote]
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TopGearFTW
Joined: 15 Aug 2007
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Location: Leeds, W.Yorkshire, England.
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alexhaz64 
Joined: 01 Mar 2008
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| Posted: Thu Aug 16, 2012 7:44 pm Post subject: |
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| TopGearFTW wrote: | | getting up-close to an eruption with no repercussions (None were specified, so I'm assuming there are none)? Yes please. |
Well assuming you can see and hear what's going on, getting too close would probably run the risk of blindness and especially deafness. I'd imagine those repercussions would be the most likely, at least.
As far as when I would want to go back to? I think I would have to go back to the peak of an ancient civilization, to see how it compares to our modern recreation. I mean, we can't truly imagine the magnitude of Rome, Greece, Egypt, or even Aztec civilaztions from our standpoint. Imagine what we could learn about our history by visiting one of these time periods. Or, perhaps more interesting, would be investigating one of those "lost" civilizations, like the Easter Island folks, or the Olmec, or that supposed city in the Mediterranean that was inspiration for Atlantis. I feel like any number of anthropological possibilities open up with time travel, it would certainly be awesome to explore any of them.
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2:59 alexhaz64: I'm like 6th place on that song
2:59 alexhaz64: pretty neat
2:59 alexhaz64: :p
2:59 JohnnyGrey: No Alex, I don't care how good your score is
2:59 JohnnyGrey: DAMMIT
2:59 alexhaz64: XD
alexhaz64 flexes
2:59 psxfreak101: too slow on the trigger there, boyo
2:59 alexhaz64: that seems to be the case all night
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2:59 psxfreak101: XD
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Vampyromaniac
Joined: 08 Feb 2008
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| Posted: Fri Aug 17, 2012 1:24 am Post subject: |
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| TopGearFTW wrote: | Honestly, I'd really want to see the Krakatoa eruption.
Yeah, I know there's probably much more important stuff (who actually shot JFK, or something like that) but I mean come on, it completely ripped an island apart, and you could hear the bang from god knows how far away.
That or the other eruption that wiped out something like 90% of all human life (We're talking waaayyy back, not like the 1700s or anything)
Not that I'm a volcanologist or something, but getting up-close to an eruption with no repercussions (None were specified, so I'm assuming there are none)? Yes please. |
There have been hundreds of eruptions worse than the Krakatoa one. Make no mistake: out of all natural disasters, including such things as meteors and GRBs, volcanoes are by far the most likely to wipe out all or the majority of humanity. iirc Krakatoa was a rank 5 volcano, and the scale goes to 7. There have been lots of sevens. Still, even Krakatoa killed 40,000+ people, blew an island apart, changed the golbal temperature and weather patterns for years, and sent a shockwave that circled the earth seven times.
The caldera under Yellowstone park is thousands of times the size of Krakatoas.
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bclare
Joined: 21 Jun 2008
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| Posted: Fri Aug 17, 2012 2:19 am Post subject: |
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I'd like to see what the hell the Tunguska event actually was.
(also, recommending this for a spin-off thread)
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inv4der
Joined: 16 Sep 2007
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| Posted: Fri Aug 17, 2012 2:40 am Post subject: |
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| bclare wrote: | | recommending this for a spin-off thread |
Yeah, that'd be for the best.
I'll adjust the question to address things I didn't think of mentioning as well.
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youhas
Joined: 21 Jul 2006
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| Posted: Fri Aug 17, 2012 3:47 am Post subject: |
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| TopGearFTW wrote: | | (who actually shot JFK, or something like that) |
Heh - the JFK assassination was actually the first thing that came to mind, though I mulled things over for a couple of minutes and eventually dismissed it. It's been what, half a century at this point? All I'd learn is whether JFK was killed by one set of presently old, musky, and mostly dead men or a different set of presently old, musky, and mostly dead men. I'd love to know, but it didn't seem "important" enough.
| TopGearFTW wrote: | | Honestly, I'd really want to see the Krakatoa eruption. ... Not that I'm a volcanologist or something, but getting up-close to an eruption with no repercussions (None were specified, so I'm assuming there are none)? Yes please. |
He did say that we were experiencing these events incorporeally, yes? So I sort of assumed that we were there in a ghost-like haze: able to observe, unable to directly affect nor be directly affected by anything.
If that's actually the case, I'm going for broke: I want to see the K-T Extinction Event. (Earth wasn't human-inhabited then, natch, but I'm pretty sure it was human-habitable.) Get there a bit early, just to soak everything in and appreciate how everything's a little bit... off. The stars are in the wrong place in the sky. The moon looms slightly larger that we're used to. Plants and squidgy little mammals are kicking around that look almost-but-not-quite just like something you might see in the present day. And, of course, there are the dinosaurs: we get to see whether we were even close to getting their general structure and coloring correct, or if there are some crazy-pants specimens we ain't never found fossils close to matching, or anything else along those lines.
And then, Act II: getting to verify that there really was an asteroid or similar slamming the hell into the Yucatan Peninsula, yielding the unholy mother of all impossible-grade heat-and-light shows as a shock wave races 'round the planet. If so: yay verification! If not: well, OK, what the hell was going on, then? I'm not sure this is the most important thing we could find out with the machine, but it's probably one of the more awesome.
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inv4der
Joined: 16 Sep 2007
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Location: Meridian, ID
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| Posted: Fri Aug 17, 2012 4:19 am Post subject: |
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Gonna note that the time during the K-T extinction event would hardly be humanly habitable. You might get a look at what started it though.
Volcanic eruptions are also notably not a place humans can live.
Creativity could get you around both issues.
Also, as a note, the machine only would go back, since knowing anything about the future in the present qualifies as affecting the past. Paradoxes and such.
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