tag:blogger.com,1999:blog-8611810694571930415.post4669430853449757829..comments2024-03-28T05:37:00.890-04:00Comments on the daily howler: ONE HUNDRED YEARS LATER: Reviewing the problem we hope to address!<b>bob somerby</b>http://www.blogger.com/profile/02963464534685954436noreply@blogger.comBlogger16125tag:blogger.com,1999:blog-8611810694571930415.post-49791686461115856282016-04-13T16:57:25.283-04:002016-04-13T16:57:25.283-04:00deadrat, why would she not conclude that she sees ...deadrat, why would she not conclude that she sees the one strike first because she is moving towards it and that therefore the strikes happened at the same time?<br /><br />also how is it an eureka moment?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8611810694571930415.post-63558209785836627142016-04-13T10:28:23.539-04:002016-04-13T10:28:23.539-04:00Also read Appendix 1, where Einstein derives the L...Also read Appendix 1, where Einstein derives the Lorentz transformation. With that, given the time and position of an event in the platform (or embankment) coordinates, you can calculate the time and position in the train coordinates.impCaesarAvghttps://www.blogger.com/profile/03384806750440039982noreply@blogger.comtag:blogger.com,1999:blog-8611810694571930415.post-39507894217162892562016-04-13T07:48:10.129-04:002016-04-13T07:48:10.129-04:00I recommend reading Issacson's book about Eins...I recommend reading Issacson's book about Einstein if you want to learn about the life of Albert..Its not the book to read to fully understand physics.Daily Howler isn't nor will he be the last person to get his mind all twisted in knots trying to understand relativityAnonymoushttps://www.blogger.com/profile/00812216638653319170noreply@blogger.comtag:blogger.com,1999:blog-8611810694571930415.post-41974229255316167292016-04-13T02:40:13.915-04:002016-04-13T02:40:13.915-04:00To this day, we can't explain the point the No...<i>To this day, we can't explain the point the Nova broadcast was making in the passage under review. Almost surely, you can't explain it either.</i><br /><br />You can't explain it because you insist on being an ignoramus. Don't tell me what I can and can't do.<br /><br />Man B and Woman B are irrelevant distractions. Both Man B and Woman B, along with other people who can think straight, understand that if two events are simultaneous in your frame of reference, you will see the closer one first. You can work out the time each occurred using the formula c=d/t, where <i>c</i> is the speed of light, <i>d</i> is the distance to the event, and <i>t</i> is the time it took the light to report the event to you.<br /><br />Stop changing the thought experiment. Stick with the Man and the Woman. The lightning strikes when the two are adjacent, he on the platform, she on the train. The light from each strike reaches the man at the same time, because each is the same distance from the man (one half the train car length) and light always travels at the same speed.<br /><br />The Woman on the train measures the same distance for the light to travel (one half the car length because she's in the middle of the car), and she measures the same speed of light. But she'll see the light from the strike at the front of the car first because she's moving toward it. If the speed of the light from each strike is the same, and the distance the light from each strike has to travel is the same, then what is she to conclude from the fact that she sees the light from the first strike first? It must be that for her, the front strike happened first. <br />deadratnoreply@blogger.comtag:blogger.com,1999:blog-8611810694571930415.post-48700801006851838102016-04-13T02:21:31.843-04:002016-04-13T02:21:31.843-04:00Let's conduct another thought experiment. Sup...Let's conduct another thought experiment. Suppose Man A is traveling along County Road 123, when he realizes that he's lost, although he'd thought he was thoroughly familiar with the area. He pulls up to the general store in Middleboro to ask for directions from Man B who is sitting on the porch there.<br /><br />"Hey, there friend," says Man A to Man B. I thought I knew my way around Route 123, but I'm lost. Can you tell me where Middleboro is?<br /><br />"Sure, stranger," says Man B. "We're a few miles down 123 from Centralia. Does that help?"<br /><br />"No," says Man A. "I've never heard of Centralia."<br /><br />"Really?" says Man B somewhat skeptically. "Well, if you go a fair piece farther in one direction, you'll come to East Bumfuck. If you go in the other direction, you'll come to West Bumfuck.<br /><br />"Oh, sure," says Man A. I know where East and West Bumfuck are."<br /><br />"There ya go," says Man B. "Actually Middleboro is equidistant from East and West Bumfuck."<br /><br />"Really?" says man A, whose turn it is to be skeptical. "How do you know?"<br /><br />"It's easy," replies Man B. "If two drivers start out at the same time for Middleboro, one from East Bumfuck and one from West Bumfuck, and they drive at the same speed, they'll get here simultaneously."<br /><br />Man A is about to say that the explanation is convincing, when a boy on the porch pipes up. "Not so easy," the boy says. "I don't think we can rely on the two drivers to tell us that Middelboro is the same distance between the Bumfucks."<br /><br />"Why not?" Man A asks, not noticing that Man B is rolling his eyes.<br /><br />"Well," says the boy. "If a driver starts out from East Bumfuck and another driver starts out from Centralia, they won't get here simultaneously."<br /><br />Man A says to Man B, "Are all of you that stupid? Is it genetic inbreeding or something in the water around here?"<br /><br />Man B replies, "None of us around here is an Einstein, but that's just Bob. He's kinda slow, but we like him."<br /><br />"Really?" Man A asks again.<br /><br />"Well," says Man B, "He's really slow.deadratnoreply@blogger.comtag:blogger.com,1999:blog-8611810694571930415.post-79352282647076255722016-04-12T23:42:44.719-04:002016-04-12T23:42:44.719-04:00The western edge of the platform would maintain it...<i>The western edge of the platform would maintain its own relative distance from the man at the middle of the platform.</i><br /><br />I think from the perspective of the woman this might not be true. I think as the platform comes into her view, as it seems to be moving towards her from the west, she sees it as elongated with the man looking like he's closer to the east end of the platform than the west end.<br /><br />When he is exactly south of her she thinks there are equal lengths of the platform to his west and his east. And when the platform is getting farther away it looks to her like the platform was shorter than it was on its approach and that the man is back to being closer to the east end.<br /><br />I think this is because as the woman approaches the platform from east she's seeing daylight (not the light from the lightning strike) which reflected off the east end of the platform more recently than the daylight she's seeing at the same time from the west end of the platform. Therefore she's seeing the west end of the platform when the platform was farther away than the platform was when she's seeing the east end of the platform. <br /><br />When the platform is receding from view she is seeing light reflected off the east end of the platform from where the platform, itself, was at an earlier time (less far away, sort of) than when the light she's seeing from the west end gets to her at the same time. It's sort of like a doppler shift without the shift- she's always seeing the leading edge of the platform's direction of travel, relative to herself, look scrunched up relative to its trailing edge.<br /><br />I could be completely wrong about all this so I'd appreciate any input from someone who is following what I'm saying. CMikehttps://www.blogger.com/profile/13481861530761114492noreply@blogger.comtag:blogger.com,1999:blog-8611810694571930415.post-55269206260514432072016-04-12T22:37:56.623-04:002016-04-12T22:37:56.623-04:00The strikes each occur in an instant at a specific...The strikes each occur in an instant at a specific place relative to the woman- some of the light from the first strike moves away from the strike point towards the man who is moving away from what the woman perceives as where he and the middle of the platform were when the first bolt struck. The woman perceives the western edge of the platform, also, as moving relative to her. In other words, the edge is moving away from where it was when it was when it was struck by the first lightning bolt. The western edge of the platform would maintain its own relative distance from the man at the middle of the platform. Some of the light from the strike would be moving eastward faster than the platform or the man is moving eastward relative to the woman. That is why she ends up seeing some of the light from the first strike reaching the man.<br /><br />(I think.)<br /><br /> CMikehttps://www.blogger.com/profile/13481861530761114492noreply@blogger.comtag:blogger.com,1999:blog-8611810694571930415.post-50910543864982273182016-04-12T20:24:11.577-04:002016-04-12T20:24:11.577-04:00"The woman would conclude the light from the ..."The woman would conclude the light from the strikes which occurred at separate times reached the man at the same time because he was moving away from the first strike and towards the second strike."<br /><br />I think if the woman would see the man move she is also going to see the strikes move since they are on the same plane as the man, so it would not seem like he was moving away from the first strike.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8611810694571930415.post-18586341659390903982016-04-12T19:32:14.097-04:002016-04-12T19:32:14.097-04:00" It adds some clutter..."
And also mak..." It adds some clutter..."<br /><br />And also makes transparent that Nova's simplistic summary ["Simultaneity...depends on how you're moving"] is utterly inadequate -- really, it's a misunderstanding dressed to parade as understanding.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8611810694571930415.post-41212717839478969282016-04-12T19:20:04.289-04:002016-04-12T19:20:04.289-04:00Now how did I know you were going to pick up on my...Now how did I know you were going to pick up on my use of "stringing" just that way? Guess you can't always be creative.CMikehttps://www.blogger.com/profile/13481861530761114492noreply@blogger.comtag:blogger.com,1999:blog-8611810694571930415.post-26101863674988615262016-04-12T19:11:35.308-04:002016-04-12T19:11:35.308-04:00No, I'm not stringing you along, CMike. I don&...No, I'm not stringing you along, CMike. I don't understand string theory at all.impCaesarAvghttps://www.blogger.com/profile/03384806750440039982noreply@blogger.comtag:blogger.com,1999:blog-8611810694571930415.post-65122868470061385382016-04-12T19:06:36.917-04:002016-04-12T19:06:36.917-04:00Right, right impCaesarAvg. And not to say your wry...Right, right impCaesarAvg. And not to say your wry comments aren't appreciated, but I write up my comments and replies on this subject for my own benefit. I use these threads as a prompt to work out a run through of my own version of this thought experiment and whenever I get stuck with it I use the various cheat sheets that are available on the net for help. Go ahead and enjoy, take all the satisfaction you can derive from thinking you're stringing me along, but that's not what's going on here.CMikehttps://www.blogger.com/profile/13481861530761114492noreply@blogger.comtag:blogger.com,1999:blog-8611810694571930415.post-41065304042692214752016-04-12T19:06:19.624-04:002016-04-12T19:06:19.624-04:00Adding the 2nd set of observers is just another wa...Adding the 2nd set of observers is just another way of restating the issue. The first set has the stationary observer seeing the 2 lightning strikes as simultaneous, the moving observer sees them as sequential.<br /><br />With the 2nd set of observers, the moving observer sees the 2 strikes as simultaneous, the stationary observer sees them as sequential. The difference is from the time it takes light to travel the distance between the 2 sets of observers. It adds some clutter to the example by restating the basic hypothesis as an inverted example.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8611810694571930415.post-48509432200350951222016-04-12T17:30:43.738-04:002016-04-12T17:30:43.738-04:00And the Milky Way is moving toward the Andromeda G...And the Milky Way is moving toward the Andromeda Galaxy. And the Local Group of galaxies is moving toward the Virgo Cluster.impCaesarAvghttps://www.blogger.com/profile/03384806750440039982noreply@blogger.comtag:blogger.com,1999:blog-8611810694571930415.post-39666122244717037282016-04-12T16:54:02.836-04:002016-04-12T16:54:02.836-04:00Peak ahead to Chapter 10 first and the discussion ...Peak ahead to Chapter 10 first and the discussion of distance.<br /><br />The man in the center of the platform knows he's standing still and he knows where the bolts struck. (As for the man standing still, others might point out he's on the surface of the earth which is spinning on its axis and revolving around the sun, while the sun, itself, is revolving around the center of the Milky Way galaxy.)<br /><br />The woman knows she's standing still and where the bolts struck. Sure, she can see the platform (or the embankment) where both of the bolts struck is moving past her but that doesn't matter as to whether she is standing still. Why she can pour herself a cup of tea without spilling a drop.)<br /><br />For her, the platform is not as long as the train she is on (or, rather, the distance between the two strike points on the embankment were not at points as far apart as the length of the train). If she is facing south, and the man who is facing north thinks the train she is on is moving west, the woman will know it was <b>when</b> the western edge of the platform moving past her was next to the locomotive that that was <b>when and where</b> the first bolt struck. Later, <b>when</b> the eastern edge of the platform was next to the caboose, that was <b>when and where</b> the second bolt struck.<br /><br />Both the man and the woman would agree, the light from the strikes reached the man at the same time and the light from the strikes reached the woman at different times. The man would conclude the light from the simultaneous strikes reached the woman at different times because she was moving towards one strike point and away from the other. The woman would conclude the light from the strikes which occurred at separate times reached the man at the same time because he was moving away from the first strike and towards the second strike.<br /><br />Should the train and the platform ever be at rest next to each other the train would be longer than the platform but not by as great of a distance in length as the woman thought there was when the platform rushed past her.CMikehttps://www.blogger.com/profile/13481861530761114492noreply@blogger.comtag:blogger.com,1999:blog-8611810694571930415.post-57447810933582571752016-04-12T15:34:38.425-04:002016-04-12T15:34:38.425-04:00OK, I just reread Chapter 9. It's lucid, and, ...OK, I just reread Chapter 9. It's lucid, and, even better, it's correct. If you don't understand it, read Chapters 1-8, then try again.<br /><br />Forget Nova and forget Isaacson.impCaesarAvghttps://www.blogger.com/profile/03384806750440039982noreply@blogger.com