Didymus

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Posts posted by Didymus

If that's the case, swan, when two objects travel relative to each other, their relative speeds are definitively equal. If A is traveling away from B at a speed, B is moving away from A at an identical speed. Thus, relative speed can not yield assymetrical time dilation.

alternate ways to measure light.

Can you reference when this technique was used in an experiment testingthe speed of light where the source and receiver or moving relative to each other?

Preferably testing both a moving source and stationary receiver vs. A moving receiver and stationary source.

alternate ways to measure light.

Correct me if I've misread, but that sounds like that only measures the delay based on light transferring through different mediums rather than relative speed.

I.e. measuring timing over a fixed distance rather than actually measuring the relative speed of the incoming photons. No?

I'm particularly interested in the tests verifying that the speed of light is the same even with a moving source. Once the light bounces off the first mirror in the array, that mirror is the new source of light and the speed of light is still only being measured relative to a stationary source (each mirror it bounces off of).

alternate ways to measure light.

Giving this another honest shot. It's said that long ago, we proved that a source of light traveling either toward or away from measuring equipment will still emit light that will be measured at C.

The only ways I would know to measure the speed of light would involve bouncing that light off of an array of mirrors.

My question is: Does anyone know of a an experiment to measure the speed of light from a source moving relative to the measuring equipment that used a method that did not involve reflecting that light through a mirror array?

Can anyone describe how it would be measured without a mirror array?

So then if clocks are said to catch up in time based on the difference in symmetry, would the duration of each trip be irrelevant? Since it's been claimed that time will catch back up when two symmetrical objects stop.

So if youre floating in deep space when suddenly a clock flies past. You see whether it's ticking slow from your perspective... Then catch up to it and look at it again.

Are you suggesting that you can definitively detect which one accelerated more during their trip by noting which clock jumps forward in time when the inertial frames meet back up?

If both clocks experienced equal acceleration, it's been suggested that both clocks would jump forward and synch. It seems that one could compare the ratio of how each object had accelerated during it's trip by noting how much each clock adjusts when they come together.

Al goes left at .8c and Bert goes right at .7c, but turns around early so they still meet back at the same time. They still had a relative velocity of nearly the speed of light, so the whole trip, each would see the other's clock run slower. Right before they decelerate, they compare how far behind the other clock is. Even if they don't see the clockove forward during deceleration... Once they stop, they can then compare which clock jumped forward more than the other.

Is that a fair interpretation of your suggestion? If not, where do you disagree?

New post: md65- that's why I suggested a straight line through curved space to limit the "acceleration" to a change in relative velocity. If it's not a matter of G-forces, the. What function differentiates the two inertial frames? When the ship turns around the star, from its perspective, it's going straight and hasn't accelerated at all.... Instead his home planet rapidly changed from flying away at a certain speed, decelerated, then accelerated flying toward the ship at that speed.

If SR is a matter of relative velocity, it can't be asymmetrical.

I'm aware that it will alter the calculations a bit relative to the time spent in the gravity well. But the observer on the home planet will also be experiencing Gr time dilation for the gravity well he's been sitting in the whole trip. Assume the two to be proportional (less gravity, but more time in the field) to cancel out the GR variable. The gravity well is just to provide a situation where a person is inarguably accelerating to leave a planet, then accelerating in the same direction to catch up to the planet again without the planet experiencing any acceleration itself. Just to eliminate variables.

If acceleration sets the time dilation, dilation may be asymmetrical, but every acceleration/deceleration would compound the slowing of time. There would be no function for acceleration in one direction to slow time, but equal acceleration in the opposite direction to speed it up again.

If acceleration doesn't play a role, and only relative velocity affects time... Then there is no function for asymmetric time dilation.

How can they be reconciled?

Curious about how dilation differentiates between "deceleration" and "acceleration" in the opposite direction? See the illustration a couple posts up.

So then the net result of time dilation is a function of acceleration rather than time spent moving at a certain velocity?

If so, how do you differentiate between acceleration and deceleration?

I.e. for the sake of direction, imagine a 2D map of a planet sitting to the south of a neutron star. You accelerate (say at .5c) toward the north to get a closer look from within the star's gravity well. Once you hit your speed, you just coast the rest of the way on a trajectory that will send you just close enough to curve your path close enough to your planet (since this isn't a gravitational force slingshoting you, but a straight path through curved spacetime, there's no further acceleration).

As you get to the neutron star, you maintain your inertial frame... Just rotate your ship to keep the star in your forward window even on your way back. Now, from your inertial frame, you're just floating through space, and you see your planet wizzing by from behind you at a speed of .5c. You have to accelerate to catch up to it.

Did your rate of time normalize relative to your planet when you went through curved space to change direction without accelerating?

Or did you normalize when you accelerated to catch up to the planet after it wizzed by?

Or did time slow relative to your planet both when you left and then again once you caught back up with it? Forever giving you Flash-like super powers since everyone else is so slow?

So if two people are moving relative to eachother, yet watching the other one's clock the whole time, each will see the other's clock moving at a slower rate and get farther and farther behind their own clock. Say they travel like this for a year and one clock is a month behind the other clock.

If, when they come to the same inertial frame, their clocks are once again synched... How do you suppose that works? Does do you believe deceleration will make the clock on the opposite ship seem to jump forward however much is needed to catch up to the normal time?

How would this change if they each accelerated to .8c for 10 seconds then decelerated vs. Staying at that pace for 10 years... Seeing the other clock fall farther behind the whole time.... And then catching up all at once?

Or, are you suggesting that when they stop, the rates will cat hbup to one another, but each pilot will still see the other clock as reading a different time according to how far behind that clock appeared to be from their perspective before they decelerated?

While this tangent is worth discussing, I feel like others may disagree with your assertion.

Are you suggesting that if two objects are traveling past eachother at nearly the speed of light, they'll each see the other's clock running more slowly than their own clocks. yet, when they meet up, their clocks will be synched again as long as their accelerations were identical?

Do you suggest that neither clock is actually ever running slower, that they just appear to be doing so from the perspective of the other person? Or do you suggest that each is actually running slower than the other, but that they speed back up when the two decelerate?

Or am I misunderstanding you?

So, to eliminate variables, assume Al and Bert are in space ships that accelerate and decelerate instantly without killing anyone. Acceleration is another topic... We're going with straight special relativity time dilation based on relative motion at different inertial frames. If it makes you feel better, assume they start accelerating on the other side of the ship and Al and Bert simply begin their journies by passing the space station simultaneously.

How will Al and Bert compare their clocks with eachothers and Bobs?

From Bob's perspective, yes.

But when as Al travels, it's Bob's clock that runs slower. Bert's clock runs even slower as his speed relative to Al is so much closer to the speed of light. So how do Al and Bert see eachother from their frames of reference?

Note, avoid general relativity's affect on time dilation by assuming that they're all on space ships in negligable gravity and Al and Bert's ships have the technology to accelerate/decelerate very quickly without smashing the occupants. After Al and Bert get to speed, they are no longer accelerating, so still count as an inertial frame just like Bob.

(Sorry, I wall o' text. For ease of skipping to the question Blue text is a remedial preface. Orange text is the explanation someone else gave for the problem in the blue text. Black text is my question about the orange explanation of the blue problem.)
I saw an explanation of the twin paradox online that tried to explain the twin paradox. I understand the theory that relative motion dilates time. Hense, a twin travels at .8c to an object 5 lightyears away. From their perspective about 15 years has passed, but when they come back to earth, everyone else has experienced closer to 25 years. The problem comes from the notion that all frames of reference are equally valid. As two objects pass each other, each will experience their time as normal and see the other person's clock running slow. Thus, if the twin that leaves could see the clock of the twin on earth the whole time, the twin that left would come back and everyone on earth will have experienced less time, thus would be younger. So, when the two are reunited... how does each see the other as nearly a decade younger than themselves?
They offer that time dilation is asymetrical due to the asymetrical nature of the trip. They explain that if each brother sends out pings every second. Since the two are traveling apart, each will experience pings from the other party as coming in slower than once per second. But, when the ship turns around, it will receive pings faster than one per second, while the earth still receives pings at a rate slower than one per second. Thus, time is subjective to the same extent that they each experience different number of pings per second.
Now, we'll ignore the G-force dyssemetry for now, since that's a whole different set of problems and this is tangled enough as it is, but... there seems to be a serious flaw in this reasoning in that they changed how they treat those pings half way through the trip.
If we assume these pings travel at a constant speed relative to a medium, then yes, the ship will receive pings more slowly as it travels away from the earth to the same exact extent that it will receive pings faster as it travels back toward the earth. The earth will receive pings at a normal rate throughout the journy. They exactly even out.
If, instead, we assume the pings travel at a speed constant to their source... we get the same exact result with a different explanation. Pings coming from the earth will put along at normal speed. The ship will receive them red-shifted as it travels away and blue-shifted to the same extent on the way back. Yes, it'll get more pings on the way back because the pings have to catch up to the shift... but that doesn't mean "more time has passed" ... it's just lag. The difference of having pings move common to their source rather than a medium is that the earth will also receive red-shifted pings as the ship travels away and blueshifted pings as the shift travels toward it. Again, evening out exactly.
There's only a discrepant number of pings if you change the rules halfway through the trip.
Further, if Asymmetry is the problem... remove that variable. Assume they're triplets. One person stays home, the other two take the same journy in opposite directions at a speed of about .8c for 5 lightyears and back. How old does each person see the other ones when they all come back? (For ease of explanation, Say Bob stays home, Al goes to left and Bert goes right).

Seems that Bob will see Al and Bert as the same (younger) age. But Al and Bert both see the other one as significantly younger than themselves (and younger than Bob sees either of them).

Theoretically if you passed the speed of light, would there be a sonic boom equivalent?

An important thing to consider is that sound travels at a constant speed relative to the medium regardless of how fast the object creating the sound is going.

Light, on the other hand travels at a constant speed relative to it's source and requires no medium.

So an object can go faster than sound and nothing will hear that object until the object passes. On the other hand an object traveling at any speed will emit light traveling away from it.

Bill Nye the Science Guy vs Ken Ham

I think this video give plenty of evidence about the trees...

(video)

There are list of citations of where the info comes from as well on the youtube page...

http://en.wikipedia.org/wiki/Polystrate_fossil

Indeed... in the "debunking" they suggest that polystrate trees are indicative of a catastrophe where sediment is laid down very quickly. The problem is every time there's not a tree there "These layers can only be laid down after millions of years each. No way a flood could do this." But every time there's a polystrate fossil "except this one area that had a flood."

As for the first part... the video claims "no soft tissue," "No Osteocytes" etc. based on their reading of her paper.... well... I'm not sure whether they were talking about one of per papers in particular, but the first one on the topic I found talks quite a bit about both of those things.

Abstract

Soft tissues and cell-like microstructures derived from skeletal elements of a well-preservedTyrannosaurus rex (MOR 1125) were represented by four components in fragments of demineralized cortical and/or medullary bone: flexible and fibrous bone matrix; transparent, hollow and pliable blood vessels; intravascular material, including in some cases, structures morphologically reminiscent of vertebrate red blood cells; and osteocytes with intracellular contents and flexible filipodia. The present study attempts to trace the occurrence of these four components in bone from specimens spanning multiple geological time periods and varied depositional environments. At least three of the four components persist in some skeletal elements of specimens dating to the Campanian. Fibrous bone matrix is more altered over time in morphology and less likely to persist than vessels and/or osteocytes. Vessels vary greatly in preservation, even within the same specimen, with some regions retaining pliability and other regions almost crystalline. Osteocytes also vary, with some retaining long filipodia and transparency, while others present with short and stubby filipodia and deeply pigmented nuclei, or are pigmented throughout with no nucleus visible. Alternative hypotheses are considered to explain the origin/source of observed materials. Finally, a two-part mechanism, involving first cross-linking of molecular components and subsequent mineralization, is proposed to explain the surprising presence ofstill-soft elements in fossil bone. These results suggest that present models of fossilization processes may be incomplete and that soft tissue elements may be more commonly preserved, even in older specimens, than previously thought. Additionally, in many cases, osteocytes with defined nuclei are preserved, and may represent an important source for informative molecular data."

... etc.

Haven't rocks of nearly 4 billion years been dated from the Earth? If so the idea that deep time is flawed is debunked. The problems with dating methods is that the correct one has to be used in the correct circumstances. C-14 dating is not considered accurate in dating marine organisms due to their carbon not coming directly from the atmosphere. Dinosaur bones cannot be carbon dated because they are too old and don't contain carbon. The tree trunks Ken Ham mentioned that were encased in millions of year old rock but dated a few tens of years old was misdated due to the natural radioactivity of the basalt, radioactivity turns C-12 into C-14 and will give you erroneous readings. These are well known problems and can be compensated for.

And that's exactly the kind of honesty most people are looking for. Even as a creationist, I'm not looking to ban the big bang and evolution from schools. I'd just like less brainwashing. Less presentation in the text books that "these are established facts. And questioning them discredits you."

The problem is people don't seem to take into consideration "this can't be dated a certain way because it was exposed to water or could have been near something else with enough radiation to yield erroneous results." ... if the test matches what you're looking for, it's assumed to be correct. If it doesn't match what you're looking for, we look for variables that can correct it to that date... and stop looking for variables once our preconceived date is reached.

I'm not a YEC, so I really don't object to the possibility of fossils being millions of years old... but an intellectually honest person should be able to admit the fallibility of some of the processes geologists use.

Teaching my children evolution and the big bang.

But it does refute YEC and if people want their children taught religion they should take them to church. All the available evidence points to a big bang, nothing points to a god...

I agree. If people want to learn about any unprovable theories about where something came from that can not be observed, or even explained in a way consistent with the laws of physics as we understand them... it should be taught in a church of philosophy classroom or anywhere other than a science classroom stating that "this idea is right and all others are blasphamous."

Teaching my children evolution and the big bang.

You can give good evidence to oppose Young Earth Creationism with the tree-rings, sure. But trees being more than 6,000 years old doesn't necessitate the big bang.

Teaching my children evolution and the big bang.

If the universe was created by one or more deities, the dissenting viewpoint stands that the existence of a deity has never been objectively proven.

The mainstream interpretation of the big bang has matter escaping a universal singularity... At the event horizon of any given black hole, the laws of physics break down because time and space are infinitely compressed. Radiation is expelled from a black hole, true, but common theory is that it's from particles being torn apart at the event horizon rather than expelled from within that point. With the big bang, a universal singularity is in no better situation than any other black hole... In addition, there's supposedly no outside forces or gravity fields to affect it. The dissenting viewpoint would state that if the energy required to escape a black hole is infinite.... An object with the combined masses of all black holes (and the rest of the universe) would require a specific explanation as to how matter could escape. Unfortunately... The laws of physics don't apply until after the big bang. ... Which inherently makes the time before that illogical.

Most still accept it.... But to say there is no dissenting viewpoint would be dishonest.

Also, if a single object "exploded" (for lack of a better term), conservation of angular momentum would dictate that all objects should be rotating in the same direction as the original object. This is nowhere near the case as various moons within our own system rotate counter to each other.

Teaching my children evolution and the big bang.

Moderation with all things. Give them an open, honest explanation of different viewpoints and the evidence for each viewpoint along with the problems with each viewpoint.

Telling your kids that their science teacher is a liar and they need to accept that goddidit without question.... Will probably give them an unhealthy perspective. Likewise, if your intent is to teach them that the big bang is unquestionable fact and that anyone who says differently is a liar... You'll do just as much damage. There are rational dissenting viewpoints to both theories.

But you're right in your correlation between teaching magical physics defying creation stories in the classroom to magical physics defying creation stories with a different power source in the classroom. Both belong in a philosophy class.

Bill Nye the Science Guy vs Ken Ham

Phone gets horrible connectivity at my work, so I can't search for sources for you at the moment, but I'll try to dig up some pictures when I get off.

As for talkorigins... It very adequitely debunks a lot of claims.... Others, not so much. For example, most people who believe in a flood laying down sediments quickly instead of the geologic column taking millions of years would point to polystrate trees as a sign of this....

Talkorigins "debunks" it by stating that the tree didn't have to stay verticle for millions of years.... Those layers could have formed rapidly in a flood. Which is exactly the point.

Look into their responces to all of the examples of radiometric dating yielding completely erroneous results.... Last I looked they almost all made one excuse or another about these mistakes all being one time flukes that we should just trust never happen outside those... Dozens and dozens of times.

(keep in mind, I'm just providing the unrepresented viewpoint. Even with deistic creation, I see no reason dinosaurs couldn't have lived millions of years ago. And like most creationists, I believe in observable evolution. There may be many different types of birds that came from a common bird... That doesn't necessarily validate the leap in faith that a sexually reproducing animal came from an asexually reproducing bacteria, which came from the still unexplained process of biogenesis.)

I do not get it...

The family of people who came from Jews:

1: Jews. Believe in one God. Everyone else believes their book is legit, but the rest believe there are later books too. Jesus isn't in the Hebrew scripture, but most Jews would acknowledge that he was a nice Jewish boy.

2: Christianity. Mainstream Christianity teaches a trinity. While they self identify as monotheistic, other religions consider the "three persons of one God" as polytheism... There are "unitarian" Christians like the Jehovah's witnesses that believe the same bible, but interpret some scriptures differently. Like when they see Jesus saying "the father is greater than I" and 1st corinthians 8:6 saying "there is for us only one God, the Father."... They believe that IInstead of the opposite of that.

3a: Islam believes in the same roots, but as Jesus changed people's understanding of the Hebrew scriptures, muhammad changed the understanding of Jesus. Back to one God, but Jesus was just a prophet, not the son of God. Although they don't famously get along with Jews... -every time- they use the names Abraham, Isaac, Jacob, Jesus (and some others), they respectfully say "peace be upon him" (if you ever see "pbuh" in a forum).

3b: Mormons.... Don't believe in Islam, but similarly believe in a new book that redefines the old. They believe in one God for earth, but that all enlightened people can go to heaven and become gods and have out own planets.

And now you know.

Bill Nye the Science Guy vs Ken Ham

IMO, bills original YouTube video that spawned this debate was horribly rude and unprofessional... I had lost a lot of respect for him... But, in the debate, he seemed more in control of himself. I respect that bill made at least some effort to touch on some of the actual points made... At least better than most.

As for ken... I was pretty disappointed. It seemed like he was just a less charismatic, less prepared version of Kent hovind. All of his points have been made more fluently in the past by his tax evading predicessor.

As for he debate... I would have liked to have seen bill expand a bit more on the winter/summer layers of ice a bit more. Personally, I don't doubt it, but I can freeze a bottle of water overnight and get a dozen visible layers. I'm curious what is interpreted as a summer/winter cycle.

Likewise, ken claimed that different dating methods, each considered reliable, often wildly disagree. He gave two examples, but not enough.

bill did step in a few times when he said that just one example of a few things could change his mind and ham failed to cite Plenty of examples of polystrate fossiles doing exactly what bill said was impossible. And modern human tools found in coal dated hundreds of thousands of years in the past. Also, when bill claimed that Noah was obviously an amature at woodworking, ken could have pointed out that, a woodworker with a decade of experience is more efficient than a novice. A woodworker with 20 years of experience will be considerably better.... If the story were accurate, Noah was hundreds of years old in a generation that gave him a couple hundred more healthy years to live... That would insinuate him being pretty experienced at his craft. No one said there were no lakes in those days, so boat building may have already been a science... And it was said that people could grow to giant proportions then. Beyond that, the instructions were said to be given by God. If he could create the universe, he could tell a burly dude with hundreds of years of experience how to build a boat.

To be fair, I'm a Christian too and not all Christians are young earth creationists. The best point bill made was that Ken's viewpoint wasn't even necessarily that of all religious people... Just his interpretation of the bible according to his preferred translation.

A few points I would argue with against ken:

One can believe in the bible and see that in the beginning God created the heavens and earth. It goes on to say what he did on earth, but gives NO indication that the "6 days" started when he started creating things. He could have spent a billion years on each galaxy for all we know, then at some point 6,000 years ago, began focusing on earth.

Even then, each "day" isn't necessarily 24 hours. The bible uses the same word for "day" when talking about God's sense of time... That from the perspective of a universal energy being, a thousand years is like a day, yet a day is like a thousand years. Each day was simply a "step" taken.... How long it took or exactly how he did it is not even hinted at. Therefore trees being 10,000 years old isn't a problem for all creationists... Just Yec.

Also, the bible never said that -nothing- died until humans sinned. Human sin was the beginning of human death. Dinosaurs could have eaten each other for millions of years before Adam was around.

The flood also could have been on a smaller scale.... WhiIe I could buy a worldwide flood assuming a major geological event such s major oceanic trenches closing, causing the water to rise significantly... I've always suspected that Noah lived in the valley that is now the mediterranian sea. I'm guessing that valley used to be blocked off, after a big rain, the natural dam broke allowing the ocean to flow in, flooding as far as Noah could see.

I'd like to see Bill Nye debate a creationist that isn't Yec.

Ever found yourself lying to kids about Heaven?

+1 for Stetson here.

There's a difference between "we don't know what happens after death" and "because I can't prove that heaven exists, it must be a vicious malicious lie."

You -know- Santa doesn't exist because people have to pretend to be him and the authors of the books about him admit the works to be purely fictional. The flat out rejection of any hope after death based on a rejection of anything describable as a higher power is just as ignorant as a blind faith in a particular higher power.

Express your belief and your reasons for it, but be open to the idea that not everyone shares your belief.

ice stratifictation aging?

Watched the Bill Nye vs. Ken Ham debate the other day, and one point was made I've never really looked in to: Bill Nye pointed to ice core layers showing hundreds of thousands of summer/winter cycles. This doesn't bother me because I'm rather confident the earth is old enough for that, but I approach all new information with what I consider to be a healthy dose of skepticism. Not everyone agrees with my unit f measurement, but that's irrelevant.

So, what is looked for in the ice to define a summer/winter cycle? Is it anything beyond simple stratification? Or are individual gas samples taken to look for seasonal changes?

Anyone able to link me to some good pictures showing such layers? How can we be sure each layer represents a summer/winter cicle as opposed to given layers brought by individual storms rather than year cycles?

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