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#### Al Steiner Returns!

jr88

Al Steiner, the author of several of the top 50 rated stories on SOL, has returned!

http://storiesonline.net/library/authorBlog.php?id=18

Replies:   Jim S
transdelion

Yeayyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy!

The Outsider

Woohoo!

mman0114

Awesome news!

Grant

Yes, I was very happy to his blog post.

Jim S

@jr88

Al Steiner, the author of several of the top 50 rated stories on SOL, has returned!

And, apparently, hasn't lost anything during the layoff. That first chapter is very, very good. Hopefully, a long story.

Gauthier

Metric time...

I suppose from the story that
1 metric minute = 100s
1 metric hour = 100 metric minutes = 10.000s
I'm sure that 1 day is 10 metric hour

My rational is that by keeping the same second 1 day is about 1.15 Earth day which is acceptable.

I suppose without much supporting evidence that 1 week is 10 days. I'm not sure what a month or a year is.

IIRC, in the greenies universe, the year and poeple age was measured according to local planetary year length. But with so much planetary systems involved, It's probably not the case anymore.

Orbital mechanic...
Looking at his assertion that Proxima Centauri escape velocity is a bit below their current 412km/s speed when in fact in the SI unit system it would be a bit above 549km/s from Proxima Centauri surface and or 508km/s from the 18000km above corona they are supposed to go, I'm not even sure their second is the same length as ours.

Alternatively, the term escape velocity is used incorrectly and he is referring to another speed.

The maneuver around Proxima is climbing 1233km from 18000km above the corona and rotating 98° in 17 metric minutes. (By the way the continuing usage of degree in angle measurement seems to support a 12 month year...)

The minimal speed needed to do that without propulsion is aound 280km/s but travel would be around 600s not the 1700s I expected in 17 metric minutes.

At the speed reported 412km/s transit time should be a bit over 460sec.

Any tips on the metric time definitions?

Replies:   Jim S  Gauthier
Crumbly Writer

Any tips on the metric time definitions?

Yeah, send him this list and see if anything changes in the future (as he's never been great at answering emails).

Jim S

@Gauthier

My rational is that by keeping the same second 1 day is about 1.15 Earth day which is acceptable.

He can have any number of metric seconds in a metric day by changing the duration of a second from what we currently use. As I remember, national time is kept at the Naval Observatory in Colorado and a second is defined by the time of radioactive decay of some specific element. Makes it simple to change a second to whatever you want it to be.

Replies:   REP  rustyken
REP

@Jim S

Makes it simple to change a second to whatever you want it to be.

True, but there are many things based on the duration of a second. Our calendar who also have to be changed. Double the duration of the second, and a year would only have about 183 days. :)

Replies:   Jim S  Wheezer
Jim S

@REP

I believe Al did that in the story, i.e. years of differing lengths. He always has done his homework (research) well. Thats one of the things that make him so impressive.

Wheezer
Updated:

@REP

Double the duration of the second, and a year would only have about 183 days. :)

Changing the duration of a second only changes the number of seconds in a day on Earth. It does not alter the rotational speed of Earth, which defines a day on Earth, nor does it alter the number of days Earth takes to orbit Sol, which is the definition of a year. Venus has a shorter 'year' and Jupiter has a much longer 'year,' for example. Steiner's metric time removes Earth/Sol-based units from the equation. How well human bio-rhythms can adapt to extreme variations in the day-night cycle has not been fully studied, but iirc, there are limits.

Replies:   REP  REP
REP

@Wheezer

Evidently you misunderstood my comment.

I didn't say doubling the length of a second would have any effect on the amount of time required for our planet to complete one revolution on its axis nor did I say it would affect the length of a solar year. The same for the other planets' days and solar years.

what I did say was the periods would only have half the number of 'doubled seconds' when compared to the number of 'current duration' seconds

Replies:   Wheezer
REP
Updated:

@Wheezer

nor does it alter the number of days Earth takes to orbit Sol, which is the definition of a year.

An Earth year is defined as the amount of time required for the planet to complete 1 orbit around the sun (i.e. a solar year). That period of time happens to be 365 1/4 Earth days. That is why a leap year is 1 day longer than a standard year.

Replies:   Wheezer
Wheezer

@REP

An Earth year is defined as the amount of time required for the planet to complete 1 orbit around the sun (i.e. a solar year). That period of time happens to be 365 1/4 Earth days. That is why a leap year is 1 day longer than a standard year.

Thanks. I've been an amateur astronomer for fifty years, and I never knew that. ;) :P

Wheezer

@REP

I didn't say doubling the length of a second would have any effect on the amount of time required for our planet to complete one revolution

I quoted your statement where you said doubling the duration of a second would reduce the number of days in a year to 183. I'm not certain how I could misunderstand that, but I'm willing to consider it if you could explain.

Replies:   REP
REP
Updated:

@Wheezer

but I'm willing to consider it if you could explain.

Currently, an Earth day is a specific fixed period of time set by the period of time required to complete 1 rotation of the Earth around its axis. That period of time is defined as a day and it can be divided into different units of time, such as: hours, minutes, and seconds. We divide an earth day into 24 hours, which gives each hour a specific period of time. Hours are divided into minutes and seconds; 60 minutes to the hour and 60 seconds to the minute. This gives the minutes and seconds fixed periods of time.

If the number of seconds, minutes, and hours in an Earth day is retained and the duration of a second is doubled, then the periods of time represented by those time units will double. Since the duration of a Day is twice what it used to be, dividing a Solar Year's period of time by the new duration of a day will result in a Solar Year having half the number of days it had before the duration of a second was doubled.

Replies:   Wheezer
BlacKnight

The second is one of the base units that other SI units are derived from. Messing with its value is a bad idea, because it has follow-on effects throughout the metric system, also changing the value of things like newtons, joules, watts, etc.

Wheezer
Updated:

@REP

As you said, a day is one rotation of the planet on its axis. How puny humans chop that up into various bits has absolutely no effect on the speed of rotation. Trying to redefine a 'day' as you are attempting to do does not change things. A day on Earth, a day on Venus, Jupiter or any of the other planets is of different duration, but a day is still a single rotation of a planet on it's axis. The ratio of Earth's planetary rotations to orbital period is still 365.25:1. A year on Earth is still about 365 days long. You are attempting to redefine the definition of a day on Earth. Won't work. It's like calling a horse's tail a leg. Call it what you want, but it's still not a leg. Steiner removes the tie-in to Earth's rotation, so his time definitions work. Thus the references he makes to his characters using a conversion program to compare local Earth time to metric time.

Replies:   REP  Ross at Play
REP

@Wheezer

You are attempting to redefine the definition of a day on Earth. Won't work. It's like calling a horse's tail a leg. Call it what you want, but it's still not a leg. Steiner removes the tie-in to Earth's rotation, so his time definitions work. Thus the references he makes to his characters using a conversion program to compare local Earth time to metric time.

I never attempted to redefine the definition of a day on Earth. I also never challenged Steiner's use of different time units in the Greenie Universe. I don't know where you got those ideas. If you go back through the thread:

Gauthier was talking about Al Steiner's metric units of time and the difference between the length of a Greenie year relative to an Earth year.

Jim S then said, Al could have:

any number of metric seconds in a metric day by changing the duration of a second from what we currently use." ... Makes it simple to change a second to whatever you want it to be

I ignored his comment about a second being defined by the time of radioactive decay of some specific element. Radioactive decay of Cesium is used to measure the length of a second, it does not define it.

I jumped in and said,

True, but there are many things based on the duration of a second. Our calendar who also have to be changed. Double the duration of the second, and a year would only have about 183 days. :)

That was an example. There are many measurements based on the duration of a second. Change the duration of a second and you have to go through and update/change every measurement that is based on time.

At that point, you jumped in with your comments about the orbital mechanics of Earth, Venus, and Jupiter. You then stated that, "Steiner's metric time removes Earth/Sol-based units from the equation." And went on about human biorhythms having to adapt. I'll point out the fact that the laws of physics are the same on all three planets. The use of different metric time units does not remove Earth/Sol units from the equation. It just means conversion factors are required to convert between the Earth/Sol units and the other planets' units.

Replies:   BlacKnight  Jim S  Wheezer
Ross at Play

@Wheezer

365.25:1

To be a pain in the arse, 365.2425 days per year. Years divisible by 100, but not divisible by 400 have not been leap years ever since the introduction of the Gregorian calendar in the 16th century. It's not perfect, but VERY close.
When the changeover happened one year was made 13 days (I think) shorter, which reset the calendar so the equinox was always as close as possible to 22nd March. That date is important to Catholics because the date of Easter is based on the first full moon after that date.
Orthodox churches still use the Julian calendar, with every forth year a leap year. If they don't come to their senses within the next ten millennia or so they'll be celebrating their Easter in the middle of the Northern hemisphere summer.

BlacKnight
Updated:

@REP

I ignored his comment about a second being defined by the time of radioactive decay of some specific element. Radioactive decay of Cesium is used to measure the length of a second, it does not define it.

The second is in fact defined as "the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom".

86,400 seconds roughly corresponds to the tropical rotation period of Earth. The period of Earth's rotation isn't perfectly consistent - it varies some, and is overall slowing down very gradually - so leap seconds are periodically inserted into our timekeeping to keep the rotational period in sync with the precise definition of "second", which is entirely independent of any orbital motions.

edit: In interest of strict pedantry, I should add that, due to gravitic time distortion, the reference radiation is defined to be measured at mean sea level of Earth's nominal rotating geoid, so it's not entirely independent of Earth's orbital parameters.

Replies:   REP
red61544

I love this forum! We can argue about anything!

Replies:   Grant  Jim S  Harold Wilson
Jim S
Updated:

@REP

Radioactive decay of Cesium is used to measure the length of a second, it does not define it.

Rep, with all due respect, that statement is nonsensical. What else is a second but a length of time? A second can be defined off of any fixed length constant process. Radioactive decay happens to be a convenient one. By specifying the length, you define it.

And I'll be honest. Until I read Steiner's first chapter, I had never heard of metric time. The definition that I found on the 'net doesn't seem to comport to how it appears to be defined in the story. I'm not entirely sure HOW he has it defined. Damn that Al Steiner. making me have to go all mathematical again. Thought I left that crap behind when I retired. :)

Replies:   REP
Wheezer

@REP

Double the duration of the second, and a year would only have about 183 days. :)

There, you said it again... :D

I am saying that the duration of a second (as we measure it on Earth) has nothing to do with the number of days in our year. The number of hours, minutes & seconds in our day is a human construct. The time it take the third rock from the sun to make one orbit remains approximately 365.25 axial rotations - or 'days' in the common parlance.

You are attempting to redefine how we define a day - as one axial rotation of the planet. If that's what you are trying to do, just say so.

Replies:   Gauthier  REP
Grant

@red61544

I love this forum! We can argue about anything!

Welcome to the Internet.

Gauthier

@Wheezer

You are attempting to redefine how we define a day - as one axial rotation of the planet. If that's what you are trying to do, just say so.

Considering the number of planet and orbitals, in that universe, I beleive The day to be constrained by our sleep patern, and not the rotational speed of a local planet. That said, I figured that if I replace in the text "above escape velocity" by "below escape velocity", the math timing and orbit mechanic work out (elliptic vs hyperbolic tragectory) without having to change the second duration.

Replies:   Wheezer
Jim S

@red61544

I love this forum! We can argue about anything!

Most of the arguments are driven by trolls. But what I like about SOL is that at least it has a better class of trolls than what one normally finds out there.

Replies:   Ernest Bywater
Ernest Bywater

@Jim S

what I like about SOL is that at least it has a better class of trolls than what one normally finds out there.

Controlling the quality of the trolls is easy, if they don't let in any without clothes or they smell too much.

Wheezer

@Gauthier

I have no argument with what Steiner is doing in his story. It is consistent with a spaceborn society that is scattered among numerous solar systems and planets, each with it's own unique length of day and year. My friendly debate with Rep is about something he said about time here on Earth. :)

REP

@BlacKnight

The second is in fact defined as

You got things backwards. Cesium was discovered in 1860. Second were in existence and the duration defined long before we knew about Cesium. As you indicated, Cesium's use as a time standard allows extremely accurate measurement of the duration of a second.

Replies:   BlacKnight
REP

@Jim S

What else is a second but a length of time? A second can be defined off of any fixed length constant process.

Just to clarify things I am talking about units of time here on Earth. We define seconds, minutes, and hours of time as 60 seconds to the minute, 60 minutes to the hour, and 24 hours to the day. Their durations are based on the rotation of Earth around its axis. We generally ignore the planets gradually decreasing angular rate of rotation and say it is a constant period of time.

Here on Earth, there is only one fixed length constant for defining the duration of our time units and that is the duration of 1 rotation of the planet.

As I said to BlacKnight, radioactive decay is not a standard that defines the duration of a time unit, it is a means of accurately measuring a period of time represented by that time unit.

REP

@Wheezer

You are attempting to redefine how we define a day - as one axial rotation of the planet. If that's what you are trying to do, just say so.

That is the current definition, so I am redefining nothing.

REP

The definition of a day is commonly said to be 24 hours, but that is common usage, not the technical definition of a day. As indicated below, the solar day is the basis on which our time unit durations are based.

The period of time during which the Earth completes one rotation with respect to the Sun is called a solar day.[2][3] Several definitions of this universal human concept are used according to context, need and convenience. In 1960, the second was redefined in terms of the orbital motion of the Earth, and was designated the SI base unit of time. The unit of measurement "day", redefined in 1960 as 86 400 SI seconds and symbolized d, is not an SI unit, but is accepted for use with SI.

Replies:   Ernest Bywater
Ernest Bywater

@REP

The definition of a day is

I always thought the perfect definition of Day was Doris.

BlacKnight

@REP

You got things backwards. Cesium was discovered in 1860. Second were in existence and the duration defined long before we knew about Cesium. As you indicated, Cesium's use as a time standard allows extremely accurate measurement of the duration of a second.

No. What I quoted was the current SI definition of the SI unit "second". That is, literally, how a second is defined. Not measured. Defined. It does not have anything to do with the rotation of the Earth, though it was, not coincidentally, given a definition extremely close to 1/86400th of Earth's mean tropical rotation period.

But it is not defined to be 1/86400th of a day. Earth's rotational period isn't a sufficiently precise basis for modern timekeeping needs, so the second is no longer defined in terms of it, and the "day", as a unit of timekeeping, is defined from the second, not the other way around.

Not all days are even 86,400 seconds. Some are 86,401. As I mentioned above, Earth's rotation is slowing down, and so international timekeeping standards organizations periodically insert leap seconds into days to keep the world from gradually falling behind the clock.

Replies:   Jim S
Jim S
Updated:

@BlacKnight

No. What I quoted was the current SI definition of the SI unit "second". That is, literally, how a second is defined. Not measured. Defined.

This is confusing. It implies that a second is defined one way and measured another. Yet both refer to the same measure of time. Surely, that couldn't be what you meant. If a second is defined as 1/86400 of the rotation of the planet yet measured as the period of time of radioactive decay of an element that produces a length of time inconsistent with that definition -- a day is actually 23h 56m 4.901s (86,164.901 seconds) measured at the equinoxes -- then we have confusion. At least to the scientific/engineering portion of my brain. How does such an inconsistency resolve itself, at least in this discussion?

Replies:   REP  BlacKnight
REP
Updated:

@Jim S

Jim, the confusion is created by the manner in which the second was originally defined, and the adoption of the measured value of that original period of time that represents a second, as measured using an atomic clock.

ETA: see https://en.wikipedia.org/wiki/Time#World_time

Think about watches and clocks. In the 1600's, and earlier, they were the most accurate means available for measuring the passage of time. Almost all of them had minute hands and many had second hands. The mechanics of these timepieces were designed such that they indicated the passage of 24 hours for every solar day. Compared to today's time standards they were very inaccurate. In 1874 the British Association for the Advancement of Science introduced the CGS (centimetre/gramme/second system) system, which combined the fundamental units of length, mass and time. This system defined the values of length, mass and time.

In 1960, International System of Measurements was published and adopted to replace the CGS system. The ISM system defined an ephemeris second and set its duration as equal to 1 solar second of the mean tropical year in 1900 as measured at the equator. The duration of the solar second was defined as that period of time that resulted in 86,400 solar seconds being equal to 1 solar day.

In 1967, the SI second was introduce to replace the solar second and its duration was set by using an atomic clock to measure the duration of an ephemeris second. That measured value is used as the current value of the duration of a SI second.

In this discussion, the bottom line is the original basis for the SI second's duration is the solar day. The measured duration of an SI second is – 9,192,631,770 cycles of the radiation that corresponds to the transition between two electron spin energy levels of the ground state of the 133Cs atom.

Currently, some people want to say the measured value of the existing, defined duration of an SI second is what defines its duration. I say they have the cart before the horse.

Replies:   BlacKnight
BlacKnight

@Jim S

This is confusing. It implies that a second is defined one way and measured another. Yet both refer to the same measure of time. Surely, that couldn't be what you meant.

A second is 9,192,631,770 cesium wiggles. That's how it's defined. You can't take better measurements and say, "Well, actually, it looks like it's 9,192,631,773." All you can do is refine your notion of exactly how long 9,192,631,770 cesium wiggles take.

It's like saying a foot is 12 inches. You can't take better measurements and says, "Well, actually, it looks like a foot is really 12.0003 inches." That just means that what you're measuring isn't really a foot.

You can, on the other hand, measure a ruler, and say, "This ruler is 12.0003 inches long."

Similarly, you can measure the duration of a tropical rotation of Earth using a precise and accurate atomic clock, and if that's 86,400.0003 seconds, that doesn't mean that the second is actually slightly longer than believed. It just means that rotation took 86,400.0003 seconds, and if that kind of thing keeps up, the international timekeeping standards boards will probably insert a leap second into our official timekeeping to compensate.

If a second is defined as 1/86400 of the rotation of the planet yet measured as the period of time of radioactive decay of an element that produces a length of time inconsistent with that definition -- a day is actually 23h 56m 4.901s (86,164.901 seconds) measured at the equinoxes -- then we have confusion. At least to the scientific/engineering portion of my brain. How does such an inconsistency resolve itself, at least in this discussion?

The 23:56:04.901 measurement of the length of a day is the sidereal rotation period. Notice that I've been careful to repeatedly specify "tropical" above. The mean tropical rotation is 24:00:00, within a fine margin of error.

The difference is that the sidereal rotation is the time it takes the planet to complete one actual rotation, relative to the position of the "fixed" stars. The tropical rotation is the time it takes the planet to complete one apparent rotation, relative to the position of the sun in the sky.

Because we're revolving around the sun at the same time we're rotating, when we complete a sidereal rotation, we haven't quite caught up to the apparent motion of the sun in the sky, and it takes another ~4 minutes to continue around until the same point on the surface is facing the new relative position of the sun.

In a 365.25-day year, the planet has actually made 366.25 sidereal rotations. The extra rotation disappears, in four-minute chunks, into keeping up with the compete circuit the sun makes around the sky in a year's time.

Neither the sidereal nor tropical rotation have any bearing on the definition of a second, which is defined in terms of cesium wiggles.

Replies:   Ross at Play  Jim S
Ross at Play

@BlacKnight

In a 365.25-day year, the planet has actually made 366.25 sidereal rotations.

Thanks.
That is a point that has been frustrating me while following this thread, but not enough to bother trying to write an explanation of it. :-)

Jim S
Updated:

@BlacKnight

In a 365.25-day year, the planet has actually made 366.25 sidereal rotations. The extra rotation disappears, in four-minute chunks, into keeping up with the compete circuit the sun makes around the sky in a year's time.

So our calendar is based on sidereal rotation, not solar rotation (as sidereal is the one having the extra 0.25 days)? If thats the case, why is solar time mentioned at all? Seems like science is trying to confuse us peasants. :) Especially since it has nothing to do with the definition of a second.

This conversation got me wandering around the web looking. In those wanderings, I find that Earth's rotation is slowing. One Wikipedia article maintains that certain interpolations suggest that the day was 21 hours long 600 million years ago. Simple math says that, if true, planet rotation is slowing one second every 55,500 years or thereabouts (assuming linearity). Damn. Never knew SOL was going to be so educational.

Replies:   Ross at Play
BlacKnight

@REP

In 1967, the SI second was introduce to replace the solar second and its duration was set by using an atomic clock to measure the duration of an ephemeris second. That measured value is used as the current value of the duration of a SI second.

In this discussion, the bottom line is the original basis for the SI second's duration is the solar day. The measured duration of an SI second is – 9,192,631,770 cycles of the radiation that corresponds to the transition between two electron spin energy levels of the ground state of the 133Cs atom.

Currently, some people want to say the measured value of the existing, defined duration of an SI second is what defines its duration. I say they have the cart before the horse.

The problem is that Earth's period of rotation is both slightly variable - due to orbital eccentricity, gravitational influence of other bodies (mainly the moon), and so on - and overall gradually changing - due mainly to the tidal drag of the moon. Both of these make it unsuitable for use as the basis for a timekeeping standard that, in many modern applications, needs to be more precise than that.

So the basis for our units of time is defined by something that's both precisely measurable and a universal constant. The exact value of that definition was originally chosen to closely correspond to a specific fraction of Earth's tropical rotation period, but it is divorced from that correspondence. It wasn't perfectly accurate even then, and as Earth's rotation continues to slow, the duration of the second doesn't change. It just takes more seconds for Earth to rotate, and leap seconds become more frequent.

So, yeah, the second was originally based on the rotation of the planet, but it isn't anymore. And changing it to match - or, to bring the discussion back to its origin, because you want your clock and calendar to be more orderly - is a bad idea, because, as a fundamental SI unit, the duration of a second is the basis for any number of other units and measurements.

Replies:   REP
REP

@BlacKnight

There is no problem except in your mind. The scientific community defined the durations of hours, minutes, and seconds using the Earth's angular velocity in 1900. Although, the Earth's angular velocity is changing as you described, the periods the scientists defined for the time units are still the same because the point of reference, 1900, was not changed.

Over the years, the problem with measuring the period of the time units was, there were no extremely accurate time measurement devices. That resulted in a lack of repeatability in the measured values.

So, yeah, the second was originally based on the rotation of the planet, but it isn't anymore.

Therein lies the difficulty. The period is still based on the rotation of the planet as of 1900. What has changed is we now have an extremely accurate means of measuring the time periods, and the periods' durations are expressed as specific numbers of cesium cycles.

Our scientists measured one of the defined time units using a cesium time standard around 1967. Then they used that value expressed as cesium cycles and the difference in Earth's angular velocity between 1967 and 1900 to compute values for all of the SI time units. The result was a value of 9,192,631,770 cycles for an SI second based on Earth's 1900 angular velocity. That value is a fixed, repeatable measurement of the SI second's period; but the value does not define what constitutes the duration of an SI second.

If you doubt that, consider how that measurement was probably made. Then answer the a question for me.

When the scientists made that measurement, the Start Time count was set to zero. They then recorded the number of cesium cycles that occurred between the Start Time and the time the End Time was reached.

So the question is, How did the scientist know when to stop counting the cesium cycles (i.e. When the End Time was reached), if the duration of the time unit being measured was not known and used to determine the End Time?

And changing it to match - or, to bring the discussion back to its origin, because you want your clock and calendar to be more orderly - is a bad idea, because, as a fundamental SI unit, the duration of a second is the basis for any number of other units and measurements.

Once again, I am not trying to change clock (duration of the time units) or the calendar. And as I said earlier, changing the time units' values would be a very bad idea.

Ross at Play
Updated:

@Jim S

Simple math says that, if true, planet rotation is slowing one second every 55,500 years or thereabouts (assuming linearity).

That would not be linear. There is a gradual decrease in the rate at which the planet's rotation is slowing. As I understand it, the main reason the rotation is slowing is the drag caused by shifting tides in the oceans. Tides are caused by the moon but the moon is slowing drifting further away from the earth. The shifting weight of water in the tides means the moon is always revolving around a centre of gravity of the earth fractionally closer to it than its "central" location over a longer period of time.

So take any opportunity you can to catch any lunar eclipses that happen near your way. Before long the moon will be so far away from the earth there won't be total eclipses anymore. :(

Replies:   Jim S  AmigaClone
Jim S

@Ross at Play

There is a gradual decrease in the rate at which the planet's rotation is slowing.

I strongly suspected that to be the case, but I was trying to keep the calculation simple. Hence my qualifier.

It makes sense that the decrease is non linear as the main variable in the decrease, the moon and it's gravitational pull, is changing. i.e. its distance and gravitational impact on the planet. Depending on which scientist you believe, the moon is either moving in and will eventually break up close to the planet, or moving out and will eventually spin off on its own. About the only certainty here is that no one knows for sure.

Replies:   Ross at Play
Ross at Play

@Jim S

Depending on which scientist you believe, the moon is either moving in ..., or moving out

I recall reading that a laser beam directed at a mirror left on the surface of the moon has been used to prove it is moving away from earth at a rate consistent with a catastrophic separation not much more than 4 billion years ago.

Replies:   Dominions Son
rustyken

@Jim S

The SI definition of second is "the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom

So if would seem to be unaffected by location in the universe...well unless you are next to a black hole.

Cheers

Dominions Son
Updated:

@Ross at Play

I recall reading that a laser beam directed at a mirror left on the surface of the moon has been used to prove it is moving away from earth at a rate consistent with a catastrophic separation not much more than 4 billion years ago.

The problem with that, is that the measurements are equally consistent with the theory that the moon's orbital distance was stable until they started shining a laser at a mirror on the moon's surface.

There may well be other data to support the catastrophic separation theory, but those laser measurements don't really support it.

There are all sorts of events that could happen that could disrupt the moon's orbit. Without periodic measurements all the way back to the point of separation, measurements showing that the moon is moving away from the earth now, those measurements are equally consistent with thousands of possible theories.

Replies:   Ross at Play
Ross at Play

@Dominions Son

those measurements are equally consistent with thousands of possible theories.

I cannot dispute that.

richardshagrin

Al Turns once. Can you say he re-turns the second time he turns?

AmigaClone

@Ross at Play

So take any opportunity you can to catch any lunar eclipses that happen near your way. Before long the moon will be so far away from the earth there won't be total eclipses anymore. :(

While eventually there will not be any more total lunar eclipses, those will continue to occur for some time after the last total solar eclipse occurs.

The reason for this is the different diameters of the Earth and the Moon, and since the Earth has a much larger diameter it will continue to give a total lunar eclipse even after the moon is to far to completely block the sun.

As I write this there is a partial lunar eclipse visible from among other places Australia.

Replies:   Ross at Play
Ross at Play

@AmigaClone

Whoops ... and WTF was I thinking?

My looking up was faulty. I meant 'solar eclipses'. 'Lunar eclipses' are far more common, and boring.

But, I've been telling others what to do what I did not do myself!
The last total eclipse, just over a year ago, was visible in Indonesia. The hypocrite was living there but missed it. :(

The next total solar eclipse will Thursday of next week, and visible in a wide swathe from Tennessee to Oregon.

I'll need to live another 11 years before another one comes near my way in Australia. :(

Replies:   merlyn2748  AmigaClone
sejintenej
Updated:

marvellous news.
Having read his blog which I understood included his latest story into the Greenies Universe it took just a bit of searching to find that "Homebodies" http://storiesonline.net/s/16328:190482/homebodies-chapter-1
is not included in that Universe.

Harold Wilson

@red61544

I love this forum! We can argue about anything!

merlyn2748

@Ross at Play

The next total solar eclipse will Thursday of next week, and visible in a wide swathe from Tennessee to Oregon.

Not to be a stickler, but I've been planning on this eclipse for quite a while.

It starts on Monday, August 21 at about 1:30PM EST and runs for about 3 hours. It will be a total eclipse from Oregon, all the way to Georgia. If you are within 70 miles of it's path it will be total. Other parts of the Contiguous US will see a partial eclipse to varying degrees depending on how close they are.

Again, don't want to be a pain, but I figured I would correct the date.

Replies:   Ross at Play
Ross at Play
Updated:

@merlyn2748

Again, don't want to be a pain, but I figured I would correct the date.

SORRY.

I stuffed up badly when I wrote that post. The date I saw was August 21, and I've no idea how I ended up with Thursday.
The correct date is Monday, August 21.
Perhaps you can post a link here, so those in the US can find out if they're in the path of totality, and if so at what time.
In fact, given that I have misinformed people already, perhaps you should start a new thread titled, 'Total Eclipse on Monday, August 21'.

Joe Long

I had stayed away from this post, but I find you guys are arguing!

Here's a thought exercise: It's been established since ancient times that a circle is 360 degrees, which is very close to the 365.2425 days it takes the sun to complete it's path through our sky, and thus a likely impetus for choosing that measure of a circle.

However, if the ancients had considered a year to be 360 days, it would be off by 5.2425 days and thus only take 5 years for the equinox to be off by a whole month.

Perhaps 5000 years ago a year (one revolution around the sun) actually was 360 days (one rotation on Earth's axis) and that is what has physically changed since then.

Lookup Emmanuel Velikovsky's Worlds in Collision

Replies:   Gauthier  REP
Gauthier

@Joe Long

Perhaps 5000 years ago a year (one revolution around the sun) actually was 360 days

Not possible at all.

Replies:   Joe Long
AmigaClone

@Ross at Play

I'll need to live another 11 years before another one comes near my way in Australia. :(

There are some locations within the path of totality of this year's solar eclipse that will be seeing another total eclipse in April 8, 2024.

I was born and lived a few years within the path of totality of the February 26 1979 Total eclipse (although it was not visible there due to clouds.) I observed that eclipse as a partial one while living within a couple of miles of the center of the path of totality of this year's eclipse.

This year I am living within the path of totality of the April 8, 2024 eclipse.

Replies:   Wheezer
Gauthier

@Gauthier

Got a reply from Al Steiner, he said:

As for time keeping: Seconds are the basic unit and they are the same as ours. 100 seconds = a metric minute. 100 metric minutes = a metric hour. Ten metric hours = a metric day. 100 metric days = a cycle. 3 cycles = a metric year. A believe that is the system I cam up with but I do not have my story notes in front of me.

That would put a metric year at about 347,22 earth days.

Joe Long

@Gauthier

Not possible at all.

If the Earth's distance from the sun was less than it is now.

Replies:   Dominions Son
Dominions Son

@Joe Long

If the Earth's distance from the sun was less than it is now.

Over millions of years maybe, but that's too big a change to have happened in the last 5K years.

Another possibility (at millions of years, but not 5K years) is changes in the earth's rotational rate.

The Earths rotational rate is decelerating slowly due to drag from the moon's gravitational pull.

However, it has also been observed that large scale geological events (major earthquakes and large volcanic eruptions) can cause small changes in the Earth's rotational rate in both directions.

Astronomical events could also have an impact there. A near enough miss by a large enough rogue body could cause an acceleration in the earth's rotation.

However, as with a major change in the earth's orbit, a change large enough to add 5 extra days a year in the last 5K years is extremely unlikely to have been able to happen without leaving more evidence of it's occurrence behind.

Replies:   Joe Long
Joe Long

@Dominions Son

However, as with a major change in the earth's orbit, a change large enough to add 5 extra days a year in the last 5K years is extremely unlikely to have been able to happen without leaving more evidence of it's occurrence behind.

I made the reference to Velikovsky. His hypothesis was that a planetary near miss had thrown Earth into a larger orbit and had been described in history. Venus had been ejected from Jupiter and crossed paths with Mars and Earth before settling into it's current orbit.

Replies:   Dominions Son
BlacKnight

Velikovsky was a nutjob.

Dominions Son

@Joe Long

His hypothesis was that a planetary near miss had thrown Earth into a larger orbit and had been described in history. Venus had been ejected from Jupiter and crossed paths with Mars and Earth before settling into it's current orbit.

There are two immediately obvious problems with that.

1. Jupiter is a gas giant and Venus is a solid body.

2. The direction is wrong for pushing the earth into a more distant orbit.

A shift in the Earth's orbit from a near miss by a large astronomical body would necessarily happen in the direction the body was moving as the shift would be caused by gravitational drag during the near miss.

Venus is closer to the sun than the Earth. For Venus to be ejected from Jupiter and have a near miss on the earth, that would pull the Earth inward towards the Sun into a shorter orbit, not outward into a longer orbit.

Replies:   Ross at Play
Ross at Play
Updated:

@Dominions Son

There are two immediately obvious problems with that.

More immediately obvious problems with that are:

1. The mind-boggling coincidence that after such a random birth Venus ended up in an orbit that's very close to circular.
2. The mind-boggling coincidence that after such a random birth the orbit of Venus ended up in an almost identical plane as the other planets.

Replies:   Dominions Son
Dominions Son

@Ross at Play

1. I missed that, but you are correct. With such a origin, it should have ended up with an elliptical orbit.

2. I don't see that as such a large issue. Jupiter's orbit is far enough out that ejecting a large mass on any trajectory significantly off from the plane of it's own orbit would more likely than not simply result in the ejected body leaving the solar system rather than being captured in a solar orbit.

REP

@Joe Long

Lookup Emmanuel Velikovsky's Worlds in Collision

Better yet, read Immanuel Velikovsky's background. He had a medical degree and practiced psychiatry. Apparently little to no scientific training or background in the field of astrophysics or other related discipline.

https://en.wikipedia.org/wiki/Immanuel_Velikovsky

Wheezer

@AmigaClone

This year I am living within the path of totality of the April 8, 2024 eclipse.

I have to drive about 150 miles to get to my viewing location. Got my campground space reserved and ticket in hand.

Jim S

Just a thought as I'm reading Ch. 4. It seems to me that Al is equating homers and spacers in that both suffer irrational fears brought on by their own ignorance and/or lack of experience with the subject at hand. A good example is the spacer's fear of water and the homers fear of anything from off planet. As I said, just a thought.

Replies:   StarFleet Carl
StarFleet Carl

@Jim S

It seems to me that Al is equating homers and spacers in that both suffer irrational fears brought on by their own ignorance and/or lack of experience with the subject at hand. A good example is the spacer's fear of water and the homers fear of anything from off planet.

You caught that as well? I suspect that was done deliberately. While I have no clue about where he's going with this, I suspect that Gath is going to do major things towards reconciliation between homers and spacers. Al has shown the strong case for WHY spacers act like they do - I'm actually rather surprised that other groundies haven't called them on it already.

Replies:   Jim S
Jim S
Updated:

@StarFleet Carl

I've pretty much suspected something similar. Not a reconciliation perhaps but some other partial resolution. I don't see how it could believably be a complete resolution given the white hot hatred of the homers and the spacers complete avoidance of a finer interference in their, i.e. homer, affairs. For a complete resolution, both of those have to be overcome and that complete of a change in values takes a long time.

But where else can he go with the conflict that he has presented? This will likely be a long story as it will take some time (read: kilobytes) to flesh it out properly before a resolution can be presented, this in order to be believable. And he is already up to 440k. We may be (hopefully) in for a long ride.

Replies:   maroon
maroon

@Jim S

It looks like the plot also involves the question of whether the wormhole circuits are natural or placed there by a sentient intelligence, I lean toward the latter. I would think that a natural circuit entry point would be located at the barycenter for the entire solar system, instead of somehow identifying individual massive objects and so it can have a circuit at the barycenter for Sun/Jupiter. The story doesn't mention periods of time when circuits were unusable, so either the entry point is located at the barycenter for Jupiter's mean distance, or their shielding is good enough to access it when Jupiter is at perihelion. Jupiter has an elliptical orbit, so the barycenter for Sun/Jupiter ranges from 10000 to 82000 kilometers above the sun's photosphere radius, depending on how close to aphelion/perihelion it is.

It seems circuits are placed at the barycenters for massive object pairs, so star systems can have more than 1 circuit entry-point if they have more than 1 sun and/or have massive-enough gas giants distant-enough to have the barycenter above the photosphere radius. The barycenter for Sun/Saturn is around 300k kilometers below the Sun's 'surface', so that's why our solar system doesn't get a 2nd circuit. The star systems out there without a massive-enough distant-enough gas giant aren't accessible because there's no star/planet barycenter outside that star.

If you add up the effect of Saturn/Uranus/Neptune, if they're on the same side of the Sun they can combine to have a barycenter further away from the Sun than Sun/Jupiter alone. The wikipedia page for barycenter has a map of the barycenter for the entire solar system wandering in and out of the sun over the years. When Jupiter and the other gas giants are all on the same side of the sun, they can pull the barycenter as much as 700k kilometers further out than for just Sun/Jupiter alone. But on the other hand, when Jupiter and Saturn are on the opposite side from each other, their masses largely cancel each other out, and the solar system's barycenter can move very near the sun's core. That would significantly change the plot because there would be years at a time when the barycenter would be deep within the sun.

Pluto and its satellite Charon are not mentioned as having a circuit at their barycenter in space between them, so the circuit requires either more mass or uses the star's fusion as a power source. The barycenter for Earth/Moon is around a thousand miles below the Earth's surface, so that location would also be inaccessible.

The sun is massive enough to have a surface area of 6 trillion square kilometers, so either there was an enormous fluke that allowed the initial probe to accidentally get sucked into the circuit, or the entrance is very large and you don't need a bullseye to get passed through it.

Also not mentioned so far is whether an object needs to be massive enough to trigger the circuit, because otherwise there'd be a constant flow of solar wind getting sucked through the circuit at both ends, and the circuit could have been detectible from either the missing material or from the other star's spectrum particles appearing out of 'nowhere'.

There's software at https://celestiaproject.net/ to simulate the motions of the solar system. I've seen videos on youtube from it, but so far I've not figured out how to get it to show planetary orbits from perpendicular to the orbits instead of head-on.

Replies:   Jim S
Jim S
Updated:

@maroon

The story doesn't mention periods of time when circuits were unusable, so either the entry point is located at the barycenter for Jupiter's mean distance, or their shielding is good enough to access it when Jupiter is at perihelion.

Al did mention the Sol barycenter was located 3000 km inside the coronal layer, which still puts it pretty far from the surface, i.e. millions of kilometers. So I doubt that the location of Jupiter matters much as the effect is only tens of thousands of kilometers.

Replies:   maroon
maroon

@Jim S

The corona layer of the Sun's atmosphere does extend a distance of millions of kilometers, i.e. multiple solar diameters. I was reading the '3000 km inside' to be counting from the inside border, that's closer to where the Sun/Jupiter barycenter is located than near the outside border of the corona. The Sun's radius is 696000 km, and the Sun/Jupiter barycenter ranges from 706000-778000 at perihelion/aphelion, which ranges from 1.5% to 12% of the solar radius above the Sun's surface. 3000 km is only 0.5% of the Sun's radius, so in solar terms the distance from Los Angeles CA to Detroit MI isn't very far. In fact, the movement of the Sun/Jupiter barycenter of 778000-706000km from the Sun's radius is 72000km difference, which is 12x as long as the 3000km mentioned.

But in reading more about the corona, it seems the temperature of the corona is in the millions of degrees compared to the thousands of degrees at the Sun's 'surface'. The corona is described as a wildly fluctuating region with huge changes in temperature, density, and magnetism - so it's hard to tell what the typical conditions at the Sun/Jupiter barycenter's 'altitude' would be.