• (cs)

Ok you win. I'm just trying to entertain myself between long boring drabs at work. My understanding of time dilation must be lacking so I'll just take your word for it. I'm also saddened by the lack of something fresh to comment on today. I'll be around to argue something new and different tomorrow :)

• (cs) in reply to Hmmmm
Hmmmm:
Crisw:
How does that handle time dilation at speeds approaching c?

I suspect the number of visitors to this site that can reason intelligently about relativity is less than or equal to the number of states that a boolean can have...

Now that Einstein is dead, I suspect you can extend that set to include all humans.

Actually, MM/DD/YYYY is the only correct way because it is how people actually say dates.
Tell me, ever been to a foreign country? Preferably one that doesn't speak American?
• Nagesh (unregistered)

I am not finding oficial definition of "daily." Here in Hyderabad, it mean every time Sun apears on Easturn horizon. What it is meaning in country where this site is being hosted?

• Jay (unregistered) in reply to PiisAWheeL
PiisAWheeL:
I say they just subtrack 662709600000 (If my math is right) from the current Unix timestamp. 21 Years exactly.

Close, but no. That number comes out to 7670.25 days. You will never have 1/4 of a day in "21 years exactly", not 21 calendar years, anyway. That number is apparently taking the length of a year as 365.25 days. But no year is 365.25 days: some are 365 and some are 366. You do not have 5.25 leap years in 21 years: you have either 5 or 6, depending on the end-points. From 2002 to 2023 there are 5 leap years: 2004, 2008, 2012, 2016, and 2020. But from 2003 to 2024 there are 6 leap years: 2004, 2008, 2012, 2016, 2020, and 2024.

Oh and by the way, from 1985 to 2006 there were only 4 leap years: 1988, 1992, 1996, and 2004. 2000 was not a leap year, under the obscure multiple-of-400 rule.

• Jay (unregistered) in reply to Therac-25
Therac-25:
frits:
This makes me wonder why the Euros are all pushing for a metric calendar. I mean the Leap Year problem is a pretty good example why the Gregorian Calendar should be considered harmful.

What other solutions are there for the problem? i.e. the rotation of the earth is not in perfect sync with it's orbit, so you can't create a measurement of the orbit that is perfectly factored by a measurement of it's rotation.

I take it by "not in perfect sync" you mean that a year is not an exact integer number of days. But this is one of those things that makes me say, So what? Why is it assumed that our calendar year must exactly match one revolution of the Earth around the sun?

I propose we create a calendar consisting of 13 months of exactly 4 weeks each. (http://johansens.us/sane/offthewall/cal.htm) Think of the advantages: Every month is exactly the same length. As every month is an integer number of days, the days of the week fall on the same date every month, not just from year to year but also from month to month. That is, the 1st is ALWAYS a Sunday, the 2nd is ALWAYS a Monday, etc. Date calculations would be so much simpler. Holidays, pay days, and other things scheduled by day of the month wouldn't shift day of the weeks. Scheduling in general would be simplified as "twice a month" and "every two weeks" would be synonymous, ditto for other such formulas. Etc.

Yes, this year would be only 364 days. Before you tell me that that means it would be "wrong" ... who says? Where is it written that our calendar year must exactly match the time it takes the Earth to go around the sun? It doesn't exactly match now: 3-point-something years out of 4 are slightly short and just under 1 year out of 4 is slightly long. Under my proposed calendar, every year the seasons would move by 1.25 days. So what? In 10 years, winter would start in early January instead of late December. In 130 years, winter would be in July. If we just got used to that and accepted that the name of the month tells you little about the weather you can expect outside, we could have all the advantages of a greatly simplified calendar.

• Jay (unregistered) in reply to nerd
nerd:
Happens to me every weekend: "DATE_NOT_FOUND"

If no one can find my date, that just means I hid the body well. Hee hee hee.

• Jay (unregistered)

Whoops, brain freeze on my own example. Of course 2000 WAS a leap year, because of the 400 rule. 1900 and 2100 were NOT leap years because of the 100 rule.

I hasten to correct myself before someone else gets to do it, thus spoiling your fun.

• Jay (unregistered) in reply to Anonymous Coward
Anonymous Coward:
There is also the matter of leap seconds. There's been a few of those in the last 21 years.

Yes, we certainly should modify all of our computer timekeeping systems to factor in these leap seconds. Heaven forbid that our clocks should differ by 1 second from the time shown when the Earth was in the same position relative to the Sun last year. That's well worth adding twenty levels of complexity to every time keeping system in the world.

I think the person who invented leap seconds should be locked up next to the guy who thinks he's a bottle of ketchup.

• Jay (unregistered) in reply to ContraCorners
ContraCorners:
Gurth:
I looked at the date on my (digital) wristwatch this morning, and noticed it said it was the 1st of March. Pressing the Adjust button, I discovered that setting back the date by one day put it on 29 February — which, of course, it had skipped past at 00:00 this morning.

Now, on the couple of previous digital wristwatches by this same manufacturer I've owned, you could set the year and the watch handled leap years automatically and correctly. (Those watches had the problem that their date couldn't go past 2000 and 2020, IIRC.) I can't really work out what the designers were thinking here … let's save memory by not storing the year, but then let's add a check to see if the user is turning the date back from 1 March so it can go to 29 February … WTF?

Set a reminder for yourself now, so you don't forget. On 2013-03-01, set your watch back a day. I'm curious to see whether it goes back to the 28th or 29th.

Be sure to post here when you do. We'll all be sitting here waiting for the results.

• geoffrey, MCP, PMP (unregistered) in reply to Tractor
Tractor:
geoffrey:
Big deal. So the site doesn't work one day every four years. There are more important things to deal with in any enterprise.

Actually, failing once every 4 years, excluding every 100 years but then failing again every 400 years.

But that's not the point, it shows that too many Enterprisey systems re-implement things that are readily available, an do so faultily (yes, that's a word). If you find yourself molesting numbers to get the date you want, that's a sign you need read up a bit on the language or platform you're using.

Thank you for such a pedantic reply.

That's an awful lot of "reading up" for so little benefit, is all I'm saying here. Focus on the big picture.

• Jay (unregistered) in reply to Jasper de Vries
Jasper de Vries:
And the Daylight Savings Time changes. Twice a year, you can set the clock by it.

Daylight Savings Time is an atheist plot to disrupt church schedules twice a year.

• Jay (unregistered) in reply to Hmmmm
Hmmmm:
Crisw:
How does that handle time dilation at speeds approaching c?

I suspect the number of visitors to this site that can reason intelligently about relativity is less than or equal to the number of states that a boolean can have...

And then consider that the average intelligence level of people on this site is significantly above the national average, and it's really scary.

• Jay (unregistered) in reply to Myth
Myth:
PiisAWheeL:
Crisw:
Carl:
Now that we are on the verge of becoming a spacefaring civilization, it is long past time to discard our backwater planet-centric timekeeping system in favor of something Universal.

I propose a simple floating point counter of seconds since the big bang. Should work anywhere, forever. Leap second, leap year, Y2K, December 2012... who cares? Just keep incrementing that counter!

How does that handle time dilation at speeds approaching c?

It doesn't. You will need to do the math to adjust the rate at which your counter increments as you increase in speed.

But what do you use as the universal reference point? The Earth? The center of the Galaxy?

You have to use a Hollywood actress. They all know they're the center of the universe.

• Jay (unregistered) in reply to Rick
Rick:
Silverhill:
Rick:
On a related note... The length of a year is natural. The length of a month is almost natural. Why seven days for a week? Purely biblical? One of the few factors of 28?
The principal lunar phase changes (new-->first quarter, first quarter-->full, etc.) are very close to seven days long.
This is not quite my area of expertise, but isn't the first quarter somewhat arbitrary? Why not a fifth moon?

Umm, not clear what that proves. To say that a week is approximately 1/4 of a month isn't much evidence that it was INVENTED by taking the length of a month and dividing by four. If a week was some other lenth, it would still be SOME fraction of the length of a month.

I'm not aware of any basis for the length of a week other than Genesis. Not to say there isn't another possibility, but I don't think this suggestion is it.

• (cs)

One game I played had their own custom calendar. It only had 6 days in a week, had 5 weeks in a month, and all months were 30 days. This simplified some of the game mechanics in a very nice and convient way. Instead of having Sunday and Saturday it had Holiday.

• Thomas (unregistered)

Speaking of the devil, Microsoft Azure cloud service is said to be down due to leap year bug!! Ha ha ha :-)

http://www.techweekeurope.co.uk/news/windows-azure-leap-year-glitch-takes-down-g-cloud-63920

• Ben Jammin (unregistered) in reply to Jay
Jay:
I take it by "not in perfect sync" you mean that a year is not an exact integer number of days. But this is one of those things that makes me say, So what? Why is it assumed that our calendar year must exactly match one revolution of the Earth around the sun?

I propose we create a calendar consisting of 13 months of exactly 4 weeks each. (http://johansens.us/sane/offthewall/cal.htm) Think of the advantages: Every month is exactly the same length. As every month is an integer number of days, the days of the week fall on the same date every month, not just from year to year but also from month to month. That is, the 1st is ALWAYS a Sunday, the 2nd is ALWAYS a Monday, etc. Date calculations would be so much simpler. Holidays, pay days, and other things scheduled by day of the month wouldn't shift day of the weeks. Scheduling in general would be simplified as "twice a month" and "every two weeks" would be synonymous, ditto for other such formulas. Etc.

Yes, this year would be only 364 days. Before you tell me that that means it would be "wrong" ... who says? Where is it written that our calendar year must exactly match the time it takes the Earth to go around the sun? It doesn't exactly match now: 3-point-something years out of 4 are slightly short and just under 1 year out of 4 is slightly long. Under my proposed calendar, every year the seasons would move by 1.25 days. So what? In 10 years, winter would start in early January instead of late December. In 130 years, winter would be in July. If we just got used to that and accepted that the name of the month tells you little about the weather you can expect outside, we could have all the advantages of a greatly simplified calendar.

A year must exactly match the time it takes for the earth to travel around the sun... by definition. "Not in perfect sync" means the point on the Earth at which the sun is the zenith right now, will not be the same point the next time the Earth is in this spot.

Your calendar is workable with a few modifications. Under the assumption that you won't be able to convert everyone (yay metric vs standard) and will need to convert between the two calendars.

1. You will need different month names. Messing up conversions between metric and standard can cause horrible things for Nasa, but confusing July 4th with June 17th really messes up my fireworks watching. At least I don't have to guess which one I'm using if Christmas is in Smarch.

2. I'm not really sure why you limit yourself to 7-day weeks. That is imposed by a religion and by the American Constitution, there is a separation between church and calendar. 5-day work weeks should be in place. Not only can I count them on one hand, but 40 hour work weeks mean every day is work day, and we lose this hub bub about week ends. (You can also easily go into a 365 day calendar.)

3. Happy New Year's / Resync Day! Every January 1st @ 8am, your calendar and Greg's get resynced. The last day.25 just rolls into Resync Eve celebrations. This is to keep the seasons from switching around so I don't confuse my grandkids when I tell then winter was when summer is. It will work like my weekday calendar (since I'm already on 5-day weeks.) Basically, my 5-day week resyncs Monday at 8 when I come into work, and Friday lasts for approximately 72 hours.

• (cs) in reply to Gurth
Gurth:
Actually, MM/DD/YYYY is the only correct way because it is how people actually say dates.
Tell me, ever been to a foreign country? Preferably one that doesn't speak American?
Take Scotland, for instance, with its famous Forth of July.
• Ben Jammin (unregistered) in reply to Myth
Myth:
PiisAWheeL:
Crisw:
Carl:
Now that we are on the verge of becoming a spacefaring civilization, it is long past time to discard our backwater planet-centric timekeeping system in favor of something Universal.

I propose a simple floating point counter of seconds since the big bang. Should work anywhere, forever. Leap second, leap year, Y2K, December 2012... who cares? Just keep incrementing that counter!

How does that handle time dilation at speeds approaching c?

It doesn't. You will need to do the math to adjust the rate at which your counter increments as you increase in speed.

But what do you use as the universal reference point? The Earth? The center of the Galaxy?

Obviously, you would use Greenwich.

• Ben Jammin (unregistered) in reply to frits
frits:
Hmmmm:
Crisw:
How does that handle time dilation at speeds approaching c?

I suspect the number of visitors to this site that can reason intelligently about relativity is less than or equal to the number of states that a boolean can have...

Now that Einstein is dead, I suspect you can extend that set to include all humans.

I guess Einstein would be the FILE_NOT_FOUND boolean value.

• (cs) in reply to Nagesh
Nagesh:
I am not finding oficial definition of "daily." Here in Hyderabad, it mean every time Sun apears on Easturn horizon. What it is meaning in country where this site is being hosted?
In the West, the sun does not always shine. Alex looks out of the window some days, says: "Nope, cloudy today, no WTF."
• (cs) in reply to Anketam
Anketam:
One game I played had their own custom calendar. It only had 6 days in a week, had 5 weeks in a month, and all months were 30 days. This simplified some of the game mechanics in a very nice and convient way. Instead of having Sunday and Saturday it had Holiday.
Someone else said something about 6 days in a week. I think this is a very bad idea. Not from a "keep the days straigt" point of view, but from a work ethic point of view. If people switched over to that you know that most businesses would require 5 working days, which would basically screw 90 percent of the workforce out of an extra day off each week.

Since I'm one of those 9-5ers, I'll keep my 7 day slightly off calendar and you can keep your precision for your own day off.

• (cs) in reply to Jay
Jay:
Whoops, brain freeze on my own example. Of course 2000 WAS a leap year, because of the 400 rule. 1900 and 2100 were NOT leap years because of the 100 rule.

I hasten to correct myself before someone else gets to do it, thus spoiling your fun.

Drat, I was going to comment and say: "I remember it defly was a leap year because I was actually there." If you hadn't have corrected yourself, that's the sort of fun I would have had. And I think you will agree that fun it would have been.

• Jack (unregistered) in reply to PiisAWheeL
PiisAWheeL:
Bernard Kerckenaere:
That depends on the number of leapyears there's in those past 21 years.

I think I calculated for it. 21365.25246060*1000=662709600000

First of all, it's 365.2425.

Second, this does not line up with how we normally reckon age.

The value for Jan 2, 1993 at 23:00:00 GMT is 726015600000. If you add your number, you get 1388725200000, which is Jan 3, 2014 at 5:00:00 GMT. So your program wouldn't allow this person to purchase alcohol for more than a day after s/he turns 21 by any normal person's reckoning.

• (cs) in reply to Jay
Jay:
Jasper de Vries:
And the Daylight Savings Time changes. Twice a year, you can set the clock by it.

Daylight Savings Time is an government plot to disrupt everyone's schedules twice a year.

FTFY

• (cs) in reply to Rick
Rick:
On a related note... The length of a year is natural. The length of a month is almost natural. Why seven days for a week? Purely biblical? One of the few factors of 28?
The sun, moon and five visible planets add up to 7.
• Chuk (unregistered) in reply to Gurth

My watch did the same thing, then this morning it said it was Friday.

• Nagesh (unregistered) in reply to Matt Westwood

Here in Hyderabad, we are having scolars who can determine what is day and what is nite. Is Western Theology prevntion of knowlege of astromonical phenomenon?

• (cs) in reply to Jay
Jay:
Anonymous Coward:
There is also the matter of leap seconds. There's been a few of those in the last 21 years.

Yes, we certainly should modify all of our computer timekeeping systems to factor in these leap seconds. Heaven forbid that our clocks should differ by 1 second from the time shown when the Earth was in the same position relative to the Sun last year. That's well worth adding twenty levels of complexity to every time keeping system in the world.

I think the person who invented leap seconds should be locked up next to the guy who thinks he's a bottle of ketchup.

They've had leap seconds since 1972, which is before most of those computerized timekeeping systems were created.

• magaggie (unregistered) in reply to Mason Wheeler

And timezones. God preserve us all from timezones.

• (cs) in reply to Jay
Jay:
PiisAWheeL:
I say they just subtrack 662709600000 (If my math is right) from the current Unix timestamp. 21 Years exactly.

Close, but no. That number comes out to 7670.25 days. You will never have 1/4 of a day in "21 years exactly", not 21 calendar years, anyway. That number is apparently taking the length of a year as 365.25 days. But no year is 365.25 days: some are 365 and some are 366. You do not have 5.25 leap years in 21 years: you have either 5 or 6, depending on the end-points. From 2002 to 2023 there are 5 leap years: 2004, 2008, 2012, 2016, and 2020. But from 2003 to 2024 there are 6 leap years: 2004, 2008, 2012, 2016, 2020, and 2024.

Oh and by the way, from 1985 to 2006 there were only 4 leap years: 1988, 1992, 1996, and 2004. 2000 was not a leap year, under the obscure multiple-of-400 rule.

Um... what? Were you alive in 2000?

• Peter (unregistered) in reply to PedanticCurmudgeon
PedanticCurmudgeon:
The sun, moon and five visible planets add up to 7.
Five visible planets? I suspect that if you look straight down, you'll find a sixth planet that's remarkably visible.
• (cs) in reply to Gurth
Gurth:
Actually, MM/DD/YYYY is the only correct way because it is how people actually say dates.
Tell me, ever been outside Niobrara County, Wyoming?
FTFY
• (cs) in reply to Peter

There's the small snag with that, that back when people first noticed the planets, they didn't realize the Earth was one of them too. So sun, moon and five planets.

Well it "seems" the easy way.

1. Screw year checks alltogether.
2. Always go to 1st of March after Feb 28.
3. Add a handler for Feb 29 - each four years the customer will have to do one adjustment.

That above means no leap-year logic at all and just adding one feature (feb.29). Maybe not the right way, but there is certainly some logic in it.

Sobi:
Maybe I should not keep the word "year" to name the new year concept... What do you think of nyear? It would be easy to understand (new year). But maybe the sound is too close. Nyur then? It's only four letters long and should be pretty easy to type on any mobile phone (well, it is on my Nokia 5110) which is very important since we want children to adopt it.

nyur = year *4.00000000000017641010234764856 ? :)

Coyne:
geoffrey:
Big deal. So the site doesn't work one day every four years. There are more important things to deal with in any enterprise.

Try explaining that to your CEO.

That is the beautiful part:

"No, it's not a leap-year bug. The problem was that the buzzword buzzword techie-phrase buzzword geek-speak.

I'll get right on it. It may be done by the end of july, ok? But I think we'll need some more memory here."

• Original (unregistered) in reply to pjt33
pjt33:
frits:
This makes me wonder why the Euros are all pushing for a metric calendar.
We are?
• (cs)

Spot the bug in this code:

// JavaScript date constructor adds 1900 to years between 0-100, so create dates in two steps: var d = new Date( 0, month, day, hour, minute, second, ms ); d.setFullYear( year );

(I wrote that, and learned a valuable lesson wednessday: always include 29/2 in your unittests).

• Iain (unregistered)

All the comments about the calendar being based on one Earth orbit around the sun... come on people this isn't rocket science.

The Gregorian calendar is based on a solar, or equinocal, year so that with the periodic corrections, the equinoxes and solstices fall on approximately the same dates every year. Effectively the calendar is tied to seasons which are determined by axial tilt.

Now an orbit of the Earth around the sun is called a sidereal year and it is slightly different. The changes aren't noticeable in a human lifetime but they mount up over centuries; hence the "lost" days when countries adopted the Gregorian calendar in favour of the Julian one.

So on, say 20th April, the position of the Earth relative to the sun is increasingly different every year.

• Rob Smallwood (unregistered) in reply to Ben Jammin
Ben Jammin:
Myth:
PiisAWheeL:
Crisw:
Carl:
Now that we are on the verge of becoming a spacefaring civilization, it is long past time to discard our backwater planet-centric timekeeping system in favor of something Universal.

I propose a simple floating point counter of seconds since the big bang. Should work anywhere, forever. Leap second, leap year, Y2K, December 2012... who cares? Just keep incrementing that counter!

How does that handle time dilation at speeds approaching c?

It doesn't. You will need to do the math to adjust the rate at which your counter increments as you increase in speed.

But what do you use as the universal reference point? The Earth? The center of the Galaxy?

Obviously, you would use Greenwich.

Everybody knows the centre of the universe is Huddersfield

• Hammer (unregistered) in reply to PiisAWheeL
PiisAWheeL:
Myth:
PiisAWheeL:
Crisw:
Carl:
Now that we are on the verge of becoming a spacefaring civilization, it is long past time to discard our backwater planet-centric timekeeping system in favor of something Universal.

I propose a simple floating point counter of seconds since the big bang. Should work anywhere, forever. Leap second, leap year, Y2K, December 2012... who cares? Just keep incrementing that counter!

How does that handle time dilation at speeds approaching c?

It doesn't. You will need to do the math to adjust the rate at which your counter increments as you increase in speed.

But what do you use as the universal reference point? The Earth? The center of the Galaxy?

Nothing. You are the one moving through space at a higher rate of speed. Your clock is the one that is going to be ticking at a different rate compared to everyone else. You detect the gravitational forces that are affecting your spacecraft in real time and factor that into the equation that is calculating how fast your clock should tick. It will adjust the rate of time measurement in real time so that YOUR clock is the same as everyone elses when you slow back down again.

You're not understanding. There is no universal frame of reference to make these corrections. That's the whole point of the theories of relativity. All measurements are relative.

Also, "gravity" would only be felt when the ship is accelerating or decelerating. The travellers can move at 0.999 c, say relative to the galactic center, and be free floating in their vessel.

• Carra (unregistered)

Hah, our French colleagues had the same bug today.

They picked the current day, current month, current year - 5. Result: their application did not start up yesterday.

• Nagesh (unregistered) in reply to Matt Westwood
Matt Westwood:
Nagesh:
I am not finding oficial definition of "daily." Here in Hyderabad, it mean every time Sun apears on Easturn horizon. What it is meaning in country where this site is being hosted?
In the West, the sun does not always shine. Alex looks out of the window some days, says: "Nope, cloudy today, no WTF."
Here in Hyderabad, we have similre phenomonon with newspapering. Some days it is coming and some days not. Sometime also, monkeys are steeling it.
• Zunesis, In the Flesh! (Your mom's!) (unregistered) in reply to Hammer
Hammer:
PiisAWheeL:
Carl:
Now that we are on the verge of becoming a spacefaring civilization, it is long past time to discard our backwater planet-centric timekeeping system in favor of something Universal.

I propose a simple floating point counter of seconds since the big bang. Should work anywhere, forever. Leap second, leap year, Y2K, December 2012... who cares? Just keep incrementing that counter!

But what do you use as the universal reference point? The Earth? The center of the Galaxy?
You're not understanding. There is NO universal frame of reference to make these corrections. That's the whole point of the theories of relativity. All measurements are relative.

Also, "gravity" would only be felt when the ship is accelerating or decelerating. The travellers can move at 0.999 c, say relative to the galactic center, and be free floating in their vessel.

Sigh... Thank you!

This whole conversation reveals a sad truth about the human condition and scientific discovery. We're not learning to answer questions, just ask more confounding ones.

• @Deprecated (unregistered) in reply to Mason Wheeler
Mason Wheeler:
szeryf:
“There are only three hard things in Computer Science: cache invalidation, naming things, and handling of the 29th of February."
...and off-by-one errors.

and scheduling processes at 12:30AM combined with DST. April: My job didn't run! Workaround: Wait until October.

• Kasper (unregistered)

In related news in one place multi-ride tickets for public transportation would be stamped with the 1st of March instead of 29th of February. That is one of the least surprising manifestations of leap year related bugs. However after they got that fixed a more interesting variation turned up the next day when they naturally counted up from the 29th of February to the 30th of February.

On http://www.dr.dk/P4/Kbh/Nyheder/Koebenhavn/2012/03/02/133644.htm you can see a photo of such a ticket with a stamp indicating the 30th of February.

• Jeff (unregistered) in reply to Iain
Iain:
All the comments about the calendar being based on one Earth orbit around the sun... come on people this isn't rocket science.

The Gregorian calendar is based on a solar, or equinocal, year so that with the periodic corrections, the equinoxes and solstices fall on approximately the same dates every year. Effectively the calendar is tied to seasons which are determined by axial tilt.

Now an orbit of the Earth around the sun is called a sidereal year and it is slightly different. The changes aren't noticeable in a human lifetime but they mount up over centuries; hence the "lost" days when countries adopted the Gregorian calendar in favour of the Julian one.

So on, say 20th April, the position of the Earth relative to the sun is increasingly different every year.

The changes aren't noticeable in a human lifetime... or ever. It's not like there's a signpost out there that we fly by every 1.000001 years that says "you are here, the same place you were about a year ago".

• (cs) in reply to Jeff
Jeff:
Iain:
All the comments about the calendar being based on one Earth orbit around the sun... come on people this isn't rocket science.

The Gregorian calendar is based on a solar, or equinocal, year so that with the periodic corrections, the equinoxes and solstices fall on approximately the same dates every year. Effectively the calendar is tied to seasons which are determined by axial tilt.

Now an orbit of the Earth around the sun is called a sidereal year and it is slightly different. The changes aren't noticeable in a human lifetime but they mount up over centuries; hence the "lost" days when countries adopted the Gregorian calendar in favour of the Julian one.

So on, say 20th April, the position of the Earth relative to the sun is increasingly different every year.

The changes aren't noticeable in a human lifetime... or ever. It's not like there's a signpost out there that we fly by every 1.000001 years that says "you are here, the same place you were about a year ago".

You obviously don't know shit about astronomy, fuckwit.