Earth slowing; time adjusted

[StreetCowboy]

Will you think me silly if I tell you the earth rotates 366 times in a year (to the nearest whole number)?

No I'd not think you were silly, but I would know that you were wrong. The earth revolves around the sun 365.242 times per year - the closest whole number is 365 not 366

I don't think he's silly either, but he's correct.

There are approximately 365 days in the year, a product of approximately 366 revolutions and 1 orbit about the sun.

Try again and use a calculator if necessary, or get a friend to help you. Now, is 365.242 closer to 365 or 366 ? Think carefully !

I don't see why you are trying to change the subject.

If the Earth did not spin on its axis, and it rotated round the sun, how often would the sun cross the horizon?

Take an orange and an apple, and paint a line on each, if this helps; or a tomato - any round fruit would do....

SC

[slipperylobster]

Earth is slowing down...? Good news for Thailand.

[wabothai]

Now I know what is wrong with me !!

[halloween]

Just to clear up any confusion. Leap seconds are added due to the fact that the earth take slightly longer than 24 hours to make a complete rotation. The earth is slowing due to tidal lock, but the slow is not very drastic. Therefore, it needs to be adjusted every so often. If you look at the moon, you always see the same side because it is tidally locked to the earth. Thanks to a molten outer core, plate tectonics, and vast oceans, earth is not yet tidally locked to the sun. Eventually it will be, but we will all be long dead or some kind of robot-human hybrid before that happens.

There is no such thing as centrifugal force. What what an object feels when something spinning is actually a change in momentum which is tangent to a rotating object. The force is pushing towards the center of a rotating body. Otherwise said momentum would carry the object away. This force is called centripetal force. This is easily tested by spinning a ball on a string. The only force exerted is you pulling to the center on a string. When you let go, it flies off tangent to the circle. It's analogous to when you brake a car quickly. You feel yourself move forward, but there is no force pushing forward. Your momentum is carrying you forward and the force of your seat belt or amulet pushes you back into your seat. There was no forward force, just momentum. (okay technically there is a forward force on the bottom of your tires, but that isn't what you feel)

If the only force acting on a spinning ball is you pulling on a string, why does it stay in equilibrium? Why doesn't it accelerate towards you and hit you in your face?

Because the ball's momentum is always tangent to the circle, so it is moving 90 degrees from the direction of the force.

My apologies, I shouldn't have strung you along. I do understand that Centrifugal is only an apparent force, and the centripetal force is continually accelerating (the direction component of the vector) the ball.

Edited June 16, 2015 by halloween

[tigermonkey]

Will you think me silly if I tell you the earth rotates 366 times in a year (to the nearest whole number)?

No I'd not think you were silly, but I would know that you were wrong. The earth revolves around the sun 365.242 times per year - the closest whole number is 365 not 366

I didn't think anybody would bite.

"In one year the earth makes one complete orbit of the sun.

It rotates 366¹/₄ times on its own axis so we see the stars appear to rotate 366¹/₄ times and we experience 365¹/₄ noons - i.e. 365¹/₄ solar days."

http://www.wallingfordclock.talktalk.net/Sidereal%20Time.htm

Sorry about the faint print. if you prefer try www.youtube.com/watch?v=VYKnWYu6fiU

When I replied, I was earthbound and presumed you were also. That is why my response is couched in terms of solar days and not sidereal days, which you are referring to. Certainly, there are two answers - 365 solar days and 366 sidereal days. BTW in which solar system do you reside which allows you to use sidereal days to discuss my home planet ?

[halloween]

Will you think me silly if I tell you the earth rotates 366 times in a year (to the nearest whole number)?

No I'd not think you were silly, but I would know that you were wrong. The earth revolves around the sun 365.242 times per year - the closest whole number is 365 not 366

I didn't think anybody would bite.

"In one year the earth makes one complete orbit of the sun.

It rotates 366¹/₄ times on its own axis so we see the stars appear to rotate 366¹/₄ times and we experience 365¹/₄ noons - i.e. 365¹/₄ solar days."

http://www.wallingfordclock.talktalk.net/Sidereal%20Time.htm

Sorry about the faint print. if you prefer try www.youtube.com/watch?v=VYKnWYu6fiU

When I replied, I was earthbound and presumed you were also. That is why my response is couched in terms of solar days and not sidereal days, which you are referring to. Certainly, there are two answers - 365 solar days and 366 sidereal days. BTW in which solar system do you reside which allows you to use sidereal days to discuss my home planet ?

Did I mention days? and the answer for rotations is?

[BritTim]

The IERS is not French based but has its headquarter in Frankfurt/Germany

Pretty much everything else in the article was wrong, so they were just being consistent placing it in France. The July 1 date, which does appear to be correct, was probably lazily left that way on the assumption that we would assume it could not be right.

[JAG]

Gorden Bennet! And I thought teaching the future continuous tense to P6 was a challenge!

Edited June 16, 2015 by JAG

[StreetCowboy]

Will you think me silly if I tell you the earth rotates 366 times in a year (to the nearest whole number)?

No I'd not think you were silly, but I would know that you were wrong. The earth revolves around the sun 365.242 times per year - the closest whole number is 365 not 366

I don't think he's silly either, but he's correct.

There are approximately 365 days in the year, a product of approximately 366 revolutions and 1 orbit about the sun.

Try again and use a calculator if necessary, or get a friend to help you. Now, is 365.242 closer to 365 or 366 ? Think carefully !

365.

Actually 364 and a quarter days in a year. Its why every 4 years we have a leap year.

My Rolex adjusts accordingly.

I'll be taking my calendars back to the shop now.

For mis-information, though, the assertion that the earth revolves around the sun 365.242 times per year is probably the most spectacular in this thread to date (my underlining). It would be more sensible to say that the sun revolved around the earth 365.242 times, and from a certain perspective you could justify that as a fair approximation for most practical purposes.

Probably the claim that gravity was related to rotation was the most potentially misleading, though. I hope that no-one more gullible, naive or ignorant than the posters is reading this thread and learning from it...

SC

[rubl]

365.

Actually 364 and a quarter days in a year. Its why every 4 years we have a leap year.

My Rolex adjusts accordingly.

I'll be taking my calendars back to the shop now.

For mis-information, though, the assertion that the earth revolves around the sun 365.242 times per year is probably the most spectacular in this thread to date (my underlining). It would be more sensible to say that the sun revolved around the earth 365.242 times, and from a certain perspective you could justify that as a fair approximation for most practical purposes.

Probably the claim that gravity was related to rotation was the most potentially misleading, though. I hope that no-one more gullible, naive or ignorant than the posters is reading this thread and learning from it...

SC

It might have been a recent event. I noticed a certain dizziness and blamed it on the weekend's activities

[Ceruhe]

" .... in order to meet international standards, deputy director Vice Admiral Jarin Bunmoah said yesterday."

Guess there is a first for everything ...

Sorry to disappoint you, some 4 weeks back we had an "to meet international standards" for motorcyles (in bangkok...) not going through the underpasses

Well, as long as the Earth doesn't instantly stopps....otherwise I'd like to be in a spaceship to watch the destruction instead of just being insta dead.

[StreetCowboy]

" .... in order to meet international standards, deputy director Vice Admiral Jarin Bunmoah said yesterday."

Guess there is a first for everything ...

Sorry to disappoint you, some 4 weeks back we had an "to meet international standards" for motorcyles (in bangkok...) not going through the underpasses

Well, as long as the Earth doesn't instantly stopps....otherwise I'd like to be in a spaceship to watch the destruction instead of just being insta dead.

We'd all have to start pedalling westwards in tandem, to get it going again, just like in the yogi bear cartoons with the barrel

[krisb]

Will you think me silly if I tell you the earth rotates 366 times in a year (to the nearest whole number)?

No I'd not think you were silly, but I would know that you were wrong. The earth revolves around the sun 365.242 times per year - the closest whole number is 365 not 366

I don't think he's silly either, but he's correct.

There are approximately 365 days in the year, a product of approximately 366 revolutions and 1 orbit about the sun.

Try again and use a calculator if necessary, or get a friend to help you. Now, is 365.242 closer to 365 or 366 ? Think carefully !

365.

Actually 364 and a quarter days in a year. Its why every 4 years we have a leap year.

My Rolex adjusts accordingly.

I'll be taking my calendars back to the shop now.

For mis-information, though, the assertion that the earth revolves around the sun 365.242 times per year is probably the most spectacular in this thread to date (my underlining). It would be more sensible to say that the sun revolved around the earth 365.242 times, and from a certain perspective you could justify that as a fair approximation for most practical purposes.

Probably the claim that gravity was related to rotation was the most potentially misleading, though. I hope that no-one more gullible, naive or ignorant than the posters is reading this thread and learning from it...

SC

So does this mean beer o clock now starts at 4.58 ? because I'm confused now.

[Basil B]

there have been 25 leap seconds added since 1972, that about 1 every 1.8 years, so a leap second added at the end of this month is long overdue and proves there is some fluctuation in the Earth's spin rate.

And that equates to about 55 leap seconds every century, far short of an hour century.

In actual fact the mean spin rate of the Earth has only slowed down by 1.7 milliseconds in the last century, meaning that a day is 1.7 milliseconds longer than in 1915, so the Earth is slowing down at about 45 Nanoseconds (0.000,000,045 second) a day.

[StreetCowboy]

...

So does this mean beer o clock now starts at 4.58 ? because I'm confused now.

That experience where you go into the pub at 8 pm, and moments later it's 2 am and you're somewhere the wrong side of the Silom Line is not due to somebody adding on 6 leap hours behind your back.

Is it?

[tigermonkey]

365.

Actually 364 and a quarter days in a year. Its why every 4 years we have a leap year.

My Rolex adjusts accordingly.

I'll be taking my calendars back to the shop now.

For mis-information, though, the assertion that the earth revolves around the sun 365.242 times per year is probably the most spectacular in this thread to date (my underlining). It would be more sensible to say that the sun revolved around the earth 365.242 times, and from a certain perspective you could justify that as a fair approximation for most practical purposes.

Probably the claim that gravity was related to rotation was the most potentially misleading, though. I hope that no-one more gullible, naive or ignorant than the posters is reading this thread and learning from it...

SC

Sorry if you believe that I have been spreading mis-information (sic). What I intended to say and believed that I had said was that the earth rotated 365.242 times per year (on its own axis) while rotating once around the sun (one year). Thus we have 365.242 revolutions of the earth per year relative to the sun - during one solar year. However, if one were to observe this from another solar system, the earth makes 366.242 sidereal revolutions. .

[StreetCowboy]

365.

Actually 364 and a quarter days in a year. Its why every 4 years we have a leap year.

My Rolex adjusts accordingly.

I'll be taking my calendars back to the shop now.

For mis-information, though, the assertion that the earth revolves around the sun 365.242 times per year is probably the most spectacular in this thread to date (my underlining). It would be more sensible to say that the sun revolved around the earth 365.242 times, and from a certain perspective you could justify that as a fair approximation for most practical purposes.

Probably the claim that gravity was related to rotation was the most potentially misleading, though. I hope that no-one more gullible, naive or ignorant than the posters is reading this thread and learning from it...

SC

Sorry if you believe that I have been spreading mis-information (sic). What I intended to say and believed that I had said was that the earth rotated 365.242 times per year (on its own axis) while rotating once around the sun (one year). Thus we have 365.242 revolutions of the earth per year relative to the sun - during one solar year. However, if one were to observe this from another solar system, the earth makes 366.242 sidereal revolutions. .

Or if one were to estimate the rotation of the earth by observation of a fixed point other than the sun;

it's a bit like playing roulette on the waltzer (I expect, I'm not a gambling man)

[halloween]

Sorry if you believe that I have been spreading mis-information (sic). What I intended to say and believed that I had said was that the earth rotated 365.242 times per year (on its own axis) while rotating once around the sun (one year). Thus we have 365.242 revolutions of the earth per year relative to the sun - during one solar year. However, if one were to observe this from another solar system, the earth makes 366.242 sidereal revolutions. .

Both cannot be true. It is a matter of your point of reference. If you are looking at the axis point, the extra revolution is so gradual that you don't notice it, being less than 1 degree per day. If you look at something more distant like the stars you will count 366 revolution, as they would observing you.

The links I gave you have graphical representations to explain it.

[StreetCowboy]

Do you believe that the moon rotates on its axis, and circles the earth, or do you believe that the moon rotates around the axis of the earth?

I'm wishing now I'd disassembled my old Sturmey Archer hub

[krisb]

Why does the sky look more blue on some days than others?

[tigermonkey]

Sorry if you believe that I have been spreading mis-information (sic). What I intended to say and believed that I had said was that the earth rotated 365.242 times per year (on its own axis) while rotating once around the sun (one year). Thus we have 365.242 revolutions of the earth per year relative to the sun - during one solar year. However, if one were to observe this from another solar system, the earth makes 366.242 sidereal revolutions. .

Both cannot be true. It is a matter of your point of reference. If you are looking at the axis point, the extra revolution is so gradual that you don't notice it, being less than 1 degree per day. If you look at something more distant like the stars you will count 366 revolution, as they would observing you.

The links I gave you have graphical representations to explain it.

Both are true. If you are sitting in a fixed orbit of the sun ( rather warm) you would count 365+ revolutions of the earth during one year . If you were in a fixed orbit of another sun, you would count 366+ rotations of the earth. The difference ? One extra rotation of the earth around the sun. No charts needed

[dickyknee]

Sorry if you believe that I have been spreading mis-information (sic). What I intended to say and believed that I had said was that the earth rotated 365.242 times per year (on its own axis) while rotating once around the sun (one year). Thus we have 365.242 revolutions of the earth per year relative to the sun - during one solar year. However, if one were to observe this from another solar system, the earth makes 366.242 sidereal revolutions. .

Both cannot be true. It is a matter of your point of reference. If you are looking at the axis point, the extra revolution is so gradual that you don't notice it, being less than 1 degree per day. If you look at something more distant like the stars you will count 366 revolution, as they would observing you.

The links I gave you have graphical representations to explain it.

Both are true. If you are sitting in a fixed orbit of the sun ( rather warm) you would count 365+ revolutions of the earth during one year . If you were in a fixed orbit of another sun, you would count 366+ rotations of the earth. The difference ? One extra rotation of the earth around the sun. No charts needed

I'm standing on the earth, and it rotates 360 degrees ie. 1 full rotation, how many times does it do this in a year?

[halloween]

Sorry if you believe that I have been spreading mis-information (sic). What I intended to say and believed that I had said was that the earth rotated 365.242 times per year (on its own axis) while rotating once around the sun (one year). Thus we have 365.242 revolutions of the earth per year relative to the sun - during one solar year. However, if one were to observe this from another solar system, the earth makes 366.242 sidereal revolutions. .

Both cannot be true. It is a matter of your point of reference. If you are looking at the axis point, the extra revolution is so gradual that you don't notice it, being less than 1 degree per day. If you look at something more distant like the stars you will count 366 revolution, as they would observing you.

The links I gave you have graphical representations to explain it.

Both are true. If you are sitting in a fixed orbit of the sun ( rather warm) you would count 365+ revolutions of the earth during one year . If you were in a fixed orbit of another sun, you would count 366+ rotations of the earth. The difference ? One extra rotation of the earth around the sun. No charts needed

And this optical illusion is caused by what? the extra rotation is THERE, you just don't notice it. this is covered in any number of astronomy websites.

Edited June 16, 2015 by halloween

[tigermonkey]

Sorry if you believe that I have been spreading mis-information (sic). What I intended to say and believed that I had said was that the earth rotated 365.242 times per year (on its own axis) while rotating once around the sun (one year). Thus we have 365.242 revolutions of the earth per year relative to the sun - during one solar year. However, if one were to observe this from another solar system, the earth makes 366.242 sidereal revolutions. .

Both cannot be true. It is a matter of your point of reference. If you are looking at the axis point, the extra revolution is so gradual that you don't notice it, being less than 1 degree per day. If you look at something more distant like the stars you will count 366 revolution, as they would observing you.

The links I gave you have graphical representations to explain it.

Both are true. If you are sitting in a fixed orbit of the sun ( rather warm) you would count 365+ revolutions of the earth during one year . If you were in a fixed orbit of another sun, you would count 366+ rotations of the earth. The difference ? One extra rotation of the earth around the sun. No charts needed

I'm standing on the earth, and it rotates 360 degrees ie. 1 full rotation, how many times does it do this in a year?

388.242

[tigermonkey]

Sorry if you believe that I have been spreading mis-information (sic). What I intended to say and believed that I had said was that the earth rotated 365.242 times per year (on its own axis) while rotating once around the sun (one year). Thus we have 365.242 revolutions of the earth per year relative to the sun - during one solar year. However, if one were to observe this from another solar system, the earth makes 366.242 sidereal revolutions. .

Both cannot be true. It is a matter of your point of reference. If you are looking at the axis point, the extra revolution is so gradual that you don't notice it, being less than 1 degree per day. If you look at something more distant like the stars you will count 366 revolution, as they would observing you.

The links I gave you have graphical representations to explain it.

Both are true. If you are sitting in a fixed orbit of the sun ( rather warm) you would count 365+ revolutions of the earth during one year . If you were in a fixed orbit of another sun, you would count 366+ rotations of the earth. The difference ? One extra rotation of the earth around the sun. No charts needed

And this optical illusion is caused by what? the extra rotation is THERE, you just don't notice it. this is covered in any number of astronomy websites.

There is no optical illusion !Of course the rotation is there. You don't notice it if you are looking at the sun, but you do notice it if you are looking at the stars.

[StreetCowboy]

Sorry if you believe that I have been spreading mis-information (sic). What I intended to say and believed that I had said was that the earth rotated 365.242 times per year (on its own axis) while rotating once around the sun (one year). Thus we have 365.242 revolutions of the earth per year relative to the sun - during one solar year. However, if one were to observe this from another solar system, the earth makes 366.242 sidereal revolutions. .

Both cannot be true. It is a matter of your point of reference. If you are looking at the axis point, the extra revolution is so gradual that you don't notice it, being less than 1 degree per day. If you look at something more distant like the stars you will count 366 revolution, as they would observing you.

The links I gave you have graphical representations to explain it.

Both are true. If you are sitting in a fixed orbit of the sun ( rather warm) you would count 365+ revolutions of the earth during one year . If you were in a fixed orbit of another sun, you would count 366+ rotations of the earth. The difference ? One extra rotation of the earth around the sun. No charts needed

I'm standing on the earth, and it rotates 360 degrees ie. 1 full rotation, how many times does it do this in a year?

How do you measure a full rotation? If you base it by the position of the sun in the sky, then it's more than 360 degrees (approx. 360/365 of a degree more), because in the intervening day, the sun has moved relative to the earth (or vice versa); if you base it by the position of some remote star in the sky, then it's 360 degrees. In the first case, there are 365.242 (apparently) rotations of slightly more than 360 degrees each. In the other case, there are 366.242 rotations.

We can be fairly confident that the earth does not rotate about remote stars, because the apparent rotation is the same for remote stars in opposite directions.

You really ought to try this out using a marker pen, a large table and a selection of soft fruit. If you want to model the behaviour of distant stars, you'll want a large piece of felt - I would prefer green, but your choice may differ - and some smarties, or M & Ms if you can't get smarties. If the worst came to the worst you could use grapes or olives, but green grapes (or olives) would not show up well against the felt. You might also want a protractor.

By the way, it's not an extra rotation - we lose a day because the effective annual progression around the sun is effectively in the opposite direction to the rotation of the earth - but probably best not to mention this when renegotiating your contract, except under pension entitlement

SC

[Zyxel]

Do you believe that the moon rotates on its axis, and circles the earth, or do you believe that the moon rotates around the axis of the earth?

I'm wishing now I'd disassembled my old Sturmey Archer hub

The moon rotates exactly 360° around its axis when it completes one rotation around the earth, so we see always the same side of the moon.

[Basil B]

So do we in the UK see the same image as seen in Thailand?

[Maestro]

Shall we be gracious and assume that Jarin said it correctly, ie every 1,000 years, and the newspaper printed it wrong? He probably spoke Thai. What did the Thai papers print, ร้อย or พัน่?

[Thai at Heart]

Only in Thailand was this a headline