General Question

Ltryptophan's avatar

Is the earth in essentially the same position it was everyday before?

Asked by Ltryptophan (12091points) May 6th, 2020 from iPhone

The earth spins and creates our days. My understanding is that at noon each day, the sun is generally at the highest point.

Does the position of earths spin offer any insight into what time of day it is in such a way that, if one had a model of earth on a fixed axis, like a globe, that one could say with some certainty if the position of the sun was also at a fixed position, you could tell what time it is by looking at the planet’s face?

Would the elliptical orbit around the sun make this impossible without a more complicated mechanical solar system model?

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13 Answers

RedDeerGuy1's avatar

No. The sun is also rotating revolving around the galaxy. About once every 100 million years or so. So every day is a new location.

Ltryptophan's avatar

@RedDeerGuy1 I meant, Earths face can’t tell time with just where it is in its own spin.

RedDeerGuy1's avatar

@Ltryptophan Oh. Are you suggesting an updated sundial? High noon is what we used to call the brightest time of day. Every province or state had their own time for high noon. The error made it difficult to trade with different time zones. With train crashes and other problems that I can’t recall right now.

I don’t fully understand your question, but I appreciate the attempt at real science.

RedDeerGuy1's avatar

@Ltryptophan I hope this link helps? I haven’t watched the whole nine minute video. How To Fix your Position at Noon from the Sun

Or you can look up sun sights?

zenvelo's avatar

@Ltryptophan One can tell the approximate time by knowing where the sun appears to be in the sky. But one also has to account for the relative angle of the earth in comparison to the ecliptic.

At the Solstice, the sun appears to be as far north or south in the sky, while at the equinox it appears to be directly overhead.

kritiper's avatar

There was a time when if the sun was directly overhead, it was noon. But the railroads put a stop to that because in every town the time was a little bit different and the trains couldn’t run on time or without danger of crashing into another train that was on a different time. This time standardization came into being at 12 noon, 90th Meridian time, Nov. 18, 1883.
Other than that, the sun shines differently depending on which day of the year it is and how high or low the sun is in the sky.
I have a house where the back is facing South. There is one large and one small kitchen window in this part of the house. As the sun climbs or falls during the year, the sun will either start to shine through these windows or will stop shining through these windows. With the large window, the sun will start to enter at noon on Oct. 9 and will cease to enter at noon on March 6. With the small window, the sun will begin to enter at noon on Nov. 4 and will cease to enter at noon on Feb. 7. It is the same every year.

Ltryptophan's avatar

If I could hold a 2 in diameter hologram of earth being filmed in real time, and I set the hologram to always have my house in the very middle would anything about this setup tell me my current time?

Or, if I had a virtual solar system of just earth and the sun, could I look at this display and know what time it is on earth, simply by the physical position of the respective bodies?

stanleybmanly's avatar

The answer (as the rather confusing question stands is an emphatic no). The planet’s face won’t tell you anything beyond night and day. In more ways than you can name, the earth will NEVER be in the same position it was the day before. Even inclusion of the essential clause “relative to the sun”, the earth must fail the test—thus the seasons. The fact that the days grow shorter or longer is proof right off the bat that the sun cannot be in same place in the sky at noon 2 days in a row. For any point on the earth, the arc of the sun must daily be either longer or shorter across the sky. Another way of stating this is that the sun must be either higher or lower in the sky at noon from day to day. “Position of the earth’s spin?” Direction I understand, but position? And finally, the earth’s axis is not fixed.

Ltryptophan's avatar

@stanleybmanly yes, therefore it would not be possible to use earths position at any moment to decide with a glance, the time, since divers systems are at play.

Not even a solar chart with a position time reference on earth could accurately predict the time.

Since, just by looking you would only know if the sun were “up” at any locale.

In conclusion it would be highly inefficient, for any refernce except maybe an initial measurement to start a time system.

gondwanalon's avatar

The Earth is never in the same place it was 24 hours earlier. The Earth travels around the Sun at 66,621 miles per hour. The Sun and our solar system is traveling 514,453 mph around the Milky Way Galaxy. The Milky Way Galaxy is hurtling through space at 1.3 million miles per hour.

stanleybmanly's avatar

We must be clear in our terms. And of course if you talk about time on the earth it must depend totally on WHERE you are on the earth. Noon will be that point in the day when a straight line drawn from you through the sun’s center is shortest.

Call_Me_Jay's avatar

Not even a solar chart with a position time reference on earth could accurately predict the time.

That would be a sundial.

It has to be calibrated for your latitude and time of year which can be done thus:
Noon will be that point in the day when a straight line drawn from you through the sun’s center is shortest.

If you marked solar noon on your sundial every day for a year you would have the basis of your chart.

Caravanfan's avatar

I’m a proficient amateur astronomer and I don’t quite understand the question. Can you please restate it? I think I’m missing something.

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