Changing Earth's Orbit: How Has the Speed Around the Sun Evolved?

AI Thread Summary
The Earth's orbit around the sun has evolved significantly over billions of years, with its orbital period decreasing from approximately 0.89 years shortly after the solar system's formation to a predicted 1.15 years in the future. Current studies indicate that the distance from the Earth to the sun has also changed, from about 138 million kilometers to a projected 164 million kilometers over the same timeframe. Temperature variations associated with these orbital changes have been relatively minor, with only slight increases and decreases observed over the past and future million years. Tidal braking is identified as a contributing factor to changes in Earth's orbit, while the expanding universe does not significantly impact this aspect. Overall, the evidence suggests that while Earth's orbit and climate have changed, these changes are not as drastic as previously assumed.
Juswannaknow
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I understand that the Earth takes 365 days (give or take) to orbit the sun. I also understand that the physics of the universe are in continual flux (expanding universe, cooling suns, etc).

Question: Is it plausible to assume that the Earth took a shorter/longer time to orbit the sun a billion (5 billion, 10 billion) years ago? If so, is there any studies or evidence indicating the rate of change?
 
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With a little help from google I got:

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After the formation of the solar system (-4.5 Byr) the Earth orbit was at 1.38E08 km (presently 1.50E08 km) and the Earth period was 0.89 years. In the future (+4.5Byr), they are predicted to be 1.64E08 km and 1.15 yr. At -4.5 Byr, present temperatures of -50, zero, and + 50 C were higher at -40.5, 11.7, and 63.9 C, respectively. It is predicted that in +4.5 Byr, these temperatures will have decreased to -60.0, -12.2, and 35.5 C. In the past million years, the present -50, 0, and +50 C temperatures were about 0.03C higher, and will be about 0.03 C lower in another million years. These results indicate that temperature changes due to solar-Earth orbital interactions do not significantly contribute to the observed Earth global warming observations.

Above is from:

American Geophysical Union - 2007 Fall Meeting
Earth Orbit, Period, and Temperature - Past and Future
(Abstract)

Presentation:
10–14 December 2007
Ingo H. Leubner Rochester
Institute for fundamental Research
 
So, causes of change in Earth-Sun distance:

- expanding universe: no
- tidal braking: yes
 
Hmmm.. thank you very much! I had the impression that the changes would be much greater.
 
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