Preserve Fresh Meat: Spin at Relativistic Speeds?

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Discussion Overview

The discussion revolves around the hypothetical scenario of preserving fresh meat by spinning it at relativistic speeds, exploring the implications of time dilation and temperature in this context. Participants examine the feasibility of using high-velocity centrifuges and the energy costs associated with achieving significant time dilation, while also considering the physical effects on the meat and the mechanics of temperature in relation to motion.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants propose that spinning fresh meat at high speeds could theoretically extend its shelf life due to time dilation.
  • Others argue that the energy required to achieve significant time dilation would be prohibitively high compared to conventional freezing methods.
  • A participant mentions that while a high-velocity centrifuge could be used, the centrifugal forces would likely destroy the meat and the centrifuge itself.
  • Another participant calculates that even at extreme speeds, the time dilation effect would be minimal, resulting in negligible preservation benefits.
  • There is a discussion about the relationship between temperature and motion, with some participants expressing confusion about how motion affects temperature.
  • Participants clarify that temperature and motion are independent, and discuss different definitions of temperature in various reference frames.
  • One participant questions the validity of the definition of temperature in the context of relativistic speeds.

Areas of Agreement / Disagreement

Participants express differing views on the practicality and effectiveness of using relativistic speeds for food preservation, with no consensus reached on the feasibility of the proposed methods or the implications of temperature in this scenario.

Contextual Notes

Limitations include the assumptions about the physical integrity of the meat and centrifuge at high speeds, the energy calculations for achieving relativistic speeds, and the definitions of temperature in different frames of reference.

guigabyte
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Let's assume there is a device that can hold fresh meat in a stationary position, and this device can spin at relatively high speeds. Would this allow fresh meat to last longer without freezing?
 
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I guess it might, but it would take astronomically more energy than just running a freezer :smile:
 
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You could put it in a high velocity centrifuge, yes. In principle.

But the energy cost to achieve significant time dilation is pushing the annual energy output of a country - per kilogram. And the centrifugal force would turn the meat into strawberry jam. And probably disintegrate the centrifuge with devastating consequences for any nearby cities.
 
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The meat would disintegrate. In addition, the center would not experience time dilation.

If the meat survives 1000 g and we build a racetrack around the whole Earth, we can give the meat a maximal speed of ##v= \sqrt {R \cdot 1000 g} = 250 \frac{km}{s}##. This leads to a time dilation factor of 1.00000034. For 1 day for us, the meat experiences 0.03 seconds less. Not a very effective way to preserve it.

Let's make a big ring around Earth following the Moon's orbit. We can now achieve a speed of 1900 km/s. We now have a time dilation factor of 1.000019. For every day on Earth the meat ages 1.7 seconds less. Unfortunately the meat needs some time to get to this ring - much more than 1.7 seconds.

Let's dismantle Earth and replace it by a ring around the Sun with the same diameter as Earth's orbit. Now we can increase the speed to 40,000 km/s, more than 10% the speed of light. The time dilation factor is now 1.0084, for every day the meat experiences 12 minutes less. Still not very effecive. Note that "days" are not a good measure of time any more as there is no rotating Earth left in this scenario.
 
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Very interesting. Time dilation preserve food. I would like to add here a point of temperature. I am still puzzled freeze meet is cooled or warmed by motion?
 
Temperature and motion are independent.
 
Some old books say differently [tex]T=T_0,T=\frac{T_0}{\gamma},T=\gamma T_0[/tex] I agree ice is ice for everybody not boiling water to anyone.
 
These equations are different relations between temperatures as seen by different frames, for different choices of the definition of temperature. If you want things to boil at the same temperature, for example, you need the first one, where temperature is the same in all reference frames.
You can freely choose the temperature of the meat in its rest frame independent of the velocity.
 
Is the definition of temperature as ##\partial U / \partial S## still valid in this case?
 

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