The A.U. is collectively fixed

The recent meeting in China drew to a close last month with the collective agreement that the definition of the Astronomical Unit (distance between the earth and the sun) should be simplified and fixed as one number.

One of the stalwart units of astronomy just got a makeover. The International Astronomical Union, the authority on astronomical constants, has voted unanimously to redefine the astronomical unit, the conventional unit of length based on the distance between the Earth and the sun.

This fixing of the variable seems like a move to undermine all future space travel. Since we can no longer accurately calculate stellar distances within our own solar system. The rationale:

The revision also makes the unit easier for engineers, software designers and students to understand, Klioner and his colleague Nicole Capitaine, of Paris Observatory, noted.

Since the entire community has agreed upon this less accurate method for calculating true distances it raises an interesting question about the accuracy of all the terms used to define distance. We are simplifying and fixing these numbers with a knowledge that on this planet those discrepencies don't add up to much, but when traveling to the moon or mars, a few feet does matter. It could be life and death.

Ask yourself how any measurement is made without reducing the many variables down to some fixed constants to make it easier to calculate. Every tool man has created for making such measurements incorporate some assumptions and minor falsehoods. So any solution is bound to carry with it one of those +/- means, or degrees of accuracy.

I'm only raising this odd point because I've always believed that if there is any falsehood in my solutions then the entire outcome is false. I've never found what I'm seeking 100% of the time, maybe its not possible?

when traveling to the moon or mars, it is obvious that more precise calculations would be used...i fail to understand what your point is here. this "new AU" would of course, be an approximation.

Originally posted by RedDogJT
This fixing of the variable seems like a move to undermine all future space travel. Since we can no longer accurately calculate stellar distances within our own solar system.

I'm sure you have a source for what you quoted above. Did you forget to post it?

If it was a variable it was never very useful for calculations. As a constant now could more useful, but I don't really know who uses the AU in calculations, but it's easier to work with a constant than a variable, so it seems like the exact opposite of what you said is true. The AU is too small for "stellar distances". Cosmologists use a unit called the "parsec", as AUs are way too small for them.

The only problem will be in 1000 years when the distance from the Earth to the sun is no longer 1 AU, people will comment on the archaic origin of the unit, but they will simply say the distance is 1.01AU or whatever it actually is at that time, instead of 1.00 like it is now.

reply to post by Arbitrageur

I bring this up because it is one of my pet peeves.

The quote was from both Space.com and the I.A.U. website. They have been "discussing" it for over 20 years arguing about accuracy versus (to use your words) "usefullness" in calculations. I only brought this up as a point about accuracy in general. When we look at the terms used to define most all scientific principles we find the same issue cropping up: accuracy of the actual item being measured or observed, versus the collective agreement of a fixed value for the term for usefullness in calculations. Trust me I understand the latter, but I cannot help the sinking feeling that so much of the underlying foundations of all scientific endeavours have this same fatal flaw, from drug development to airplanes to space travel. Yet few ever question this natural tendency to simplify the equation down to 1 inch, because doing so is a form of mathematical holy grail.

Plus when you look at the picture on the IAU website of them all voting to agree on this fixing of the A.U. They all seem none to happy about it.