Hi Yanirru,

Your explanation only addressed why the balloon doesn't get so thin that it bursts.

What I am interested in is the question of a meaningful definition of length. If we define length to be based on the size of some particles, then we would indeed discover that the universe is expanding. But if we could somehow make marks on space itself, then from what you describe, these marks would move apart as new space is created between them. Using this definition of length, the universe would stay the same size, but all material structures would be shrinking.

Either method seems unreliable to me. Do you know of a way to define 'length' that is trustworthy?

Warm regards,

Paul

• Definition of time and length - alexander - November 22, 2001 - 19:39 UTC
  • But you must make assumptions to make the definitions - pmartin - November 22, 2001 - 22:45 UTC
    • Both wavelength and frequency do not change. - alexander - November 22, 2001 - 23:35 UTC
      • How can we be so sure h, e, or c don't change? (nt) - pmartin - November 23, 2001 - 07:18 UTC
        • I predict... - luis_hamburgh - November 23, 2001 - 07:44 UTC
          • Wavelength of light changes - yanniru - November 23, 2001 - 15:07 UTC
          • Luis, you often makes wrong conclusions. - alexander - November 23, 2001 - 18:46 UTC
            • It was a prediction, not a conclusion - luis_hamburgh - November 23, 2001 - 21:19 UTC
              • Space is expanding, not structures. - alexander - November 23, 2001 - 22:47 UTC
                • So, how did our universe attain its current size? - luis_hamburgh - November 25, 2001 - 20:26 UTC
                  • The dark side - yanniru - November 25, 2001 - 21:31 UTC
                    • Thanks, Richard - luis_hamburgh - November 26, 2001 - 02:46 UTC
                      • Universal expansion not detectable - yanniru - November 26, 2001 - 16:05 UTC
            • Sums it up - bruce - November 23, 2001 - 22:54 UTC
              • To see the derivation for fsc.. - bruce - November 23, 2001 - 22:57 UTC