第1个回答 2008-12-15
你接触一下混沌理论吧,有人认为这是可以与爱因斯坦的相对论相提并论的,我也认为有一点道理。
混沌理论说,最开始是从天气预报理论推出来的,是说不管科学技术如何发达,人类都不可能预知两周之后的天气。推论到人类不管如何发达都不可能预知将来。
你如果接触过计算科学就应该知道,在计算很多数据时,只要起始量做一点很好的变化,多次计算结果进行迭代后,结果就会产生很大误差,这样说,比如如果想得到一个数周之后的天气,那么对于现在的测量量的微小误差,足以使结果不可信。
要想得到精确结果,就得一而再地提高现在的初始量,如根据海森堡理论,微小粒子不可辨性,小到一定程度,两个值就无法分离开来,这样,从理论上说,任何事情到超过一定的界限,人类就再也无法预测到。
混沌理论从理论上说明了人类科学再发展也逃不出的恶魔之爪,我认为很有意义。
第5个回答 2008-11-30
Since, as Paola Zizzi says in gr-qc/0007006, ( with some editing by me denoted by [ ] ): "... the quantum register grows with time. ... At time Tn = (n+1) Tplanck the quantum gravity register will consist of (n+1)^2 qubits. [ Let N = (n+1)^2 ] ...", we have the number of qubits at Reheating:
Nreh = ( n_reh )^2 = ( 2^128 )^2 = 2^256 = 10^77
Since each qubit at Reheating should correspond, not to Planck Mass Black Holes, but to fermion particle-antiparticle pairs that average about 0.66 GeV, we have the result that
the number of particles in our Universe at Reheating is about 10^77 nucleons.
After Reheating, our Universe enters the Radiation-Dominated Era, and, since there is no continuous creation, particle production stops, so
the 10^77 nucleon Baryonic Mass of our Universe has been mostly constant since Reheating,
and will continue to be mostly constant until Proton Decay.
The present scale of our Universe is about R(tnow) = 10^28 cm, so that its volume is now about 10^84 cm^3, and its baryon density is now about 10^77 protons / 10^84 cm^3 = 10^(-7) protons/cm^3 = 10^(-7-19-5) gm / cm^3 = 10^(-31) gm / cm^3 = roughly the baryonic mass density of our Universe.
Since the critical density of our Universe is about 10^(-29) gm / cm^3, it is likely that the excess of the critical mass of our Universe over its baryonic mass is due to a cosmological constant.
上面说宇宙中所有核子的数目大概是10^77,也许这就是上面那个上限的来源