They interpreted the weak sources as being the more distant ones, and the stronger ones as being nearer. Then there appeared to be less common sources per unit volume of space for the nearby sources than for the distant ones. This could mean that we are at the center of a great region in the universe in which the sources are fewer than elsewhere.
Alternatively, it could mean that the sources were more numerous in the past, at the time that the radio waves left on their journey to us, than they are now. Either explanation contradicted the predictions of the steady state theory.
Moreover, the discovery of the microwave radiation by Penzias and Wilson in 1965 also indicated that the universe must have been much denser in the past. The steady state theory therefore had to be abandoned.
Another attempt to avoid the conclusion that there must have been a big bang, and therefore a beginning of time, was made by two Russian scientists, Evgenii Lifshitz and Isaac Khalatnikov, in 1963. They suggested that the big bang might be a peculiarity of Friedmann’s models alone, which after all were only approximations to the real universe. Perhaps, of all the models that were roughly like the real universe, only Friedmann’s would contain a big bang singularity. In Friedmann’s models, the galaxies are all moving directly away from each other - so it is not surprising that at some time in the past they were all at the same place. In the real universe, however, the galaxies are not just moving directly away from each other - they also have small sideways velocities. So in reality they need never have been all at exactly the same place, only very close together. Perhaps then the current expanding universe resulted not from a big bang singularity, but from an earlier contracting phase; as the universe had collapsed the particles in it might not have all collided, but had flown past and then away from each other, producing the present expansion of the the universe that were roughly like Friedmann’s models but took account of the irregularities and random velocities of galaxies in the real universe. They showed that such models could start with a big bang, even though the galaxies were no longer always moving directly away from each other, but they claimed that this was still only possible in certain exceptional models in which the galaxies were all moving in just the right way. They argued that since there seemed to be infinitely more Friedmann-like models without a big bang singularity than there were with one, we should conclude that there had not in reality been a big bang. They later realized, however, that there was a much more general class of Friedmann-like models that did have singularities, and in which the galaxies did not have to be moving any special way. They therefore withdrew their claim in 1970.
Velocity 速度
他們將弱源解釋為更遙遠的源，強源為較近的源。結果發現，單位空間體積內普通的源在近處比遠處稀少。這可能表明，我們處於宇宙的一個巨大區域的中心，在這兒的源比其他地方稀少。另外的一個解釋是，宇宙在射電開始發出的過去的那一時刻具有比我們現有的更密集的源。任何一種解釋都和穩態理論相矛盾。況且，1965年彭齊亞斯和威爾遜的微波背景輻射的發現又指出，宇宙在過去必須密集得多。因此穩態理論必須被拋棄。
1963年，兩位蘇聯科學家歐格尼·利弗席茲和伊薩克·哈拉尼可夫做了另一個嘗試，設法避免存在大爆炸並因此引起時間起點的問題。他們提出；大爆炸可能只是弗利德曼模型的特性，這個模型畢竟只是真實宇宙的近似。也許，所有大體類似實在宇宙的模型中，只有弗利德曼模型包含大爆炸點。在弗利德曼模型中，所有星系都是直接互相離開——所以一點不怪，在過去的某一時刻它們必須在同一處。然而，在實際的宇宙中，星系不僅僅是直接互相離開——它也有一點橫向速度。所以，在現實中它們從來沒必要在同一處，只不過非常靠近而已。也許，現在膨脹著的宇宙不是大爆炸點的結果，而是從早期的收縮相而來的；當宇宙坍縮時，其中的粒子可以不都碰撞，而是互相離得很近穿過然後又離開，產生了現在的宇宙膨脹。何以得知這實際的宇宙是否從大爆炸開始的呢？利弗席茲和哈拉尼可夫研究的模型大體和弗利德曼模型相像，但是考慮了實際宇宙中的星系的不規則性和雜亂速度。他們指出，即使星系不再總是直接互相離開，這樣的模型也可從一個大爆炸開始。但是他們宣稱，這隻可能發生在一定的例外的模型中，星系在這兒以正確的方式運動。他們論證道；似乎沒有大爆炸點的類弗利德曼模型比有此點的模型多無限多倍，所以我們的結論應該是，實際中沒有過大爆炸。然而，他們後來意識到，存在更為廣泛的具有性的類弗利德曼模型，星系在那兒並不需要以任何特別的方式運動。所以，1970年他們收回了自己的宣佈。
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