Like Neptune, Pluto was initially discovered through mathematical predictions rather than by observation.

和海王星一样，冥王星最初由数学预测，而非观测发现。

Of that total, about 9,200 are estimated to exist based on mathematical predictions but have not yet been identified by science.

根据数理预测，据估其中约有9200个未知树种存在，但尚未经科学证实。

It's the most dense of the outer planets and the only planet found by mathematical prediction rather than by empirical observation.

它是密度最大的外行星，也是唯一一颗通过数学预测而非经验观察发现的行星。

Neptune was the first planet to be discovered through mathematical predictions instead of being seen, as it is too faint to be observed with the unaided eye.

它还是首个由数学测算而非观测发现的行星，由于它太过暗淡，所以无法用肉眼观察到。