1·A discovery that neutrinos, virtually massless particles, convert into other forms known as muon and tau before they leave the sun, solving a 40-year-old mystery.
发现中微子(几乎是无质量的粒子)在离开太阳之前可转化介子，解开了一个40年的谜。
2·This medium is called Ether, which is an omnipresent, boundlessly resilient, massless medium unable to be sensed that was formerly theorized as the medium that carried light.
这种介质称为以太，它是一种无所不在的，有无限弹性的，无质量的，不不能被感知的介质，在从前它被理论化为能运载光的介质。
3·A massless rope is wrapped around a hollow cylinder of radius 12 cm whose central axis is fixed in a horizontal position.
一个无质量的绳子缠在一个半径为12厘米的空心圆柱上，其中心轴固定在一个水平位置。