The physical and chemical nature of life must begin with the Sun， actually the Sun’s very center， not the Earth. The source of the energy is from the center of the Sun.
Here the Sun constantly pours out energy out into space as light billions upon billions of nuclei of hydrogen atoms at the center of the Sun collide with each other and fuse together to form nuclei① of helium②， during which the energy stored in the nuclei of atoms is liberated. The output of light and heat of the Sun requires that some 600 million tons of hydrogen be converted into helium every second in the Sun. This convertion of the Sun has been doing for several thousands of millions of years.
The nuclear energy is released as high-energy gamma radiation， a form of electromagnetic radiation like light and radio waves at the Sun’s center. This radiation has a very much shorter wavelength. The gamma radiation is absorbed by atoms inside the Sun to be reemitted at slightly longer wavelengths. This new radiation is absorbed in its turn and re-emitted③. As the energy filters through the layers of the solar interior， it passes through the X-ray part to become light at length. At this stage， energy reaches the surface that we call as the solar surface， and can escape into space without being absorbed further by solar atoms. Only a very small fraction of the Sun’s light and heat is emitted in such directions without being hindered to pass through interplanetary④ to hit the Earth.
① nuclein. (nucleus的复数) ［核］(原子)核
② heliumn. ［化］氦
③ emitv. 散发，放射；发出
④ interplanetaryadj. 行星间的
能量的来源
生命的物理和化学特性应该从太阳——确切地说，是太阳的核心，而非地球来说起。能量来自太阳的核心。
这里，太阳不停地向空间以光和热的形式倾泻能量。数十亿计的氢原子核在太阳的核心碰撞并且聚变生成氦。在此过程中一部分原本储存于原子核中的能量就被释放出来。太阳所产生的光和热需要以每秒6亿吨的速度将氢转化为氦。这样的转化在太阳中已经持续几十亿年了。
核能在太阳的核心被释放为高能的，就像光波和无线电波一样的电磁射线，也称为伽马射线。这种射线的波长要短得多，在被太阳内的原子所吸收后，会重新释放为波长稍长一些的光波。这新的射线被再次吸收，而后又释放。能量从太阳内部一层层渗透出来，在这个过程中，它经过了光谱中X射线部分，最后变成了光。这个阶段中，能量到达我们所称的太阳表层，并且离散到空间而不再被太阳原子所吸收。只有很小一部分太阳的光和热未被阻挡由此方向释放出来，穿越星空，到达地球。
