| 1. | Mercury and venus are inferior planets in the solar system as they are nearer to the sun than the earth
内行星凌日现象水星和金星是太阳系中的内行星，它们比地球更接近太阳。 |
| 2. | Figure 1 the relative positions of the sun , an inferior planet and the earth during the transit of the inferior planet
发生内行星凌日现象时，太阳、内行星及地球的相对位置。 |
| 3. | This phenomenon does not occur every year because of the inclination of the inferior planet s orbit to that of the earth ( figure 1 )
由于内行星围绕太阳公转的轨道与地球的轨道并不是在同一平面上，内行星凌日现象并不是每年都会发生( |
| 4. | Mercury is an inferior planet of the solar system . whenever it comes between the earth and the sun , the tiny silhouette of mercury will be found passing the suns disc slowly
水星是内行星，每当它运行至地球和太阳之间，水星细小的剪影便会在日面缓缓掠过，这个现象称为水星凌日。 |
| 5. | An inferior planet is in superior conjunction when in line with the sun and the earth and on the far side of its orbit with respect to the latter ; when it lies between the sun and the earth it is said to be in inferior conjunction
当内行星运行至与地球和太阳成一直线时，称为上合，而运行至太阳和地球之间时，称为 |
| 6. | A transit of an inferior planet occurs when the inferior planet , the sun and the earth align in a straight line with the inferior planet in between . during the transit , the inferior planet appears as a dark dot across the sun s disc
内行星及地球三者连成一直线而内行星在太阳与地球之间，视觉上内行星会尤如一个黑色圆点在太阳的圆面上横过。 |
| 7. | The angular distance between the sun and a planet or the moon . it is also the difference in ecliptic longitude between the sun and other celestial objects . when an inferior planet follows the sun in its daily motion , appearing east of the sun in the evening , it is in eastern elongation
距角是太阳和太阳系内天体的角距，亦即是太阳和它们相差的黄经，以在日落后见于西方的内行星来说，这时内行星在处于太阳的东面，若这时的角距是在这段时间内最大的，便是 |
