Final answer:
Three astronomical factors that affect the amount of solar radiation striking the earth and cause glacial and interglacial fluctuations within ice ages are changes in Earth's orbit, changes in solar intensity, and changes in the tilt of Earth's rotational axis.
Step-by-step explanation:
The three astronomical factors that affect the amount of solar radiation striking the earth and cause glacial and interglacial fluctuations within ice ages are changes in Earth's orbit, changes in solar intensity, and changes in the tilt of Earth's rotational axis. Changes in Earth's orbit, known as Milankovitch cycles, have a significant impact on climate over tens of thousands of years, causing both long periods of cold temperatures (ice ages) and relatively warmer interglacial periods. Changes in solar intensity, which is the amount of solar power the sun emits, directly affect the Earth's temperature. The tilt of Earth's rotational axis, produced by the gravitational effects of other planets, also plays a role in triggering ice ages.