Astronomy and Space Science Fundamentals

After the full moon, the moon begins waning (shrinking). The waning gibbous phase comes after the full moon as the illuminated portion decreases toward the last quarter. The options 'New moon' and 'Waxing gibbous' are incorrect because waxing means growing. Option D has a typo (wanning instead of waning) but is the correct phase.

The lunar cycle is approximately 29.5 days. A full moon occurs roughly halfway through the cycle, about 14 to 15 days after a new moon.

Energy in the electromagnetic spectrum is directly proportional to frequency. X-rays have a much higher frequency and energy than microwaves, infrared, or ultraviolet radiation.

Scientists use the electromagnetic spectrum to study objects in space by detecting the various wavelengths of radiation they emit, such as radio waves, which can penetrate dust clouds.

The Hertzsprung-Russell diagram shows that stars with average temperature and brightness fall along the main sequence, where our Sun is located.

For main sequence stars, there is a direct correlation between temperature and luminosity. Hotter stars appear brighter and bluer, while cooler stars appear dimmer and redder.

Distances in space are so vast that using standard units like kilometers or miles would result in unmanageably large numbers. A light year is a unit of distance based on how far light travels in one year, which simplifies astronomical calculations.

When the North Pole is tilted toward the sun, the Northern Hemisphere receives more direct sunlight for longer periods, resulting in summer. The tilt of the Earth's axis is the primary driver of seasonal changes.

Earth's rotation on its axis causes the cycle of day and night, sunrise and sunset, and affects global wind patterns via the Coriolis effect. Seasons are caused by the Earth's axial tilt and its revolution around the sun, not its rotation.

Earth's revolution is the path it takes around the sun, which takes approximately 365.25 days, or one year. Option D is a humorous distractor.