Final answer:
The main parts of a comet as it nears the Sun include the gas tail, dust tail, and nucleus. The gas tail is straight and composed of ionized gases, while the dust tail contains small particles and curves slightly. The nucleus, made of ice, gas, and dust, is the core that releases the materials forming the tails and coma.
Step-by-step explanation:
When a comet nears the Sun, several distinct parts become more visible. The main parts of a comet as it approaches the Sun include the gas tail, the dust tail, and the nucleus. The nucleus is the core of the comet, composed of ice, gas, and dust, and is typically a few kilometers in size. As a comet gets closer to the Sun, the nucleus heats up and releases gases and dust that form the comet's atmosphere or coma. The dust tail and the gas tail (also known as the ion tail), are two different types of tails that form from the coma. The dust tail consists of small particles the size of smoke grains, often extending up to 10 million kilometers in length and curving slightly as it spreads out along the comet's orbit. Contrarily, the gas tail, which can stretch up to hundreds of millions of kilometers, is primarily made up of ionized gases that are pushed directly outward from the Sun by the solar wind, forming a straighter tail than the dust tail.