托福閱讀天文類背景材料：水星的幾個之“最”記錄

水星是太陽系八大行星中離太陽最近的一顆行星,，因其獨特的特性而備受關注。本文將探討水星在太陽系中的幾個“最”記錄,，幫助托?？忌玫乩斫膺@一神秘的行星,。

離太陽距離最近

水星與太陽的平均距離為5790萬公里，約為日地距離的0.387倍,，迄今為止尚未發(fā)現比水星更靠近太陽的行星,。

軌道速度最快

由于水星離太陽較近，受到的引力也最強,，因此它在軌道上的運動速度為每秒48公里,，超過了其他任何行星，比地球快18公里,。這意味著水星只需15分鐘便可環(huán)繞地球一周,。

表面溫差最大

水星幾乎沒有大氣層來調節(jié)溫度，因此在陽光直射下,，向陽面的溫度最高可達430℃,，而背陽面夜間溫度則降至零下160℃，造成晝夜溫差接近600℃,，使其成為一個極端的火與冰的世界,。

衛(wèi)星最少

在太陽系中，已發(fā)現超過60顆衛(wèi)星,，但水星與金星是唯一沒有衛(wèi)星的行星,，這使得它們在衛(wèi)星數量上名列前茅。

時間最快

水星的“年”是太陽系中最短的,，僅需88天便完成一次公轉,，遠遠少于地球的365天。這種快速的公轉速度使得水星的象征與希臘神話中的使者相聯系,，他腳穿飛鞋,，手持魔杖，象征著迅捷,。

水星日

盡管水星的“年”時間最短,，但其“日”卻比其他行星更長。水星自轉一周需要58.646天,，而公轉一周僅需88天,。因此，水星上一晝夜的時間相當于地球上的176天,。水星的自轉與公轉之間的關系,，使得這顆行星的時間概念顯得尤為獨特。

托福閱讀天文類背景材料：水星的幾個之“最”記錄,，展示了水星在太陽系中的獨特地位,。這些特性不僅讓水星成為一個有趣的研究對象，也為托?？忌峁┝素S富的知識背景,。了解這些信息,，將有助于你在托福考試中取得更好的成績,。

Mercury: Characteristics and Records ??

As a TOEFL test taker, understanding various topics can enhance your reading and listening skills. One fascinating subject is Mercury, the closest planet to the Sun. This article will explore Mercury's characteristics and its unique records, which may also serve as interesting content for your writing tasks.

1. Basic Characteristics of Mercury ??

Mercury is the smallest planet in our solar system, with a diameter of about 4,880 kilometers. It is only slightly larger than Earth's Moon. Due to its proximity to the Sun, Mercury has extreme temperature variations. During the day, temperatures can soar up to 430°C (800°F), while at night, they can plummet to -180°C (-290°F). This stark contrast is due to Mercury's thin atmosphere, which is unable to retain heat. ???

2. Surface Features ??

The surface of Mercury is heavily cratered, resembling that of our Moon. Major features include the Caloris Basin, which is one of the largest impact craters in the solar system, measuring about 1,550 kilometers in diameter. The planet also has large cliffs, known as lobate scarps, which can rise up to a kilometer high. These formations suggest that Mercury has shrunk over time as it cooled. ???

3. Rotation and Revolution ?

Mercury has a unique rotation and revolution pattern. It takes approximately 59 Earth days to complete one rotation on its axis, but only about 88 Earth days to orbit the Sun. This results in a 3:2 spin-orbit resonance, meaning that for every two orbits around the Sun, Mercury rotates three times on its axis. This peculiar relationship affects how we observe the planet from Earth. ??

4. Historical Records and Exploration ??

Mercury has been observed since ancient times, and its swift movement across the sky led to its association with the Roman messenger god. However, detailed studies began with the advent of telescopes. The first spacecraft to visit Mercury was Mariner 10, which conducted flybys in the 1970s. More recently, the MESSENGER mission, launched in 2004, orbited Mercury from 2011 to 2015, providing valuable data about its geology and magnetic field. ??

5. Interesting Facts ?

One intriguing aspect of Mercury is its weak magnetic field, which is about 1% the strength of Earth's. Scientists believe this may be due to its large metallic core, which constitutes about 75% of the planet's radius. Additionally, Mercury has no moons, making it unique among the terrestrial planets. ??

6. Conclusion ??

Understanding Mercury not only enriches your knowledge of our solar system but also provides excellent material for TOEFL writing and speaking tasks. By familiarizing yourself with its characteristics and historical records, you can improve your ability to discuss scientific topics effectively. Remember to practice using relevant vocabulary and structuring your responses clearly, as these skills are crucial for success on the TOEFL exam. Good luck! ??

Understanding Astronomy in TOEFL Reading ??

For many students preparing for the TOEFL exam, reading comprehension can be a challenging section. One topic that frequently appears is astronomy. This article aims to provide insights and strategies specifically for tackling astronomy-related passages in the TOEFL reading section.

Key Vocabulary ??

Familiarizing yourself with essential vocabulary is crucial. Here are some common terms you might encounter:

• Galaxy: A vast system of stars, gas, and dust held together by gravity.
• Nebula: A cloud of gas and dust in space, often a site of star formation.
• Supernova: An explosion of a star at the end of its life cycle.
• Black Hole: A region in space where the gravitational pull is so strong that nothing can escape from it.

Sample Passage ??

Here is a brief example of what a typical astronomy passage might look like:

"The Milky Way galaxy is home to billions of stars. Among these, the Sun is a relatively average star. However, it plays a critical role in sustaining life on Earth. The process of nuclear fusion in the Sun's core produces energy, which radiates outward and warms our planet. Without this energy, Earth would be a frozen wasteland."

Typical Questions ?

After reading such a passage, you might encounter questions like:

• What is the primary function of the Sun as described in the passage?
• According to the passage, how does the Sun's energy affect Earth?

Effective Strategies ??

1. Skimming and Scanning: Quickly read through the passage to get a general idea. Look for keywords related to astronomy, such as "galaxy," "star," or "energy." This will help you locate important information when answering questions.

2. Highlighting Key Information: If you're allowed to take notes, highlight or underline significant points, especially definitions and processes mentioned in the passage.

3. Using Context Clues: When encountering unfamiliar words, try to deduce their meanings from the context. For example, if the passage states, "A supernova is an explosive death of a star," you can infer that it refers to a dramatic event in a star's lifecycle.

Practice Makes Perfect ??

To excel in the reading section, consistent practice is essential. Here are some resources you can use:

• Online platforms that offer TOEFL practice tests.
• Astronomy books and articles to enhance your knowledge and vocabulary.
• Flashcards for memorizing key terms and concepts.

New Topics and Predictions ??

As the TOEFL test evolves, new topics may emerge. Keep an eye out for advancements in astronomy, such as:

• The exploration of Mars and its potential for human life.
• Discoveries related to exoplanets and their atmospheres.
• Current theories about dark matter and dark energy.

Conclusion ??

By focusing on vocabulary, practicing reading strategies, and staying informed about recent developments in astronomy, you can improve your performance in the TOEFL reading section. Remember, understanding the context and main ideas is key to answering questions accurately. Good luck with your studies! ??

Mercury's Place in the Solar System

As a TOEFL test taker, understanding the solar system can be quite beneficial, especially when it comes to reading comprehension and essay writing. Today, we will explore Mercury's position in the solar system and its significance. ??

1. Introduction to Mercury

Mercury is the closest planet to the Sun, orbiting at an average distance of about 57.91 million kilometers (36 million miles). Due to its proximity to the Sun, it has a very short orbital period of just 88 Earth days. This unique characteristic makes Mercury an interesting subject for study. ??

2. Physical Characteristics

Mercury is known for its small size; it is the smallest planet in our solar system, with a diameter of about 4,880 kilometers (3,032 miles). Its surface is covered with craters, similar to our Moon, due to a lack of atmosphere which means that there is minimal erosion. The temperature on Mercury varies drastically, ranging from extremely hot during the day (up to 430°C or 800°F) to extremely cold at night (down to -180°C or -290°F). ????

3. Importance of Studying Mercury

Studying Mercury helps scientists understand the formation and evolution of terrestrial planets. Its geological features provide insights into the history of our solar system. Additionally, the study of Mercury's magnetic field and its thin atmosphere contributes to our knowledge of planetary science. ??

4. Challenges in Exploration

Exploring Mercury poses several challenges due to its extreme temperatures and proximity to the Sun. Spacecraft must endure intense heat and radiation while capturing data. NASA's MESSENGER mission, which orbited Mercury from 2011 to 2015, provided valuable information about the planet's surface and environment. ??

5. Mercury's Unique Features

One of Mercury's most fascinating features is its large iron core, which makes up about 85% of the planet's radius. This unique composition contributes to its strong magnetic field, which is unusual for such a small planet. Furthermore, Mercury has a very weak atmosphere composed mostly of oxygen, sodium, hydrogen, helium, and potassium. ??

6. Conclusion: Why Mercury Matters

Understanding Mercury's characteristics and its role in the solar system enhances our comprehension of planetary science. For TOEFL students, being familiar with topics like these can improve reading skills and provide content for essays. When preparing for the exam, consider how you might incorporate information about Mercury into your writing or speaking tasks. ??

Sample TOEFL Writing Prompt:

"Discuss the significance of Mercury in the context of the solar system. Include details about its physical characteristics, exploration challenges, and what we can learn from studying this planet."

Vocabulary to Know:

• Orbit
• Terrestrial
• Geological
• Atmosphere
• Magnetic field

By familiarizing yourself with these concepts and practicing your writing, you will be better prepared for the TOEFL exam. Good luck! ??