1 . Studies of Mercury — the planet closest to the sun-show that it has shrunk by about 11 kilometers across since the solar system’s birth 4.5 billion years ago. As the planet cooled and contracted (收缩), its surface had many long curved ridges (山脊) similar to the wrinkles on a bad apple.
A new research on these ridges, called lobate scarps (瓣状陡坡), has found more of them, with steeper faces, than ever before. The discovery suggests that Mercury shrank by far more than the previous estimate, says Paul Byrne, a planetary scientist. The finding helps explain how Mercury’s huge metallic core (中心) cooled off over time. It may also finally settle the differences between theoretical scientists, who had predicted a lot of shrinkage, with observers who had not found evidence of that — until now. “We are resolving a four-decade-old argument here,” Byrne added.
Planetary scientists have been arguing over Mercury’s lobate scarps ever since the Mariner 10 spacecraft flew past the planet three times in 1974-1975. Researchers can use measurements of the length and height of the scarps to calculate how much planetary shrinkage they represent. That shrinkage is a product of Mercury’s strange structure — “like a core floating through space with a thin outer blanket,” says Byrne. Most of the planet is made of that large core, and so it would have cooled rapidly as heat rushed toward its surface.
The latest data, coming from NASA’s MESSENGER probe and covering the entire planet, showed many lobate scarps with sharp steeper faces, Byrne said. It also uncovered details on another kind of surface feature that may be related to shrinkage. These “wrinkle ridges” are less pronounced than the lobate scarps but may also have formed during contraction. Combined, the data on the lobate scarps and the wrinkle ridges suggest that Mercury’s diameter (直径) has shrunk by 11.4 kilometers, Byrne said.
1. How does the author explain the formation of the ridges on Mercury?| A．By making a comparison. | B．By providing some figures. |
| C．By describing the process. | D．By following the order of time. |
| A．It helps explain why Mercury has a huge metallic core. |
| B．It shows Mercury shrinks much less than previously thought. |
| C．It reveals there are less ridges on Mercury than people thought. |
| D．It helps settle the argument between theoretical scientists and observers. |
| A．It’s large core with thin surface. | B．The lobate scarps and wrinkles. |
| C．The pronounced wrinkle ridges. | D．The length and height of the scarps. |
| A．The latest data came from NASA’s Mariner 10 probe. |
| B．The lobate scarps may have formed before Mercury’s contraction. |
| C．The latest data provided supporting evidence of Mercury’s shrinkage. |
| D．The data suggests that Mercury’s diameter has shrunk to 11.4 kilometers. |
2 . Having a conversation on Mars would be difficult. That’s partly because Mars can be really cold, and your teeth may be shaking. But it’s also because the Red Planet’s thin atmosphere of mostly CO3 doesn’t carry sound well. In fact, someone speaking next to you on Mars would sound as quiet as if they were talking 60 meters away on Earth.
A team studied some of the first sound recordings ever made on the Red Planet. The recordings had been picked up by a microphone on American Perseverance rover (探测器). This space robot has been exploring Mars since February 2021.
The recordings Perseverance got weren’t the sounds of events on Mars. They were noises made when the rover fired a laser (激光) at small rocks nearby. These data allowed the researchers to measure the speed of sound on Mars — and discovered a surprise. Within the range of human hearing, high sounds travel at about 250 meters per second. Low sounds travel slower — about 240 meters per second. Those low waves will travel just a few meters before becoming unhearable. Unexpectedly, the higher sounds die away over even shorter ranges.
When a sound wave moves through air or a fluid, it adds energy to the molecules (分子) around it. Air will gradually move that energy around. This is called the relaxation effect. For sound waves traveling through air, relaxation depends on the frequency of the sound and the type of molecules in the air. On Mars, the relaxation after a high sound happens faster than after a low sound. That’s because the atmosphere has low pressure and is mostly composed of (由……组成) CO2.
Measuring the speed of sound can give scientists an exact way to study the Martian atmosphere. Air pressure, temperature and humidity (湿度) all affect the speed of sound. So, by measuring changes in the speed of sound over time, researchers can learn more about Martian weather. With Perseverance broadcasting more sounds back to Earth, scientists will be able to study bow its soundscape changes over the course of Martian seasons.
1. Compared with on Earth, the sounds on Mars ________.| A．travel faster | B．travel a shorter distance |
| C．are clearer | D．are more powerful |
| A．The low sounds spread faster. |
| B．The sounds can spread endlessly. |
| C．The higher sounds travel a shorter distance. |
| D．All sounds spread the same distance. |
| A．The low pressure made by high sounds. | B．The ways sound waves move. |
| C．The less energy carried by high sounds. | D．The composition of the atmosphere. |
| A．Study the climate on Mars. | B．Research the Martian soil. |
| C．Learn the development of Mars. | D．Explore the possible living things on Mars. |
3 . It is hard to imagine that plants or animals could ever exist on Mars. But scientists continue to look for evidence. NASA, America’s space agency, has found evidence that, a long time ago, there was surface water on the Mars. Scientists believe water is necessary for life as we know it. So since that discovery, they have been looking for chemicals that would be present if there once was or still is life on the planet.
At a December 13 meeting in California, NASA scientists reported an important discovery on Mars. They said for the first time that they had found very small amounts of boron(硼). Boron is important because it could help build RNA molecules(分子). And RNA molecules are important because they are one of the basic building parts for life.
One of the next steps in the scientists’ search for life on Mars comes soon. The next spacecraft is planned to launch. It will bring rocks from Mars back to Earth. Scientists in Britain are getting ready for those Mars rocks now. Before this, using a powerful microscope(显微镜), they have already examined 200-million-year-old volcanic rocks found deep in the Pacific Ocean. The microscope showed holes on the rocks caused by tiny living things called microbes(微生物). Microbes are the oldest form of life on Earth.
Next, the scientists in Britain will examine rocks which contain ancient material from Mars. The material comes from a time when Mars would have been more likely to support life. The scientists hope to get the same findings in the rocks from Mars as the ones they saw in the ocean rocks. If they do, they predict that the rocks coming directly from Mars will also show signs of life. That, in turn, could finally prove that we are not alone in the universe.
1. What caused scientists to look for evidence of life on Mars?| A．The discovery of plants. | B．The discovery of chemicals. |
| C．The discovery of surface water. | D．The discovery of RNA molecules. |
| A．It is hardly seen on the earth. | B．It might prove the existence of life. |
| C．It might cause the holes on the rocks. | D．It is the most necessary part of life. |
| A．Tiny living things. | B．Ancient material from Mars. |
| C．Volcanic rocks. | D．Holes caused by microbes. |
| A．Scientists Try To Look For Life On Mars |
| B．Does Surface Water Really Exist On Mars? |
| C．A Discovery Of Life In The Pacific Ocean |
| D．Boron-An Important Chemical Supporting Life |
4 . Scientists attach great importance to identifying and tracking near-Earth objects because some of them could present threats to our planet. With this in mind. NASA launched a spacecraft last November that aimed to demonstrate a possible defensive method against asteroids that might threaten the earth.
Historically, the American space agency NASA used powerful ground-based telescopes and its NEOWISE spacecraft to identify asteroids and other near-Earth objects, NASA also used tracking systems to follow the movements of asteroids.
Recently, scientists have used a new tool to discover more than 100 asteroids that had not been identified before. The new tool used a complex computing method, which was also called an algorithm, to search for asteroids that had not been discovered before. They were not discoverable because existing telescopes and image examination tools could not recognize them.
The discovery of 104 new asteroids was announced by the American-based non-profit Asteroid Institute. The organization hoped the new asteroid search tool would led to the discovery of more asteroids in the coming years. The Asteroid Institute, which is part of the B612 Foundation, explained on its website that it aimed to combine computer science, instrumentation and astronomy to find and track asteroids. Ed Lu, who is the director of the B612 Foundation and also a former NASA astronaut, said, “Discovering and tracking asteroids is key to understanding our solar system, promoting the development of space and protecting our planet from asteroid impacts.”
The institute called its discovery tool Asteroid Discovery Analysis and Mapping, or ADAM. This system used the algorithm to link points of light in different sky images that were consistent with asteroid orbits. The tool was trained to find asteroids based on existing data and to calculate their orbits well enough to be recognized by international astronomy organizations. Joachim Moeyens, a researcher from the University of Washington said the latest identifications were just the beginning. He predicted the asteroid search tool would result in thousands of new discoveries in the future.
1. What is the purpose of identifying and tracking near Earth objects?| A．To prove the power of telescopes. | B．To make existing data more accurate. |
| C．To prevent possible threats to the earth. | D．To follow the movements of new asteroids. |
| A．By using ADAM. | B．By using satellites. |
| C．By using NEOWISE spacecraft. | D．By using ground-based telescopes. |
| A．Doubtful. | B．Hopeful. | C．Carefree. | D．Unclear. |
| A．The Methods of Astronomy Being Further Developed |
| B．Fewer Than One Hundred Asteroids Have Been Found |
| C．Scientists Used a Technology Tool to Discover New Asteroids |
| D．The Importance of Protecting Our Planet From Asteroid Impacts |
5 . The US space agency NASA has revealed an astonishing picture revealing new secrets of the Earth’s home galaxy (星系), the Milky Way. The sun is just one of hundreds of billions of stars that form the huge shape of our galaxy. Our solar system sits in an outlying region but the new image focuses on the centre of the Milky Way, a “noisy” area because of all the crowded stars. Light from this region takes about 26,000 years to reach Earth. For comparison, light takes just eight minutes to reach us from the sun.
The researchers use the data collected by two telescopes that see the sky in ways that are very different from the visible light our eyes can see to form the new image. Most of the data comes from 370 different pictures taken over the past 20 years by NASA’s Chandra X Observatory. This satellite telescope detects X-rays out in space. X-rays are a from of radiation that is sent out when violent events heat matter to temperatures of millions of degrees. Other data comes from the MeerKAT telescope in South Africa, which can detect radio waves from space. These waves have much less energy than X-rays. They are usually produced by cooler material, such as huge clouds of gas between the stars.
The brightest sources include neutron stars which are the cores of huge stars that ran out of fuel and collapsed to city-sized balls of super hot matter. Many neutron stars and black holes jet out gases that appear in the picture as purple streaks (斑纹). Powerful magnetic fields in the area cause the jets to bend as they get further from their source. Astronomer Dr Daniel Wang, who has worked on the image over the past year, said the new picture described “a violent or energetic ecosystem”.
1. What can be learned about the Milky Way?| A．The center of it remains unknown. |
| B．The sun isn’t located in the center of it. |
| C．Its center is very peaceful. |
| D．Its center features fewer stars. |
| A．The collection of space data. |
| B．The function of the MeerKAT telescope. |
| C．The differences of space waves. |
| D．The formation of the new image. |
| A．They will absorb surrounding materials. |
| B．They will form super big matter. |
| C．They get bent if away from their source. |
| D．They are likely to explode when superheated. |
| A．Our galaxy’s violent heart | B．An attempt to travel in outer space |
| C．Radio waves from outer space | D．Stars’ purple streaks |
6 . Just as it does on Earth, it snows on Mars. However, scientists have found that Martian snow is “dustier” than it is on Earth, which could mean it’s warmer and more likely to melt into water, a new study suggests.
“There is a chance that this dusty and dark ice might melt a few centimeters down,” said the study’s lead author, Aditya Khuller, in a statement.
In June, a separate study suggested that there maybe more water on the Red Planet than previously thought, including “dozens” of lakes less than a mile beneath the surface of the Red Planet.
The scientists believe that the ice that was dug up by the Phoenix lander in 2008 (and subsequent falling snow) occurred from a snowfall sometime over the past million years.
“It is widely believed that Mars has experienced multiple ice ages throughout its history, and it looks like the ice being exposed throughout the mid-latitudes of Mars is a relic of this ancient dusty snowfall,” Khuller added.
If researchers are able to better learn about the prospects of water on Mars, then they may be able to better learn about its prospects for once hosting life.
“Characterizing these properties can significantly improve models of ice stability on Mars and inform us about its age and origin,” the researchers wrote in the study.
The researchers say that more work is required to determine if the ice actually melts into water.
Kuller added, “We are working on developing improved computer simulations of Martian ice to study how it evolves over time, and whether it might melt to form liquid water. The results from this study will be integral to our work because knowing how dark the ice is directly influence how warm it gets.”
Although scientists confirmed in 2018 that Mars still has lakes filled with liquid water, it has been somewhat difficult to find.
1. Why does the ice on Mars melt easier than that on Earth?| A．Because Mars’ ice is dustier and darker. | B．Because it snows more often on Mars. |
| C．Because Mars’ ice is exposed to the sun for long. | D．Because the temperature is not stable on Mars. |
| A．To help reduce ice’s meiting on Mars. | B．To better learn if Mars is potentially capable of hosting life. |
| C．To accelerate its turning into water. | D．To research how much water there is on Mars. |
| A．Impossible. | B．Unbelievable. | C．Essential. | D．Interesting. |
| A．It’s easy to find lakes with liquid water on Mars. |
| B．The Phoenix lander was the first explorer to land on Mars. |
| C．It’s impossible to learn the origin of Mars’ ice. |
| D．Scientists are striving for improving ice stability on Mars. |
China and the United Arab Emirates(UAE) sent
The trips to Mars come at a time when both countries have made quick progress in space programs.China's space program brought moon rocks back to Earth in December.That is the first time that a spacecraft
China's spacecraft will send a vehicle, called a rover, to land on the Marian surface. The goal is to search for
8 . 阅读下面短文，在空白处填入1个适当的单词或括号内单词的正确形式。
The return capsule of China's Chang'e-5 probe touched down in Siziwang Banner, north China's Inner Mongolia Autonomous Region, Dec. 17, 2020. The Chang'e-5 mission
As China's most complicated space project, the Chang'e-5 mission has achieved the sampling outside the earth and returning for the first time.
Noting that there is no end for space exploration, all members
Chang'e-5 mission has achieved many major breakthroughs including China's first lunar surface sampling and sealing, first liftoff
The success of the Chang'e-5 mission
