1 . Imagine a warm spring day 66 million years ago. These could have been the very last moments of the dinosaur era when a city-sized asteroid struck Earth, killing off three quarters of all species on the planet. According to a study published in Nature on Feb 23,the asteroid hit in springtime.
Scientists have long been confused over the time of year the asteroid hit, and how some animals managed to survive while dinosaurs didn’t, according to USA Today.
Researchers in 20l9 discovered fossilized fishes in North Dakota that died shortly after the asteroid hit Earth. They examined the fossils with a particle accelerator and found out there was seasonal growth on the bone. All fish bone cell densities and volumes can indicate the season. Because the accelerator also could capture the sizes, researchers were able to determine when in the year the asteroid hit, Dennis Voeten told USA Today.
“I think spring puts a large group of the late Cretaceous biota in a very unprotected spot because they were out and about looking for food, tending to offspring after the winter,” Melanie During, the main author of the study.
In the Southern Hemisphere, it was autumn. Therefore, life in the Southern Hemisphere was a lot more prepared for this event.
It is unclear whether small animals in the Northern Hemisphere actually did worse than those in the south. There is evidence that Northern Hemisphere turtles were wiped out in the asteroid strike, after which their habitats were later repopulated by turtles from the south, Voeten told The Guardian.
Nothing much larger than a house cat survived the asteroid impact and many species would have been killed whenever it hit, Daniel Field, a professor at the University of Cambridge, told The Guardian.
1. Which probably helps find the time of year the asteroid hit?| A．The types of fossilized fishes. | B．The location of fossilized fishes. |
| C．The number of fish fossils in the area. | D．The volume and density of the fish bone cells. |
| A．The season of the hit. | B．The size of asteroid. |
| C．The group size of species. | D．The body shape of animals. |
| A．Chances of survival depended on it where the species lived at the time. |
| B．Many species could have survived the asteroid strike but for the season. |
| C．Many species had little chance to survive even if it was a different season. |
| D．Animals from the Southern Hemisphere were less affected by asteroid strikes. |
| A．The Science behind the Asteroid | B．Occurrence of the Natural Disaster |
| C．The Effect of Dinosaurs’ Extinction | D．New Research on the Asteroid Strike |
2 . “We are running out of space and the only places to go to are other worlds.... Spreading out may be the only thing that saves us from ourselves. I am convinced that humans need to leave Earth.” These are the words of the famous scientist Stephen Hawking, spoken at a science festival in Norway in 2017, a year before his death.
Hawking was not alone in this view. Many experts feel that the only way for humanity to last far into the future is to colonize （移民） other planets. That way, if an asteroid （小行星）, a terrible disease, nuclear war, or some other disaster strikes Earth, civilization would still have a chance. Mars is one of the ideal destinations. NASA, SpaceX, and Mars One all have plans to send humans there. “Either we spread Earth to other planets, or we risk going extinct,” SpaceX founder Elon Musk said at a conference in 2013.
But not everyone agrees that colonizing Mars or any other planet is such a great plan. The most common argument against going is that it’s just too expensive or dangerous. It will take huge amounts of money and other resources just to get people there, let alone set up a place for them to live. It’s not even clear if humans could survive on Mars.
Maybe all the time and money people would pour into a Mars mission would be better spent on more urgent projects here on Earth, like dealing with poverty or climate change. Some experts argue that handling a problem like an asteroid strike or disease outbreak while staying here on Earth would be much easier and less expensive than surviving on a new planet.
In addition, moving to a new planet could harm or destroy anything that already lives there. Human visitors change or damage the Martian environment. Some feel that’s too much of a risk to take.
1. What is Stephen Hawking’s view according to paragraph 1?| A．The earth is likely to blow up. |
| B．Humans are using up natural resources on Earth. |
| C．It is necessary to spread out to other planets. |
| D．We should explore our world to save ourselves. |
| A．Because there will be a nuclear war in the near future. |
| B．Because human can live better on Mars. |
| C．Because it is a way for earth civilization to last. |
| D．Because it is a way to test our space technology. |
| A．It is wiser to deal with problems on Earth. |
| B．It is easy to stop a disease outbreak. |
| C．Human will not survive on Mars. |
| D．It is impossible to set up a place for people to live on Mars. |
| A．Leaving Earth to Other Planets | B．Should We Colonize Mars? |
| C．New Home on New Planet | D．A Mar Mission Is on The Way |
3 . A study confirmed that the cracks (裂缝) found on the surface of Mars last year by the Curiosity Rover are evidence of ancient lakes that likely dried up about 3.5 billion years ago. The new study provides further evidence of what the climate on the Red Planet may have been like in its ancient past.
The study, published online in Geology, proved that cracks on Mars’s surface previously photographed by Curiosity are dry mud cracks which could have only been formed when wet ground was exposed to the air. This conclusion was based on an analysis of a single area of rock known as “Old Soaker.”
Researchers used the Curiosity Rover and information from its many tools including the Mars Hand Lens Imager, ChemCam Laser-Induced Breakdown Spectrometer (LIBS) and the Alpha Particle X-Ray Spectrometer (APXS) to study both the physical appearance and the chemistry of the rock, which is described as no bigger than a coffee table.
The analysis showed that cracks on the rock were formed by exposure to air, rather than heat or the flow of water. In addition, the shape of the cracks suggests it experienced a single drying event on the planet, rather than getting wet and drying over repeatedly. The position of the cracks, closer to the center of the ancient lake rather than alongside it, also suggests that the lake levels changed often, rising and falling over time.
“The mud cracks are exciting because they help us to understand this ancient lake system,” lead study author Nathaniel Stein, a geologist at the California Institute of Technology in Pasadena, said, referring to the ancient lake system on the planet.
Scientists have known of the existence of ancient water on Mars for years. A 2015 NASA study that measured water in Mars’s atmosphere suggested that ancient oceans may once have had more water than our own Arctic Ocean. However, because the planet has less gravity and a thinner atmosphere than Earth, this water evaporated into space over the course of several billion years.
1. What is the Curiosity Rover underlined in Paragraph 1?| A．A research organization. | B．An automatic machine. |
| C．An ancient remain on the planet. | D．A space telescope on earth. |
| A．The cracks are near the center of an ancient lake. |
| B．Mars was getting wet and drying more than once. |
| C．The lake level on Mars seldom changes over time. |
| D．The cracks on the rocks were formed by water flow. |
| A．Ancient water still exists on Mars now. |
| B．The gravity on Mars is stronger than that on Earth. |
| C．The atmosphere on Earth is thicker than that on Mars. |
| D．The ancient Arctic Ocean had more water than it has now. |
| A．Water on Mars. | B．A trip to Mars. |
| C．A study on Mars. | D．Cracks on Mars. |
4 . New observations of the Moon show that lunar water may be more accessible than originally thought. The new data is particularly exciting for NASA, which hopes to make use of the Moon’s resources — especially water ice existing in the soil — to help future astronauts live and work on the lunar surface.
In one study, researchers discovered water directly on the lunar surface, finding the molecule(分子) on areas of the Moon lighted by the Sun. A second study speculates （推测）that water ice might be trapped in tiny areas or small holes spread all over the Moon’s surface, making water more abundant (大量的) and more accessible than we could have imagined. The two studies were published in the journal Nature.
This isn’t the first time water has been discovered on the Moon. But the only water we’ve been able to find until now is really difficult to reach. It seems to be primarily located in large holes at the lunar south pole that are in continuous shadow. The freezing holes are dangerously cold — possibly reaching -400 ℉ — making them almost impossible to access with modern technology.
The research published today raises the possibility that astronauts can find water in other areas of the Moon that are far less deadly. “If we find that it’s abundant enough in certain locations, it would be easier to access versus going into these very cold, very dark places,” Casey Honniball, an expert at NASA’s Goddard Space Flight Center and lead author on one of the studies, tells The Verge.
It seems to be good news for NASA. But there are still a lot of unknowns related to this research. Though the first study discovered water, the researchers didn’t find a lot. Besides, if the water is existing in the lunar dirt as expected, it’s going to take a lot of work to get it. “The method to get that water would be to melt the glass, so that the water can be released,” Honniball says. “This is a difficult process, compared to some other methods.”
1. Where can we read about the new studies？
| A．From NASA. | B．In The Verge. |
| C．From Space Flight Center. | D．In the journal Nature. |
| A．The only water found is located on areas lighted by the Sun. |
| B．The deadly cold situation stops people from accessing the holes. |
| C．It is the first time that people have found water on the Moon. |
| D．It can reach a temperature of -400 ℃ in the holes. |
| A．Great efforts will be needed to melt the glass. |
| B．There is not enough water on the Moon. |
| C．We don’t know where to find the water. |
| D．We don’t know how to get the water. |
| A．NASA plans to send astronauts to the Moon. |
| B．A lot of unknowns exist in making use of the Moon. |
| C．Using water on the Moon will be key to a future lunar base. |
| D．Water ice on the Moon may be easier to reach than we thought. |
5 . Space is becoming more crowded. Quite a few low-Earth-orbit (LEO) satellites have been launched into the sky, which are designed to move around the Earth only a few hundred kilometres above its surface. SpaceX and OneWeb plan to launch LEO satellites in their thousands, not hundreds, to double the total number of satellites in orbit by 2027.
That promises to change things on Earth. LEO satellites can bring Internet connectivity to places where it is still unavailable. This will also be a source of new demand for the space economy. Morgan Stanley, a bank, projects that the space industry will grow from $350 billion in 2016 to more than $1.1 trillion by 2040. New Internet satellites will account for half this increase.
For that to happen, however, three worries must be overcome. Debris (碎片) is the most familiar concern. As long ago as 1978, Donald Kessler, a scientist at NASA, proposed a scenario (设想) in which, when enough satellites were packed into low-Earth orbits, any collision could cause a chain reaction which would eventually destroy all spacecraft in its orbital plane. Solutions exist. One solution is to grab the satellites with problems and pull them down into the Earth’s atmosphere. Another is to monitor space more closely for debris. But technology is only part of the answer. Rules are needed to deal with old satellites safely from low-Earth orbits.
Cyber-security is a second, long-standing worry. Hackers could take control of a satellite and steal intellectual property, redirect data flows or cause a collision. The satellite industry has been slow to respond to such concerns. But as more of the world’s population comes to rely on space for access to the Internet, the need for action intensifies. Measures will surely be taken to protect network security.
The third issue follows from the first two. If a simple mistake or a cyber-attack can cause a chain reaction which wipes out hundreds of billions of dollars of investment, who is responsible for that? Now the plans of firms, wishing to operate large numbers of satellites are being studied. But there is a long way to go before the risks are well understood, let alone priced.
As space becomes more commercialized, mind-bending prospects open up: packages moved across the planet in minutes by rocket rather than by plane, equipment sent to other small planets, passengers launched into orbit and beyond. All that and more may come one day. But such activities would raise the same questions as LEO satellites do. They must be answered before the space economy can truly develop.
1. What can we learn about LEO satellites from the passage?| A．They will limit the space economy |
| B．They will increase in large numbers. |
| C．They will move beyond the Earth as far as possible. |
| D．They will monitor old satellites. |
| A．To avoid network attack. |
| B．To make the Internet accessible to backward areas. |
| C．To lighten the financial burden of space firms. |
| D．To accelerate the development of bank industry. |
| A．block low-Earth orbits with packed satellites |
| B．pull down satellites into Earth’s atmosphere |
| C．put the disposal of old satellites at high risks |
| D．bring destruction to spacecraft in the same orbit |
| A．It should be further confirmed for its ownership. |
| B．It should be continued because of its advantages. |
| C．It should be done carefully to avoid potential risks. |
| D．It should be stopped in the face of the space economy. |
6 . Scientists who study the Sun watch for sunspots—violent storms that can affect communications，navigation systems and even electric power stations on the Earth.
Sunspots are a product of huge electromagnetic storms on the Sun. Scientists on the Earth are able to observe sunspots eight minutes after they happen. That is how long it takes for the Sun’s light to reach us.
The first electrically charged particles (颗粒）from a sunspot enter the Earth’s atmosphere about 20 to 30 minutes after the storm happens. These particles can harm human beings. So before they arrive, astronauts on the International Space Station move into special areas designed to protect them from their effects.
About a day or two later, the biggest part of the storm arrives. It is called a coronal mass ejection. “That is billions of tons of solar material that's blown away from the Sun. It’s traveling millions of kilometers an hour, but that is relatively slow.” says Alex Young, the Associate Director for Science at NASA's Heliophysics Science Division.
Several civilian government agencies and the U.S. Air Force watch weather conditions in space 24 hours a day. NASA does so because it must protect its astronauts and the electronic devices on its spacecraft.
Scientists are also trying to understand why the number of sunspots rises and falls at almost regular intervals every 11 years. In other words, scientists can almost predict the amount of solar activity. Sometimes the intensity (强度）is higher，sometimes lower，For example, the current solar cycle, as it is called, is much lower than the previous one.
Several satellites watch the Sun and the environment between the Sun and tho Earth. Pictures and other information from the satellites tell scientists what is happening on and near the Sun.
Alex Young says we have only been looking at the Sun with powerful instruments for about 30 to 40 years. Thai is a very short time compared to ll\o four billion years that tho star has been shining.
1. Why do astronauts on International Space Station move into special area?| A．To avoid being harmed. | B．To charge the battery. |
| C．To watch the Sun closely | D．To protect devices on the spacecraft. |
| A．About 8 minutes. | B．About 20 to 30 minutes |
| C．About 11 years. | D．About 30 to 40 minutes |
| A．Environmental changes. | B．Good weather conditions |
| C．Advanced instruments. | D．Government agencies |
| A．The role of satellites. | B．findings about sunpots |
| C．Observation of space. | D．Communication on the earth. |
