2 . NASA’s spacecraft Dart hit an asteroid (小行星) 11.3 million kilometers away at a speed, changing the asteroid’s orbit and lowered its cycle period by 15 minutes, the space organization announced on Monday.

Some said the move shows the world might now be able to prevent asteroids—the kind that made the dinosaurs extinct—from hitting the Earth. The asteroid that was controlled belonged to a double-asteroid system. It had a 160-meter diameter while the other asteroid’s diameter is over 500 meters. The bigger asteroid can be compared to the one that ended the dinosaur era 67 million years ago. A hit from an asteroid that size can cause unimaginable destruction.

However, it is too early to assert that the world has gained the ability to prevent asteroids from hitting us. The asteroid that was controlled was only 160 meters in size. Its cycle period was changed, without changing its orbit significantly. It is still not clear if the orbit of a much larger asteroid headed toward the Earth can be changed successfully.

In brief, NASA’s success in changing the course of a harmful asteroid is definitely praiseworthy, but much more needs to be done before we can say the world’s security from some unpredictable asteroid is guaranteed.

It should be noted that changing the orbit of an asteroid involves more than just sending an object into space and commanding it to hit the asteroid. While it is hard enough to hit an asteroid, it is even more difficult to lock onto one in the first place. It means having the ability to observe approaching asteroids, measuring their respective speeds, and deciding which ones might pose a danger to the Earth.

Therefore, there’s more to Dart hitting the asteroid than meets the eye. And these are key areas where global scientists need to work harder in the future.

4 . The surface of Mars is etched with ancient river valleys and lake basins. Some researchers think that liquid water once flowed on the Red Planet. Today, Mars is too cold for much, if any,   liquid water to exist. And 3.8 billion years ago, when the flowing water formed, the sun was fainter than it is today, making it even harder to imagine a warm Martian climate. That’s why many researchers think Mars may have gone in and out of deep freezes.

Some researchers have suggested that early Mars only thawed out when large asteroid impacts or volcanic eruptions temporarily warmed the planet. But Kasting, a geologist at Penn State University, thinks warm windows from such dramatic events would have been too brief to carve the vast canyons that exist on Mars. Now, Kasting and his colleagues have come up with an alternative explanation. They think Mars may have experienced a series of climate cycles.

The idea goes like this: When Mars was cold and frozen, volcanoes continued to belch out the greenhouse gases like carbon dioxide and hydrogen into the atmosphere. There, the gas blanket trapped heat and warmed the planet up until liquid water began to flow, forming Mars’ rivers and lakes. However, warm temperatures and abundant water would also have sped up certain chemical reactions that consumed carbon dioxide, reducing the greenhouse effect and cooling the planet back down again. Then the cycle would repeat.

Kasting shared his theory with other astronomers at the December meeting of the American Geophysical Union in San Francisco, and in the journal Earth and Planetary Science Letters. So far,   Kasting’s team has only shown that such an explanation is possible,   according to climate models. But the researchers say field trips could help test the idea by looking for evidence of multiple warm events, and their durations.

7 . Exciting new research suggests there could be living things in the clouds above Venus, whose orbit brings it closer to the Earth than any other planets. A study of Venus’ atmosphere shows a type of gas is in its atmosphere. The gas, on the Earth, is only produced by very small creatures. If such creatures are found on Venus, it might be the first evidence of life existing somewhere else in the universe.

Scientists found the gas in thick clouds about 35 miles above Venus’ equator. On the Earth, the gas is produced by special forms of life that live in airless environments such as swamps (沼泽). It can also be made in factories but neither explanation helps scientists to understand what the gas is doing on Venus.

To get to the bottom of the mystery, the scientists have now made their data public in the hope that others may be able to find a clue that they have missed. Professor Greaves explained that the gas might be produced by some non-living natural process that we haven’t yet discovered, but for now, the idea of life on Venus has to be considered. She added, “In my whole career, I have been interested in the search for life elsewhere in the universe, so I’m just blown away that this is even possible. We are sincerely encouraging other people to tell us what we might have missed. This is how science works.” If scientists on the Earth are unable to find an explanation, then a future mission to Venus might be needed to prove whether or not life exists there. The US space agency NASA is already planning an exploration that they would float on a balloon through the clouds of Venus, and this could be launched sometime in the 2030s.

8 . Construction has started on the largest telescope array (阵列) on Earth. The Square Kilometre Array (SKA), which will contain hundreds of radio antennae (天线) spread across two continents, is now under construction in both South Africa’s Karoo region and Western Australia’s Murchison Shire.

Together, the two sites – named SKA-Mid and SKA-Low, for the types of radio frequencies they will primarily detect – will enable high-resolution imaging of the whole sky, according to the Square Kilometre Array Observatory (SKAO), the organization that oversees the telescope. The sensitivity of the telescope will allow scientists to pick up even faint signals left over from the earliest days of the universe.

“The SKA project plan has been many years in the making,” SKAO committee chair Catherine Cesarsky said in an address at the South Africa site on Dec. 5. “Today, we gather here to mark another important chapter in this 30-year journey that we’ve been on together, a journey to deliver the world’s largest scientific instrument.”

The Australia site will host 131,072 low-frequency antennae placed as far as 65 kilometers apart. Together, they’ll act as a radio telescope with a lens spanning nearly 400,000 square meters. Each antenna station is 2 ms tall and contains 256 antennae in an arrangement that looks a bit like a pine tree. By catching very-low-frequency signals from the whole sky, SKA-Low will be able to dig into some of the oldest echoes left over from the first billion years of the universe.

The site is on the land of the Native Wajarri Yamaji, who signed a land-use agreement to ensure that the telescope did not interfere with any cultural sites and that locals would receive economic and educational benefits from the site. As a part of the agreement, the Wajarri Yamaji awarded the traditional name “Inyarrimanha Ilgari Bundara” on the site, which means “sharing the sky and stars.”

Scientists around the world plan to use data from the telescope to study questions ranging from the fundamental nature of dark energy to the nature of mysterious fast radio bursts from distant galaxies (星系).

10 . Benefits of Space Exploration

On April 12, 1961, the Russian astronaut Yuri Gagarin became the first human to journey to outer space.     1     Why should we spend so much time and money to explore dangerous environments? Well, the answer is simple. The benefits of space, including medical, technological and economic benefits, are more than the dangers of it.

● Medical benefits.

    2     Analyzing the effects of zero-gravity on blood circulation led to many discoveries on how to prevent some types of heart failure. And the experiments and measurements of bone strength and bone loss in astronauts have helped doctors better understand bone diseases.

●     3    

The space race has led to technological advancements in the shortest period of time, such a vacuum-sealed (真空密封的) food, fireproof materials and modern vacuum cleaners. Today, we still use them in our daily lives. Yet, we even don’t know that some NASA engineers originally developed them for the Apollo program that took humankind to the moon.     4     Who knows what kind of new technologies could be developed that will make our lives easier in the future?

● Creation of STEM jobs.

Space exploration is one of the industries that require the largest percentage of STEM (Science, Technology, Engineering, and Mathematics) jobs. A lot of those jobs are positions for engineers, data analysts, doctors, biologists and so on. Although these positions require highly qualified people to fill them, they are some of the highest-paid jobs in the market.     5