高级练习题

Most people assume Mars is completely dry today. After all, the surface looks like a cold, lifeless desert — reddish rocks, howling dust storms, and no liquid water in sight. But China’s Zhurong rover has revealed something surprising: signs of water activity that may be far…

On May 15, 2021, China made history. Its Tianwen-1 spacecraft successfully landed a rover named Zhurong on the surface of Mars — making China only the second country ever to operate a rover on another planet. The landing site was a vast, flat lowland called Utopia Planitia, one…

Plastic pollution is one of the most persistent environmental challenges of the modern era. Unlike organic materials that decompose within weeks or years, most plastics remain intact in the environment for centuries. Recycling offers a partial solution, but conventional…

Alzheimer’s disease is the most common form of dementia, progressively destroying memory, reasoning, and the ability to perform everyday tasks. For decades, the dominant scientific framework focused on two hallmark features of Alzheimer’s brain tissue: amyloid plaques —…

The universe contains black holes of almost incomprehensible extremes. Some are relatively modest — the collapsed remnants of individual massive stars, containing between 5 and 50 times the mass of our Sun. At the opposite end of the spectrum sit supermassive black holes,…

When the ground shakes, it leaves marks — not just in broken buildings, but in the earth itself. Geologists have developed a discipline called paleoseismology, the study of ancient earthquakes using the evidence preserved in geological layers, to reconstruct thousands of years…

For more than a century, physicists have worked to understand the forces shaping the universe. Gravity pulls matter together. But something else is pushing the universe apart — and it is winning. Astronomers call this mysterious force dark energy, and a landmark instrument has…

Mars has fascinated scientists for generations, but recent discoveries have pushed the question of Martian life closer to the center of scientific debate than ever before. NASA’s robotic explorers — the Curiosity and Perseverance rovers — have identified chemical and geological…