Why does China use iron instead of stainless steel for its railway tracks?China's railway construction, from the birth of the Shanghai Public Tramway in 1861 to the nationwide railway network today, has spanned over a century, witnessing technological advancements and the changing times. Throughout this long development process, the materials used for railway tracks have evolved from cast iron to steel and then to high manganese steel...

Why Did China's Space Station Choose Japan Over South Korea? A Complex Calculation...

Why Do Planes Avoid Flying Over Tibet?Tibet boasts eight civilian airports, but why do most planes choose to take longer, fuel-consuming routes instead of flying directly over the region? Do airplanes experience "altitude sickness" too?The Tibetan Plateau, a vast expanse averaging over 4,000 meters in elevation, appears as a "vacuum zone" on airline route maps. One might wonder if it's simply the high altitude that prevents planes from flying over it...

Why Do We Always Board Planes from the Left? Historical and Safety ConsiderationsHave you ever noticed that, regardless of the aircraft you board, we always enter through the left side door? This isn't a coincidence; it's rooted in a rich history and thoughtful safety considerations.A Habit Stemming from the Age of SailingThe tradition of boarding planes from the left can be traced back to ancient seafaring...

Why Do Female Astronauts Take Birth Control? Unveiling the Secret Challenges of SpaceIn 1961, Soviet cosmonaut Yuri Gagarin became the first human in space, ushering in a new era. Today, countless astronauts have ventured into space, but what remains largely unknown is that the number of female astronauts is remarkably small, and almost all of them are required to take birth control pills before missions...

Tesla "Returns" Tom Zhu, Why Does Musk Value the Chinese Market So Much?Elon Musk, CEO of Tesla, has once again made a surprising move by "returning" his trusted lieutenant, Tom Zhu, to China, sparking widespread attention. What makes Zhu, who Musk calls the "king of rolling up his sleeves," so extraordinary? Why does he receive such high regard from Musk? Can he once again save Tesla's Chinese market upon his return? Let's delve into the story behind this "firefighting hero" of Tesla...

Why Do Female Astronauts Take Birth Control Pills Before Going to Space? Can Space Menstruation Really Be Life-Threatening?From ancient times to the present, humanity has harbored a deep fascination with "ascending to heaven," with countless stories about gods and deities passed down through generations. This demonstrates our profound curiosity about life and places beyond Earth...

Inland Provinces in China Invest Heavily in Canal Construction: Why are Inland Provinces Still Fond of Water Transport in the Era of High-Speed Rail?It is well known that waterway shipping is the most economical mode of transportation. A developed waterway system can generate substantial economic revenue and drive regional overall development...

Why Does the Qinghai-Tibet Railway Still Use American Locomotives? When Will Domestic Locomotives Be "On Duty"?The Qinghai-Tibet Railway, spanning the Qinghai-Tibet Plateau and known as the "Roof of the World", has been in operation for 18 years since its opening in 2006. This railway, considered a marvel of Chinese engineering, connects Xining and Lhasa, bringing once-inaccessible Tibet closer to mainland China...

C919: China's Global Dream, Why Is It Still Struggling to Break Through?On July 22nd, the Farnborough International Airshow kicked off in the UK. As the world's second-largest aviation event after the Paris Air Show, this Farnborough event attracted over 1200 exhibitors from around the globe...

Apollo 11 Moon Landing 55th Anniversary: Why Did the Comments Section Turn into a "Massive Skepticism Contest"?Recently, NASA posted on social media to commemorate the 55th anniversary of the Apollo moon landing, intending to celebrate this monumental achievement in human history. However, the comments section unexpectedly transformed into a battleground for a "massive skepticism contest," with numerous questioning the veracity of the moon landing, sparking global discussion...

Why does my phone say "The person you are trying to reach is currently on another call"?Many people have encountered this strange problem: when calling someone, or when someone calls you, the phone shows a message saying "The person you are trying to reach is currently on another call". What's going on? Why can't you get through, and why does it say "on another call"?There are many reasons why you might get a "The person you are trying to reach is currently on another call" message when trying to make or receive a call, including but not limited to: The other person is actually on a call: This is the most common reason...