2024年12月27日，智利天文台通过“小行星陆地撞击持续警报系统”（ATLAS）首次观测到这颗天体，其轨道与地球交叉，被归类为“阿波罗型近地天体”，它的直径40-90米，2032年12月22日存在撞击地球风险。

On December 27, 2024, the Chilean Observatory first observed this celestial body through the "Asteroid Terrestrial-impact Last Alert System" (ATLAS). Its orbit intersects with Earth, classifying it as an "Apollo-type near-Earth object." With a diameter of 40-90 meters, it poses a risk of impacting Earth on December 22, 2032.

关于 2024 YR4

About 2024 YR4

小行星 2024 YR4 由 ATLAS 望远镜与 2024年12月27日发现，就在它接近地球的短时间内，当时它正以 830000 公里（约为地月距离的 2.15 倍）的距离略过地球。

Asteroid 2024 YR4 was discovered by the ATLAS telescope on December 27, 2024, during its close approach to Earth. At that time, it passed by Earth at a distance of 830,000 kilometers (approximately 2.15 times the distance between Earth and the Moon).

目前，小行星 2024 YR4 距离地球 4300万公里，并持续远离中，然而，它的轨道最终将再次接近地球，计算表明，小行星 2024 YR4 有可能在 2032年12月22日撞击地球，这距离现在仅剩 8 年，在针对这颗小行星计算出的六个可能得撞击日期中，这个日期是时间最近且风险最高的。

Currently, Asteroid 2024 YR4 is 43 million kilometers away from Earth and continues to move further away. However, its orbit will eventually bring it close to Earth again. Calculations indicate that Asteroid 2024 YR4 could potentially impact Earth on December 22, 2032, just eight years from now. Among the six possible impact dates calculated for this asteroid, this date is the nearest and carries the highest risk.

通过科学的计算，这颗小行星的直径估计在 44 - 100 米之间，其大小相当于波音 737 飞机或自由女神像，虽然这个尺寸不足以终结人类文明，但其蕴含的能量，足以摧毁任何一座大型城市。

Scientific estimates suggest that the asteroid's diameter is between 44 and 100 meters, comparable in size to a Boeing 737 aircraft or the Statue of Liberty. While this size is not enough to end human civilization, the energy it carries is sufficient to destroy any major city.

小行星 2024 YR4 有多危险？

How Dangerous is Asteroid 2024 YR4?

小行星 2024 YR4 在都灵指数上得分为 3 分（满分10分），这意味着这颗小行星在未来十年内撞击地球的概率为 1% 或更高，但小于 3%，有小概率会造成局部的破坏，由于其存在的风险较高，国际小行星预警网络（IAWN）已于 2025年1月29日发布了潜在小行星撞击通知，旨在提醒公众和航天机构关注小行星可能的撞击风险，并为进一步观测、风险评估和潜在的应对措施预留时间。

Asteroid 2024 YR4 scores a 3 on the Torino Scale (out of 10), meaning there is a 1% or higher chance of it impacting Earth within the next decade, but less than a 3% chance. There is a small probability that it could cause localized destruction. Due to its relatively high risk, the International Asteroid Warning Network (IAWN) issued a potential asteroid impact notification on January 29, 2025, to alert the public and space agencies to the possible impact risk and to allow time for further observations, risk assessments, and potential mitigation measures.

但不必过于担心，这颗小行星虽然被认为是最危险的小行星之一，但并未被列为“潜在威胁小行星”。

However, there is no need for excessive concern. Although this asteroid is considered one of the most dangerous, it has not been classified as a "potentially hazardous asteroid."

让我们深入了解小行星 2024 YR4 撞击地球可能带来的后果，以及 1% 的撞击概率在天文学上意味着什么。

Let's delve deeper into the potential consequences of Asteroid 2024 YR4 impacting Earth and what a 1% impact probability means in astronomical terms.

根据国际小行星预警网络（IAWN）发布的声明，潜在的撞击风险走廊横跨东太平洋、南美洲北部、大西洋、非洲、阿拉伯海和南亚。这意味着印度、巴基斯坦、孟加拉国、尼日利亚、苏丹、埃塞俄比亚、厄瓜多尔、哥伦比亚和委内瑞拉等人口密集地区可能受到影响。

According to a statement released by the International Asteroid Warning Network (IAWN), the potential impact risk corridor spans the eastern Pacific, northern South America, the Atlantic Ocean, Africa, the Arabian Sea, and South Asia. This means densely populated areas such as India, Pakistan, Bangladesh, Nigeria, Sudan, Ethiopia, Ecuador, Colombia, and Venezuela could be affected.

那么如果其撞击地球，会发生什么？What Would Happen if it Impacts Earth?

· 如果假设其实际直径约为50米（接近最低估计值），撞击能量约为8百万吨TNT当量。这场爆炸的威力可能是车里雅宾斯克事件的16倍，当年那场事件的冲击波震碎了7000座建筑物的窗户，并造成1500人受伤。If we assume its actual diameter is about 50 meters (close to the lower estimate), the impact energy would be approximately 8 megatons of TNT. This explosion would be 16 times more powerful than the Chelyabinsk event, whose shockwave shattered windows in 7,000 buildings and injured 1,500 people.
· 如果按照最大估计值，即直径100米计算，撞击能量将达到50百万吨TNT当量，大致相当于一枚氢弹爆炸（相当于沙皇炸弹或3333枚“小男孩”原子弹）。If we take the maximum estimate, with a diameter of 100 meters, the impact energy would reach 50 megatons of TNT, roughly equivalent to a hydrogen bomb explosion (similar to the Tsar Bomba or 3,333 "Little Boy" atomic bombs).

撞击区域：那些地方会面临风险？Impact Zones: Which Areas Are at Risk?

· 最可能的撞击场景之一是小行星落入海洋（太平洋、大西洋或阿拉伯海）。如果撞击发生在浅海区域，可能会引发几十米高的海啸，对沿海城市造成严重破坏。如果撞击发生在深海区域，海浪会较小，但仍可能扰乱全球航运。One of the most likely scenarios is that the asteroid could fall into an ocean (the Pacific, Atlantic, or Arabian Sea). If the impact occurs in shallow waters, it could trigger a tsunami tens of meters high, causing severe damage to coastal cities. If it occurs in deep waters, the waves would be smaller but could still disrupt global shipping.
· 如果撞击发生在人口密集的城市（如孟买、拉各斯或波哥大），冲击波可能会摧毁方圆10-30公里范围内的建筑物，在人口稠密地区造成数十万至数百万人的伤亡。If the impact occurs in a densely populated city (such as Mumbai, Lagos, or Bogotá), the shockwave could destroy buildings within a 10-30 kilometer radius, potentially causing hundreds of thousands to millions of casualties in densely populated areas.
· 如果撞击发生在远离大城市的区域，环境影响仍然不容忽视。爆炸可能引发森林大火，冲击波在数百公里范围内都会被感受到。If the impact occurs in a region far from major cities, the environmental impact would still be significant. The explosion could trigger forest fires, and the shockwave would be felt hundreds of kilometers away.

全球各地的天文学家给出的估算结果从 0.5% 到 6% 不等，在 2025年1月，欧洲航天局（ESA）提供的估算值已从 0.99% 上升到 1.32%；目前已升至 2%，NASA目前的估算值为 2.1%，由于观测仍在进行，目前下定论还为时过早。

Astronomers worldwide have provided estimates ranging from 0.5% to 6%. In January 2025, the European Space Agency (ESA) revised its estimate from 0.99% to 1.32%; it has now risen to 2%. NASA's current estimate is 2.1%. As observations are still ongoing, it is too early to draw definitive conclusions.

由于撞击概率前所未有地高（大多数近地小行星的撞击概率低于 0.00001%），而且这颗小行星的尺寸足以造成严重破坏，联合国支持的两个小行星应对组织（国际小行星预警网络（IAWN）和空间任务规划咨询小组（SMPAG））已启动相关应对措施，这两个机构将继续监测小行星，并制定进一步策略，包括可能的航天器偏转任务。

Given the unprecedented high impact probability (most near-Earth asteroids have an impact probability of less than 0.00001%) and the asteroid's size, which is sufficient to cause significant damage, two United Nations-supported asteroid response organizations—the International Asteroid Warning Network (IAWN) and the Space Mission Planning Advisory Group (SMPAG)—have initiated response measures. These agencies will continue to monitor the asteroid and develop further strategies, including potential spacecraft deflection missions.

小行星 2024 YR4 的观测窗口预计将持续到 2025年4月初，也许之后的计算结果会表明 2024 YR4 对地球是安全的，就像之前许多曾被认为会接近地球的小行星一样，到 2029年初，天文学家将能够使用望远镜重新观测这颗小行星，并进一步修正其轨道，到那时，距离可能的撞击时间仅剩四年，希望这足够让人类制定并实施防御方案。

The observation window for Asteroid 2024 YR4 is expected to last until early April 2025. Subsequent calculations may indicate that 2024 YR4 is safe for Earth, as has been the case with many asteroids previously thought to be approaching Earth. By early 2029, astronomers will be able to re-observe the asteroid using telescopes and further refine its orbit. By then, only four years will remain before the potential impact, hopefully providing enough time for humanity to develop and implement defense plans.

如果你是地球指挥官，你会选择哪种防御方案？

If you were the Earth Commander, what defense strategy would you choose?

#2024 YR4#

2024 YR4：可能撞击地球的小行星 A Potential Earth Impact