中國(guó)科學(xué)院國(guó)際合作局出品

Produced by Bureau of International Cooperation, Chinese Academy of Sciences

最近的月全食，你是否也抬頭看到了那輪紅紅的血月？在我們的眼中，它是視覺(jué)盛宴；而在高能X射線(xiàn)波段，它又完全不同。

Did you look up and catch the recent total lunar eclipse—the red "Blood Moon"? To our eyes, it's a spectacular sight, but in high-energy X-rays, it looks completely different.

為什么月亮?xí)兗t？

Why Does the Moon Turn Red?

月球繞地球公轉(zhuǎn)，地球繞太陽(yáng)公轉(zhuǎn)。當(dāng)月球進(jìn)入地球的影子中，部分月面失去直射光，就出現(xiàn)了月食。地球大氣吸收藍(lán)、綠、黃光，只剩紅光折射到月面，于是月全食時(shí)的月亮呈現(xiàn)紅色，也就是我們看到的“血月”。

The Moon orbits the Earth while the Earth orbits the Sun. When the Moon passes through Earth's shadow, parts of it lose direct sunlight, creating a lunar eclipse. Earth's atmosphere absorbs blue, green, and yellow light, allowing only red light to bend onto lunar surface—hence the Blood Moon.

天關(guān)衛(wèi)星如何“看”月全食？

How Does the Einstein Probe (Tianguan Satellite) "See" a Total Lunar Eclipse?

月球本身不發(fā)光，它反射太陽(yáng)光。月球的X射線(xiàn)輻射主要由太陽(yáng)X射線(xiàn)激發(fā)月表元素產(chǎn)生。天關(guān)衛(wèi)星通過(guò)監(jiān)測(cè)這些X射線(xiàn)亮度變化，就能捕捉“高能版的月全食”。

The Moon does not emit light on its own; it reflects sunlight. Its X-ray emission is mainly produced when solar X-rays excite elements on the lunar surface. By monitoring changes in X-ray brightness, the Einstein Probe (Tianguan Satellite) can capture the high-energy version of a total lunar eclipse.

天關(guān)衛(wèi)星在地球軌道上運(yùn)行，并不跟隨月球移動(dòng)。通過(guò)姿態(tài)控制系統(tǒng)，它可以將X射線(xiàn)望遠(yuǎn)鏡始終指向月球，連續(xù)記錄來(lái)自月球的X射線(xiàn)光子。

The satellite orbits Earth, not the Moon. Using its attitude control system, it keeps the X-ray telescope locked onto the Moon and continuously records X-ray photons coming from it.

當(dāng)月球進(jìn)入地球本影時(shí)，直射太陽(yáng)X射線(xiàn)被擋，月球被激發(fā)產(chǎn)生的X射線(xiàn)明顯減少，探測(cè)亮度下降。這就是X射線(xiàn)版本的“月食變暗”。

When the Moon enters Earth's shadow, direct solar X-rays are blocked, X-rays generated from the lunar surface drop, and the detected brightness decreases—this is the X-ray version of the eclipse dimming.

紅點(diǎn)從哪里來(lái)？

Where Do the Red Dots Come From?

天關(guān)衛(wèi)星的X射線(xiàn)圖中，每個(gè)紅點(diǎn)都是一個(gè)被探測(cè)的光子，主要來(lái)自太陽(yáng)X射線(xiàn)激發(fā)月球表面元素所產(chǎn)生的熒光輻射。月全食時(shí)紅點(diǎn)減少，少量殘余可能來(lái)自地球高層大氣散射、地球磁尾的高能粒子與月球作用。

In EP's X-ray images, each red dot represents a detected photon. Most are fluorescent X-rays produced when solar X-rays excite elements on the lunar surface. During a total lunar eclipse, the number of red dots drops sharply. The remaining photons may come from X-rays scattered by Earth's upper atmosphere or from interactions between high-energy particles in Earth's magnetotail and the Moon.

天文與高能的完美結(jié)合

Astronomy Meets High-Energy Physics

在我們眼中，月全食是血月；在天關(guān)衛(wèi)星眼中，它是一場(chǎng)天然空間實(shí)驗(yàn)：太陽(yáng)是光源，月球是反射屏幕，地球影子是遮擋器?？茖W(xué)家借此研究地月物質(zhì)和能量交換，分析地球磁尾與月球的相互作用并驗(yàn)證模型，甚至還可標(biāo)定儀器。

To us, a total lunar eclipse is a Blood Moon. But to EP, it's a natural space experiment: the Sun serves as the light source, the Moon as a reflective screen, and Earth's shadow as a natural shutter. This precise geometry allows scientists to study the exchange of matter and energy between Earth and the Moon, explore interactions between Earth's magnetotail and the lunar environment, test theoretical models, and even calibrate instruments.

下次抬頭看血月時(shí)，不妨想一想：地球軌道上的天關(guān)衛(wèi)星，也正靜靜“看著”這輪高能版的紅月亮。

Next time you look at a Blood Moon, remember: the Einstein Probe (Tianguan Satellite) in Earth orbit is quietly watching this high-energy version of the red Moon.