第一張銀河系中心黑洞影像有哪些科學意涵？

第一張銀河系中心黑洞影像具有那些科學意涵？

  1. 藉這項實驗，天文學界取得了空前未有的最高角解析力，20微角秒，能分辨到月球上的橘子或甜甜圈。

  2. 影像中的光環證明愛因斯坦廣義相對論描述的「重力甚至會彎曲光」（光沒有質量）；因為重力使空間本身的幾何形狀變形。黑洞周圍的陰影證明物質落入黑洞所發出的光因該光本身朝黑洞彎曲因而永遠無法到達我們（此特指靠黑洞太近的那部分光）。

  3. M87 黑洞和銀河系中心黑洞（註１）非常不同，兩者質量相差了 1000 倍，兩者平均密度更是相差達 1,000,000 倍，然而兩者影像特徵相同，這表明自然法則以及光在黑洞周圍的行為方式在很大範圍內都是相同。我們對宇宙以及自然律如何運作的理解當然有必要在極端條件下測試。而到目前為止，愛因斯坦是一而再、再二三地證明他的想法是對的！

  4. 掉入黑洞是產生能量的最有效方式。它比化學方式（燃燒）、核能方式（如太陽上的核融合或炸彈中的核分裂）效率更高許多，因為掉入黑洞的話，所利用到的是重力場中所有的質量。掉入黑洞的能量和我們跳傘時從飛機上獲得的能量相同，但因為下落的幾乎等於是黑洞的事件視界，所以得到的能量會最大。不過別擔心，我們離黑洞很遠。

  5. M87黑洞陰影的大小和太陽系差不多。銀河系中心黑洞陰影的大小則大約只有和水星的公轉軌道差不多。 銀河系中心黑洞的平均密度約為水的1000倍。

（註１：對如今我們所認識的「銀河系中心黑洞」，長久以來，天文學家習慣上早已用＂Sgr. A*＂的英文縮寫來稱呼，Sgr. A*對應至中文的學術專用名詞應該是「人馬座Ａ星」）

(Source: Academician Paul Ho in 2022 May)

原文為English <<< click here to view the original >>>

(1) This experiment has made the highest angular resolution possible in astronomy, at 20 microarcseconds, at the resolution to see an orange or a donut on the moon.

(2) The ring of light is the proof of Einstein’s General Relativity theory, where gravity will bend even light (which has no mass), because gravity is deforming the geometry of space itself. The shadow around the black hole is the proof that light emitting from matter falling into the black hole, are themselves (the light) bent towards the black hole and therefore can never reach us (the part of the light which is too close to the black hole). (3) M87 and SgrA* are very different because their mass is different by a factor of 1000. Their average density is different by a factor of 1,000,000. Yet their signatures are the same, which shows that the laws of nature, and how light behaves around a black hole, are the same over a large range in conditions. Our understanding of the universe, and how nature works, demands tests in extreme conditions. So far, Einstein is right again and again! (4) Falling into a black hole is the most efficient way to generate energy. It is much more efficient than chemical means (burning), nuclear means (fusion as on the sun, or fission as in the bomb), because we are utilizing all of the mass in a gravitational field. The energy from falling into a black hole is the same as the energy we gain when we jump out of a plane while skydiving. Because the infall is almost to the event horizon of a black hole, you get the maximum energy out. But not to worry, we are not anywhere near a black hole. (5) The shadow of the M87 black hole is about the size of the solar system. The shadow of the SgrA* black hole is about the size of the orbit of mercury around the sun. The average density of SgrA* black hole is about 1000 times that of water.