Telescopes are time machines. As light travels at a finite speed (around 300,000 kilometres or 186,000 miles a second), the further away an object is, the further back in time we see it. When we look at the Andromeda galaxy, which is 2.5 million light years away, we are seeing it as it was 2.5 million years ago.
In principle, with a good enough telescope, the furthest we can look back is around 13.5 billion years in time to the point where the universe became transparent when atoms formed. Before then, matter was electrically charged and soaked up any passing light. The light that was zipping around the universe when it became transparent is still out there. (DARK MATTER & DARK ENERGY: The Hidden 95% of the Universe, by BRIAN CLEGG, Icon Books, 2019, Chap 3)
天文學，以至宇宙論，處理的是光線，當然這裡所說的光線，不止是肉眼所能見的範圍，而是電磁波的光譜，但是這件事說明，光線就是穿越時空的信差，意思是說，八識之首的眼識，就是 Time Machine，意思是說，耳識的聽覺，倏忽即逝，不是 Time Machine，其他鼻舌身亦然，第六識意識，比較複雜，有點像把前五識，炒成一盤五味雜陳的雜燴，然後第七識末那識，宣稱這盤雜燴就是自己，到了第八識阿賴耶識，才知道原來，那盤雜燴是宇宙的，
以上也說明，視覺帶來時間，帶來歷史，所謂眼見為信，意思是說，耳聞不足為信，意思是說，心理治療，從頭到尾，都是耳聞，不足為信，
回到光 （線），與之相對，就是黑暗，所謂黑洞，暗物質，暗能量，榮格的暗影，佛洛依德的死之欲，佛洛姆的戀屍性，negativity，necropolitics (thanatopolitics)，Harry Bosch the tunnel rat，所謂「來到一個沒有光的所在」，簡單講，帶來生命的是光，禮讚生命，就是 「let there be light」，
