Wednesday, October 9, 2019

Mountain Shadows being cast into Deep Space

If you find somewhere where the Earth is very smooth, and drop a mountain onto that spot, something amazing happens. At sunrise and sunset, the mountain does something more normally assigned as a task for clouds: casting shadows not just through the air to project onto the ground, rather casting shadows through the air and on out, into deep space.

The giant dark stripes in the sky are the shadows of three mountains, in fact the largest mountain on the Earth is one of them: Mauna Loa, Mauna Kea, and Haleakala.

The unusual aspect is that these mountains rise out of a very smooth ocean with often very clear air. These shadows are going *up* and will not be cast on the ground, at least not at the time of this photo. These mountains are east of where I was to take this picture. The sun has not risen where I am. These shadows are diverging and actually rising up away from the dark side of our world. This is because their bases are still in darkness, before sunrise, while their tops nearly three miles above project into air that is illuminated by the sun.

The shadows are not cast onto the Earth. They actually continue all the way through the atmosphere and out, into deep space.

Almost twenty years ago I watched the first dawn of the Third Millenium from atop one of these, watching my shadow join the shadow of the larger mountain and together cast into deep space. That was twenty years ago. My shadow has passed many stars since then.

On January 1st, the sun is in Sagittarius, roughly near the position 18h 44m  -23° 03'. The point opposite that in the sky is where the shadow went: 6h 44m +23 03'. That point lies within the constellation Gemini. The major stars of the constellation range from 33.8 to more than 1763 light-years away. While my shadow has not reached any of the major stars, it has passed the distance of several of the lesser stars. Gliese 251 is about the closest star in the constellation at about 18.22 light-years distance. Some minuscule portion of the light blocked by our world from our star I personally blocked that morning. If there are entities out there looking for transiting exoplanets orbiting stars along the ecliptic, we would be visible as one of their detectable exoplanets. One morning almost 20 years ago, I helped a tiny, tiny bit.

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