2) If you have a source of hydrogen: water. Bonus as you don't have to make the dome hold pressure. A layer of water of the right depth will generate the force needed, the structure only needs to keep itself level. The only pressure holding is outside that, enough to keep the water from boiling. And, well, it's water--if it's hit by a rock that isn't too big you'll just have hole in the top layer, easily fixed. The same general idea would work on the Moon but the water is far from transparent if you pile up enough of it and you need a lot of hydrogen.
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1) Why do you need sunlight?
2) If you have a source of hydrogen: water. Bonus as you don't have to make the dome hold pressure. A layer of water of the right depth will generate the force needed, the structure only needs to keep itself level. The only pressure holding is outside that, enough to keep the water from boiling. And, well, it's water--if it's hit by a rock that isn't too big you'll just have hole in the top layer, easily fixed. The same general idea would work on the Moon but the water is far from transparent if you pile up enough of it and you need a lot of hydrogen.