Answer:
I am a protector. I sit on a bridge. One person can see right through me while others wonder what I hide.
I beam I shine I sparkle white. I’ll brighten the day with a single light. I’ll charm and enchant all I’ll bring the best in you all.
Physicists have built devices to move me very fast. My last seven letters can be commonly found in newspapers magazines and journals.
Lovely and round, I shine with pale light, Grown in the darkness, a lady’s delight.
I am owned by the poor the rich does not need me. If you eat me you will die!
Give it food and it will live, give it water and it will die.