defy description — to be impossible to describe adequately in words

two astronomers stand with their telescopes pointed upward at an incredible aurora that fills the entire sky with swirling colors. The aurora displays patterns and colors that seem to shift and dance in ways that appear almost magical. One astronomer drops his notebook while staring upward with his mouth agape. The other astronomer removes her glasses and rubs her eyes as if she cannot believe what she is seeing. Both scientists struggle to find words as they point and gesture at the overwhelming celestial display above them. Their equipment sits forgotten as they become completely absorbed by the indescribable beauty. something so magnificent that it is impossible to describe adequately in words