Take the following as truth: Newgrange may be the world's oldest solar observatory the whole edifice is aligned in such a way that during several days of the winter solstice, light from the sun floods the inner chamber for approximately 17 minutes, a spectacular effect (the guide on the tour attempts to give an idea of this effect by plunging the chamber into darkness and slowly bringing up the light).
Then the following statement: "Newgrange is a solar observatory." is true, false, or inconclusive?