Set the observer's latitude to 40°, the latitude of new york, and click zoom in to examine the local sky. experiment with changing the star's right ascension and declination until it appears straight up in the sky and directly over the observer. use the graticule to measure the altitude of the star.

a mid-ocean ridge or mid-oceanic ridge is an underwater mountain range, formed by plate tectonics. this uplifting of the ocean floor occurs when convection currents rise in the mantle beneath the oceanic crust and create magma where two tectonic plates meet at a divergent boundary.a geomagnetic reversal is a change in a planet's magnetic field such that the positions of magnetic north and magnetic south are interchanged.