Why does a planet like Earth appear to not fall ?

Its orbit (which contributes to the magnetic field) gives the Earth angular momentum. The earth travels at enough speed while in orbit so that it doesn't fall into the sun, but not so much speed that it gets flung into deep space. Ironic since the earth's gravitational force is also being affected by the sun's mass. In the bigger picture (galaxies) there's also dark matter that exerts a gravitational force that gives larger clusters of bodies their integrity.