A low number of atoms or molecules in a relatively large volume of space. Atoms or molecules are spread apart relative to each other. An instrument that measures the point of impact of a particle and the energy loss of the particle through a gas inside the counter. A magnetic storm on Earth. Gradual flares One of two general types of solar flares.
Gradual flares accelerate mostly protons and last for several days.
They occur mainly near the poles of the Sun and happen, on average, about 100 times per year. Gravity A physical force attracting one object to another object. Ground station Ground stations are the link between the control system and a satellite in orbit. They track a satellite's signal to find it's location, and the status of equipment onboard and distribute that information to interested parties. They are also used to transmit operational signals back to the satellite to help control it.