Gravitational waves are invisible. However, they are incredibly fast. They travel at the speed of light (186,000 miles per second). Gravitational waves squeeze and stretch anything in their path as they pass by.
bad bad bad. running your car low on oil can cause the engine to lock up and that means a rebuild. you should check your oil weekly along with other fluids. check your oil after your car has set for about 30 minutes or before you start it for the day. not doing this will give you unaccurate readings.
Do not drive the vehicle if the oil light comes back on. If you add oil and the light comes back on, it means the issue is oil pressure, not the amount of oil. Oil pressure is created by the oil pump forcing the oil through the engine.