it depends if the object encounters any others on it's eternal journey through the cosmos. newtons first law of motion (also known as the Law of inertia) states that an object at rest tends to stay at rest and that an object in uniform motion tends to stay in uniform motion unless acted upon by a net external force. this state of affairs would only really apply in a hypothetical universe in which the only existing thing is the object in question. in our universe, an object set moving in any direction would eventually be diverted from it's course by the gravitational influence of any matter it happened to move close enough to interact with.