KentuckyFC writes "Last month, NASA declared that Earth's most distant probe had finally left the Solar System. But the announcement may now turn out to be premature. It was prompted by a dramatic increase in the density of plasma in the region of space the spacecraft is now in. However, there has been no change in the local magnetic field, which is what astrophysicists would expect if Voyager had entered interstellar space. Instead, space scientists think the probe may be caught inside a magnetic portal known as an interstellar flux transfer event. This occurs when the magnetic fields from two different objects briefly become connected through a tube-like magnetic structure. This process happens between the Earth and Sun's magnetic field about every eight minutes, so similar events are expected between the Sun's field and the interstellar field. This magnetic tube would allow particles in from outside the Solar System, increasing the density of plasma, while maintaining the same magnetic field. If so, Voyager 1 hasn't yet left the Solar System after all."