Particle entanglement, as described by quantum mechanics, is a phenomenon where two or more particles become linked together in such a way that the quantum state of one particle is dependent on the state of the other(s). When two entangled particles are separated and their states are measured, the outcomes of those measurements can be correlated, regardless of the distance between them.
However, it is important to note that entanglement does not allow for faster-than-light communication. Even though the measurement outcomes may be correlated, the process of measuring one particle's state does not instantly affect the state of the other particle, regardless of the distance between them. The information about the measurement outcome must still be transmitted conventionally at or below the speed of light.
This principle is known as the "no-communication theorem" and is a fundamental consequence of the theory of relativity, which sets a maximum speed limit for information transfer. The correlations observed in entangled particles do not violate this speed limit because the measurement outcomes are random and cannot be used to communicate information in a faster-than-light manner.
Therefore, while entanglement is a fascinating phenomenon with potential applications in areas such as quantum computing and cryptography, it does not provide a means for practical interstellar communication.