No, we cannot effectively communicate with other planets through sound waves in space. Sound waves require a medium, such as air, water, or solid objects, to propagate. In the vacuum of space, where there is no air or other material to transmit sound, it is not possible for sound waves to travel from one planet to another.
In space, communication between planets or spacecraft is typically achieved using electromagnetic waves, such as radio waves. These waves can travel through the vacuum of space and are used for various forms of long-distance communication, including transmitting data, images, and signals between Earth and space probes or satellites.
As for your second question, if you were to scream at full force outside on Earth's surface, the sound would propagate through the air, but its intensity would quickly diminish as it spreads out in all directions. The loudness of a sound wave decreases with distance due to the inverse square law, which states that the intensity of a sound wave decreases in proportion to the square of the distance from the source.
In an open outdoor environment, the sound would eventually dissipate and become inaudible over long distances. Factors such as atmospheric conditions, obstacles, and the presence of other sounds would also affect the propagation and audibility of the scream. Therefore, the sound of a scream would not travel very far in terms of interplanetary distances, as the vastness of space and the absence of a medium for sound transmission prevent it from reaching other planets.