A dinâmica do Tesseract / cubo cósmico não é facilmente definida, mas parece alterar o espaço-tempo o suficiente para conectar dois pontos de maneira semelhante a um buraco de minhoca.
Evidence suggests the gravitational effects of Earth can be felt through the portal. Since the portal was a disruption in space time, it may have had its own gravity well in addition to Earth's gravity. Stark fell at a rate consistent with (or perhaps) even faster than normal gravity.