Final answer:
Gravity exists beyond the explored reaches of space, evidenced by astronauts' experiences of weightlessness due to free-fall, and is supported by predictions from Einstein's general relativity and observations of black holes and gravitational waves.
Step-by-step explanation:
Scientists have explored only a small portion of space, but there is convincing evidence that gravity exists everywhere, even beyond our current explorations. One piece of evidence is the behavior of astronauts on the International Space Station (ISS) who experience weightlessness not because gravity is absent, but because they are in continuous free-fall around Earth.
Furthermore, general relativity, a theory proposed by Einstein, predicts the effects of gravity and is supported by observations of phenomena such as black holes and gravitational waves, which suggests that gravity operates outside of our immediate environment. Indeed, general relativity has been tested both on Earth and in space, providing additional evidence that gravity's effects are universal.