In other systems, Hot Jupiters are gas giants that orbit very close to their stars and thus have a very high surface temperature. Hot Jupiters were, until the advent of space-borne telescopes, the most common form of extrasolar planet known, perhaps due to the relative ease of detecting them from ground-based instruments.
Gas giants are commonly said to lack solid surfaces, but it is more accurate to say that they lack surfaces altogether since the gases that constitute them simply become thinner and thinner with increasing distance from the planets' centers, eventually becoming indistinguishable from the interplanetary medium. Therefore landing on a gas giant may or may not be possible, depending on the size and composition of its core.
Since then Union Survey ships pay close attention to gas giants, not only as fuel source but as a planet of potential life.