The speed of a crash landing on its surface is typically between 70 and 100% of the escape velocity of the target moon, and thus this is the total velocity which must be shed from the target moon’s gravitational attraction for a soft landing to occur. For Earth’s Moon, the escape velocity is 2. 38 kilometres per second (1. 48 mi/s). The change in velocity (referred to as a delta-v) is usually provided by a landing rocket, which must be carried into space by the original launch vehicle as part of the overall spacecraft. An exception is the soft moon landing on Titan carried out by the Huygens probe in 2005. As the moon with the thickest atmosphere, landings on Titan may be accomplished by using atmospheric entry techniques that are generally lighter in weight than a rocket with equivalent capability.
"Makemake is in the class of rare Pluto-like objects, so finding a companion is important. The discovery of the moon has given us an opportunity to study Makemake in far greater detail than we ever would have been able to without the companion," Dr. Parker continued to explain. The Ocean Worlds Of Our Solar System. There are more than 100 moons in our Solar System that do their mysterious gravitational dance around the eight major planets belonging to our Sun's family. Most of them are icy and small, containing only tiny quantities of rocky material, and they circle around the quartet of giant gaseous planets that dwell in the outer regions of our Solar System. The four majestic, giant denizens of the outer limits--Jupiter, Saturn, Uranus, and Neptune--are cloaked in blankets of gas, and they are orbited by sparkling, icy moons and moonlets. Of the quartet of relatively small, rocky terrestrial planets--Mercury, Venus, Earth, and Mars--Mercury and Venus are moonless, and Mars is circled by a pathetic duo of tiny and somewhat deformed moons (Phobos and Deimos). The two little moons of Mars are interesting objects, frequently considered to be asteroids that escaped from the Main Asteroid Belt between Mars and Jupiter, only to be snared by the Red Planet's gravitational pull when our Solar System was young. Earth's own beautiful, beguiling, bewitching Moon is the only large one inhabiting the inner kingdom of our Solar System. The Solar System forms a tiny part of the Milky Way Galaxy, a vast conglomeration of stars and planets. What makes astronomy so thrilling is that despite its size, the Milky Way is not the only galaxy in the universe. There are hundreds of billions of galaxies out there, probably more. The closest galaxy to our own Milky Way is Andromeda. Now, brace yourself for the distance: it is 2.3 million light years away. One of the most exciting phenomena for astronomers is the black hole. It is an area of the universe where the concentration of mass is so massive (no pun intended) that the gravitational pull it generates sucks in everything around it. Everything includes light. Remember that the escape velocity for any object in the universe is the speed required to escape the objects gravitational pull. The escape velocity for the Earth is slightly over 11 kilometers per hour while for the Moon is 2.5 kilometers per second. Well for a black hole, the escape velocity exceeds the speed of light. That is how strong the pull is.