There is thus some travel involved. Gathering of planetary data is done either via unmanned spacecraft missions or from earth based telescopes. These include public lectures, school visits, appearances on local or national news shows, etc. It is a poetic term. No, but the place where I work, has built several instruments that have gone to Venus and Jupiter and in orbit around the earth.
Gravity is an innate property of matter.
As to why an object with a mass has that property, we do not know. Because a shooting star is not really a star, whereas the Sun is a star, that creates its own energy by nuclear reactions in its interior. We don't know yet. Only recently have we acquired the ability to detect stars with planets around them, and about half a dozen have been discovered so far. It is expected that many more will be discovered in the future.