Doubling the mass of the star would increase the gravitational attraction between the star and its planet. The force of gravity is directly proportional to the product of their masses, so doubling the mass of the star would double the gravitational force between them.
No, a planet's moons and atmosphere do not directly affect its gravity. Gravity is primarily determined by the mass of the planet itself; the more massive the planet, the stronger its gravitational pull. While moons can influence tidal forces and an atmosphere can affect pressure and weather, they do not change the fundamental gravitational force exerted by the planet.
Mercury, because it's the smallest if you don't consider Pluto to be a planet.
Gravity depends largely on mass, the bigger the planet the greater the gravity should be
Of course there is gravity in Australia. There is gravity everywhere on the planet.
A planet
Research has shown that the planet Venus has its atmosphere temperature increased by the greenhouse effect
I makes the planet spheical in shape.
simple, the larger the planet, the greater the force of gravity.
One main reason is the gravity a dense object like a terrestial planet has. As gravity depends on the density of a object and a rocky planet has much density...our earth is the densest object in the solar system but Jupiter's gravity is more as gravity depends upon size too. The gravity holds the gases forming the atmosphere. Another reason is the core which has a magnetic effect and forms a magnetic layer which has some effect on the atmospheric gases and saves it from going away to the space by attracting the gases towards the pole where the gravity is the highest.
gravity
The international dateline has normal gravity; our time zone conventions have no effect on the gravity of the planet Earth.
weight
scientists theorize that it was jupiters gravity that kept it from forming
There certainly is enough material in the asteroid belt to form another planet, however the immense gravity of Jupiter prevented a planet from forming.
YES! the size of the planet does effect your throwing ability! If you get each planets' gravity number then you will notice that the smaller the planet the less gravity force/attraction it will have. If you go to Jupiter and throw a football the gravity will pull down on the football faster and make your throw much shorter than it would on Earth because Jupiter has a bigger gravity number then Earth.
In our solar system, at least, the planet with the greatest mass does happen to be the one with the most known moons. But I think the cause and effect work the other way. It's not the moons that give the planet strong gravity. It's the strong gravity of the planet that captures a bunch of moons.