In our solar system, the planets Jupiter, Saturn, Uranus and Neptune are more massive.
There are over 300 extra-solar planets known to be circling other stars; in most cases, only very massive planets can be detected at such ranges. It is likely that other smaller planets also exist, but we have no indication of that so far.
Most of the known extrasolar planets are more massive than Earth because massive planets are easier to detect. We have detected planets smaller than Earth.
The most massive planets in our solar system are Jupiter, Saturn, Uranus, and Neptune. Jupiter is the most massive planet by far, containing more than twice the mass of all the other planets combined.
Inside our sollar system, the planets Jupiter, Saturn, Uranus and Neptune are all larger and more massive than Earth.
Earth
None of the planets that scientist know is exactly 15 times more massive than earth, but the closet one is Saturn, it is 18 times more bigger than earth,
Jovian means Jupiter-like - these planets are made of gas and are several times more massive than the Earth - like Jupiter.
Most known extrasolar planets are more massive than Jupiter because they are easier to detect with current technology. More massive planets exert a stronger gravitational pull on their parent stars, causing a more noticeable wobble or dimming of light that can be detected. Smaller planets like Earth are harder to observe due to their smaller size and weaker gravitational influence.
The Earth stays in its orbit under the force of gravity from the Sun, which is much more massive than all the planets.
From the Sun:Mercury is innermost and smallest (about the size of our Moon.)Venus is next and almost exactly the size of the Earth, just a shade smaller.Earth is next and it is - well- the Earth!Mars is the last of the rocky - Earthlike planets and it is smaller than Earth.See a picture comparing the sizes at: http://en.wikipedia.org/wiki/File:5_Terrestrial_planets_size_comparison.png
It depends on where you are. In most pars of space you are far away from any massive objects, so gravity will be much weaker than it is at Earth's surface. At the height of low Earth orbit, gravity is slightly less than it is at the surface. Only near very massive objects such as giant planets and stars will you experience stronger gravity than on Earth.
Jupiter is the largest and most massive planet in our solar system. It is over 300 times more massive than Earth and is known for its colorful atmospheric bands and swirling storms, including the famous Great Red Spot.
Saturn is the second-largest planet in our solar system, with a mass about 95 times that of Earth. It is significantly less massive than Jupiter, the largest planet, which has a mass over 300 times that of Earth. In comparison to the other gas giants, Uranus and Neptune, Saturn is more massive than both, with Uranus being about 14 times and Neptune about 17 times the mass of Earth. Overall, Saturn's mass places it firmly as one of the most massive planets in our solar system.