Table of Contents
What causes the different sizes of planets?
Planets come in different sizes and so have different gravity levels. Mars is smaller than Earth so has less gravity. On Mars you weigh less and would be able to carry more. Smaller planets are also less likely to have an atmosphere, as there may not be enough gravity to hold the gases to the surface.
How are planet sizes determined?
The most common is to measure the apparent angular diameter of the planet – how big it looks against the sky – very precisely using a telescope. Combining this with a measure of its distance (deduced from its orbit around the Sun) reveals the planet’s actual size.
Do planets get bigger or smaller?
If, however, it continues to grow larger, then it captures more and more gas which forms an atmosphere that causes it to swell to the size of Neptune (four times Earth’s radius) or Jupiter (11 times Earth’s radius). Therefore, a planet either stays small and rocky, or it becomes a large, gaseous planet.
How do planets change over time?
The motions of the planets are governed by the forces acting on them. The largest of these forces is the sun’s gravity, which keeps the planets in their orbits. These are smaller in magnitude than the sun’s gravity, but large enough to cause planets to change their positions over long periods of time.
Why is the solar system so big?
Our solar system is huge. There is a lot of empty space out there between the planets. In an effort to bring these vast distances down to Earth, we’ve shrunk the solar system to the size of an American football field. If the Sun were the size of a dime on the goal line, Neptune would be 60 yards away.
Why are some planets smaller than others?
Since the planets were closer to the sun, the heat made the gases go away. Then the smaller, planets were made because there isn’t a lot of gas. Basically, the smaller planets are small, dense and mostly made out of rock. One of the factors that affect the size of a larger planet is the temperature.
How and why did the orbits of the planets change over time?
Earth’s orbit and axis orientation are constantly changing because they are being deformed by the gravitational attractions of other bodies. These changes affect the distribution of sunlight hitting our surface, which in turn affects climate, and the kinds of sediments that are deposited.
Do planets ever change order?
Yes, the orbits change massively over time. For example, Earth’s eccentricity (how close to a circle the orbit is), its axial tilt (what causes seasons), and precession (which direction the Earth’s spin axis points) change on these huge cycles, tens of thousands to hundreds of thousands of years long.
How do astronomers measure the size of planets?
The most common is to measure the apparent angular diameter of the planet – how big it looks against the sky – very precisely using a telescope. Combining this with a measure of its distance (deduced from its orbit around the Sun) reveals the planet’s actual size. Another method involves studying the motion of moons as they eclipse the planet.
How big are the planets in the Solar System compared to the Sun?
This illustration shows the approximate sizes of the planets relative to each other. Outward from the Sun, the planets are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune, followed by the dwarf planet Pluto. Jupiter’s diameter is about 11 times that of the Earth’s and the Sun’s diameter is about 10 times…
Why do planets weigh different amounts on different planets?
The strength of gravity depends on how far away one object is from another. That’s why the same object weighs different amounts on different planets. It’s sometimes easier to compare planets using a measurement that isn’t quite so complicated.
How big are the outer planets compared to the inner planets?
The inner planets are rocky and have diameters of less than 13,000 kilometers. The outer planets include Jupiter, Saturn, Uranus, and Neptune. The outer planets are called gas giants and have a diameter of greater than 48,000 kilometers. Pluto, which used to be considered the ninth planet,…