How do scientists measure the size and mass of planets in the solar system?

Measuring the size and mass of planets in the solar system is a challenging task that requires advanced scientific instruments and techniques. Here are some of the methods used by scientists:

• Transit Method: This method involves observing a planet as it passes in front of its parent star, causing a small dip in the star's brightness. By measuring the depth and duration of the dip, scientists can determine the size and shape of the planet.
• Radar Astronomy: Using radar waves, scientists can determine the distance to an object in space and its size. This technique is particularly useful for measuring the size and shape of planets that are difficult to observe using optical telescopes.
• Gravitational Pull: By measuring the gravitational pull of a planet on its moons or other objects, scientists can calculate the planet's mass. This technique was used to discover the existence of Neptune and Pluto.
• Doppler Spectroscopy: This method involves measuring the slight wobble of a star caused by the gravitational pull of an orbiting planet. By analyzing the light emitted by the star, scientists can determine the planet's mass and orbit.

These methods have enabled scientists to measure the size and mass of all the planets in the solar system and many other objects beyond it.