How the radius and Distance of a planete is found ?

[my_books]

How the radius and Distance of a planete is found ?

 

[z_ghadiani]

Hey

To measure the distance of a planet, It is possible to measure the time of flight of a laser pulse.
And radius, I am not sure but having the distance and image of the planet, it is straight forward to calculate the radius of the planet.

Best

 

[echo47]

Are you referring to historical measurements of planetary distances in our solar system?
Parallax is the straightforward approach. Here's an introductory description for school kids:
https://spaceplace.nasa.gov/en/kids/phonedrmarc/2002_november.shtml

After you know the distance, the radius is a simple geometric ratio, as z_ghadiani described.
The object must be big enough and close enough to appear as a disk, and not just a pinpoint.

 

[premagg]

Wonderful approach cassini
Hats off to you