Question

who discovered world first​

Answer 1

Eratosthenes

Eratosthenes then measured the angle of a shadow cast by a stick at noon on the summer solstice in Alexandria, and found it made an angle of about 7.2 degrees, or about 1/50 of a complete circle. He realized that if he knew the distance from Alexandria to Syene, he could easily calculate the circumference of Earth.

$\bold \purple \star \bold \green {Answer \: by \: @Neelraj} \bold \purple \star$

Answer 2

Answer:

Five planets have been known since ancient times — Mercury, Venus, Mars, Jupiter, and Saturn. The first new planet discovered was Uranus. It was discovered by the English astronomer Sir William Herschel in 1781.

...

Explanation:

hope it is helpful to you