NASA doesn't have its own "opinion" on the size of Earth. They rely on scientific measurements and data.

Here's what we know about Earth's size:

* Circumference: Approximately 40,075 kilometers (24,901 miles) at the equator.

* Diameter: Approximately 12,756 kilometers (7,926 miles) at the equator.

* Surface area: Approximately 510 million square kilometers (197 million square miles).

These measurements are based on various methods like:

* Satellite measurements: Satellites use precise instruments to measure Earth's shape and size with high accuracy.

* Geodetic surveying: Ground-based measurements and calculations are used to determine distances and elevations.

* Gravitational measurements: Earth's gravitational field can be used to calculate its mass, which can be related to its size.

So, NASA doesn't "think" Earth is any particular size. They use scientific methods to determine its size with great accuracy.