Experiential Fact
At say 65 mph, one can travel on a highway in a calm interior only if all the windows are rolled up.
How then does this model of the earth
Zipping through the space of a heliocentric model

At 66,622 mph – 666 22 hmmm … – (107,218 km/h) Mean Orbit Velocity
(NASA Science > SOLAR SYSTEM > Earth > BY THE NUMBERS)
Keep its atmosphere?!

Cf.
– Earth’s Upper Atmosphere | NASA
– Peeling Back the Layers of the Atmosphere | NOAA
Conclusion
The Heliocentrism model demands a firmament!
In fact, just the model of an atmosphere adjacent to the vacuum of space demands a firmament.
To just state:
The atmosphere consists of layers of gases, called “air”, that surround the planet and are retained by Earth’s gravity. (Cf. The NOAA link above.)
is to be dogmatic, antithetical to their philosophy, science, and the experiential facts given above (car on a highway – even more if such a speed is on a round track since the heliocentric model has the earth moving in an orbit – and air open to a vacuum). Note that the model of the earth spinning on its axis hasn’t been factored in, which would further compound the issue: different rotational speeds, max at the equator and decreasing to zero at the poles as one moves along the longitudes.
Also, let them explain why the earth’s waters, its inhabitants, its atmosphere, are all not flung toward such a required firmament if not pinned to it.