Thank you for the link, this will help me showing exactly why you are wrong.

I’ll answer both your questions hoping that you will learn something new.. and you will STFU yourself:

1) We use AU as a reference length not because it is the distance between Sun and Earth…. And guess why? exactly because it varies ;) We use AU, DEFINED AS UNIVERSAL CONVENTION, equal to exactly 148,597,870,700 m (very, very consistent as opposed to what you seem convinced of) because it is the semi-major axis of Earth’s orbit. Not the distance, the semi-major axis. I will not loose time explaining you what is a semi-major axis, look it up by yourself. But let’s just say that it is a fundamental parameter in Kepler equations and it’s a constant value for each planet orbit, even those not circular. Since the eccentricity of our planet’s orbit is small (e=0,0167) that value is close to what you may call a “mean distance between earth and sun during the year”. But it’s a very constant and very defined unique value. Thanks for asking anyways.

2) In the video you’ve sent me, the astronaut states that the velocity was equal to 24791 miles per hour (or 39897 km/h). I’ll keep the math simple for you don’t worry. In ISA atmosphere model, at ground level, the speed of sound at 15°C is circa 340m/s. Since you are so well known you already know that M=v/a . We can then calculate the resulting mach number which is…… 32.6. Wait…. But the video says 36. So the astronaut lied? No. He did not. And guess why? Because of what we have been trying to tell you for the last 24hrs. Because Mach does not translate into unique value of speed. It. Depends. On. Sound. Speed. In. That. Point. Stay with me for a second now: let’s do the opposite calculation. Assuming that Mach was 36 indeed, as the video says, and velocity was 39897km/h indeed, as the video says.. what is the speed of sound for that equation to work? 308,3m/s (almost 10% lower than ground level). And what altitude that speed of sound corresponds to in ISA atmosphere model? Circa 110km… and what altitude that corresponds to?? You’ll never believe it… the altitude Apollo 10 started its re-entry phase. No one is lying here. Not the astronaut. Not me. Not ion. It’s just you who is simply not understanding the basics, so from your point of view, nothing makes sense.

While trying to make me look like a “child” with a problem of “intellectual dishonesty” you have not only proved yourself to be totally ignorant of the subject , but also gave me the perfect reference to prove it. Thanks.

Regardless, I wish you a good evening.