pzkpfw

For one thing, a body is made of parts. If you lift a 60 kg weight with your arm, the arm has to cope will all 60 kg. A 60 kg person lifting themselves, does it in parts. Their neck lifts their head. Their core lifts their torso plus neck plus head. Their legs lift all the above. It's not an apples to apples comparison. A 60 kg person doing a one-handed pull up or press up, would be a fairer comparison.

*there

The deepest mystery in physics is people who don't know things, complaining about the people who do know things - not everything - and who are trying to learn more. Why is it so? Possibly the Dunning–Kruger effect.

We're watching you.

I try to avoid magical thinking, but a certain, um, speculators recent ranting threats had me wondering.

The OP also included "... What about home stereos, car stereos; do they lack the CD now ? From 8 track to cassette to CD to MP3 to nothing. Where do modern people keep their music, videos, movies ..." and that's where a lot of the conversation went. As for personal files, for years I've seen a heck of a lot more USB connected hard drives (now transitioning to SSD) used than CD. Add to that a good cloud backup solution, still no need for CD's. I'm not sure I'd trust a writable CD for very long term storage. Not a regular HDD either. Probably they key with digital information is to keep transferring to newer formats (and in multiples). (... don't want to end up like NASA, with data stored on tapes for which they have trouble finding readers.)

My large pile of CD's is in a box somewhere, next to my two beer crates of vinyl. Not taking up room in my lounge, not getting scratched or lost. Instead, everything I ever owned - and much much more - is available via Spotify, on my PS3, connected to my stereo. (No antivirus needed.) I already have internet etc anyway, so that's no extra cost. And Spotify itself costs less per month than one CD per month would have cost. And in any case, it's bundled with my cell phone plan so works out cheaper than sticker price. (Yes, no free lunch and all that.) With bluetooth, and access via my phone, which has GB and GB of space (and Spotify allows downloads) I have my music everywhere. I don't miss CD's.

Ever been in a 747 and have a ships' radar pick you out?

You started the thread, it's up to you to provide something of substance to back up your claim of a "theory". Instead you've spent most of your time complaining about another poster. Let it go. Try "doing science".

*you're *medal

Post #49 here contains some great animations that I think are relevant: https://www.physicsforums.com/threads/the-velocity-of-a-moving-frame-of-reference.972860/page-2

Polarising filters may be relevant.

You've heard of clouds?

It's not about transparency, it's about the light from stars being dim and being washed-out by daylight. Your eyes can't cope with bright light from your surroundings, and see the stars. Same reason photos taken on the Moon generally don't show stars - even though there's practically no atmosphere there. A satellite camera will be arranged so that direct sunlight doesn't cause the same issue. There's no reason for simple air to be one-way transparent. edit: at night, where do you think the atmosphere goes to make stars visible?

The news today has an item about Trump calming the hawks. I wouldn't put it past them for this to all be a beat-up to give Trump a "victory". i.e. manufacture a near-crisis out of nothing, so he can be shown to have averted it. (I really hate to sound conspiracist. But here it is.)