The video is evidence from a quite reasonable source (CBS).
So, if you like to know, whether matter can disappear without a trace, you should actually have a look at that video.
You could watch other videos of 9/11, of course, if you prefer to do so.
And there are actually millions of videos available from that day.
But I cannot possibly comment all of them, hence took the video from CBS.
Sure, but the effects visible at the video are far more exotic than simple rust.
I wanted to prove, that more than a million to of building materials vanished without a trace.
These masses of steel and concrete simply went away and nobody knows to where.
This is actually a physical problem and related to the topic of this thread (which is still 'energy and mass').
The question to explore is actually:
is mass 'conserved'?
This is so, because 1 mio to of steel and concrete usually do not get blown away.
That's why physicists could take such a rare event and treat it as a (well documented) scientific 'experiment'.
Well, yes. But 'fine dust' would need an explanation, too, because skyscrapers rarely turn into fine dust.
Ok, the skyscrapers turned into fine dust, which was blown away.
BUT: since when do skyscrapers turn into fine dust?
No, not at all.
I personally thought, that an exotic weapon was used, which could turn large structures of steel and concrete into fine dust.
But I would have doubts about al-quida having such a device.
Dust blows away, that's true.
But how would you transform a 400m skyscraper into fine dust??
It also happened in mid-air, because the fine dust was blown away, before it had reached the ground.
My guess was therefor some VERY unusual weapon, which was possibly stationed in space and which shot down from the orbit.
The very first shots were apparently a near miss, because the first building blown up wasn't one of the twin-towers, but the costums building WTC-6.
That happened earlier than the collapse of the towers.
My additional guess:
if this event was actually caused by an exotic weapon, then 9/11 would have been a collosal stupidity.
The reason: if such a device would exist, it would be absolutly crazy to actually use it in such a way, because now every single despot on planet Earth wants such a device, too.
TH