What is the physically strongest & weakest Superman has ever been written?

In a SuperBOY comic he once lifted the earth for a photo shoot. It looked like he was just doing a handstand but it was verified the earth moved. Don’t know why his hands just didn’t sink into the ground.

And I think Uncle Ben (or an identical parallel universe clone or something) is back. It was in a Peter David story arc around the time I quit Spidey.

Back in 1971 or so, something happened to all the kryptonite on earth, causing it to no longer be any threat to Superman. It was, IIRC, part of a big “power corrupts, absolute power corrupts absolutely” story arc in which he, no longer fettered by his vulnerability to k-nite, went a little ca-ca.

Given that this was also near the height of his Silver Age planet-juggling, sun-extinguishing powers, that would probably be the peak of his invulnerability, which certainly isn’t exactly what the OP asked, but probably should be considered.

The secret is to distribute the weight of the Earth evenly between the palm and fingertips.

Also: lift with the legs, not the back.

That’s not quite how I remember that storyline. As I recall, all the kryptonite on Earth was turned into iron, and Morgan Edge speculated that, now that he was virtually unfettered (magic being quite rare in those days), Superman would be corrupted. But the same explosion that transmutated all the K also resulted in S losing about 1/3 of his strength (presumably meant to include his speed & invulnerability as well), so it was a net loss.

No, the missiles kicked Clark around, not the other way about. But yes, as to the explanations in this thread. Batman hits Clark with an assortment of nasties - missiles, sonics, everything the city’s power-grid can provide, thermite and acid - and just about manages to tag him hard enough to annoy him… eventually. Only after the kryptonite hits does it really start to hurt.

One of Superman’s lesser-used Silver Age powers was anti-fusion breath.

This is truth.
Oh, and the weakest I (as a non-comics guy) have ever seen Superman written was once in the TV show, when – I’m sure this has been pointed out here before – the bad guy would use all his bullets bouncing them off of the big guy’s chest, so he’d throw the gun, and Superman would duck.

RR