How does Heat vision worK?

[Psybertrack]

Well when air is heated rapidly it expands, and creates kinetic knockback.

yeah a little, but unless inside a closed area no explosive results, and not a monodirectional knock back  even if in an enclosed area. And not enough.  I'm talking heat vision that knocks an opponent twenty or even hundreds of feet backwards like super breath would.

In the case of heat on say a rock which drastically changed temperature due to microwave/heat vision i could see a sort of explosion of the rock but not a pushing of the rock back instead.

Still you have a very good point. If there's any pressure at all like in a boiling/lidded pot there'd be kinetic force , so maybe I'm just splitting hairs.

[Psybertrack]

Shockwaves from rapidly expanding air from heating is possible here.

Also, photons themselves possess a miniscule momentum so a tiny degree of recoil is involved in just turning on a flashlight. Solar sails are based on that principle so they use the momentum of impinging solar photons instead of air molecules to drive them. Our own artificial satellites are deflected measurably by solar radiation annually. Of course, it would take a tremendous energy discharge to produce such a measurable effect as knocking back a man-sized object noticeably.

Well, not so much shock . Or else the whole room would melt too and kill all nearby civilians.  Boyles Law of gasses would apply in an airtight container though and could give shockwaves. , like a balloon popping.
solar sail photon pressure theory? not enough. would only work in space  where you are weightless and nearly frictionless and only because the solar sail is so humongously big like a hundred by hundred yard area.
To knock back a super strong guy who has planted his feet firmly to resist you need  a battering ram type force , much like Storm in the xmen does with her wind-gusts against say the Toad.

Here's a link describing the physics of photon momentum and solar sails including the formulas for those so inclined.

good site , thanks,
again solar sails won't work in an atmosphere of a planet with the strong force of gravity on them and the air resistance to slow you down. If your starship had solar sails as proulsion you could go from space near the earth to say space near Mars, but to land on Mars and take off again you'd need a smaller shuttle powered by rocket fuel or some other kind of engine or drive. Solar sails wouldn't be enough for lift off from Mars.

[Captain Kal]

You missed the point.  We're not talking about meagre sunlight pressure.  I said it would take a tremendous energy discharge to produce knockback of the kind seen in the books.  For instance, a milligram of mass converted into heat vision energy could have a momentum equivalent to a tonne slamming into its target at over 200 mph.  Heat vision can exceed 40 megaton nukes even in the early Byrned era which is over 1,860,000 times that milligram conversion figure.

And I've yet to do what RedSun said on the grav/time thread ...

[RedSunOfKrypton]

And I've yet to do what RedSun said on the grav/time thread ...

Heh, sorry CK, didn't meant to put you on the spot there.  :wink:

[Psybertrack]

You missed the point. We're not talking about meagre sunlight pressure. I said it would take a tremendous energy discharge to produce knockback of the kind seen in the books. For instance, a milligram of mass converted into heat vision energy could have a momentum equivalent to a tonne slamming into its target at over 200 mph. Heat vision can exceed 40 megaton nukes even in the early Byrned era which is over 1,860,000 times that milligram conversion figure.

Thanks for your comment. In the early days hv was almost non existent so it is the power I know least about.
Yeah ok  your right I did miss the point. I had no idea his HV was that powerful. He must have incredible range and control since he can cook with it too! It seemed at first that the large amount of sunlight pressure/heat vision pressure you were referring to would to be to hot to handle in a city, like Johnny Storm's Nova flame power used in a gas station, r.e. collateral damage, but on reconsideration of the extremely high degree of control he has and fine tuning on his heat vision, perhaps he can use his hv at will to give a blast with high knock back pressure and without too much corresponding heat, so as not to fry the hostages in their shoes.

[Captain Kal]

Since you mentioned degree of control, the current Superman has deliberately used a side-function of his heat vision to emit high luminosity, low temperature beams at least twice during Schultz's run on MOS.  He did it once to blind the JLA spying on him in the Watchtower and another time to blind an alien goon in OWAW.

This ability to emit blinding flashes of visible light jibes with Maggin's version of heat vision in Miracle Monday where young Clark discovers his optic nerve has both the passive mode we have and an active mode where he can project what he can see, hence his ability to project the heat and X-rays he can passively detect.

[Psybertrack]

So superman has a multivision power of sorts:
Vision:
telescopic,
microscopic,
x-ray,
heat: heat beams
         concussion beams
         drilling beams
         flash vision/ blinding light emmission