# How rapidly would air be drawn into space?

Whenever it is swung, the "sword of the abyss" cuts open a 1 ft diameter portal to outer space. The portal will close by itself after two seconds. The portal shrieks as air rushes into it. As a result of the air motion, to some extent anything nearby is pulled towards the portal.

Further details: The portal opens at the fastest point of the sword's swing, which we may suppose occurs when the wielder's arm is fully extended, just before the sword strikes the enemy. The portal is a two-sided circular disk, i.e. stuff may enter it from either direction (effectively two portals back to back). The portal opens so it just touches the point of the sword, and a flat side of the portal is perpendicular to the sword at the moment of creation.

I know that the speed of air at the portal will stabilize at the speed of sound. But perhaps there is a ramp-up period where it isn't going that fast for a second or two (I don't know, do you?).

Possible effects I can think of:

• Everyone within X ft (6 ft? 10 ft? how far?) of the portal is yanked off their feet by the sudden wind
• The sword of the abyss, being the object closest to the portal when it is created, is yanked from its wielder's hand into the portal
• Or maybe neither of those things happens, and the wind is manageable

What are the melee combat effects of the air flowing into such a portal? (1 ft diameter portal, open for two seconds)

• Hard-science answers require hard-science conditions. Swords are swung in an arc. Where does that 1FT diameter hole appear? At the beginning of the arc? At the end of the arc? When it collides with something? At the base of the sword? At the tip? Is the portal perpendicular to the sword's axis? flat of the blade? wielder? How fast must the sword be swung? Can it happen while sheathed? Take a moment to think very carefully about exactly what's happening and give us the excruciating detail of one specific instance of use - because that's the kind of answer you're asking for.
– JBH
Jul 18, 2022 at 18:32
• Related, not duplicate, different hole diameter, and not hard science - no equations. Jul 18, 2022 at 18:34
• Is this a spherical or circular portal? A spherical portal has 4x the surface area and thus will cause significantly stronger effects. Jul 18, 2022 at 18:42
• @JBH edited with "Further details" section Jul 18, 2022 at 19:01
• @JBH It is open two seconds. Yes, it closes regardless of what happens to the sword. Yes, a nimble fighter could open multiple portals. No, it takes a full swing to create one portal. Jul 18, 2022 at 22:21