GDO Question

[Admiral Mappalazarou]

Hi guy

I've just been thinking, you know like the iris closes after the last team member gets through the gate after a mission? Well is it because the last person to go through the gate has the thier GDO activated and the current that goes through the gate to tell Walter to keep the iris open somehow keeps the gate activated until the GDO is out of range (aka. when they enter the stargate last)?

If that makes sense...

[fallenexile452]

Walter just closers it after they all come through?

[Pasankoon]

Thats a brilliant explanation! I never thought of that before. There has always been issues of what determines the closure of the wormhole. If the last person to enter the gate is carrieng the GDO that transmits the radio signal wich keeps the wormhole open then the gate should close the moment they come out.

[mikeroq]

Usually the Iris only is closed after they come in hot.

[Anonmatel]

I think you are correct. Something sends a signal (GDO, Radio, MALP, Nintendo DS, etc) until it's needed, then is either switched off by walter or someone offworld.

[Major Tyler]

The gate closes once there is no reason to stay open anymore.

Very simple.

[VSHARMA]

The gate closes once there is no reason to stay open anymore.

Very simple.

Yep if the leave you hand in the event horizon, the gate remains open until you move it all the way though or pull your hand back and doesn't automatically close, or you’ll loose a hand (as seen in SG-1 Shades of Grey 3x18) Or 38 Minutes until a gate closes itself (as seen in SGA Thirty-Eight Minutes 1x04)

[Keeper]

since it would suggest that there's something specifically holding the gate open, it would suggest that there's something on the other side to recieve such a signal. yet there's times going outwards from earth that the gate stays open waiting for ppl to go through - does the gate determine itself whether its needed? i reckon it doesn't, and that a signal doesn't maintain it either. just the power supply - if the power gets cut off, then the wormhole will close. simple as.


btw... just to refresh, what was the reason for the gate shutting down after 38 minutes? i know thats the longest a constant radio signal can hold the gate open, i'm just curious why it stops at that point even when there's power available.

[Major Tyler]

btw... just to refresh, what was the reason for the gate shutting down after 38 minutes? i know thats the longest a constant radio signal can hold the gate open, i'm just curious why it stops at that point even when there's power available.

The power requirements for keeping a wormhole active increases exponentially the longer it is maintained due to cumulative destablization and entropy. The 38-minute mark is the point where the exponent jumps from just barely maintainable with current power, to unmaintainable without a ridiculously powerful energy source.

Put another way, if the power requirements for maintaining a wormhole multiplies by itself every five minutes, the 38-minute mark is the point where the increase is so great that it overwhelms the energy-generating capacity of any reasonably accessible power source. It seems that ZPMs and blackholes are the only power sources capable of generating the requisite power to keep a wormhole open longer.

Let's assume that the first five minutes of maintaining the Stargate requires 0.5 kilowatts (or 500 watts) of energy, and that every five minutes after that the energy requirements multiply by itself. The energy would, of course, increase every second the gate is active...the 5-minute point is simply where the increase becomes an exponent.

5 Minutes = 0.5 kilowatts
10 Minutes = 1 kilowatt
15 Minutes = 2 kilowatts
20 Minutes = 4 kilowatts
25 Minutes = 16 kilowatts
30 Minutes = 256 kilowatts
35 Minutes = 65.5 megawatts
(38 Minutes = 4.29 gigawatts)
40 Minutes = 12.64 gigawatts

It's clear that once you hit the 38-minute mark, 4.29 gigawatts (or 4290 megawatts) is an astoundingly large amount of energy. We can assume that most power sources (presumably all except a ZPM) are simply unable to produce the necessary energy after the 38-minute mark, so the gate shuts down.

Edit: I base my initial estimate of 0.5 kilowatts for the first five minutes because, in the episode "1969," a number of car batteries was sufficient to activate the gate for a brief period of time, and 0.5 kilowatts is consistant with the amount of energy the shown number of car batteries could conceivably generate.