Radio waves in the Stargate franchise are capable of going both ways. I started thinking about this a bit, and wondered:

  • Could you send radar signals through the gate to determine what's on the other side?

It would obviously only work if you could detect it via radar, but I'm wondering if there's anything in the laws of Stargate physics that would prohibit this?

1 Answer 1


To answer the question, yes, theoretically RADAR (either radiowaves or microwaves) could penetrate the Stargate and be emitted on the other side as radiation. Radio waves were able to be effectively emitted, but curiously enough, light was not. You were not able to see across the event horizon.

  • In this raw form, would this be useful to anyone on Earth? No.

  • Certain kinds of technology would be necessary for the gate to be able to receive the emitted signals to be interpreted and a useful signal to be returned to Earth.

enter image description here

There are several things that need to be understood about how RADAR works in order to see why this would not work. While RADAR is a commonly used tool on Earth for information gathering, its application for the Stargate Program would both be harder to implement and of questionable value considering the physical limitations of the Stargate and its placement on planets.

Why would we want to use RADAR through the wormhole in the first place?

  • The information provided by radar includes the bearing and range (and therefore position) of the object from the radar scanner. It is thus used in many different fields where the need for such positioning is crucial.

  • The first use of radar was for military purposes: to locate air, ground and sea targets. This evolved in the civilian field into applications for aircraft, ships, and roads.

  • In aviation, aircraft are equipped with radar devices that warn of aircraft or other obstacles in or approaching their path, display weather information, and give accurate altitude readings.

  • Marine radars are used to measure the bearing and distance of ships to prevent collision with other ships, to navigate, and to fix their position at sea when within range of shore or other fixed references such as islands, buoys, and lightships.

  • In port or in harbour, vessel traffic service radar systems are used to monitor and regulate ship movements in busy waters.

  • Police forces use radar guns to monitor vehicle speeds on the roads.

  • Meteorologists use radar to monitor precipitation and wind. It has become the primary tool for short-term weather forecasting and watching for severe weather such as thunderstorms, tornadoes, winter storms, precipitation types, etc.

  • Geologists use specialised ground-penetrating radars to map the composition of Earth's crust.

Each type of radar requires specialized technology for the signal to be sent and interpreted by its receiver. So the Stargate program would have to determine which of these types of information they were seeking before they created a radar-technology to be used in conjunction with the Stargate.

Lots of good reasons to do it, But you still say it wouldn't be done. Why not?

The problem isn't with the Stargate but with how radar is propagated. Radar is a series of radio waves which are sent out and due to interference with how those waves are interacted with by matter, the reflection of those waves are gathered, and analyzed.

  • On Earth, the technology commonly used is a dish or bar designed to emit and receive said signals. Yes, they come in a variety of sizes, some small enough to be put on a fishing boat, but the smaller the emitter, the less effective the signal emitted and lower quality of signal returned, in this instance, SIZE DOES MATTER.

Israeli air traffic control system

Israeli military radar is typical of the type of radar used for air traffic control. The antenna rotates at a steady rate, sweeping the local airspace with a narrow vertical fan-shaped beam, to detect aircraft at all altitudes.

  • Different kinds of matter react differently to radar so it is interpreted by how high a signal returns from the emitted wave. Metals return a high quality signal which is why radar is still used by modern militaries.

  • It is possible to make radar-resistant materials which return a lower profile of signal. Certain types of organic plastics and ceramics are capable of being radar-transparent. See: Stealth Aircraft

  • For the Stargate to be able to use a radar signal generated from Earth, the Stargate itself would have BE a compatible radar emitter and receiver. Then it would have to absorb the radio waves reflection information and transmit them to Earth to a proper receiver station.

  • There is one other reason this might not work. The gate itself could be immune to high energy transmissions outside of the transmission of matter through the gate. For the gate to be able to send information (people and materials) through it, it may be proof against any kind of high order radiation bursts to prevent disruption of the flow of matter. This would be a safety feature to prevent someone from sending a radiation burst through an active gate and preventing someone from utilizing an active connection.

But let's say Stargate Command really wanted it, Could they do it?

It is still unlikely that radar would be a viable technology to use with the Stargate because of how radar works. However:

  • You could ship a radar-emitting unit through the portal and once its on the other side, have it activate its radar, send, receive and interpret a signal and THEN send the information signal through the gate.

  • The signal would be limited by the size, output and height of the emitter. A ground based emitter would not return much useful information because it would be too difficult to interpret the signal from any close objects (any structures, buildings, trees) would be enough to make the signal almost unreadable.

  • The best emitter would be able to vary its height and position from the stargate (i.e. an aerial drone for instance) to give more diverse readings which could be interpreted from multiple locations.

enter image description here

  • While we are lead to believe the wormhole propagates radio waves from one side of the wormhole to another, no information is given about how the signal is controlled, contained, encrypted or boosted to ensure its faithful transmission. Nor is it explained why the signal isn't affected by the intense energies of the Einstein-Rosen bridge being created.

Using science we have seen from the show, was it even remotely possible?

  • Yes, assuming the interface for the Stargate was capable of being used as a transmitter and receiver of low frequency energies. Technically we know it is capable, because it has to be able to accepting an incoming radiation signal to know when to start up, so the capacity is definitely within the device. We also know the device can be remotely activated, so it has to be able to receive radio signals.

  • The very first burst wave emitted by the Stargate indicates the gate is capable of sending radiation beyond the surface of the gate. If a signal could be isolated from that initial burst, and its reflection captured, the data could be sent back along with the signal indicating a connection has been made.

  • I can also see attaching receivers to the ring itself, it is certainly wide enough to act as a receiver of a limited type of signal, and then sending that signal through the gate. This would require someone to attach the radar emitting and receiver technology after arrival. This would be inelegant and not able to be done if a gate is already owned by hostile forces.

  • 2
    Wow...fantastic answer
    – The Fallen
    Commented Jul 24, 2013 at 19:11
  • 2
    Thank you. Having worked in the military with this technology gives me an advantage, too... Commented Jul 24, 2013 at 19:48
  • You could ship a radar-emitting unit through the portal and once its on the other side, have it activate its radar, send, receive and interpret a signal and THEN send the information signal through the gate. - From what I remember that's exactly what they did (in most episodes).
    – Mario
    Commented Jul 25, 2013 at 21:36
  • Maybe the gate decoheres electromagnetic radiation enough that it makes radar useless (no reliable directionality), but not so much that it interferes with audio/video signals. The same explanation could account for not being able to see through the "puddle".
    – Anthony X
    Commented Sep 1, 2014 at 16:28

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