
Microwave Ovens Posing as Astronomical Objects - jonbaer
http://spectrum.ieee.org/tech-talk/aerospace/astrophysics/microwave-ovens-posing-as-astronomical-objects
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hydrogen18
This is embarrassing to the observatories involved. If you go to the National
Radio Astronomy Observatory in the US, one of the first things they show you
is a microwave oven inside of a stainless steel sealed box. It is there so
people can heat their lunch without interfering with the observatory. They
also have a small display where you can place your digital camera, cell phone,
etc. and look at its emissions across the spectrum.

They encourage visitors but you really have to leave everything electronic
behind. The staff uses old diesel vehicles without electronics. Any on site
radio communications is done on a frequency below the cutoff of the
observatory.

~~~
NoMoreNicksLeft
You'd think they could install a gas stove.

~~~
gcr
Does flame give off EM emissions?

Edit: Radio emissions, I mean. Of course we can see it :)

~~~
pasbesoin
You'd want one with a pilot light, not the now omnipresent electronic/spark
ignition.

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zhte415
> The astronomers were flummoxed—that is, until one of the testers, during a
> third attempt, opened the door of a microwave oven before the magnetron was
> shut off by the timer. They found that although the door shuts the magnetron
> off, a whiff of gigahertz radiation could escape.

I assume it is miniscule level that escapes - there is no 'lock' feature on
any microwave I've seen, forcing power off before door opening - but in the
future I'm going to leave a microwave a rest for a second before opening the
door.

~~~
madaxe_again
This is tangential, but if you have an old microwave that you don't mind
perhaps getting a bit dirty, you can make ball lightning in the comfort of
your own home. Discovered this during my "I wonder what will happen to _this_
when I microwave it!" phase.

1) Take a tealight. Bog standard little candle.

2) Remove the metal casing. Snip the little metal foot off the bottom end of
the wick. You now have a little puck of paraffin with a wick in it.

3) Place said candle in a glass tealight holder. Ikea sell 'em for a few
pence.

4) Light it. Stick it in the microwave, right in the centre, without the
turntable.

5) Engage. Observe with wonder as the paraffin vapour enters a plasma state
and hovers in the middle of your microwave, contained by the microwaves.

I dare say this works better in some than others, and perhaps depends on the
shape of the standing wave in your microwave, and I make no guarantees as to
your or your microwave's safety - but it's a really neat demo, either way.

~~~
MengerSponge
If you try this, put a glass of water inside the microwave with the candle.
You don't want the microwave to run empty, and the water will keep that from
happening.

~~~
madaxe_again
As I said, old microwave you don't care about. Glass of water would likely
absorb most of the energy that would otherwise be gleefully wasted on making
plasma.

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antognini
We were talking about this yesterday in my astronomy department and one of the
professors here told a similar story about some radio interference at the
Green Bank telescope. The astronomers there had noticed that for some time
there had been a small burst of radio interference every day right around 5pm,
plus or minus about 5 minutes.

One of the employees at the observatory is a guy who drives around and talks
to the locals to try to track down any sources of interference that the
telescope is detecting. He went around asking people if they were using their
microwaves, cell phones, wifi, etc., and none of them were. He eventually went
to one lady's house and happened to be there right around 5pm. He was asking
the usual questions and she said she hadn't been using her microwave, etc.,
but then she said, "Oh, could you hold on a moment? I have to feed my cat."
And then she put a can of cat food in an automatic can opener. That turned out
to be the source of the interference.

I just heard this story second-hand, so I can't vouch for the accuracy of all
the details, but it seems plausible enough to me.

~~~
sehugg
Seems plausible to me too .. they use antique diesel trucks on-site because
they don't have spark plugs or onboard computers:

[http://www.autoblog.com/2014/04/24/national-radio-
astronomy-...](http://www.autoblog.com/2014/04/24/national-radio-astronomy-
observatory-old-diesel-trucks-read-this-report/)

~~~
nitrogen
Isn't there an intelligence listening post near the observatory that would
also be affected by EMI?

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NoMoreNicksLeft
So basically if someone with an undergrad in EE decided he hates astronomers
the way Ted Bundy hated women, he could screw up that field of science for the
next few centuries with no one being the wiser for it?

~~~
mmagin
He could probably set back research a bit while researchers figure out what
he's doing, but not that long. Also, unless he's operating from right near one
of these radio astronomy observatories, he would likely be violating FCC or
similar regulations in doing this and would face legal action against him once
sufficient evidence had been collected.

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evolve2k
In case your interested in the back story of how this was 'discovered', I
posted earlier the original article interviewing the PHD student who
discovered the phenomenon -
[https://news.ycombinator.com/item?id=9490371](https://news.ycombinator.com/item?id=9490371)

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imglorp
I'm guessing quick transients are the issue here?

Long-lived ones can be ruled out by looking for some characteristic strength
curve as the antenna (earth) sweeps across the sky onto and off of the
presumed source. A terrestrial source, including satellites and planes, would
have a different curve. SETI has software to filter on this.

