Episode: 3857
Title: HPR3857: Yesterday I saw a solar flare
Source: https://hub.hackerpublicradio.org/ccdn.php?filename=/eps/hpr3857/hpr3857.mp3
Transcribed: 2025-10-25 06:45:09

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This is Hacker Public Radio Episode 3857 for Tuesday the 16th of May 2023.
Today's show is entitled, yesterday I saw a solar flare.
It is hosted by Andrew Conway and is about 11 minutes long.
It carries a clean flag.
The summary is, in account of the first time, I saw a solar flare with my own eyes.
Hello Hacker Public Radio people, this is Mick Nalu, also known as Andrew.
And today I'm going to tell you about a solar flare that I saw yesterday.
Now when I see I saw a solar flare, I mean I saw it with my own eyes.
And that isn't usually an easy thing to do.
I should also say that my background is, as many of you might know, is in astrophysics.
And specifically I used to do research and write papers on solar physics and specifically
energetic particles and their movement around magnetic fields during solar flares.
So you might think that would mean I know quite a lot about solar flares, isn't it?
I know something about it, it's been years since I've worked on it.
But you know I've never seen a solar flare before, and in fact I don't think many people
have.
Certainly many of the solar physicists that worked on solar flares, they've looked at
a lot of data from solar flares, but never seen a solar flare with their own eyes as
I certainly had not done until yesterday.
Now what happened was, it was a sunny day, sunny days aren't that common where I live
in Glasgow in Scotland.
But it's been sunny all week and quite cold and clear nights, great for a nighttime
astronomy too.
But I have this small solar telescope that belongs to the Astronomical Society of Glasgow.
And I set it up and pointed it at the sun.
And this is, I should stress, a telescope that is designed to be pointed at the sun.
So don't go around doing this with any old telescope.
You will blind yourself and maybe set fire to things.
And it's got what's called an H alpha filter.
So H alpha is a very specific wavelength of hydrogen, which corresponds to energy transition
in the hydrogen atom.
So it's quite a good one to look at, because I can tell you a fair amount about what's
going on in particular parts of the sun, particularly at its surface, what we call the photosphere
and the chromosphere, which is above it.
Anyway, I don't want to get into jargon.
So I was looking through this telescope and you see this, the sun is of course very bright,
but with this filter in place, it's probably thicker than a welding glass type filter.
You shouldn't use welding glass type filters to look at the sun, I'm not 100% sure
why not.
Anyway, this telescope was designed for the purpose, so it was fine to do that.
And I was looking at the sun and I was at a massive sun spot, and you could put several
earths inside the sun spot, pretty near the centre of the disk of the sun.
And I was looking at that and then I noticed, oh it's another, quite prominent spot,
not quite as big.
And then I looked at this other spot and as I was looking at it, it was, well, when you
look at the sun, and I'm not talking about an inverted image here, when you look at
the sun, you generally talk about location in the sun in terms of self being at the bottom
of the sun, because that point down towards the southern point of the horizon.
So if you imagine being northern hemisphere, you're looking south at the sun, let's say
at noon, then if you look at the sun, then south will be underneath the sun, north will
be behind you, opposite direction to the sun, and west will be to the right and east to
the left.
So that's when I say north, east, south and west, when I look at the sun, I'm referring
to that.
So the big spot, as I said, was in the middle of the disk, but this other thing that I saw
was at the north east corner of the sun, okay, corners, closer to the edge, not quite
at the edge, but in the north east quadrant, if you like.
And it looked like a spot at first, but then I noticed it had a bright strand like a line
I went with that.
Very unusual, I've never seen that before.
And more I looked at it the more odd it seemed, and it seemed like the bright strand was
getting brighter.
And so I assumed what I was looking at was some kind of solar event, probably a solar
flare that was visible at the H alpha wavelength, and you often get solar flares near sunspots.
And the reason is, the common element is the magnetic field, it's all tangled up in
these regions which cause sunspots, they also cause solar flares to happen there.
But not often, most of the time you look at them, you don't see any solar flares.
And I don't have never seen one in the H alpha before, not with my own eyes.
Anyway, I wasn't sure at this point what I was looking at, and it just so happens
I went and up next door to get my neighbour and came back, and when we looked at it, he
saw it too, although it peered a little bit less bright.
It was maybe, it was there, but less bright.
And then we were chatting for a while, and I looked again, maybe about five minutes later,
and it was gone, there was no bright patch, and there was no sunspots, I could see, there
was just nothing at all, where this had been.
So I thought, oh, maybe some cloud has passed in front of the sun or something, and has
blotted it out, blurred it out, so I could see the rest of the sun quite fine, and I could
see this big sunspot, and there was two other spots on the other side of the sun that
were still there.
So I thought, oh, maybe it's just that side, the sun's a cloud drifting past, but no,
I waited, and that never returned, and I didn't see the bright patch, didn't see the
why thought were sunspots.
Now at this point, I picked up a phone to a friend of mine who was my mentor and friend
laterally, and explained what I'd seen to him, and he said, oh yes, it does sound like
a solar flare, but that darkening that you mistook for a sunspot, that's odd.
So he pointed me to some sources of data, and I indeed was able to verify using the
GOES satellite data, which looks at X-rays, and that data is used to classify flares, and
it indicated that at first, the first thing I saw was an M1.7 flare, then I went next
door to get my neighbour, and by the time I came back with him a few minutes later,
a second flare had started up, the first one had finished, and the second flare had started
up, and it was a smaller M1.1 flare.
So these classifications, it's a bit like the decibels scale, so I don't know what,
I can't remember what the letters stand for exactly, but it's, an M class flare is a
big flare, an X class flare is 10 times larger in terms of its X-ray output, and that would
be an enormous flare, they're very rare, but M class flares are big, but nothing to write
home about, and the fact that it was an M1 flare, M1.7, the first one, that's all, it's
on the smaller end of the scale, so M9 would be at the upper end of that scale, and the
whole class, a factor of 10 below that, is called the C class flares, and they're pretty
common.
Anyway, so M class flares would be a small one, I was surprised to see the fact that I saw
that in H-Alpha, I was quite surprised, because it wasn't a huge flare, it was a big
one though, not very big.
So I went off, and I then confirmed for myself that, yes, there had been flares at these
times, and then I looked at magnetograms of the solar disk, which shows you where the
magnetic field is at strongest, and I was able to see the region I was looking at, did
indeed have two spots, and you can actually see them in what's called white light images,
as unfiltered light images that you can get from various observatories around the world.
I could see that there were some spots there, but they were really rather small, smaller
than I could see with the telescope that I was using.
So although the worst spots there, that wasn't what I saw, and I could see when the air
was still, I could see there was something there through the telescope, but it just looked
like an indistinct patch, I couldn't make out spots on spots.
Later on, I was able to locate satellite data from the SDOAAIA instrument, and I think
that's at a wavelength of 304 nanometers, I think that's if I'll correct myself in
the show notes if I've misremembered that, and in that, I was able to put together a
movie using a website called HelioViewer.org, and that movie clearly shows the events that
took place at that time, although that wasn't in H alpha, it was now a wavelength that
is related, I think it's to do with Helium, that one, so Helium's the second biggest
constituent of a star, hydrogen is 75% of a star by mass, and 25%, well just under 25%
is Helium, and then a small amount of lithium and a tiny amount of everything else.
Anyway, so Helium is also a good thing to look at if you want to see what's going on.
In conclusion, yes, I did see a solar flare, and I was able to verify it, and I don't
know whether I'll ever see another one, but I'm going to try, now I know that it can
be seen, I'm going to try and see another one, see if I can get lucky in, and the moment
the sun's fairly active is plenty of spots, so anytime it's clear I'll try and set it
up and have a look.
Today I had a look, the big spot was still there, I could see, I did nice to take a photograph
just by holding my phone to the telescope, which I didn't manage to do yesterday, but
I filled her under the settings on my phone, and managed to get an okay photograph, so
I'll stick that in the show notes, and the other treat that I got today was while I was
looking at the sun, hoping for another flare, but I didn't get one, what I did get was
a plane with its contrales go right over the disk of the sun, I couldn't believe it was
like a black silhouette, in the last two meters, but it was really striking, and I looked
up using this app called Flight Radar, and it wasn't just any old plane, it wasn't a passenger
jet, it was a US Air Force C17A Globe Master, so there you go, solar flares and US Air
Force planes, things that I didn't think I would see through my telescope. Have you
ever seen a solar flare or a jet photobombing your astronomical image, if so let me know
in the comments or even better, do an HPR show about it, thanks very much, bye bye.
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