we've finally detected x-rays from uranus!
oh, you're a professional becky gah! In all seriousness though this is a big
deal we know so little about uranus which is one of the weirdest planets in the solar
system spinning completely on its side and detecting x-rays from it might just
give us an insight into this the most mysterious planet in the solar system
now we've detected x-rays from all over the solar system from comets and asteroids
mercury venus earth mars jupiter saturn some of jupiter's moons and even tiny pluto that's not as
weird as you might initially think because most of those objects are just reflecting the sun's light
back at us you know in the same way that trees and mountains and us we don't emit light but we can
still see those things because we reflect other sources of light like the sun's light for example
but the sun doesn't just emit in optical light visible light that we can see it emits across
the entirety of the electromagnetic spectrum the full spectrum of light anything from radio waves
to ultraviolet which is what gibson's sunburn and also x-rays which thankfully for us are blocked by
the earth's atmosphere no you know potentially damaging or dangerous x-rays make it down to
the surface they're reflected back out into space which means the earth is also giving off an x-ray
signal because it's reflecting the sun's x-ray light back out into space and so you'd be able
to see it in x-rays now it's great news for us the the earth's atmosphere blocks x-rays it's
not so great news if you're an x-ray astronomer and you want to view the sky using x-rays because
it means you can't do it with a telescope from the ground you have to launch a satellite or telescope
into space to be able to do this and that way using that telescope you can detect anything
from the x-ray light from the sun to the x-rays reflected by planets for example jupiter's aurora
its northern and southern lights give off x-rays this is caused by high energy particles which
stream off the sun interacting with jupiter's magnetic field and they give off this high energy
x-ray radiation the same thing actually happens with earth's magnetic field as well just to a
lesser extent because the magnetic field's a bit weaker now we know a lot about jupiter and that's
because we've sent so many probes emissions there previously so for example the voyager
probes flew past in the 80s cassini flew past jupiter on its way to saturn and then also new
horizons flew past jupiter on its way to pluto but also because the galileo mission spent seven
years in orbit around jupiter in the late 90s and then also we've currently got nasa's juno probe
in orbit around jupiter right now sending back honestly some of the most drool-worthy images that
i have ever seen but it's a very different story for uranus the only mission to come anywhere close
to uranus was voyager 2 in 1986 and there are no future missions planned to uranus either now while
the data collected from voyager 2 taught us a lot like what makes up the atmosphere of uranus what
the weather's like in it it also discovered ten more moons on top of the five that we already knew
and it studied uranus's rings finding two new ones plus it studied at uranus's magnetic field which
was one of the weirdest results to come out of the flyby of voyager because it showed that the
magnetic field of uranus isn't actually lined up with the planet it doesn't pass through the center
of uranus and that could be something to do with the fact that uranus spins on its side
as it orbits the sun so if you think about sort of the solar system you've got the sun
spinning on its axis and that's what we define as sort of like solar system north if you will
and then you've got all the planets orbiting in a roughly flat plane that's perpendicular to that
so a perfectly aligned system would be a planet that's essentially orbiting the same angle as the
sun right but uranus doesn't it orbits on its side about 97 degrees from the sun's north so uranus is
essentially rolling on its side as it orbits the sun and this is what makes it such an interesting
system to study because it's nothing like what we have on earth or satin or jupiter that we've
studied so intently you actually have a magnetic field that is directly pointing at the sun and
pointing at all those high energy particles that are streaming off it as well so it makes for a
really complex system now voyager detected aurora on uranus during its flyby in 1986 and astronomers
using the uv detectors on the hubble space telescope also spotted aurora back in 2012. so
there could also be x-rays coming from the aurora the magnetic field around uranus as well but we
never detected it and we've also never detected the amount of x-rays you'd expect from just uranus
reflecting back the sun's light you know from the size of it and from how reflective uranus should
be that's not for lack of trying people tried in the 90s with an x-ray telescope called rosat but
couldn't detect anything above what we call the background noise of x-rays you know just kind
of like the general background of x-rays that's just sort of floating around the universe you know
that sort of overpowered the signal from uranus at least with this telescope with brosa however a
study came out this year by dun and collaborators who claimed that they finally detected x-rays from
uranus using data from the chandra x-ray telescope and this was data that it actually managed to grab
that had been taken in 2017 and also way back in the archive from 2002 when uranus just sort of
happened to be in shot when it was observing something else now this data that they have
is not pretty i'll warn you now here it is there's three observations one in 2002 two in 2017
every blue dot you can see here is a particle of x-ray light that has hit
the detector the red circle is where uranus is so you can see the observation from 2002 that most
of the x-ray emission detected came from that red circle it came from uranus the 2017 observations
are a little bit different and that's because they have come from a different detector on the chandra
x-ray telescope which is much more sensitive not just to the high-energy x-rays that you'd expect
planets and planet auroras to be giving off but also the lower energy x-rays as well that
make up a little bit more of the background noise so you can see that really clearly here
right there's a lot more x-rays detected in the background outside of where uranus is on the
detectors so a lot of work goes into figuring out if there's statistically more x-rays been
detected in that red circle where uranus is than you'd expect given the average background noise
in the rest of the image now in the observation from 11th of november in 2017 there's apparently
not according to the authors but a day later on the 12th of november 2017 there is statistically
more x-rays in that red circle where uranus is then you'd expect from the background that you
detect elsewhere in the image and you can kind of see that by eye too just by comparing those two
observations and that's really interesting that those two observations that are only a day apart
are so so different it suggests that the x-rays that are coming from uranus aren't like intrinsic
to a property of the planet so they're not like constant like you would expect from the sort of
constant reflection of the sun's light backwards but they could be from something like an aurora
which is changeable day to day right it's the same thing we see on earth it's dependent on how
many high energy particles are burped up by the sun and in fact when don collaborators actually
did the calculation of okay how many x-rays have we detected and is it more than you would expect
from just the general reflection of light from the sun they found that it was suggesting there
was some extra process going on here which is very exciting but it can't actually be pinned
down on the aurora of uranus just yet because it actually could be something else that's producing
the x-rays like for example uranus's rings in the same way that we've actually detected x-rays from
saturn's rings as well figuring out though whether it's the aurora or the rings or something else on
uranus that's producing these x-rays is gonna be really difficult and it's not something you can
really do with this chandra data that they've been working with here you need a much better location
for where the x-rays have come from you need a higher resolution telescope the best thing you
can do at the minute is essentially compare what the hubble space telescope observed of
the aurora at the exact same time as the x-ray observation that you made but you can see it's not
really precise enough to make any firm conclusions about whether the x-rays are actually coming from
the aurora or not so the paper describing the study ends in pretty much the same way as most
astrophysics papers do just by saying we need more data essentially and that could either come
again from the chandra telescope by perhaps a heat uranus again with a longer exposure time this time
so looking for longer and recording what they see for longer and that'll help you collect more
signal from uranus as opposed to just the general background noise plus an extra observation would
essentially give you like another data point right to work out if the amount of x-rays you get from
uranus really is that changeable right and just working out if the 11th of november observation
or the 12th of member observation were just like random flukes instead but with chandra
you're still not going to get the location data you need to pinpoint whether it's coming from
the aurora or from the rings just because that telescope is limited by the resolution it has
but esa are planning to launch a new x-ray telescope called athena in 2031 so it's a bit of
a weight away but that will have a much better resolution and you should be able to pinpoint
where the x-rays from uranus are coming from or perhaps the people who study these ice
giants of the solar system uranus and neptune they might finally actually get emission
to either one or both of these planets in the same way that we've sent cassini to saturn juno to
jupiter and even new horizons to pluto think about how much more we learn about all of those planets
by doing that that's what they're hoping for with uranus and neptune at some point in the distant
future and then hopefully that'll help to dispel some of the mystery around uranus one of the
weirdest planets in the solar system before we get to the bloopers i just want to say a big thank
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and now let's roll those bloopers oh so hungry come on nothing like lunch to move that you're not
now we know a lot about jupiter because we've sent a lot of probes or missions to jupiter in
the past so for example the voyager probes it flew plastic plus they flew plastic actually turned out
to be sort of the weirdest result that came out of that fly pie - fly pie fly pie it's like it's a
python package flypy import flypy but it's a very different story for uranus the only probe to ever
head anywhere probe i really can't say the word pro but i'm talking about you and it's gonna oh my
inner child needs squishing as well so maybe you will sort of start you know like just scratching
the surface you know of the mystery of yours it's scratching the mystery of uranus oh my god
think before you speak no probes no scratching nothing like that