Scientists have discovered a new form of ice using diamonds, x-rays, and a bunch of ultra-powerful
lasers, and this new ice could tell us more about the inside of planets.
I know that sounded like science-themed mad libs, but I promise you it’s true.
The first thing you should know is there are way more known iterations of ice than you
probably expected.
The kind you’d find in your freezer or in your drink is called ice I.
Actually, there are two forms of Ice one, that kind is called ice Ih, the h stands for
“hexagonal” after the hexagon shape the frozen water molecules form which differentiates
it from the more cuboidal shape of ice Ic.
Wow, two forms of ice?
Ice, ice, baby.
Can it get any crazier?
Oh, yes it can.
It can get crazy 17 more times, because including this newly discovered form of ice, we’re
up to 19 total crystalline arrangements of H2O.
Water can form so many different lattice structures in part because of the molecule’s bent shape
plus its hydrogen bonds to other water molecules which can lead to complex arrangements.
But our newest confirmed form of ice, called ice XVIII, is something altogether different.
Instead of being like the ice in your fridge, white and cold, it’s black and hot.
It was first predicted by a computer model from 1988.
The simulation suggested a new form of ice occurs at high temperatures and pressures,
above 2000 kelvin and above 100 gigapascals.
For reference, water at the deepest point on the ocean floor is under about 1000 times
less pressure.
These conditions rip the hydrogen atoms off their oxygen partners, losing their electrons
and essentially becoming positively charged protons.
The oxygen atoms are packed into a cubic lattice, while the freed protons flow around them like
a liquid.
This high concentration of flowing ions should actually conduct electricity about as well
as other semimetals like arsenic or graphite, just using freely moving protons instead of
electrons.
Predicting this superionic form of ice on an old computer is one thing, but observing
it is quite another.
In order to create this form of ice, scientists compressed water between diamonds to build
up the pressure.
Then they blasted it with lasers, 6 of them in fact.
They couldn’t hit it with one big blast because that would put it over ice XVIII’s
predicted melting point.
Instead, they used timed pulses which explosively vaporized the diamond containing the water
and caused a massive spike in temperature and pressure.
In order to see what was happening inside the water at the exact moment pressure peaked,
scientists shot 16 more laser beams at an adjacent piece of iron, which vaporized and
sent X-rays through the water.
Basically, it was a flippin' laser jamboree up in there.
Based on the diffraction of the X-rays, the scientists confirmed the oxygen atoms formed
the nanometer sized cubic lattices predicted by computer models.
All of this is very interesting to planetary scientists, because the conditions for ice
XVIII are probably right inside ice giant planets like Uranus and Neptune.
Ice XVIII’s structure and properties could explain some odd phenomena of these planets,
like the shape of their magnetic fields.
Earth and most planets in the solar system have a magnetic field like a bar magnet with
two poles, and the magnetic poles line up well with the axis of rotation.
This is likely due to conductive fluids inside the planet swirling with the planet’s rotation.
But ice giants have magnetic fields that are more lumpy, with multiple poles and no correlation
with how the planet spins.
An interior made up of ice XVIII would mean the planets have a solid-ish core that wouldn’t
really churn, with a thin shell of flowing ionic water above it that could account for
the odd magnetic field.
There’s still plenty more research to do though, because ice giants probably have other
molecules like methane and ammonia in the mix that could change how the water behaves
deep below the surface.
And technology has advanced enough to take a snapshot of the oxygen atom lattice, but
we still haven’t seen the flowing hydrogen ions.
I guess that means we gotta shoot more lasers.
Sweet.
Thanks for watching, if you liked this video subscribe and check out another I did on a
new phase of matter that’s solid and liquid at the same time.
For you Vonnegut fans out there, yes there is an Ice IX, but good news, it will not destroy
the planet.
That’s all for now, see you next time on Seeker.