How Can Matter Be BOTH Liquid AND Gas?

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Supercritical Fluids are one the strangest states of matter and yet they are found everywhere from Decaf Coffee, to dry cleaning, to the atmosphere of Jupiter. When we think of an exotic state of matter we tend to think of the really weird things that matter can do in extreme circumstances - like how at very high temperatures we get the plasma that the sun is made of, or at extreme densities we get the nuclear matter of neutron stars. But there’s one state of matter - supercritical fluid - that’s not solid, liquid or gas, but is also not confined to extreme or rare environments. In fact, there are planets in our solar system completely covered with oceans of the stuff, and you’ve often been the beneficiary of its powers without even knowing it.

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[pbsspacetime]

For those who skip the comments: there will be an end of year AMA on the channel on Monday, December 19th @ 4pm EST. We hope to see you there!

[borttorbbq]

I'm really happy that he was willing to let you guys use his visuals because understanding it when actually seeing it happen is really interesting. His video was excellent and I loved how he actually went through the process multiple different times to try and go with which was really cool

[NiffirgkcaJ]

I really love it when scientific channels collaborate and let each other borrow each other's visuals to explain things much more easier.

[concrete_dog]

This really feels like an "It's not a bug, it's a feature" component of our universe

[Ryan.]

Worth mentioning while nilered shot that footage the device was provided by Ben over at applied science. He has an amazing YouTube channel where he discusses and explores all sorts of technical things. He built his own scanning electron microscope and made a liquid nitrogen generator.

[TheDaggwood]

For those curious on triple points, a very tangible example is found in geology. The crystals andalusite, sillimanite, and kyanite are made of the same material. But the pressure and temperature experienced when cooling determines what crystal precipitates. A single chunk of rock can naturally have all 3 types forming alongside each other. It's beautiful.

[CaptainCuttlefish]

I knew about supercritical fluids, but I never realized how important they are. It's honestly kind of wild that so many mundane things rely on such a weird state of matter.

[NATESOR]

Dry cleaner here. Many of us are still using a chemical called Perc (Perchloroethylene) to dry clean. It's extremely non-polar so it is great for addressing oil stains. Under ideal conditions, basically all of it is distilled off and reused. If anyone is worried about it sticking to clothes, they should know that it evaporates very readily and by the time you put it on it will be totally gone.

[vanderkarl]

Yoooo happy to see NileRed's footage (with permission) in this video! It really is a great demonstration, he made some great videos on supercritical fluids.

[WestOfEarth]

Was hoping you'd mention Venus. This fact isn't widely shared, and to me it's one of the most fascinating aspects of Venus.

[sebastianelytron]

If there's one bad thing I can say about this video, it's that it ends.



But that would be supercritical.

[ElliottCallum]

Great vid - I’m a chemical engineer currently working on a carbon capture plant. We’re having issues with reverse flow relief scenarios with supercritical CO2 depressurising and causing dry ice to form in the relief valves due to JT cooling. Great relevant video for me.

[zovisapphire]

I was JUST about to suggest you look up NileRed on this exact subject, but I didn't expect you guess literally use them in the video!
I am glad you consider Nile as a source you can trust and add to your videos. I would love to see an official PBS Space x NileRed crossover episode in the future c:

[casual_sky]

Hey! That was me! Thank you so much for the super detailed response! You guys are the best!

[RME]

This has to be the most lucid and interesting depiction of supercritical fluids that I have ever seen. It takes you far, far away from simple phase diagrams and brings the viewer to a quick 'a-ha!' understanding. Thanks, Matt!

[MnJiman]

"Ok, thats enough blah blah pressure blah blah.."
That made me too happy.

[BaronVonQuiply]

20:35 Can confirm. I have several strobe lights flickering in each eye 24/7. Been like that since around 1996. It never stops.

It also causes enlarged blind spots, which is a little weird because the brain fills in the missing area so things aren't hidden behind a wall of black, they're just deleted. eg, I walked into a step ladder one night because I couldn't see it, I ran my hand into a table saw because my hand was in a blind spot and I could not see it despite looking directly at the blade.

[SonnyBubba]

I learned more about supercritical fluids in this YouTube video than I did in the year I attempted a physics masters thesis on the stuff.

The major professor had tried to record fluid flow patterns of a supercritical fluid, but his experimental setup left much to be desired.

The heater was an old fashioned lightbulb, controlled by a laptop and a thermocouple.

But instead of putting the bulb in a socket, he had me use a soldering iron to weld the wires to the bulb (?!) (yes, this is a physics experiment).

I ended up doing a non-thesis masters.

[bigyeticane]

Thanks everyone at Space Time and helpers! Thanks to Dr. Matt for his charisma. I learn a lot from you guys.

[lisajsch]

Thanks for the featuring! And big shout-out to my current and former colleagues of IceCube who put so much work into producing these newest IceCube results. (More work than I put into this paper, actually, so they should be featured here!)