I just came for the lens cap, but ended up learning a tremendous amount about x-ray astronomy. Well done!

Seriously I could listen to Mike talk all day!

Holy crap. It's been years since I got a Sixty Symbols recommendation.

You've underplayed JAXA quite a lot. They've brought comet samples back to earth, and have landed a craft on the moon, although it fell over.

9:58 measuring the energy by measuring temperature change due to single photons is such a pure brut force way of abusing calorimetric physics principles I LOVE IT

I'm a phd student and proposed time on xrism. super cool to see it being discussed here. its the only instrument that can do the science i'm interested in...even with the lens cap lol

I love these walkthroughs of how we've come to current best practice and all the problems scientists have had to overcome. More please.

"It's very cool" referring to magnetic cooling, nice.

Hey cool! Sixty Symbols is talking about the mission I work on! Even with its problems, everyone is still pretty excited about the kinds of data we'll be able to get with XRISM

I love how the helium entropy cooling process is so similar to our everyday refrigeration. Yet in a totally different way!

Huge credit to JAXA for not giving up on getting this tech out into space. I can't even imagine how disheartening it must be to have their missions ruined by one thing or another, time after time. The fact that this detector gets a fraction of the signal it should, yet is still producing those images, kind of tells you why they've been so determined to make it happen. Definitely makes you wonder how good it would look without the stuck cover

Love the Contact reference. I do use that one more often than I probably should.

When JWST (I think) was getting fired up some smart ass had inserted an image into the boot-up stream that read: REMOVE LENS CAP BEFORE LAUNCH. I imagine several aneurysms were had in that moment. Today, that prank got some context -- and much funnier!

Merrifield and Haran , what a great team.

They can't get the lens cap off, but, luckily, it's an x-ray camera and can see through lens caps. That other part of the spectrum? We'll just call it far UV and say it's some other satellite's problem.

I was a graduate student in the 90's in the group at University of Wisconsin-Madison that was developing the x-ray quantum calorimeters. Although I've been out of academia for more than two decades at this point, I'm thrilled that there's finally a satellite flying with those detectors. My advisor studies the interstellar medium and his team has made numerous observations with these detectors using sub-orbital "sounding" rocket flights, so these would have been doing science without the collaboration with JAXA, but it's gratifying that they picked it up for a major space telescope and stuck with the concept for all this time.

I love Mike's explanation of why the emission lines of heavier elements are much shorter than those of lighter ones. For a man who until recently didn't understand magnetic cooling he explained it well enough that I can at least run with it. Excellent.

Thanks. This was all new to me. I found it very informative and well explained.

I'm a couple of years past 50 and I've had my beard for over 30 years... apart from a few weeks that will not be spoken of... and Mike still has more hair on top of his head than I had when I started my beard. Well done, sir. Clicked for the lens cap, and as always learned many new and interesting things from Professor Merrifield. I'm now curious as to whether there is a possibility of, and demand for, a more efficient x-ray mirror.

I learned here that space engineering is expensive and difficult, but perseverance gets results even if you have to wait for decades to get them.

I don't want to use the word clickbait bc this wasn't, but titling the video that way after he saved that for the end was genius!

Great to see another video with Prof Merrifield!

Very cool stuff, the magnetic cooling cycle looked very similar to regular refrigerator cooling system.

I like the “delivery” by Mike, is it? A lot of very interesting science and technology progress and some “very common” physics tools, hardly anybody has heard about, like magnetic cooling.

Turns out dark matter was lens caps all along...

As a fellow beardy, tell Mike that full set is magnificent

Random observation: At 00:01 the "Sixty Symbols" logo looks sooo confusing when you are Greek

I love the point at the end that theorists are gonna have to work harder now they actually have good data to work from. Never thought about it that way but it makes sense that your theories only really need to be as good as the current observations.

Super interesting. What a fantastic teacher.

14:50 If I remember correctly, it would have cost only 40% more to build a second JWST in parallel with the first.

Wonderful! Thanks for making these videos

"Electron Splat" is a confirmed scientific term now for X-Ray photon detection I am happy.

If I am not mistaken, in the IR and FIR instruments for satellites, they also used adiabatic cooling of salts for the later stages of the process. The Kepler satellite (formerly known as FIRST) did use that kind of cooling. If it did not, we certainly did have adiabatic colling dewars in the physics departmet lab where we tested the instruments to be installed in that staellite.

This is not a shot a JAXA, we all know space is a tremendously difficult place to work, but… it’s a testament to the amazing engineers at NASA and JPL and all the other agencies/companies that they work with, that things like James Webb just work on the first try. I know people complain when projects are delayed by years and years, but if that’s what it takes to get it right, then so be it.

I'd like to see a Sixty Symbols about how we were able to get temperatures low enough to liquefy helium and other gases - and a Periodic Videos on how we used those techniques to isolate those gases from the air.

Now i'm interested in the relationship between Entropy/Temperature and Time/Temperature.

Very interesting. 12:46 It's very cool.... lol!

I think the x-ray astronomy team needs to investigate and look for an undercover agent from the IR- or Radio-telescope teams sabotaging their efforts.

what happened to the old school way when they send specialists up who remove the stuck lens cap? that would be a nice mission for orbitersim :P

mike for president!

This telescope has strong Venera energy

"It's very cool" Yeah, you ain't kidding. Milikelvins above absolute zero is VERY cool.

Thanks! That was extremely interesting with all the explanations how the instruments work!

The magnetic cooling reminds me of stretching a rubber band quickly, holding it there for a few minutes, then releasing it. It heats up when you stretch it, the heat cools as the rubber band is held, and it cools down quickly once released. I'm pretty sure there's a video online of someone making a refrigerator that works based on rubber band cooling.

Thank you so much for these insights! And someone has been cleaning his shelves ;)

Świetna i bardzo ciekawa rozmowa. Dziękuję!

15:01 Cheers for quoting »Contact«, one of my favorite books (Carl Sagan!) and fav movies. Why build one when you can have to for twice the price? Indeed!

12:45 it's very cool... such a pun

Mike could explain accretion physics to my grandma if he wanted to

I thought that you would go for the Monty Python sketch about the castles falling into the swamp as the Easter egg…😂

12:45 "it's very cool" Brady didn't laugh at his joke!

Thank you...fascinating ( and must have been heartbreaking for so many.)

I hope Mike's colleagues from the Physics department dont watch this video and hear him talking about "degrees" Kelvin... 😱

I love that at some point he took his old brass telescope to work & parked it on the filing cabinet 🤓

This professor explains things so clearly and concisely - I bet anytime from a high school to a PhD student can easily understand what he is saying. Very fascinating topic.

I got your Contact reference, Brady.

Right on. Thanks for sharing.

Mike Merrifield: the Attenborough of astronomy.

That explanation of magnetic cooling was really bad. It left the biggest question unanswered - if we heat the mass, and then cool it again, repeating in a cycle - how does it end up cooler in the process? If entropy is to be conserved, why is the final temperature lower than the start temperature? I had to read the Wikipedia article to finally understand what's happening. Apparently, you make make sure that the heated mass is cooled down to initial temperature by radiating *away* the extra heat Q added to it, while still being locked in the magnetic field. You have to make sure you radiate the heat away from the object you want to cool down. Then you turn off the magnetic field, which then unaligns the magnetic field of the atoms, but since the total entropy needs to be conserved, the mass cools down even further. The reason why you want to do this quickly is simply because you want to keep total entropy constant.

Great vid, cheers.

Thanks. Very well explained.

Absolutely Fabulous technology and achievements.

The camera on that thing is so cool. They can do all that with 36 pixels.

Absolutely lovely video!

Reminds me of the Soviet probe they send to Venus to successfully land and making a chemical analysis of the lens cap. Given how hellish the surface of Venus is it's an achievement.

did you get a new camera? looks crrrrrrisp

Just a little on that Contact reference: I've always thought that John Hurt's character is eerily reminiscent of Neil Sloane...

3:18 I have to say, "Reasonably Close and Reasonably Hot" sounds like the title of a movie.

Magnetic cooling: It *is* very cool :D

The development of space technology is very rapid.

Great video but please sort the static background noise

love this!

That’s amazing, thanks!

That SN remnant looks like two brine shrimp squaring up for a fight.

Have they tried letting the telescope spin kinda fast and see if the centrifugal force helps dislodge the lenscap?

Oh that must be so frustrating for the fellows working on these projects!

Wow what a great leap in the S/N ratio, compared to Chandra. Go JAXA! PS with this recond of technical difficulties - I'd rather kept the cap on. If it still works - don't fix it.

Love this topic

I'm thinking of the SNL fake ad where Stevie Wonder takes the lens cap off of the guy's camera.

Magnetic cooling... Adiabatic nuclear demagnetisation! Come to Lancaster and do a whole video on our cooling techniques and fridges :)

That's some Monty Python level of a cursed mission lol. But the fourth one -stayed up- gave back comprehensible data.

Next time, soft X-rays, next time! Let's see who gets that reference 🙂

When I started here, all there was was swamp. Other kings said I was daft to build a castle on a swamp…but I built it all the same, just to show 'em! It sank into the swamp…so, I built a second one. That sank into the swamp. So I built a third one. That burned down, fell over, then sank into the swamp. But the fourth one...stayed up!

imagine you want to take photos but lens cap is on, and you go like fffffuuuuuuuu....ck!!! but your camera is in space and you can't take the sucker off

X ray is crazy

Wait if you use the ambient temperature to get rid of the heat then how do you go lower than a single step of the cycle?

Chrism is consecrated anointing oil.

It's all fun and games until an electron jumps from one energy state to another.

I always wondered how they got things cooler than liquid helium.

Couldn't they calibrate it using a star they already got many historical readings using previous telescopes?

Doesn't professor Moriarty use this type of cooling in his microscope?

Its amazing work ! Don't take me the wrong way when I say I hope i can live long enough to sense the universe in all its glory for myself. Elons, along ways away from hooking us up to that one .😮❤😂 But it does bring the anylitical & image dualistic mind scale of order into the fact that granting deterministic time on such a subjective medium of complexity that we have to question our interpretations on surly. Of course, as an ease of access for astronomical distances & and modeling it's fine. But trying to unify it with all other disciplines really brings back my childhood hearing the advocates of the day against the snow on my TV. Lol As someone with my American ancestry in my veins who lived through compromises of 1900s structuralism it can't be said we didn't compromise and try to accommodate what the greater world wanted on this topic

Woohoooo 🎉🎉🎉

That big face palm really drives the point home, and made me click on the video

Cool

What if you just take an optical telescope, but stretch the space in front of it as the light is coming in, so the xrays become visible light? :p

It's like the universe tried really hard to make sure we can't see xrays......

Should our AC’s on earth run off of magnets??? Thats what I want to know.

Could you do a new video on the state of dark matter particle searches? It looks like the last one you did was a decade and a half ago. Many of the current generation of liquified cryogenic noble gas based detectors are becoming so exquisitely sensitive to just about anything bumping into them that they're soon coming up against the background elastic coherent neutrino scattering noise floor. When they hit the limit, what then? Is it the end of dark matter searches?

16:15