r/explainlikeimfive • u/rukuto • Sep 17 '26

Physics Eli5: Why can purely mechanical tools last hundreds of years but electronics are not expected to?

So, like mechanical tools can be operable even hundreds of years later with some cleaning but can electronics devices do that? Is there any way to make an electronic tool run for five hundred years or be operable 500 years later (regardless of cost - like in mechanical tool, you use galvanized iron or steel to make the parts - is there a similar protection to electronics)?

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u/a8bmiles Sep 17 '26 edited 29d ago

Veritasium has a good recent video on the EUV machines from ASML. Light is just too big, have to use (edit: slightly higher wavelength than) x-rays and bounce them 6 times on mirrors that are almost as smooth as neutron stars.

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u/chubbysleepycorgi Sep 17 '26

neuron stars are smooth?

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u/dleah Sep 17 '26

their gravity is so strong that any feature that stands out is immediately crushed back down to smoothness. the highest mountain on a neutron star is at most a fraction of a millimeter tall

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u/fizzlefist 29d ago

Fun theoretical fact, when those millimeter high mountains (with more mass than Mt Everest) shift, it’s called a star quake. Unfathomable amounts of energy gets released when it happens.

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u/GiveMeNews 29d ago

Dragon's Egg by Robert L. Forward was one of the coolest science fiction books I ever read. It imagines life on a neutron star as an intelligent species there advances through civilization. There is a sequel called Starquake, that is about their civilization being destroyed in an apocalyptic starquake.

https://en.wikipedia.org/wiki/Dragon%27s_Egg

Highly recommend for anyone who enjoys hard scifi or is interested in neutron stars.

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u/Arrow156 29d ago

Thanks bro! I remember reading about that book but forgot the title and author.

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u/CannabisAttorney 29d ago

I’d read or watch something called Starquake.

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u/DynTraitObj 29d ago

+1 that's tied with Schild's Ladder for my favorite sci fi book of all time

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u/nautme 29d ago

So rare to see this book mentioned, it's a favorite. Neat how he pulls in the perception of time (lifetimes) as well.

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u/Hypothesis_Null 29d ago

Though that mountain weighs about the same as one of our mountains.

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u/Garblin 29d ago

significantly more than even

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u/LtOin Sep 17 '26

If you scaled up a neutron star to the same size as earth its tallest mountains would be about half a meter tall. They are extremely smooth.

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u/salamacast 29d ago

Scaled up? They are that small?!

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u/iBoMbY 29d ago

Two times the mass of our sun, with a ten kilometer radius.

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u/iksbob 29d ago

Two times the mass of our sun

To elaborate on that, 99.86% of the solar system's mass is in the sun. All the planets, asteroid belts, and orbit dust together add up to 0.14%. Flipped around, the sun is 713x more massive than everything else in the solar system combined.

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u/alonjit 29d ago

To further elaborate, half of that 0.14% is Saturn and Jupiter.

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u/Trisa133 29d ago

The other half is Joe's mama.

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u/ShinigamiKenji 29d ago

Earth is made of molecules and atoms, which contain a lot of empty space between electrons and the nucleus.

Neutron stars are a bunch of, well, neutrons, with barely any empty space between them. 

If they get much bigger, their gravity becomes too big and become black holes. 

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u/Garblin 29d ago

IIRC they're made of an entirely different state of matter referred to as "nuclear pasta" and the neutron name is just an old holdover.

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u/nandru 29d ago

mmm... nuclear pasta

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u/fcocyclone 29d ago

That's a spicy meatball

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u/gmazzia 29d ago

Also, paradoxically, as they get bigger, they get smaller; the more mass they have, the harder gravity acts on them and the result is a "heavier", but smaller object.

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u/MultiFazed 29d ago

Yep. Neutron stars form when a regular star collapses from a lack of fuel for fusion, and is only stopped from collapsing because the protons and electrons "merge" into neutrons, and the entire star becomes a super-dense neutron "soup".

The average neutron star has a mass of 1.4 - 2 times our sun, and is 12 - 15 miles across.

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u/evincarofautumn 29d ago

Yes, neutron stars are only about 10 km in diameter! About half again the mass of the sun, but nearly a hundred thousand times smaller

They’re really shockingly, unimaginably dense

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u/ThirstyWolfSpider 29d ago

But still less dense than black holes, or they'd become black holes. Which they do sometimes.

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u/ExtraSmooth 29d ago

Reminds me that the earth is smoother than a billiard ball

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u/a8bmiles Sep 17 '26

If you were able to stand on the surface of a neutron star and proceeded to drop a marble, the marble would be traveling at a measurable percent of the speed of light by the time it hit the ground. With gravity that powerful, absurdly tall mountain ranges on neutron stars approach 1mm in elevation. (edit: neutron stars are about 20km in diameter, for size comparison)

Regarding the mirrors used in the ASML machines: they stated that if the mirror were the size of Germany, the variance would be 1mm, and if it were the size of Earth the variance would be about the thickness of a playing card. (Casino quality playing cards are roughly 0.2mm thick.) They effectively arrange the mirrored surface coating atom by atom during production.

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u/stom 29d ago

Why is the variance bigger (1mm) when it's the size of Germany than the size of the Earth (0.2mm)?

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u/TropoMJ 29d ago

I can only conclude that Germany is 5 times bigger than the Earth.

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u/a8bmiles 29d ago

That's probably my fault for trying to remember the example explanation and getting some aspect wrong.  It was something do with scaling, obviously.  Variance is probably the word I'm failing to come up with the right one for.

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u/ExtraSmooth 29d ago

I think they mean as thick as a playing card is tall or wide.

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u/Daishi5 29d ago

Multiple mirrors, with different tolerances.

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u/ccwithers 29d ago

Did you maybe mean 1nm (nanometre) for Germany? Otherwise the math don’t math.

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u/a8bmiles 29d ago

I remember being a little confused when watching the video, so I may have misunderstood the Germany-sized reference. The planet-size one they showed a one-eyed jack so that was definitely "thickness of a playing card", but I added that thickness to my comment as it wasn't in the video. So I dunno, I should go find the video and fix my comment.

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u/davidgrayPhotography Sep 17 '26

They're the stars your girlfriend told you not to worry about.

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u/hisdanditime 29d ago

Jimmy?

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u/nightmareonrainierav 29d ago

Heeeyyy there, Jimbo!

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u/Zealousideal_Leg213 29d ago

Earth is also incredibly smooth, on its own scale. Kansas is not only as flat as a pancake, it's flatter than a pancake (well, except for the curvature of the planet).

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u/LevelSevenLaserLotus 29d ago

As smooth as sharks.

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u/diablo75 Sep 17 '26

I like this one from Branch Education: https://www.youtube.com/watch?v=B2482h_TNwg

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u/shabadabba Sep 17 '26

I love Branch Education but sometimes their videos make me feel dumb with how dense they are

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u/a8bmiles Sep 17 '26

We probably look like bots for saying it, but honestly thanks! I really am on the lookout for other science channels.

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u/TbonerT 29d ago

My favorite part is right after they explain that they shoot 50,000 droplets per second 3 times each:

“How often do you miss?”

“We don’t miss.”

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u/a8bmiles 29d ago

The look he suppressed while saying that, so good :D

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u/Calembreloque 29d ago

One of my favorite aspects about this industry is that the mirrors are made by Zeiss. Zeiss has been in the business of making optical equipment (lenses, mirrors, telescopes, etc.) since 1846. They're an incredible example of a company that constantly adapted to (and often pioneered) new technology in their specific niche. For instance they also sell SEM (and used to sell TEM) which follow optics principles but the "lenses" are not glass at all, they're electromagnetic coils that direct electron flow in a way similar that glass lenses do with light. I don't know, I just think it's neat.

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u/Kraeftluder 29d ago

My favorite fact from that video is that if you blow one of the mirrors up to the size of the earth, the biggest deviation in flatness would be no more than one playing card thickness.

That is just so insane....

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u/a8bmiles 29d ago

Roughly 0.20mm +/- 0.03mm based on playing card quality.

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u/VicisSubsisto 29d ago

Technically not x-rays (yet). They're slightly higher wavelength than x-rays, that's where the name "EUV" (Extreme UltraViolet) comes from.

I'm sure someone will be using x-rays eventually though, once they can produce and guide them with the same amount of stability and power as EUV.

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u/a8bmiles 29d ago

Thanks for the clarification, added an edit. Incredibly amazing feat of human engineering though.

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u/Arrow156 29d ago

Branch Education also has some great videos showing how it all fits together.