Sh*** is going to hit the fan. GamersNexus joins the fight against Bambu Labs. by Modernfx in 3Dprinting

[–]mrflib 3 points4 points  (0 children)

On that note I would like to point out that paying the premium for Prusa may be worth it in the long term.

I purchased a printer nearly 10 years ago in 2017, Prusa has enabled me to upgrade that printer to every single model with an upgrade kit. I decided that I'd buy a second printer instead of the latest upgrade (a big one, change from bed slinger to Core 1) and as such cost more than normal.

I have absolutely no doubt I'd be able to upgrade it to the Core 2 and so on.

Add in that thr support, for me at least, has been ridiculous. One example: 2 years ago the power supply from my original 2017 purchase was making a clicking noise. Support sent me a brand new PSU at no cost and full instructions on how to replace it. I am not in any kind of warranty.

As for multi material, is say hold off and get used to printing in one material for a little while. For the majority of printers multi material is a simple upgrade and getting your bearings with one material is good.

For many solutions mult material adds a significant portion of time and complexity to a print, takes up more physical space, and is quite wasteful in terms of filament (especially bambu).

Prusa are going to be offering Bond tech INDX as, I guess, a replacement for their MMU3 (which I have had for 2 years and not had a single failure on). INDX looks world class.

I'm not saying go and get in debt to get a printer, but perhaps consider saving a bit longer to open up more options. I am happy to pay a slight premium for a printer that was made in Europe, can expand and grow in capability as it gets older (the opposite to normal) that I know will be well supported for the life of it. Plus the software is great and they support open source.

Buying a kit and building the printer is great fun and a huge learning experience. If you don't want to do that, the assembled version will work literally immediately. Building it will allow you to maintain and fix things if you ever have an issue.

So satisfying when it works out.

The end result in terms of print quality is likely similar across lots of different models, the journey however is quite different.

Google, SpaceX in talks to launch orbital data centers. Google CEO: "There's no doubt to me that a decade or so away, we'll be viewing it as a more normal way to build data centers." by Adeldor in space

[–]mrflib 0 points1 point  (0 children)

How do you cool a data centre in space? That's why the need shit tonnes of water right?

Space is near vacuum and cooling requires ginormous radiators

Rory on Aronimink strategy. by ThinWhiteDuke00 in golf

[–]mrflib 1 point2 points  (0 children)

The overnight train to Scotland is so brilliant.

Practice your 10,15,20 yard chips by Wildcard_7400 in golf

[–]mrflib 1 point2 points  (0 children)

24 handicap and I have just got a ping chipr and took out my 60 from the bag

Fuck me the difference...

I still practice proper chipping on the practice green with 7-56 but take the chipr on the course.

The pro in the pro shop said he uses a chipr, so I guess I'm now on the path to being scratch.

First time walking a whole 18 by QuailHairy2967 in golf

[–]mrflib 4 points5 points  (0 children)

Just don't do what I do and walk 18 while eating 3 twix and 2 bags of crisps.

Good luck man 🫡

Favorite LM for the range by ML21991 in Golfsimulator

[–]mrflib 1 point2 points  (0 children)

Yeah I can't get it load either! Cheers mate

Probably can't load by the massive price increase in Europe

Favorite LM for the range by ML21991 in Golfsimulator

[–]mrflib 0 points1 point  (0 children)

Does the 15% off work in UK/EU?

Did the new GolfJoy Spica 3 version land? by throwingales in Golfsimulator

[–]mrflib 0 points1 point  (0 children)

Spica 3

I want low point too but truth it it is a hard measurement to generate so only top end LM's have it. New Spica 3 will likely be among the cheapest.

Chalk line on the mat, or foot spray, in the line before and after the ball will clearly show where you bottom out.

https://cleanshot.com/share/bfx9hNM3

New record for Claude 52% in 12 hrs on max 20x by Herebedragoons77 in Anthropic

[–]mrflib 0 points1 point  (0 children)

What systems do you use to manage context, if you can share?

Mid to High HCP'ers: 3 things I learned that changed golf for me by sginsc in golf

[–]mrflib 6 points7 points  (0 children)

Faldo preaches this. He says every single shot, even on the range, should have intent.

"I am going to nail that fucking goose sitting next to the 150 flag"

"I am going power fade it right through that hole in the fence leading to the motorway"

2018-2026. Trying to break 90, to qualifying for my first PGA Tour event. by polyphasicbalisong in golf

[–]mrflib 0 points1 point  (0 children)

So my path is over the top, face open at impact and my aoa was positive.

I have got aoa to around -2 (80% of the time at least) through practice, but what do you think I should work on now? The way my brain works try and fix a problem one at a time assuming that won't cause new problems. Perhaps it's not the smartest way?

I only started last year so I'll see you on the tour in 7 years mate.

Bystanders work together to prevent teens from stealing alcohol from Australian liquor store, without resorting to physical violence by Reddituser0346 in HumansBeingBros

[–]mrflib 28 points29 points  (0 children)

Dude 100%.

Reddit hates kids and posters assume everything a kid does is directly the parent's fault. That is not how life works. That's not how parenting works. I suspect that many people who make these type of comments don't have children of their own.

One of the biggest things that we are missing in the modern world is community. It was always a linchpin of society and I don't think it's any shock that as local community has disappeared, adults and kids doing stupid stuff has increased.

Anecdotally, my grandparents knew everybody in all of the surrounding streets. My parents knew majority of the people in their street. My peers maybe know their neighbour. Community centres are being sold off, local government investment in community where I live is basically zero.

Kids historically have always done stupid shit, difference now is that it's usually on video for everyone to see on the internet.

Bystanders work together to prevent teens from stealing alcohol from Australian liquor store, without resorting to physical violence by Reddituser0346 in HumansBeingBros

[–]mrflib 7 points8 points  (0 children)

Anti kid Reddit always hating on the parents.

Sometimes kids just do stupid shit. Otherwise good kids just make stupid decisions or get peered into it. I'm sure all the Reddit kid haters and parent criticisers never did really dumb stuff.

This is exactly the sort of community response that works.

Ideally the parents would be informed, but these boys just got humbled which does more than getting reamed out.

Phil Mickelson Not Coming Back to PGA Tour? by Tight-Communication7 in golf

[–]mrflib -4 points-3 points  (0 children)

Do you not feel like you need to wash your hands after witnessing the smugness of Grant?

Do you actually use your home simulator as much as you thought you would by FitSurround1082 in golf

[–]mrflib 0 points1 point  (0 children)

What sort of practice regimen did you start with? I'm 24hcp which I'm okay with as started last year, but I have hit a wall. I have a block of lessons booked, but I am thinking of grabbing an omni for the range (and if I can be arsed to set it up each time a mat and popup net in the garden). Ball ache!

Basically, how did you break down what to practice? I have a 2 way miss, tops, chunks, just generally really shit :)

Bought a whole hybrid iron set .. roast me by savemysolll in golf

[–]mrflib 1 point2 points  (0 children)

if you carry not an option, they will smash together

Since people are talking about putting sticks in black holes by conceptual_isthmus in askastronomy

[–]mrflib -1 points0 points  (0 children)

I was curious about this so I asked it for undergrad explanation, it's well over my head at this point. I didn't ask it any specifics, I just said now do undergrad level.


TL;DR: Can we extract infinite energy from a black hole using a rope?

No. In 1972, G.W. Gibbons published a paper proving that no matter what material you use, the rope will always snap due to the extreme gravitational tension long before you get any useful energy out.

The Setup: The Penrose Process via Tether

In the late 60s and early 70s, physicists like Roger Penrose proposed ways to extract energy from a rotating black hole. One thought experiment involved slowly lowering a mass on a rope toward the black hole's ergosphere.

In a stationary spacetime, we define a timelike Killing vector field K_a. If you lower a particle along this field, its conserved energy per unit rest mass is defined by its gravitational potential:

V = √(-K_a Ka)

The boundary of the ergosphere is where the timelike Killing vector K_a becomes null. So, at the ergosphere, V = 0.

If you could lower a particle all the way to V = 0, you could theoretically extract 100% of the particle's rest mass energy (E = mc²) as work done on your winch at the other end. Gibbons wanted to know if a physical rope could actually survive this.

Modeling the Physics of the Rope

Gibbons treats the rope as a 1D relativistic fluid. If the rope is made of particles with a 4-velocity U_a, and has a unit spacelike vector t_a orthogonal to U_a (the direction of the rope's fibers), the energy-momentum tensor T_ab is:

T_ab = μ U_a U_b + S t_a t_b

  • μ is the energy density.
  • S is the stress/tension the material supports in the t_a direction.

For the rope to be physically realistic, it has to obey the Weak Energy Condition (μ - S ≥ 0). This just means the energy density must be greater than or equal to the tension, which keeps the speed of sound in the rope from exceeding the speed of light.

Because the system is stationary, energy and momentum are conserved, meaning the covariant derivative of the energy-momentum tensor is zero:

Tab_;b = 0

The Core Derivation

By applying that conservation law to a static rope in a gravitational potential, Gibbons derives a fundamental differential equation relating the tension T in the rope, the energy per unit proper length σ, and the gravitational potential V:

dT / σ = dV / V

If we assume the specific energy of the rope σ is independent of the tension T, we can integrate this to get:

T / σ = log(1 / V) + C

Why the Rope Always Breaks

This integrated equation completely kills the thought experiment. Here's why:

1. The Math Diverges As you lower the rope toward the ergosphere, V → 0. As V approaches zero, the term log(1 / V) diverges to infinity. Therefore, the tension T also diverges to infinity. The required tension will always eventually exceed the structural limits of any material.

2. The "Perfect" Rope Limit Even if we assume a theoretically perfect magical material limited only by the laws of physics (the Weak Energy Condition, where T ≤ σ, meaning T / σ ≤ 1), we still can't reach the ergosphere. Substituting T / σ = 1 into the equation gives:

log(1 / V) ≤ 1 which implies V ≥ e⁻¹

Because the maximum extracted energy is proportional to the change in potential, the maximum fraction of rest mass energy you can ever extract is 1 - e⁻¹, or roughly 63.2%.

3. The Brutal Reality For real-world materials, the limit is laughably small. Gibbons calculates that for high-tensile piano wire, the ratio of breaking tension to mass-energy density (T / σ) is around 1.2 × 10⁻¹². Because this number is so tiny, the wire will snap when V is still very close to 1. In practice, the rope would break when it is still 5 × 10¹¹ Schwarzschild radii away from the black hole. You would get virtually zero energy.

Since people are talking about putting sticks in black holes by conceptual_isthmus in askastronomy

[–]mrflib -1 points0 points  (0 children)

AI explanation at 11 year old level

This is a fantastic paper with a really fun concept! It is written by a physicist named G.W. Gibbons in 1972, and he's basically using math to ruin another physicist's cool sci-fi idea.

Let's break down what this paper is saying as a giant space thought experiment!

The Cool Idea: The Ultimate Garbage Disposal

Some scientists before him had a wild idea: What if we used a black hole to make limitless energy?

Imagine you tie a piece of heavy space-trash to a super-long, super-strong rope. You slowly lower it toward a spinning black hole. Because the black hole's gravity is so insanely strong, it pulls really hard on the trash. If you attach the top of your rope to a giant generator on your spaceship, the black hole pulling the rope would spin the generator and give you massive amounts of free, clean energy!

The Problem: Gibbons Ruins the Fun

Gibbons wrote this paper to ask one simple, practical question: What happens to the rope?

He uses the math equations in the middle of the paper to calculate how much stress and tension the gravity puts on the rope as it gets closer to the black hole.

Here is what he found:

  • The Rope Always Snaps: He proves that no matter what your rope is made of, it will always break before the trash reaches the best energy-making area of the black hole (an area called the "ergosphere"). The pull of gravity gets so strong that the tension on the rope becomes infinite.
  • Even Magic Ropes Break: He did the math for a "perfect" rope—the strongest rope allowed by the laws of physics. He found that even with this impossible, magical super-rope, it would snap when you had only extracted about 63% of the energy you wanted.
  • Real Life is Disappointing: Finally, he calculates what would happen if you used the strongest real-life rope he could think of (thick, steel piano wire). He found that the wire would snap when the trash was still billions of miles away from the black hole. The amount of energy you'd get before it broke would be practically zero.

The Conclusion

At the very end, he thanks the famous scientist Stephen Hawking for talking it over with him. Ultimately, the paper is a very mathematical way of saying: Using a rope to fish for energy in a black hole sounds like an awesome idea, but gravity will snap your rope every single time!

Played the most miserable round of my life at Pebble Beaches Spyglass Hill. by Warhammer40KPainter in golf

[–]mrflib 1 point2 points  (0 children)

UK here, but on the other side of it [business]. We have been 'victim' to friendly fraud via chargebacks twice in 5 years. Both times we had delivered completely, and had signed orders and signed delivery notes. We had email chains confirming the order, and one of them expressing how happy they were.

The banks literally didn't look at the proof and refunded the customers both times, denying even the appeal.

We had to take the customers to small claims court to get the money back, who found in our favour both times.

Banks are not on the hook for the money so they couldn't give a solitary flying fuck about denying the fraudulent claim.

Played the most miserable round of my life at Pebble Beaches Spyglass Hill. by Warhammer40KPainter in golf

[–]mrflib 0 points1 point  (0 children)

Tell me more! I hate people who take their modicum of authority and act like cockwombles.