Meta & Fysikken

Meta & Fysikken: Afsnit 119: Øjet

I dag dykker vi ned i øjets anatomi og hvordan synet egentlig virker. 1: Hvordan synet virker 2: Hvad er langsynet / kortsynet 3: Grå stær 4: Laser Eye Surgery 5: Nat linser 6: Elektrisk omformning af øjet  7: Guld i Øjet 8: Chip i øjet ---------- 1: Hvordan synet virker Hjerne / Synet forbindelse https://videnskab.dk/krop-sundhed/oejet-kigger-men-hjernen-ser/ [https://videnskab.dk/krop-sundhed/oejet-kigger-men-hjernen-ser/] 2: Hvad er langsynet / kortsynet Øjets form 3: Grå stær Hvad er det? 4: Laser Eye Surgery LASIK For those who want do do away with corrective lenses, the main option is LASIK (Laser-Assisted In Situ Keratomileusis) surgery, which uses a laser to reshape the cornea by removing microscopic amounts of tissue beneath a thin flap, allowing light to focus properly on the retina. While, for those suitable for treatment, LASIK has a high success rate – around 95% of patients go on to ditch their glasses only a few days after recovering from surgery – it’s expensive and invasive, and cutting into the cornea alters the structural integrity of the eye. “LASIK is just a fancy way of doing traditional surgery,” said lead researcher and presenter Michael Hill, a professor in chemistry at Occidental College. “It’s still carving tissue – it’s just carving with a laser.” 5: Nat linser https://www.city-optik-muenchen.de/en/orthokeratologie-muenchen-ortho-k-nachtlinsen/ [https://www.city-optik-muenchen.de/en/orthokeratologie-muenchen-ortho-k-nachtlinsen/] Orthokeratology, or Ortho-K, offers a revolutionary way to correct vision without the need for glasses or daytime contacts. By wearing special contact lenses overnight, users can reshape the cornea and experience clear vision throughout the day. This method challenges the conventional approach to eyesight correction, offering a non-invasive alternative for those seeking freedom from corrective lenses. The cornea is the transparent part of the eye on which the contact lens is placed. It consists of five layers of different thicknesses. However, only the uppermost layer, the so-called epithelium, is important for us. Corneal epithelium Bowman membrane stroma Descement’s membrane endothelium The corneal epithelium is about 0.04mm to 0.06mm thick. It is the uppermost layer of the cornea and renews itself completely once in 7 days. Such an epithelium as it occurs on the eye, there is similarly also on the “normal” skin on the human body. Such an epithelium scales itself off and is thus a protection for the underlying tissue. The Ortho-K contact lens makes use of this process by pushing the top layer of the epithelium from the middle of the cornea (directly above the pupil) to the edge by adhesive forces (tensile forces). Since only the top layer of the epithelium is moved here, the natural protective mechanism of the eye is fully preserved. In addition, this effect of orthokeratology is reversible due to the rapid regeneration time of the epithelium. This means that if the contact lens is no longer worn, it will take another 7 days for the old shortsightedness to be restored. Orthokeratology is in no way harmful to the eye compared to laser eye surgery, which destroys tissue in much deeper layers (stroma) in order to achieve a lasting effect. Recent studies from the USA, on the other hand, have even pointed out that the eye dioptres in orthokeratological contact lenses remain very constant, i.e. do not change. For this reason, Ortho-K contact lenses are also used with children who are already very shortsighted at a young age. In general, there is no age limit for orthokeratology. 6: Elektrisk omformning af øjet https://bli.uci.edu/laser-free-vision-correction-uses-electrical-current-to-reshape-eye/ [https://bli.uci.edu/laser-free-vision-correction-uses-electrical-current-to-reshape-eye/] Electric Eye Treatment (EMR -  electromechanical reshaping) Denne teknik er stadigvæk ikke godkendt til mennesker, men de er i gang med kliniske forsøg. Scientists have developed a novel, non-invasive technique that reshapes the cornea using only a mild electric current and a temporary pH shift.  The cornea is the clear, dome-shaped surface at the front of the eye, acting as a transparent window that helps focus incoming light. It’s made of tightly packed collagen fibers and is designed to be strong and smooth. When light enters the eye, the cornea is the first lens it hits – and it’s here that most of light-bending (refraction) occurs in order to focus the light onto the retina at the rear of the eye. However, if the cornea has an irregular curve, it results in conditions such as nearsightedness (myopia) and farsightedness (hyperopia). What Hill and colleagues propose is instead working with the composition of the cornea to reshape the dome without removing any material from it.  Made primarily of collagen, the cornea maintains its shape thanks to the arrangement of charged molecules and proteins. The researchers discovered that by applying a low-level electrical current through a specially designed platinum “contact lens” electrode, they could change the pH of the tissue, increasing the acidity of the corneal tissue, which would make it pliable just long enough to reshape – like fitting something into a mold. In this case, the mold is the platinum lens. Then, once the current stops and the pH returns to normal, the cornea hardens again and holds its mold-fitted shape. The whole process takes about a minute, requires no cutting or removal of tissue, and, so far, has shown no structural damage or cell death in the tested samples.  7: Guld i Øjet https://www.sciencealert.com/gold-injections-in-the-eye-may-be-the-future-of-vision-preservation [https://www.sciencealert.com/gold-injections-in-the-eye-may-be-the-future-of-vision-preservation] The macula is responsible for the central, high-resolution, color vision that is possible in good light. This kind of vision is impaired if the macula is damaged, as in macular degeneration [https://en.wikipedia.org/wiki/Macular_degeneration] (AMD).  AMD:  Sygdommen ødelægger de celler i nethinden, der opfanger lys, og gør det svært at se skarpt. 20-30 procent af befolkningen over 70 år får denne sygdom. Biomedical engineer Jiarui Nie, from Brown University in Rhode Island: This is a new type of retinal prosthesis that has the potential to restore vision lost to retinal degeneration without requiring any kind of complicated surgery or genetic modification. We believe this technique could potentially transform treatment paradigms for retinal degenerative conditions. How: very fine gold nanoparticles, thousands of times thinner than a human hair, are laced with antibodies [https://en.wikipedia.org/wiki/Antibody] to target specific eye cells. They're then injected into the gel-filled vitreous chamber between the retina and the lens.  Next, a small infrared laser device is used to excite these nanoparticles and activate specific cells in the same way photoreceptors do. If the treatment makes it to us humans as well, that laser could be embedded in a pair of glasses. So far it looks like the nanoparticles could help bypass damaged photoreceptors (in Mice). Dette er endnu ikke blevet testet på mennesker 8: En microchip i Øjet https://videnskab.dk/krop-sundhed/lille-traadloes-chip-i-oejet-kan-potentielt-genskabe-synet-hos-aeldre-med-oejensygdom/ [https://videnskab.dk/krop-sundhed/lille-traadloes-chip-i-oejet-kan-potentielt-genskabe-synet-hos-aeldre-med-oejensygdom/] En anden behandling af AMD. En trådløs chip kan måske give ældre mennesker med fremskreden øjensygdom noget af synet tilbage. Opfindelsen bygger på en ny teknologi kaldet PRIMA-systemet, der består af to dele:  Første del er en fleksibel, trådløs chip på 2×2 millimeter, som erstatter de ødelagte sanseceller.  Den anden del er et par specielle briller, der opfanger billeder og sender dem som usynligt infrarødt lys til chippen, der omdanner signalerne til elektriske impulser, som sendes videre til hjernen. Forskerne forventer ikke at kunne genskabe helt normalt syn med chippen alene, men de arbejder videre på at forbedre livskvaliteten for patienterne.  »Jeg tror ikke, vi nogensinde vil kunne genskabe fuldt 20/20-syn (normal synsstyrke, red.) med implantatet alene [...], men et af de største ønsker, vi hører fra patienter, er at kunne genkende ansigter og følelser igen - og det arbejder vi hen mod,« siger han i pressemeddelesen.  Indtil videre er chippen kun godkendt til forskningsbrug, men firmaet Science Corporation har ansøgt om godkendelse til klinisk brug i Europa. Der er allerede forsøg med mennesker.  38 deltagere over 60 år på 17 klinikker i fem europæiske lande.  Efter et års brug af systemet havde 26 ud af 32 deltagere, der gennemførte hele forløbet, opnået tydelige forbedringer i synet.

Meta & Fysikken: Afsnit 118: Tid - tilbage hvor vi startede. Eller?

Sjovt nok så handlede vores allerførste afsnit om Tid og Tidsrejser (29.01.2018). Og nu tager vi lige et deep-dive tilbage til selvsamme tema. Karina’s noter til dagens afsnit: Tid - Målinger: Vi lever i en synkroniseret liv og tid er over det hel og en vigtig del af vores opfattelse af virkeligheden. Hvad er tid?  Vi kan starte med hvordan man måler den: Med et ur. Et ur er en oscillator og noget der kan tælle svingningerne. Jo finere tidsinddelingen er, jo mere nøjagtigt kan uret være. Solen er en oscillator. Den går op og ned og vi er dem der tæller. Nøjagtighenden er 1 svingning per dag. Så opfandt vi pendul uret, hvor mekanik (tandhjul) tæller. Svært at bære rundt på og det skal trækkes op.  Nøjagtighenden er ca. 1 svingning per sekund. Så opfandt vi Quartz uret. Her er det Quartz krystallen der svinger/vibrer/deformerer når den er udsat for en strøm.Her er det elektronik (digital logisk system) der tæller svingningerne. Nøjagtighed: 32 768 svingninger per sekund – approx. 10^(-13) Så kom atom uret: Cs atomer bruges her.  "A Cæsium-133 atom has a ground state with a hyperfine structure, meaning the electron can have two slightly different energy levels based on whether its spin is aligned or anti-aligned with the nuclear spin. When hit with microwave radiation at the exact frequency of 9.192.631.770 Hz (cycles per second), the atoms transition between the lower state to the higher state. That gives us a way to tune the microwave radiation precisely and we can tune other light frequencies against that." Med andre ord så tæller uret 9 192 631 770 cycles/flips til at definere et sekund. Det giver en nøjagtihed på ~ 10^(-16). Vi er altså ude på det 16 decimal i vores nøjagtighed af sekundet. Dette er SI (International System of Units) definitionen af et sekund. I dag er international atomtid TAI (Temps Atomique International) givet ved middelvisningen af omkring 400 cæsiumure, der står på 50 nationale laboratorier rundt omkring i verden. Der er planer om at lave en ny SI definition af sekundet i 2030, hvor man vil bruge et andet atom der giver en bedre nøjagtighed.  Det er der brug for. I dag i laboratorier måler man tid med en nøjagtighed på 18-20 decimaler, og så er det mærkeligt at sekundet er dårligere defineret.  Det er her i 2026 at man vil beslutte sig for hvilket atom man så vil bruge. Det skal helst være et atom der har finstruktur hvor lyset skal have mange svingninger per sekund.  En kandidat er 87^Sr som har 429000*10^9 svingninger per sekund. (Cs er 9GHz og Sr er 429 THz).  En anden kandidat er Thorium: https://www.sciencealert.com/timekeeping-is-on-the-verge-of-a-giant-leap-in-accuracy-heres-why [https://www.sciencealert.com/timekeeping-is-on-the-verge-of-a-giant-leap-in-accuracy-heres-why] Man bruger lasere til disse atom ure. Elerktroner er for store og klodsede til det.  En nøjagtighed på 10^(-18) betyder at to urer der blev synkroniseret omkring 'the Big Bang' vil i dag kun være 1 sekund fra hinanden. Hver gang nøjagtigheden er blevet bedre, er der opstået nye anvendelser, som vi ikke anede, vi havde brug for. Rum - Tid Universet som helhed har en universel tid, som skrider fremad, efterhånden som rummet udvider sig, men der findes også et andet tidsbegreb, nemlig den lokale tid. Tiden løber ikke med samme samme hastighed alle steder. Du vil ikke selv mærke / måle det. Dit ur ser for dig altid ud til at gå rigtigt. Så uanset hvor i universet du sidder med dit Cs atom så giver den dig en tidsmåling som er korrekt (for dig). Der er 2 effekter: 1) I et tyngdefelt: (gravitational time dilation) Den ene effekt af det her er når der er tyngdekraft. Når du er i tyngdefelt, er du er et sted hvor rummet er blevet bukket. Så løber tiden langsommere, end hvis du står et sted, hvor der ikke er blevet bukket.  Altså, når jeg prøver at forestille mig det her, så lukker jeg øjnene og laver et billede i mit hoved. Jeg forestiller mig et stort netværk af af linjer. Nogen der går den ene vej og nogen der går på tværs, altså vinkelret på de første linier. Det er sådan et helt fint og ensartet net. Der er lige langt mellem hvert eneste krydspunkt. Sådan ser jeg nettet hele vejen ud til alle sider rundt om mig og hele vejen opad, fordi det faktisk ikke bare er et stykke papir. Det er faktisk et 3D objekt der går hele vejen op og ned også. Hele rummet er pænt og flot, fordi der er lige langt i mellem hvert eneste krydspunkt over det hele.  Nu tager jeg og putter en masse ind et sted, og det vrider mine bitte små målestokke i mit fine spin. Nu er der ikke længere lige langt mellem krydspunkterne. Der er blevet hevet i det og nu er der længere imellem knudepunkterne. Mit fine net er ikke kun rum, det er også tid og min tid løber en bestemt afstand imellem 2 knudepunkter. Nu hvor mit net er blever forvrænget af massen er tiden også blevet forvrænget. Man kan sige at et sekund er længden mellem 2 knuder. For at gøre noget abstrakt og usynligt håndgribeligt. Tiden er en fysisk størrelse, og den hører sammen med rumtiden. Og min masse har ødelagt mit flotte fine netværk. Så er du der ikke lige langt imellem knuderne. Hvor massen har hevet i mit net og der er blevet længere imellem knuderne går tiden også langsommere. Du opdager det ikke, for dig er det normalt. Dig og dit Cs atom synes alt ser normalt ud. Men jeg kigger udefra på dig, og det ligner at du bevæger dig i slow motion. En samling masse, som fx. Jorden bukker altså rum-tiden og skaber hvad vi normalt kalder et tyngdefelt. I et tyngdefelt går tiden langsommere.  Det vil sige at på jorden går tiden langsommere i en dal end på en bjergtinde. 2) Når man bevæger sig går ens ur også langsommere: (Relativistic time dilation) Tiden går også langsommere når man bevæger sig. Især tæt på lysets hastighed ser man en stor forskel. Når ens tid går langsommere er det ikke noget man kan mærke. Det er fordi set indefra løber tiden altid lige hurtigt. Det er først når vi sammenligner vores ure at man kan se at tiden ikke løb lige hurtigt over det hele. GPS-systemer er baseret på satellitter, der suser rundt om Jorden med høj fart. De bestemmer din position ud fra tidsmålinger med atomure i fire satellitter 20.200 km over jordoverfladen. Tiden går langsommere for disse satellitter, end den gør for menneskene på Jorden. Det har man måttet kompensere for. GPS-systemet har derfor en indbygget relativistisk korrektion, så man undgår fejlmålinger. Uden korrektion ville positionsmålingerne efter bare én dag skyde omkring 10 kilometer forkert. Videnskab.dk [http://videnskab.dk/] har flere artikler om tid. Her er en af dem: https://videnskab.dk/naturvidenskab/tiden-gaar-eller-goer-den [https://videnskab.dk/naturvidenskab/tiden-gaar-eller-goer-den] At Rejse i tiden Man kan udnytte den relativistiske tids-udviddelse til at lave Tidsrejser (kun fremad): Man kan rejse frem i tiden, ved at rejse i et rumskib tæt på lysets hastighed og dermed sænke tidens hastighed for en selv. Når man kommer tilbage til Jorden er der gået mange flere år end man selv har oplevet i sit rumskib. Man har så rejst frem i tiden. Men der er ikke nogen måde at rejse tilbage i tiden på. Er tidsrejser mulige? Det er stadigvæk op til diskussion om tidsrejser er muligt. De fysiske love der beskriver vores verden giver ikke et endegyldigt svar. Fysikken beskriver virkeligheden, og med de her fysiske love kan man forudsige hvad der sker. Det er fordi naturen følger nogle love. Men de her love er ikke nogen der definerer hvad virkeligheden er. De beskriver virkeligheden, og de beskriver virkeligheden inden for den afgrænsning de kan. Det er matematiske formler, som beskriver din virkelighed.  I disse matematiske formler, er der overhovedet ingenting, der siger, at man ikke må rejse tiden. Man kommer lidt i problemer fordi man skal bruge negativ energi som er noget der måske ikke eksisterer.  Man kan godt komme til at misforstå dette, fordi de er så gode til at beskrive vores virkelighed. Så kan man godt komme til at tro at man kan rejse tiden fordi at lovene ikke modsiger det. Det er ikke nødvendigvis rigtigt. Når man har et sæt love, så skal man sætte afgrænsningsbetingelser (boundery conditions), og der mangler man egentlig bare at skrive: Gælder for t> 0. Det er der ingen der har gjort. Det er fordi at vi aldrig nogensinde er kommet derud, hvor at vi har udfordret. Vi har ikke rejst til tiden. (Altså ud over den naturlige fremad). Lovene beskriver virkeligheden, som vi kender den. Og det kan jo meget godt lige pludselig være at man finder ud af et eller andet. Det sker jo indenfor videnskaben.  Du har brug for noget negativ energi og du har brug for altså alle mulige ting som vi ikke engang ved om eksisterer for at kunne gøre det.  Men så ville man kunne.  Hvis nu at vi går tilbage til det store net med knudepunkter. Så har man en ide om at man ved hjælp af stor masse (altså sorte huller) kan fordreje det hele og få det til at så altså lave et langt overflødighedshorn. Hornets spids skal så ramme ned hvor at det det også starter. På den måde kan man lave en krumning i tid, som kunne bruges til tidsrejser. Alt sammen stadigvæk fantasier. Man skal rejse både i Tid og i Rum, ellers er Jorden et andet sted. Tidsrejse paradokser Bedstefar paradokset: hvis man kommer tilbage og møder sin bedstefar og slår ham ihjel. Hvad sker der så med en selv? -fordi du levede jo aldrig, så derfor så kunne du ikke rejse tilbage i tiden. Bootstrap Paradox (Ontological Paradox): An object or piece of information is sent back in time, becoming the cause of itself. For example, a time traveler gives Shakespeare a copy of his own plays. The question arises: who actually wrote the plays? Predestination Paradox (Closed Loop): A traveler goes back in time to prevent an event, but their actions in the past are actually what cause that event to happen in the first place. The "Writer" Paradox: A traveler brings a book back in time and gives it to the author before it is written. The book exists in an endless loop with no original author. Hitler Paradox: A common variant of the Grandfather Paradox where a traveler goes back to kill a historical figure like Hitler, but in doing so, eliminates the reason for their own future mission, creating a contradiction Ofte er løsningen af disse paradokser at der er parallel universer, og at man derfor ikke forhindrede sin egen fødsel, men fødsel af en variant af en selv i et paralel univers. Hvis Vi skulle bygge en tidsmaskine: En tidsrejsemaskine er nok ikke en æske du sætter dig ind i. Det er nok heller ikke et rumskib der sætter dig ind i. Derimod er det nok mere som at lave et Anker i rumtiden og lave halvdelen af en bro. Så skal den 2. Halvdel laves fra fremtiden af. Man kan så ikke rejse længere tilbage i tiden end da broen blev bygget fra nutidens side af. Og man kan ikke rejse længere frem i tiden end til der hvor den anden ende af broen er blevet bygget. Lad os sige at vi laver broen nu. Vi har nu fundet det her mærkelige materiale vi skal bruge. Sådan noget negativ energi og noget alt muligt eksotisk, som vi har været ude på den anden kant af universet. Og så laver vi simpelthen en bro (måske er port et bedre billede)  Vi åbner en port i rummet, og den ene halvdel har vi lavet. Der er åbent hele vejen igennem, men den anden halvdel er lavet fra fremtidens side af. Så kan man så kun rejse imellem de 2 tidspunkter. Altså du kan ikke så pludselig sige: "Nu vil jeg gerne rejse længere tilbage." Jamen, det kan du ikke, fordi der var broen endnu ikke lavet. En ny og anderledes måde at kigge på Tid: A physicist has proposed a mind-bending new idea: what if time, not space, is the true foundation of our universe—and not just one direction of time, but three? According to Gunther Kletetschka from the University of Alaska Fairbanks, time may have three dimensions, while space could simply be a byproduct. Instead of the classic four-dimensional spacetime we’ve long accepted, this theory envisions reality built on a six-dimensional fabric: three time dimensions and three space dimensions. Think of it like a painting: traditional physics says space is the canvas and time flows across it. Kletetschka flips that—time is the canvas, and space is just the paint. His work builds on previous theories that explored three-dimensional time but were mostly theoretical. His version, however, claims to make real-world predictions, including accurately calculating the masses of known particles like electrons and quarks. Three-dimensional time means there could be other “directions” of time—like stepping sideways into a different outcome of the same day, rather than just moving forward. But don’t worry: Kletetschka’s model still respects cause and effect. He believes this idea could even help scientists finally unify quantum mechanics and gravity into a long-sought “theory of everything.” While intriguing, it’s worth noting that this theory hasn’t yet been widely accepted. It was published in a lower-profile journal and hasn’t undergone rigorous peer validation. But if it holds up, it could completely reshape how we think about the universe—and ourselves. Three-Dimensional Time: A Mathematical Framework for Fundamental Physics Reports in Advances of Physical Sciences 2025 09  10.1142/S2424942425500045 https://www.preprints.org/manuscript/202507.0410/v1 [https://www.preprints.org/manuscript/202507.0410/v1] Time Crystals: Time crystals are similar to regular crystals in that they are based on structures of atoms that repeat. Rather than repeating across three dimensions of space, these ones change in a set pattern over time.  Så en Tids-Krystal står of skifter mellem 2 forskellige tilstande. Først forudsagt at de skulle eksistere i 2012. Først opdaget i 2016. Og nu har man lavet en, som er så stor at man kan se den. https://www.sciencealert.com/world-first-physicists-created-a-time-crystal-that-we-can-actually-see [https://www.sciencealert.com/world-first-physicists-created-a-time-crystal-that-we-can-actually-see] https://www.youtube.com/watch?v=4z4dY6qVrxo [https://www.youtube.com/watch?v=4z4dY6qVrxo] Subjektive opfattelse af tid: Tid kan føles som om den går hurtigt og langsomt. References: https://www.sciencealert.com/time [https://www.sciencealert.com/time] https://videnskab.dk/naturvidenskab/hvad-er-tid/ [https://videnskab.dk/naturvidenskab/hvad-er-tid/] Ubegribeligt: Podcast DR . Afsnit om tid: https://www.dr.dk/lyd/p1/ubegribeligt/ubegribeligt-2025/tid-genbesoegt-11162505177 [https://www.dr.dk/lyd/p1/ubegribeligt/ubegribeligt-2025/tid-genbesoegt-11162505177]

Meta & Fysikken: Afsnit 117: Jordens magnetfelter, verdenssituationen mv

1) Jordens Magnetfelt 2) Mennesker påvirker Jordens massefordeling og dermed magnetfeltet 3) Plastik 4) Temperaturen for 2025 er kommet ind 5) Astronauts return early (a non story?) 6) JWST black hole ripping through space: 7) Solformørkelse i Spanien ------------------------------ 1: Magnetisk Nord pol vandrer: https://www.sciencealert.com/earths-magnetic-north-pole-is-officially-moving-scientists-just-updated-its-location [https://www.sciencealert.com/earths-magnetic-north-pole-is-officially-moving-scientists-just-updated-its-location] Earth's Magnetic North Pole Is Officially Moving – Scientists Just Updated Its Location : ScienceAlert [https://www.sciencealert.com/earths-magnetic-north-pole-is-officially-moving-scientists-just-updated-its-location] Jordens magnetfelt har en Anomali: https://www.sciencealert.com/vast-anomaly-in-earths-magnetic-field-keeps-growing-satellites-reveal [https://www.sciencealert.com/vast-anomaly-in-earths-magnetic-field-keeps-growing-satellites-reveal] Vast Anomaly in Earth's Magnetic Field Keeps Growing, Satellites Reveal : ScienceAlert [https://www.sciencealert.com/vast-anomaly-in-earths-magnetic-field-keeps-growing-satellites-reveal] ------------- 2) Humanity Has Dammed So Much Water It's Shifted Earth's Magnetic Poles : ScienceAlert [https://www.sciencealert.com/humanity-has-dammed-so-much-water-its-shifted-earths-magnetic-poles] https://www.sciencealert.com/humanity-has-dammed-so-much-water-its-shifted-earths-magnetic-poles [https://www.sciencealert.com/humanity-has-dammed-so-much-water-its-shifted-earths-magnetic-poles] As we trap water behind dams, not only does it remove water from the oceans, thus leading to a global sea level fall, it also distributes mass in a different way around the world. Extra weight added to a spinning sphere pulls the weighted part towards the equator, shifting the axis around which the sphere spins. So, redistributing Earth's surface weight re-orientates its spin axis, whether that be through damming water, melting glaciers, or groundwater removal. But it's only Earth's outer crust floating over its gooey inner parts – not the inner goo generating the magnetic field – that shift, leading to a different part of Earth's surface sitting over our planet's inner magnetic north. So, while north itself hasn't really moved in space, Earth's surface has shifted around, over the top of it. This phenomenon is called true polar wander. https://www.sciencealert.com/earths-flipping-magnetic-field-heard-as-a-sound-is-an-unnerving-horror [https://www.sciencealert.com/earths-flipping-magnetic-field-heard-as-a-sound-is-an-unnerving-horror] ——— Plastik The primary source of plastic is fossil fuels, specifically crude oil and natural gas. Over 99% of plastic is produced from these non-renewable hydrocarbon sources, which are refined into monomers like ethylene and propylene, and then polymerized into plastic materials 3) Jagten på det nye plastik https://interestingengineering.com/science/biodegradable-plastic-made-from-bamboo [https://interestingengineering.com/science/biodegradable-plastic-made-from-bamboo] Plastik fra Avokado sten: https://worldbiomarketinsights.com/biofase-develops-biopolymers-from-avocado-pits/ [https://worldbiomarketinsights.com/biofase-develops-biopolymers-from-avocado-pits/] ———- 4)  In 2025, the global average surface temperature was approximately 1.44∘C- 1.47∘C above the pre-industrial (1850–1900) level. It was confirmed as the third-warmest year on record, trailing behind 2024 and 2023 despite the cooling influence of a La Niña pattern.  —————- 5) Astronauts return early https://www.sciencealert.com/nasa-brings-astronauts-home-early-after-unprecedented-medical-issue-in-space? [https://www.sciencealert.com/nasa-brings-astronauts-home-early-after-unprecedented-medical-issue-in-space?no_cache=1&fbclid=IwdGRjcAPW3r5leHRuA2FlbQIxMQBzcnRjBmFwcF9pZAo2NjI4NTY4Mzc5AAEeTWSxLoh9dBWZInemYmUx7ygddvbVT29Sq5HF30WIIw_fY0a4Cy3ybCcxqFU_aem_1K96R6re-Pv3zB6Xpxq01A#lgl0pbgzmixu4egcp1xsdc2ei7aljbv] ——————— 6) JWST black hole ripping through space: https://www.sciencealert.com/jwst-confirms-first-runaway-supermassive-black-hole-tearing-through-space [https://www.sciencealert.com/jwst-confirms-first-runaway-supermassive-black-hole-tearing-through-space] —————— 7) Solformørkelse i Spanien. Man kan komme på rejse med Michael Linden Vørnle https://smilrejser.dk/spanien/solformoerkelse-i-spanien-med-astrofysiker-michael-linden-voernle [https://smilrejser.dk/spanien/solformoerkelse-i-spanien-med-astrofysiker-michael-linden-voernle]

Meta & Fysikken: Afsnit 116: COP 30, klimanyt og mos

—————- 2: Tysklands største Hydrogen fabrik: Germany's largest commercial renewable hydrogen factory is the 10 MW plant in Schwäbisch Gmünd, opened by Lhyfe in October 2025. The facility can produce up to 4 tons of renewable hydrogen per day and is Lhyfe's largest outside of France.While it's the largest operational commercial plant, there are larger-scale projects planned for the future in Germany, such as a 130 MW plant planned for Prenzlau by ENERTRAG. https://engineerine.com/largest-green-hydrogen-plant/ [https://engineerine.com/largest-green-hydrogen-plant/] https://www.lhyfe.com/press/lhyfe-inaugurates-germanys-largest-commercial-renewable-hydrogen-production-site-in-baden-wurttemberg-to-distribute-rfnbo-certified-hydrogen-to-a-range-of-players/ [https://www.lhyfe.com/press/lhyfe-inaugurates-germanys-largest-commercial-renewable-hydrogen-production-site-in-baden-wurttemberg-to-distribute-rfnbo-certified-hydrogen-to-a-range-of-players/] A green hydrogen factory is good for the climate because it can be produced using renewable energy, with zero greenhouse gas emissions, and can replace fossil fuels in sectors that are hard to electrify, like heavy industry. When used in a fuel cell, hydrogen only releases water vapor and warm air, making it a clean energy carrier that can also store and deliver renewable energy. # Hydrogen Fuel Cell makes electricity directly. They also produce water vapor, heat and, depending on the fuel source, very small amounts of nitrogen dioxide [https://en.wikipedia.org/wiki/Nitrogen_dioxide] and other emissions. ————- 3: Skrumpende havis https://nyheder.tv2.dk/klima/2025-10-21-skrumpende-havis-er-katastrofe-men-kan-have-fordel [https://nyheder.tv2.dk/klima/2025-10-21-skrumpende-havis-er-katastrofe-men-kan-have-fordel] ------------------------- 4: Kelp farming in Norway https://www.dnv.com/news/2024/new-seaweed-farm-off-the-norwegian-coast-seeks-to-remove-co2-from-the-atmosphere-252006/ [https://www.dnv.com/news/2024/new-seaweed-farm-off-the-norwegian-coast-seeks-to-remove-co2-from-the-atmosphere-252006/] ———— 5: Canada og mos: https://greencitysolutions.de/en/increasing-biodiversity-for-cities-with-moss/#:~:text=Increasing%20Biodiversity%20with%20Moss%20in,or%20fully%20greened%20on%20request [https://greencitysolutions.de/en/increasing-biodiversity-for-cities-with-moss/#:~:text=Increasing%20Biodiversity%20with%20Moss%20in,or%20fully%20greened%20on%20request] ——— 6: Energi fra Vulkaner: https://www.sciencealert.com/scientists-unveil-radical-plan-to-drill-into-a-volcano-for-near-unlimited-energy [https://www.sciencealert.com/scientists-unveil-radical-plan-to-drill-into-a-volcano-for-near-unlimited-energy] Iøvrigt: 7: Vulkanudbrud i Afrika https://www.scientificamerican.com/article/hayli-gubbi-volcano-erupts-in-ethiopia-for-first-time-in-more-than-12-000/ [https://www.scientificamerican.com/article/hayli-gubbi-volcano-erupts-in-ethiopia-for-first-time-in-more-than-12-000/] Volcanic activity has both short-term cooling and long-term warming effects. Volcanic eruptions can release gases like sulfur dioxide (\(SO_\)), which create aerosols that reflect sunlight and cause temporary global cooling, as seen after the Mount Pinatubo eruption. However, volcanoes also release carbon dioxide (\(CO_\)), a greenhouse gas that contributes to warming, though the amount from volcanoes is significantly less than human-generated \(CO_\). Short-term cooling effects Sulfuric acid aerosols: Eruptions inject sulfur dioxide into the stratosphere, where it reacts with water to form tiny sulfuric acid droplets.Reflection of sunlight: These aerosols act like a global "umbrella," reflecting incoming solar radiation back into space and causing a temporary cooling effect that can last for several years.Examples: The 1991 Pinatubo eruption caused a global cooling of about \(0.5^ C\) for a year, and the 1815 Tambora eruption led to "the year without a summer" in 1816. Long-term warming effects Carbon dioxide (\(CO_\)): Volcanoes release \(CO_\), a greenhouse gas that traps heat in the atmosphere, contributing to global warming.Minor contribution: The \(CO_\) emitted by volcanoes is a very small fraction of the total greenhouse gases in the atmosphere, with human activities being the dominant source. For example, the \(CO_\) from the Pinatubo eruption was only about half of what humans produce in two days

Meta & Fysikken: Afsnit 115: Hvad sker der i rummet for tiden?

Vi tager endnu en runde med universelt stof! Hvad sker der i rummet lige for tiden? 1: 3I/Atlas 2: Sten fra Mars 3: Temporary Moon 4: Sattelite made out of wood 5: Starship  6: Store tal 7: Enhederne meter og sekund ----------------------------------- 1:  3I/Atlas NASA deler første fotos af 3I/ATLAS: Ikke rumvæsener [https://videnskab.dk/rummet/nasa-deler-foerste-fotos-af-3i-atlas-ikke-rumvaesener/] https://videnskab.dk/rummet/nasa-deler-foerste-fotos-af-3i-atlas-ikke-rumvaesener/ [https://videnskab.dk/rummet/nasa-deler-foerste-fotos-af-3i-atlas-ikke-rumvaesener/] NASA press release 19.11.25: ESA: https://www.esa.int/ESA_Multimedia/Images/2025/12/Comet_3I_ATLAS_shows_activity_in_Juice_navigation_camera_teaser [https://www.esa.int/ESA_Multimedia/Images/2025/12/Comet_3I_ATLAS_shows_activity_in_Juice_navigation_camera_teaser] ESA - Comet 3I/ATLAS shows activity in Juice navigation camera teaser [https://www.esa.int/ESA_Multimedia/Images/2025/12/Comet_3I_ATLAS_shows_activity_in_Juice_navigation_camera_teaser] During November 2025, ESA’s Jupiter Icy Moons Explorer (Juice) used five of its science instruments to observe 3I/ATLAS. The instruments collected information about how the comet is behaving and what it is made of. In addition, Juice snapped the comet with its onboard Navigation Camera (NavCam), designed not as a high-resolution science camera, but to help Juice navigate Jupiter’s icy moons following arrival in 2031. Though the data from the science instruments won’t arrive on Earth until February 2026, our Juice team couldn’t wait that long. They decided to try downloading just a quarter of a single NavCam image to see what was in store for them. The very clearly visible comet, surrounded by signs of activity, surprised them. Not only do we clearly see the glowing halo of gas surrounding the comet known as its coma, we also see a hint of two tails. The comet’s ‘plasma tail’ – made up of electrically charged gas, stretches out towards the top of the frame. We may also be able to see a fainter ‘dust tail’ – made up of tiny solid particles – stretching to the lower left of the frame. The image was taken on 2 November 2025, during Juice’s first slot for observing 3I/ATLAS. It was two days before Juice’s closest approach to the comet, which occurred on 4 November at a distance of about 66 million km. We expect to receive the data from the five scientific instruments switched on during the observations – JANUS, MAJIS, UVS, SWI and PEP – on 18 and 20 February 2026. The delay is because Juice is currently using its main high-gain antenna as a heat shield to protect it from the Sun, leaving its smaller medium-gain antenna to send data back to Earth at a much lower rate. Though Juice was further from 3I/ATLAS than our Mars orbiters were back in October [https://www.esa.int/Science_Exploration/Space_Science/ESA_s_ExoMars_and_Mars_Express_observe_comet_3I_ATLAS], it observed 3I/ATLAS just after the comet’s closest approach to the Sun, meaning that it was in a more active state. We expect to see clearer signs of this activity in the data from the science instruments. This includes not only images from JANUS – Juice’s high-resolution optical camera – but also spectrometry data from MAJIS and UVS, composition data from SWI, and particle data from PEP. ESA - ESA’s ExoMars and Mars Express observe comet 3I/ATLAS [https://www.esa.int/Science_Exploration/Space_Science/ESA_s_ExoMars_and_Mars_Express_observe_comet_3I_ATLAS] We have an update on 3I/ATLAS!  Until September, figuring out the location and trajectory of 3I/ATLAS relied on Earth-based telescopes. Then between 1 and 7 October, our ExoMars TGO turned its eyes towards the interstellar comet from its orbit around Mars. The comet passed relatively close to Mars, approaching to about 29 million km during its closest phase on 3 October. The Mars probe observed the comet from a new viewing angle. The triangulation of its data with data from Earth helped to make the comet’s predicted path much more accurate. The result was an impressive ten-fold leap in accuracy, reducing the uncertainty of the object’s location. Because 3I/ATLAS is passing through our Solar System fast, travelling with speeds up to 250 000 km/h, it will soon vanish into interstellar space, never to return. The comet is currently being observed with our Juice spacecraft.  Though Juice is farther from 3I/ATLAS than the Mars orbiters were last month, it is seeing the comet just after its closest approach to the Sun, when it is in a more active state. We don’t expect to receive data from Juice’s observations until February 2026.  Komet Kalender: -------------- 2: Sten fra Mars: https://www.sciencealert.com/curiosity-cracked-open-a-rock-on-mars-and-revealed-a-big-surprise [https://www.sciencealert.com/curiosity-cracked-open-a-rock-on-mars-and-revealed-a-big-surprise] Curiosity Cracked Open a Rock on Mars And Revealed a Big Surprise : ScienceAlert [https://www.sciencealert.com/curiosity-cracked-open-a-rock-on-mars-and-revealed-a-big-surprise] https://phys.org/news/2025-12-evidence-driven-climate-mars-jezero.html [https://phys.org/news/2025-12-evidence-driven-climate-mars-jezero.html] Evidence of rain-driven climate on Mars found in bleached rocks scattered in Jezero crater [https://phys.org/news/2025-12-evidence-driven-climate-mars-jezero.html] -------------------------- 3: Temporary Moon Earth currently has a temporary moon, an asteroid designated 2025 PN7, that is in a quasi-satellite orbit. It is not permanently bound to Earth like the main Moon, but rather shares Earth's orbit around the Sun, occasionally entering our planet's gravitational influence for several decades before drifting away again. Earth has had other temporary "mini-moons" in the past, and this is not expected to be the last.  About 2025 PN7 : Size: The asteroid is between 18 to 36 meters wide, or about the size of a building.     Orbit: It orbits the Sun but has been temporarily captured by Earth's gravity and is expected to remain a quasi-moon until about 2083. Distance: It does not get as close as the regular Moon, swinging between 4 and 17 million kilometers away from Earth (Moon is 384400 km away, so between 10 and 44 Lunar distances) 2025 PN7 - Wikipedia [https://en.wikipedia.org/wiki/2025_PN7]  https://en.wikipedia.org/wiki/2025_PN7 [https://en.wikipedia.org/wiki/2025_PN7] --------------------------- 4: Satelite made out of wood: https://www.esa.int/Enabling_Support/Space_Engineering_Technology/ESA_flying_payloads_on_wooden_satellite [https://www.esa.int/Enabling_Support/Space_Engineering_Technology/ESA_flying_payloads_on_wooden_satellite] ---------------------------------- 5: Starship  A: can get us really fast to Uranus: https://phys.org/news/2025-10-starship-uranus.html [https://phys.org/news/2025-10-starship-uranus.html] —————- B: Starship og kapløb med Kina https://videnskab.dk/rummet/starship-10-opsendt-med-succes-alligevel-faar-usa-svaert-ved-at-naa-til-maanen-foer-kina/ [https://videnskab.dk/rummet/starship-10-opsendt-med-succes-alligevel-faar-usa-svaert-ved-at-naa-til-maanen-foer-kina/]   ældre artikel: https://videnskab.dk/rummet/spacex-raketten-starship-10-er-eksploderet-faar-store-konsekvenser-for-amerikansk-maanelanding/?utm_medium=email&utm_source=vores-nyhedsbrev [https://videnskab.dk/rummet/spacex-raketten-starship-10-er-eksploderet-faar-store-konsekvenser-for-amerikansk-maanelanding/?utm_medium=email&utm_source=vores-nyhedsbrev] ---- 6: Store tal For at forstå store tal er det nogen gange meget godt at omregne det til noget andet.  1 * 10^6 sekunder = 11.5 dage 1 * 10^9 sekunder= 31.7 år 1 * 10^12 sekunder = 31 710 år Så kan vi måske forstå hvor meget forskel der er på en millonær og en millardær. Trillionær burde ikke eksistere.  ----------------- 7: Enhederne meter og sekund  Generelt kom jeg til at tænke på enheder.  Meter:   Historical definition: Historically, a meter was defined as one ten-millionth of the distance from the North Pole to the equator along the Prime Meridian. In 1960 the metre was thus defined in the SI system as equal to 1,650,763.73 wavelengths of the orange-red line in the spectrum of the krypton-86 atom in a vacuum. It is currently defined as the distance light travels in a vacuum in \(1/299,792,458\) of a second. Second: A second is  the base unit of time in the International System of Units (SI), defined as the time it takes for a cesium-133 atom to undergo 9,192,631,770 hyperfine transitions in its ground state when oscillating at a specific microwave frequency. This precise atomic definition provides a universal standard for time, making it a fixed and consistent unit for the entire world, unlike older definitions based on Earth's rotation which can fluctuate. A second can also refer to an ordinal number meaning "after first"  The old definition of a second was   of a mean solar day. This definition was used until the mid-20th century, when it was replaced because the Earth's rotation is not constant, making the length of a solar day slightly variable. An earlier, less formal definition was based on dividing the hour into 60 parts, each of which was called a "minute," and then dividing that into 60 parts to get a "second," as the ancient Babylonians originally did (Rabbit hole: The Babylonian number system was a sexagesimal (base-60) system that used only two symbols: a vertical wedge for one (1) and a corner wedge for ten (10). It was a positional system where the value of a symbol depended on its position, with each place representing a power of 60, similar to how our base-10 system uses powers of 10. The system lacked a true zero for a placeholder initially, creating ambiguity, but later added a symbol for this purpose.  ) Min pointe: Vores m og s var (er) defineret efter jorden og vores omløb. Enheden m/s er derfor Jordens enhed. Lysets hastighed i vacuum er en universel konstant, men en Alien vil 100% have en anden enhed end os. Også selvom at vi har fundet bedre naturkonstanter til at definere m og s ud fra.