After this week, when North Korea decided to do what they did, what else could be the theme for Friday facts than the hydrogen bomb?
  1. the hydrogen bomb is also called the H-bomb, a fusion weapon/bomb, or a thermonuclear weapon
  2. the point of a "real" hydrogen bomb is to get hydrogen to fuse, and to get a large portion of energy released from this reaction
  3. to get the hydrogen to fuse you have to make it hot enough (you try to recreate what happens in the sun) so that light nuclei will fuse and release even more energy than in a "normal" atomic bomb/nuclear weapon - the word thermonuclear means that the fusion takes place when the temperature is extremely high
  4. a hydrogen bomb is also an atomic bomb/nuclear weapon, but it was developed some years after the fission bombs ("normal" atomic bombs) that were used in 1945, on Hiroshima and Nagasaki - the only time nuclear weapons have been used (a hydrogen bomb has never been used - only tested)
  5. the first step of a hydrogen bomb is a fission bomb, which makes the temperature so extreme that fusion may start
  6. I don't understand this mushroom cloud from the North Korean bomb test on Wednesday, since they did it under ground... I think they've either had fun with photo shop, or they just "borrowed" the pictures of the cloud from somewhere else (maybe Kim Jong Un really loves mushroom clouds?)
  7. in addition to a real fusion bomb (where most of the energy released comes from fusion reactions), you could make a fission bomb that is boosted with hydrogen - this means that there will be some hydrogen in the weapon that fuses, and from these fusion reactions you get more neutrons so that even more of the fissile material will fission. Almost of all the energy released in such a weapon comes from fission, so therefore it's called a boosted fission bomb
  8. there is in theory no limits for how big a hydrogen bomb can be; you can just put more and more fusion material in it - I state that the real hydrogen bomb is the deadliest weapon ever made, and the biggest ever bomb test was the Tsar Bomba, which had an explosive power of 50 million tons of TNT (around 1500 times the total explosive power of both Hiroshima and Nagasaki combined)
  9. the first hydrogen bomb was tested in 1952, by the USA - today there are at least five countries that have these types of weapons (USA, Russia, UK, France, and China)
  10. this book is about the hydrogen bomb, and I got it from my sweet colleague, Gry, and now I'm going to read it <3
Happy weekend from Rose castle - we are going to watch West Wing and share a bottle of wine now 🙂
(I'm a frog :D)


Hi everyone 🙂
I got a question the other day about nuclear weapons and nuclear power plants. There was some confusion about something I said on the radio (Abels Tårn) a couple of weeks ago, about nuclear power and nuclear weapons... Let me divide the question into two parts:

1) How much do you have to enrich natural uranium to make a nuclear weapon, and how much do you have to enrich to make nuclear fuel?
To make a weapon you have to enrich natural uranium, that consists of 99.25% uranium-238 and 0.72% uranium-235 (and the rest is uranium-234), to you get something like 95% uranium-235 - since this is the fissile isotope.
To make fuel you only have to enrich up to around 5% uranium-235.
In theory you could have made the 95% enriched uranium into fuel, and even though it costs money to enrich (and much more money the more you enrich), you would more or less get this money back since the higher enrichment, the longer it would last (and also, the less waste you would make - but that's another question 😉 )

2) (Which was really the question I got.) Why can't we make energy from a bomb?
First of all: you could take the fissile material from a bomb and make it into fuel - it was actually done for 20 years in the Megatons to Megawatts program, and during that time 10% of all of the electricity in the US came from nuclear power plants that were fuelled with old, Russian, nuclear war heads 🙂
Second: What I was talking about on the radio was not the normal fission bomb, but a fusion/hydrogen bomb. Actually, I was talking about wether or not we manage to make fusion here on Earth, and my point was/is that we don't (yet, but maybe in the future? 😉 ) manage to make energy from fusion the way the sun does it, but it's not correct that we don't manage to make fusion at all; since in a fusion weapon (also a type of nuclear weapon, also called a hydrogen bomb or an H bomb) we do get hydrogen to fuse. But to make the conditions right, so that the hydrogen nuclei get close enough and start to fuse, to form helium nuclei, and release energy, we have to "light it" with a "normal" fission bomb first - this is what I mean by we're putting in more energy than what we're getting out. So, we make hydrogen fuse in an explosion that we start with a nuclear fission bomb - not exactly a way to produce energy 😉

Was this any clarifying at all? Or more confusing? Please let me know, and tell me if there's something I should explain in more detail <3

Today was the third (and last) day of the writing seminar. As I said yesterday, it takes time, a lot of time; and today I've spent most of that time working on a plot...
This stupid colon stole one hour of my #phdlife today... For those who know any programming you know it should be a semi colon there, and not a colon. For me, who's no where near to being an expert in programming, it took me one hour before I said to my self "I've tried everything now, and the error messages I get don't tell me what's wrong - I have to ask someone for help", and I turned to Gry, who was sitting next to me (thank god), and she saw my STUPID mistake in something like 58 seconds. And suddenly, instead of just giving me a completely blank canvas, I got exactly what I wanted - beauty, beauty, beauty:
Can I have it in pink, please? Oh, yes, I can - the magic code is "kPink+7" <3
There will be no plotting or writing tomorrow, 'cause then I actually have to go for some christmas shopping (now it sounds like I don't want, which is not true... I'm going with Anders, and I'm looking forward to it <3 ), but on Monday I'll be back at Blindern for a discussion with Sunniva Supervisor - and maybe Jon (my other supervisor) will get a draft of this paper as a christmas present 😉
But before anything else: SLEEP!

Finally, the video from the TEDxBergen conference is now on-line!

The subject of my talk was Could nuclear weapons save the planet? , and you can watch the entire thing here:
Since I talked about how to dress as a female scientist in my last blogpost, I just have to show you a close-up of the shoes I wore. These shoes from Nelly ended up as my "statement" for this talk - which I felt that I needed, since the rest of the outfit was quite simple; just tight jeans, a loose shirt, and my hair in a bun (not the tightest, but not very messy either):

One of the really great thing about this trip to Bergen (almost a month ago already!) - besides being allowed to give my third TEDx talk - was that Anders came and spent the weekend with me <3 There's nothing like sharing experiences like this with the one you love, and having Anders in the audience made me feel so much better and more secure than if I had been there all by myself... He was a great supprt!
perfect evening: I was dead tired after  a long day -  I do get really stressed before I'm giving a talk like this. We were thinking about either go to the after party with the rest of the people from the conference, or maybe go out in Bergen... But instead we stayed in the hotel; we took a looong bath (where we drank two bottles of Prosecco), before we ordered pizza to the room, ate it in bed and watched several episodes of the Big Bang Theory. It was just perfect <3


Friday again!

This week that means Bergen, and as (almost) always that means FACTS. This week I want to give you ten facts about nuclear weapons and the "Megatons to Megawatts" project - a little "taster" of what my talk tomorrow will be about (I don't know if there will be a live stream yet, but at least the entire confernce will be filmed, and go on-line later - I will of course share the link when it's ready 😉 )

  1. nuclear weapons have been used against humans two times; Hiroshima August 6th and Nagasaki August 9th, 1945 - hopefully NEVER again
  2. both "Little Boy" and "Fat Man" were fission bombs (getting their energy from fission); "Little Boy" was made of highly enriched uranium (uranium-235), and "Fat Man" was made of plutonium(-239)
  3. after WWII a nuclear arms race begun between the US and the Sovjet Union, and at one time there were more than 60 000 nuclear weapons in the world
  4. a nuclear weapon is ugly, but by mixing the fissile material in it with uranium or thorium, it can be changed into beautiful nuclear fuel (100% normal nuclear fuel for normal reactors) <3
  5. the "Megatons to Megawatts" program was an agreement between US and Sovjet/Russia that lasted from 1993 to 2013, where Sovjet made fuel out of their weapons (unfortunately not all of them) and US bought it
  6. during those 20 years (1993-2013), 500 tonnes of highly enriched uranium, from 20 000 Russian nuclear weapons have been converted into nuclear fuel and "burned" in reactors (more than 2 weapons destroyed every day!)
  7. the electricity generated from these weapons is the same amount as all the electricity in the US in two years(!)
  8. weapons uranium (highly enriched uranium) could be mixed with natural uranium to make fuel (as has been done in the program) - or, even better, with thorium
  9. if you mix weapons uranium with thorium, you can also recycle the spent fuel; this means that not only do you get rid of horrible weapons, you also get rid of a lot of nuclear waste (WIN WIN 😀 )
  10. today there are around 16 000 nuclear weapons in the world - much better than 65 000 (or whatever the peak number was), but still that's definitely 16 000 too many...:/
(I bite my lip when I concentrate - haha)

 Now I'm soon off to NHH, where the conference tomorrow will be held, for sound check, and just "feel" the stage. And when I come back to the hotel again, Anders will be here! I'm so incredibly happy he could join me here in Bergen this weekend!!! We're here until Sunday afternoon, so hopefully we'll have time to actually experience something while we're here - any recommendations from my readers?
Anyway: happy weekend to everyone <3

So, I'm spending a lot of time working on my talk for Saturday these days, and a lot of my preparation is about searching for different kinds of images that I can use in the talk. As I told you on Monday, the title of my talk is "Could nuclear weapons save the planet", and there will of course be some talking about the history of nuclear weapons. 
While searching for one thing, clicking on one link, and then clicking on another link in the first link, I came across this letter that Einstein wrote to President Roosevelt in 1939, when they had just discovered that uranium could fission and release those huge amounts of energy. And they were starting to understand that this could be used for making a very powerful weapon.
I just had to share this with my beautiful readers. This is history!

Anders I came home an hour ago, and we're going to eat some thai curry now. We'll probably watch Big Bang Theory ( <3 ), and after that we'll actually go to sleep - we've come into this mode where we go to bed really early, and get up equally early in the morning...and it feels great!
Tomorrow will be a day with more or less 100% focus on the TEDx talk; I've started on the manuscript, but I'm not even close to where I want to be. Hope it will be good in the end 😉

I dag er det et ikke så hyggelig 65-årsjubileum... 

Den 29. august 1949 gjennomførte Sovjetunionen sin aller første atomprøvesprengning: i det som i dag er Kazakhstan sprengte de bomben med det klingende navnet "RDS-1". RDS-1 liknet på "Fat Man" - bomben som USA detonerte over Nagasaki i 1945; altså en plutoniumsbombe med 22 kilotonn TNT sprengkraft. 
Prøvesprengningen førte til at USA videre utviklet et kraftigere våpen, nemlig det som kalles termonukleære våpen eller hydrogenbombe - altså fusjonsvåpen (dette er også atomvåpen, men kraftigere enn de som feks ble brukt under krigen - som var fisjonsvåpen). Den første hydrogenbomben ble testet i 1952, mens Sovjetunionen testet sin første fusjonsbombe i 1953.

 (Bildene har jeg lånt fra Physics Today)


...jeg får bare skylde på at denne helgen (og dagene før) har stått i flyttingens tegn, og jeg har vel egentlig ikke hatt tid eller hjernekapasitet til å tenke på noe annet - men det slo meg i dag tidlig, da jeg satt og gjorde siste forberedelser til foredraget jeg holdt for de nye fysikkstudentene, at det nettopp var "bombejubileum" :/ 6. august 1945 ble et kjernefysisk våpen for første gang brukt mot mennesker - i Hiroshima, og den 9. august ble kjernefysiske våpen brukt for andre og siste gang mot mennesker - i Nagasaki, i Japan.
Begge bombene var fisjonsvåpen (altså "kun" spalting av tunge atomkjerner) - fusjonsvåpen/hydrogenbomben kom senere, men Hiroshimabomben ("Little Boy") var laget av høyanriket uran, mens Nagasakibomben ("Fat Man") var laget av plutonium.
Uran-235 og plutonium-239 har forskjellige kjernefysiske egenskaper (selv om begge spaltes lett, og egner seg for å få energi fra - enten som brensel, eller som våpen), så "Little Boy" og "Fat Man" var forskjellige typer bomber: 
"Little Boy" var gun-type, mens "Fat Man" var implosion
Jeg kan sikkert skrive mer om forskjellene på uran-235 og plutonium-239, og hvorfor "Fat Man" og "Little Boy" var forskjellige - hvis det er interesse for det?
Under er mitt bilde av "Atomic Bomb Dome" - en av bygningene som sto igjen etter bombingen av Hiroshima, som jeg tok da jeg var der i vår.
Grunnen til at bygningen står igjen såpass intakt er at den sto på ground zero - altså rett under der bomben ble detonert.


Jada, dere leser riktig; atter en gang er jeg litt sent ute med å skrive om en stor hendelse i (kjernefysikk)historien, men det er vel kanskje ikke helt galt at det skjer sånn midt på sommeren, eller hva? Føler jeg blir ganske omtåket av solen om dagen, i alle fall, og det blir vanskeligere å konsentrere sag 😛
Uansett, den 16. juli 1945 ble den aller første atombombetesten - Trinity - foretatt i ørkenen i New Mexico, og det er altså 69 år siden menneskeheten fikk kjernefysiske våpen.
Dette bildet ble altså tatt 0.016 sekunder (bare litt mer enn en hundredel av et sekund) etter detonasjon av våpenet; og da er denne ildkulen allerede 200 meter i diameter - ganske ekstremt! Allikevel var denne testen bare en bitteliten sak sammenliknet med de kraftigste våpnene som er testet i løpet av den kalde krigen: Trinity hadde en sprengkraft på ca 20 kilotonn TNT, mens det kraftigste våpenet noen sinne var 30 000 ganger kraftigere...!
Som sikkert alle vet så var det videre resultatet at de japanske byene Hiroshima og Nagasaki ble bombet med atomvåpen under en måned senere; første og eneste (og la det for all del forbli slik) gang at denne typen våpen er brukt mot mennesker. Trinity var et plutoniumsvåpen sånn som den over Nagasaki - i motsetning til uranvåpen som ble brukt mot Hiroshima.
Robert Oppenheimer, som var leder for Manhattanprosjektet (der de jobbet med å utvikle atombomben) sa i et intervju i 1965:

We knew the world would not be the same. A few people laughed, a few people cried. Most people were silent. I remembered the line from the Hindu scripture, the Bhagavad GitaVishnu is trying to persuade the Prince that he should do his duty and, to impress him, takes on his multi-armed formand says, 'Now I am become Death, the destroyer of worlds.' I suppose we all thought that, one way or another.

Hei alle fine!!! Denne helgen har jeg brukt til å sove (ut) drikke kaffe, trene, stå lenge i dusjen, gå rundt i Oslo (har bare gått overtalt jeg har skullet, og liksom gjort det til en del av dagens gjøremål), og jeg har sittet i deilige Frognerparken og lest om  overkritiske kjedereaksjoner. Haha,  ja,  jeg er nerd,  og det et jeg faktisk skikkelig stolt av...Like a boss ★★★

Den egentlige grunnen til at jeg har gjort det denne helgen, istedetfor å kanskje lese et blad eller en roman, er at jeg sitter og finpusser på manusene til "Sushi og kjernekraft" - jeg skal ikke skryte på meg mye av arbeidet med disse, men som fagperson så har jeg jo liksom et visst ansvar for at det er riktig det jeg skal si, da 😉 Og nå var tiden kommet for hvor langt tid varer egentlig en atombombe-eksplosjon - eller, hvor lenge varer den overkritiske, eller superkritiske, kjedereaksjonen?

Det et jo helt sykt, for i en en sånn eksplosjon så frigjøres så helt vanvittig absurd mye energi, og det skjer på nesten uendelig kort tid. På noen tusendels sekunder så et det faktisk over;  da vil ikke det spaltbare materialet (feks uran) sitte sammen lenger;  det slynges fra hverandre og da slutter også kjedereaksjonen. Noe av det som er utfordrende med å lage atomvåpen er, så vidt jeg vet, å klare å få uranet eller plutoniumet til å sitte sammen lenge nok til at "nok" atomkjerner spaltes og frigjør energi, for med én gang dette starter så blir det jo mye kraft som presser materialet fra hverandre...dette er visst ekstra vanskelig når det kommer til plutonium, fordi den på en måte kan gå av litt for tidlig.
Sol og sommer krever sol og sommer-antrekk; elsker at det holder med en kjole og ikke noe mer - skulle ønske det skulle være sånn vær frem til september eller noe nå :/

ut og rusle i byen-klar


God mandag alle!
Her i thorium-rosa-rose-verden har ting sklidd en del ut; etter torsdagen har jeg rett og slett vært utrolig sliten (og lei meg - har hatt rødkantete øyne noen ganger), og jeg har prioritert å gjøre koselige ting og å ha gode mennesker rundt meg - noe som "dessverre" har ført til at ting som feks torsdagsanbefaling (eller blogg sånn helt generelt) ikke har skjedd i det hele tatt *lei for det*. Dermed starter en ny uke (med blanke ark?) med en bok jeg har hatt lyst til å anbefale en stund nå:

NUCLEAR WEAPONS -a very short introduction

Misforstå meg rett; da jeg anbefalte "The making of the Atomic Bomb" fikk jeg en litt kritisk kommentar på Facebook om at jeg burde ta avstand fra kjernefysiske våpen, og at jeg ikke kunne omtale atomvåpen på den måten jeg gjør. Vel, jeg mener det burde være så opplagt at jeg selvsagt ikke syns atomvåpen er en god ting at jeg faktisk ikke en gang har tenkt tanken på å "ta avstand" fra dette; men bare så det er 100% klart så mener jeg selvsagt at atombomben absolutt er en av de virkelig kjipe oppfinnelsene i menneskets historie, og jeg skulle nok absolutt ha ønsket meg en verden fri for atomvåpen. Når det er sagt så mener jeg at jeg fremdeles må ha lov til å syns at konseptet er fascinerende; og da mener jeg naturligvis ikke "konseptet med å bruke atomvåpen" (som bare er helt forferdelig), men "konseptet med å frigjøre kjernekraften". Jeg står ved at jeg syns universets sterkeste kraft er helt vanvittig spennende - og det at man kan frigjøre den, noe som blir så utrolig tydelig i en atomeksplosjon ER FASCINERENDE. Dette gjør meg på ingen måte til tilhenger av kjernefysiske våpen, eller det å bruke dem!

Min fascinasjon for kjernefysikk startet faktisk da jeg første gang så bildet av en eksploderende atombombe, og leste om Hiroshima og Nagasaki (nå har jeg jo faktisk også vært i Japan, og Hiroshima, og det som gjorde aller størst inntrykk på meg på denne turen var å se Atomic Bomb Dome), og for min del endte det altså opp med studier og forskning i atomkjernens verden, men historien rundt syns jeg også er veldig spennende, og jeg tror nesten ikke jeg kan få nok av bøker som handler om utviklingen av atombombene og alt det rundt det.

Mens "The making of The Atomic Bomb" er stor og tung som en bibel, er denne ukens bok i helt motsatt ende av skalaen - den får seriøst plass i de aller minste veskene mine - og for en som ikke er veldig inne i fagfeltet kan kanskje en sånn introduksjon være en, vel, flott introduksjon til temaet (så kan den andre være for de aller mest spesielt interesserte/nerdete - som meg selv 😛 ).
"NUCLEAR WEAPONS -a very short introduction" starter med et kapittel ("What are nuclear weapons?") som kort og greit tar for seg det aller mest grunnleggende av fysikken som ligger bak, mens videre handler det i mye større grad om historien og politikken bak utviklingen og bruken av atombombene; hvordan og hvorfor, så dette er ikke akkurat boken hvis du aller helst vil lese og lære om kjernefysikk, men personlig syns jeg jo hele historien rundt Manhattanprosjektet, og tiden etter, er veldig spennende, interessant og viktig - derfor denne anbefalingen 🙂

Amazon sier på sine nettsider:

Joseph M. Siracusa is Professor in International Studies and Director of Global Studies, at the Royal Melbourne Institute of Technology. He is internationally known for his writings on nuclear history, diplomacy, and presidential politics, and is also a frequent political affairs commentator in the media.

For all the effort to reduce nuclear stockpiles to zero, it seems that the Bomb is here to stay. This Very Short Introduction reveals why. 

The history, and politics of the bomb are explained: from the technology of nuclear weapons, to the revolutionary implications of the H-bomb, and the politics of nuclear deterrence. The issues are set against a backdrop of the changing international landscape, from the early days of development, through the Cold War, to the present-day controversy of George W. Bush's National Missile Defence, and the threat and role of nuclear weapons in the so-called Age of Terror. 

Joseph M. Siracusa provides a comprehensive, accessible, and at times chilling overview of the most deadly weapon ever invented. 

Enjoy <3