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Big Think Science, Dark Matter: Radiation Would Have Washed Away Galaxies Without It

Dark Matter: Radiation Would Have Washed Away Galaxies Without It

Dark matter is just a form of matter, which is to say it acts like matter when it comes to gravity. So it clumps together like the matter we know about. It's found in galaxies, for example, because of gravitational force. What distinguishes dark matter from ordinary matter is that it has no interaction as far as we know with light. So we see ordinary matter. It's made up of atoms. Atoms are made up of charged particles. But so far as we know, dark matter is just an entirely new form of matter not made up of atoms, not made up of the stuff we're familiar with. And the question we eventually have is what is it made up of exactly?

But as far as the physics of the universe goes, it's just a form of matter. The reason we're aware of dark matter is because of the gravitational effects. In fact, if you look at just the energy stored there's five times as much dark matter as there is ordinary matter. So you observe this gravitational effects in galaxies for example. I mean one of the ways we first knew about dark matter was by looking at the motion of stars. The motion of stars responds to the gravitational force of all the matter around. It doesn't care whether or not it interacts with light. The stars of course are bright because they interact with light. But they're responding to the gravity of the matter including the dark matter. So that was evidence for dark matter. And now there's lots of other evidence for dark matter too having to do with the way light bends or what galaxy clusters look like when they merge. So there's really a lot of physical evidence that tells us dark matter is out there in the universe. Then the question for theoretical physicists like myself becomes: What is this stuff and what do we mean by that? Well, is it an elementary particle? Is it more than one elementary particle? If it is a particle, what is the mass of that particle? Does it have any interactions at all?

So far we haven't seen any interactions with the light with which we're familiar, but maybe there's a small interaction that we just haven't seen yet or maybe it attracts in an entirely different way. The only thing we know for sure is that there is this matter and it interacts via gravity. Dark matter was actually essential to the formation of structures we see in the lifetime of the universe. Now it's important to say structures we see in the lifetime of the universe. Even without dark matter, structure would have formed. But the actual size of the galaxies that we see is only possible because dark matter was present. Ordinary matter interacts with radiation. Radiation would have washed away small objects like galaxies. Now I realize galaxies don't seem small to you, but on the scale of what radiation could wash away they're actually small. So dark matter was essential to forming objects of that size. It also was important because it meant that matter came to dominate over radiation sooner in the evolution of the universe because there was a lot more matter. And again matter domination is important for the formation of structure because radiation won't form structure. I mean just think about it. Light's not clumping into little balls the same way matter would. So both because of its abundance and because it doesn't interact with light, dark matter was actually essential to the formation of the structure that we see.

Dark Matter: Radiation Would Have Washed Away Galaxies Without It Dunkle Materie: Strahlung hätte ohne sie Galaxien weggespült Σκοτεινή Ύλη: Η ακτινοβολία θα είχε ξεπλύνει τους γαλαξίες χωρίς αυτήν Materia oscura: La radiación habría arrasado las galaxias sin ella Matière noire : Sans elle, les radiations auraient emporté les galaxies Materia oscura: Le radiazioni avrebbero spazzato via le galassie senza di essa ダークマターダークマターがなければ放射線が銀河を洗い流していた 암흑 물질: 방사능이 없었다면 은하계를 휩쓸었을 것입니다. Tamsioji medžiaga: Be jos radiacija būtų nuplovusi galaktikas Ciemna materia: Bez niej promieniowanie zmyłoby galaktyki Matéria negra: A radiação teria destruído as galáxias sem ela Темная материя: без нее радиация смыла бы галактики Mörk materia: Strålning skulle ha sköljt bort galaxer utan den Karanlık Madde: Radyasyon, O Olmasaydı Galaksileri Yok Ederdi 暗物质:如果没有它,辐射就会冲走星系 暗物质没有暗物质,辐射会冲走星系

Dark matter is just a form of matter, which is to say it acts like matter when it comes to gravity. La materia oscura no es más que una forma de materia, es decir, actúa como la materia en lo que respecta a la gravedad. La materia oscura è solo una forma di materia, ossia si comporta come materia quando si tratta di gravità. Темная материя — это просто форма материи, то есть она ведет себя как материя, когда дело доходит до гравитации. 暗物质只是物质的一种形式,也就是说,在引力方面,它的作用与物质相同。 So it clumps together like the matter we know about. Quindi si aggrappa insieme come la materia di cui conosciamo. Так что это слипается, как материя, о которой мы знаем. 因此,它就像我们所知的物质一样聚集在一起。 It’s found in galaxies, for example, because of gravitational force. Si trova nelle galassie, ad esempio, a causa della forza gravitazionale. Его можно найти в галактиках, например, из-за силы гравитации. 例如,由于引力的作用,星系中就会出现这种现象。 What distinguishes dark matter from ordinary matter is that it has no interaction as far as we know with light. Quello che distingue la materia oscura dalla materia ordinaria è che non ha interazione, per quanto ne sappiamo, con la luce. So we see ordinary matter. Quindi vediamo la materia ordinaria. Итак, мы видим обычную материю. It’s made up of atoms. È composta da atomi. Он состоит из атомов. Atoms are made up of charged particles. Gli atomi sono composti da particelle cariche. Атомы состоят из заряженных частиц. But so far as we know, dark matter is just an entirely new form of matter not made up of atoms, not made up of the stuff we’re familiar with. Ma per quanto ne sappiamo, la materia oscura è semplicemente una nuova forma di materia non composta da atomi, non fatta della materia con cui siamo familiari. Но, насколько нам известно, темная материя — это совершенно новая форма материи, не состоящая из атомов, не состоящая из того вещества, с которым мы знакомы. And the question we eventually have is what is it made up of exactly? E alla fine la domanda che ci poniamo è di cosa sia esattamente composta? И вопрос, который у нас в конечном итоге возникает, заключается в том, из чего именно он состоит?

But as far as the physics of the universe goes, it’s just a form of matter. Ma per quanto riguarda la fisica dell'universo, è solo una forma di materia. Но что касается физики Вселенной, это просто форма материи. The reason we’re aware of dark matter is because of the gravitational effects. La ragione per cui siamo consapevoli della materia oscura è a causa degli effetti gravitazionali. Причина, по которой мы знаем о темной материи, заключается в гравитационных эффектах. In fact, if you look at just the energy stored there’s five times as much dark matter as there is ordinary matter. In realtà, se si considera solo l'energia immagazzinata, c'è cinque volte più materia oscura rispetto alla materia ordinaria. На самом деле, если вы посмотрите только на накопленную энергию, темной материи в пять раз больше, чем обычной материи. So you observe this gravitational effects in galaxies for example. Итак, вы наблюдаете этот гравитационный эффект, например, в галактиках. I mean one of the ways we first knew about dark matter was by looking at the motion of stars. Uno dei modi in cui per la prima volta abbiamo saputo dell'esistenza della materia oscura è stato osservando il movimento delle stelle. Я имею в виду, что одним из способов, которым мы впервые узнали о темной материи, было изучение движения звезд. The motion of stars responds to the gravitational force of all the matter around. Il movimento delle stelle risponde alla forza gravitazionale di tutta la materia circostante. Движение звезд откликается на гравитационную силу всего окружающего их вещества. It doesn’t care whether or not it interacts with light. Non gli interessa se interagisce o meno con la luce. Ему все равно, взаимодействует он со светом или нет. The stars of course are bright because they interact with light. Le stelle ovviamente sono luminose perché interagiscono con la luce. Звезды, конечно, яркие, потому что они взаимодействуют со светом. But they’re responding to the gravity of the matter including the dark matter. Ma stanno rispondendo alla gravità della materia, compresa la materia oscura. Но они реагируют на гравитацию материи, включая темную материю. So that was evidence for dark matter. Quindi quella era una prova della presenza di materia oscura. Так что это было свидетельством существования темной материи. And now there’s lots of other evidence for dark matter too having to do with the way light bends or what galaxy clusters look like when they merge. E ora ci sono molte altre prove della presenza di materia oscura che riguardano il modo in cui la luce si piega o il modo in cui appaiono i cluster di galassie quando si fondono. И теперь есть много других свидетельств темной материи, связанных с тем, как свет изгибается или как выглядят скопления галактик, когда они сливаются. So there’s really a lot of physical evidence that tells us dark matter is out there in the universe. Quindi c'è davvero molta evidenza fisica che ci dice che la materia oscura è presente nell'universo. Так что есть действительно много физических доказательств того, что темная материя существует где-то во Вселенной. Then the question for theoretical physicists like myself becomes: What is this stuff and what do we mean by that? Poi la domanda per i fisici teorici come me diventa: Che cosa è questa roba e cosa intendiamo con ciò? Well, is it an elementary particle? Beh, è una particella elementare? Ну, это элементарная частица? Is it more than one elementary particle? È più di una particella elementare? Это более чем одна элементарная частица? If it is a particle, what is the mass of that particle? Se è una particella, qual è la massa di quella particella? Если это частица, то какова масса этой частицы? Does it have any interactions at all? Ha interazioni di qualche tipo? Есть ли вообще какие-либо взаимодействия?

So far we haven’t seen any interactions with the light with which we’re familiar, but maybe there’s a small interaction that we just haven’t seen yet or maybe it attracts in an entirely different way. Finora non abbiamo visto interazioni con la luce con cui siamo familiari, ma forse c'è una piccola interazione che non abbiamo ancora visto o forse attrae in modo completamente diverso. До сих пор мы не видели никаких взаимодействий со светом, с которым мы знакомы, но, возможно, есть небольшое взаимодействие, которое мы просто еще не видели, или, может быть, оно притягивается совершенно по-другому. The only thing we know for sure is that there is this matter and it interacts via gravity. L'unica cosa che sappiamo per certo è che c'è questa materia e interagisce tramite la gravità. Единственное, что мы знаем наверняка, это то, что эта материя существует и взаимодействует через гравитацию. Dark matter was actually essential to the formation of structures we see in the lifetime of the universe. La materia oscura era effettivamente essenziale per la formazione delle strutture che vediamo nel corso della vita dell'universo. На самом деле темная материя была необходима для формирования структур, которые мы видим во время существования Вселенной. Now it’s important to say structures we see in the lifetime of the universe. Ora è importante dire che le strutture che vediamo nel corso della vita dell'universo. Теперь важно сказать о структурах, которые мы видим при жизни Вселенной. Even without dark matter, structure would have formed. Anche senza materia oscura, le strutture si sarebbero comunque formate. Даже без темной материи структура сформировалась бы. But the actual size of the galaxies that we see is only possible because dark matter was present. Ma le dimensioni reali delle galassie che vediamo sono possibili solo perché c'era materia oscura. Но реальный размер галактик, которые мы видим, возможен только потому, что в них присутствовала темная материя. Ordinary matter interacts with radiation. La materia ordinaria interagisce con la radiazione. Обычное вещество взаимодействует с излучением. Radiation would have washed away small objects like galaxies. La radiazione avrebbe spazzato via gli oggetti piccoli come le galassie. Радиация смыла бы маленькие объекты вроде галактик. Now I realize galaxies don’t seem small to you, but on the scale of what radiation could wash away they’re actually small. Ora mi rendo conto che le galassie non ti sembrano piccole, ma su scala di ciò che potrebbe essere lavato via dalla radiazione sono effettivamente piccole. Теперь я понимаю, что галактики не кажутся вам маленькими, но в масштабе того, что может смыть радиация, они на самом деле маленькие. So dark matter was essential to forming objects of that size. Quindi la materia oscura era essenziale per la formazione di oggetti di quella dimensione. Таким образом, темная материя была необходима для формирования объектов такого размера. It also was important because it meant that matter came to dominate over radiation sooner in the evolution of the universe because there was a lot more matter. È stata anche importante perché ha significato che la materia ha finito per dominare sulla radiazione più presto nell'evoluzione dell'universo perché c'era molta più materia. Это также было важно, потому что это означало, что в эволюции Вселенной материя стала доминировать над излучением, потому что материи было намного больше. And again matter domination is important for the formation of structure because radiation won’t form structure. E di nuovo, la dominazione della materia è importante per la formazione della struttura perché la radiazione non formerà la struttura. И снова доминирование материи важно для образования структуры, потому что излучение не будет формировать структуру. I mean just think about it. Intendo, pensaci solo. Я имею в виду, просто подумайте об этом. Light’s not clumping into little balls the same way matter would. La luce non si raggruppa in piccole palline allo stesso modo in cui farebbe la materia. Свет не слипается в маленькие шарики, как материя. So both because of its abundance and because it doesn’t interact with light, dark matter was actually essential to the formation of the structure that we see. Quindi sia a causa della sua abbondanza che perché non interagisce con la luce, la materia oscura è stata effettivamente essenziale per la formazione della struttura che vediamo. Таким образом, из-за своего обилия и из-за того, что она не взаимодействует со светом, темная материя фактически была необходима для формирования структуры, которую мы видим.