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  • Dark matter has been the go-to explanation for many scientists as to why there seems to be more gravitational influence in our universe than the gravity measured by visible matter.


  • But what if there's no dark matter at all?


  • The idea of dark matter was first proposed by Henri Poincaré in 1906.

    昂利.龐加萊於 1906 年首度提出暗物質的概念。

  • Then in 1933, evidence of dark matter was found by Fritz Zwicky while studying galaxy clusters...

    接著 1933 年,弗里茨.茲威基在研究星系團時,發現暗物質的證據。

  • And then more evidence of dark matter was found based on the calculations of rotational velocities in galaxies made by Vera Rubin in 1978.

    根據薇拉.魯賓於 1978 年計算出的星系自轉速度,又發現更多暗物質的證據。

  • Our universe is made up of less than 5% of visible matter---like stars, planets, galaxies you, me, everything we can see.

    我們的宇宙由不到 5% 的可見物質構成 —— 像是:恆星、行星、星系、你、我,以及看到的每樣東西。

  • Everything else, is stuff we can't see which we call dark matter.


  • And scientists think 95% of the matter in our universe is dark matter.

    科學家認為,我們宇宙 95% 的物質都是暗物質。

  • Right now, Dark Matter is used to explain a few pesky things in astrophysics.


  • Like


  • Why hot galaxy clusters don't blow themselves apart.


  • Why stars don't get flung out into space because of galaxy rotation.


  • And also, the temperature fluctuations of the CMB -- or cosmic microwave background radiation.

    以及宇宙微波背景 (cosmic microwave background radiation) 的溫度波動。

  • That said, there are theories that are trying to explain all this without assuming it's dark matte. These are: scale invariance and emergent gravity.


  • The empty space scale invariance theory says that properties of empty space should not change based on scale.


  • An astrophysicist looked back at the early equations of Einstein, and Newtonian Dynamics, and modified an acceleration term in Newton's law.


  • With this change, the law could explain a new force.


  • This force can explain things that were explained by dark mattersuch as holding a galaxy together that's spinning at high rotational velocities.

    這種力可以說明由暗物質所解釋的事物... 像是將整個星系連在一起,就會以高轉速旋轉。

  • The only problem is, on Earth, this force can be up to billion times smaller than the force of gravity--making it difficult to measure.

    唯一的問題是,這種力在地球上可能比重力小十億倍 —— 使其難以測量。

  • It doesn't explain gravitational lensing, --which is the bending of light-- or the temperature fluctuations of the CMB.

    這解釋不了重力透鏡效應 —— 即光的彎曲,或宇宙微波背景的溫度波動。

  • The craziest, but to me the most interesting, is the holographic principle, which says that


  • our entire universe can be described on an imaginary sphere that surrounds ordinary matter.


  • It lead to the theory of emergent gravity.


  • That is the idea that gravity arises (or emerges) through the presence of matter.

    這就是重力透過物質存在而產生 (或出現) 的想法。

  • This suggests this happens the same way temperature arises from the movement microscopic particles of matter.


  • So, if gravity is formed this way then it can be used to explain gravitational phenomena again!


  • Because something is keeping galaxies gravitationally bound.


  • It's possible that the force created in the emergent gravity theory does this!


  • But it still doesn't explain the CMB temperatures...


  • Scientists are still developing theories, like these, so they can explain things like the reason our universe hasn't completely blown apart because of invisible matter.


  • And they think it might be because of a gravitational field that developed through the movement of visible matter in our universe.


  • It's all very complicated, and yet, epic.


  • For the moment, arguments for dark matter still stand tall above many of these other theories, but hey, maybe not forever.


  • Hey peeps, take a sec to subscribe for more videos.


  • Plus, check out Trace's video about a new form of matter excitonium!

    此外,來看看 Trace 的影片,關於一種叫「excitonium」的新物質

  • And one last fun fact: the holographic principle says we've always looked at life as 3 dimensions,


  • but if we looked at it as 2 dimensions then MAYBE the universe is just a holographic projection of ourselves.


  • Thanks for watching!


Dark matter has been the go-to explanation for many scientists as to why there seems to be more gravitational influence in our universe than the gravity measured by visible matter.



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