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WATCH: Questions About the Big Bang

Astrophysics offers profound insights into the Big Bang, the birth of our Universe. Through scientific observations and mathematics, we can explore the Universe's evolution, its continuous expansion, and the lingering light from the Big Bang. Yet, questions remain about the Universe's inception and whether it sprang from nothing or a pre-existing state. Here, Janna Levin discusses what we know about the Big Bang, and ponders the profound questions that remain. Created by Big History Project.

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  • duskpin seed style avatar for user Amanda  Stanley
    If the universe is always expanding, what is the cause of that?
    (4 votes)
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  • piceratops ultimate style avatar for user J J
    How did the Big Bang form from nothing?
    (4 votes)
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  • leaf orange style avatar for user Jon Donym
    Are there any compelling counter-theories besides the Big Bang theory ?
    (6 votes)
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  • aqualine ultimate style avatar for user Aoi
    Is the big bang really true or is it just a theory?
    (2 votes)
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    • starky sapling style avatar for user Justin Helps
      The big bang theory is the best explanation we have for a picture of the history of our universe which is consistent with our observations. It and the theory of evolution are theories, true, but they are supported by a great deal of evidence, just like the theory of gravity, electromagnetic theory, and many others.

      Any statement made by a scientist has some level of uncertainty associated with it. However, as more and more experiments are done and reproduced with consistent results, the doubt surrounding an idea fades away. Being truly objective, we can never claim absolute certainty about anything, but at a certain point, we become convinced. The big bang theory is at this stage for those who have studied physics. There are still many unanswered questions, some of which are mentioned in this video, but that's what keeps things interesting!

      Science depends on physical measurements, and it answers questions about the physical world. Because of this, our understanding of the big bang doesn't need to conflict with spiritual ideas. Since we do not have a way of making objective spiritual measurements, science cannot make claims about spiritual questions. These questions are left in the somewhat overlapping realms of philosophy and theology. Science is fun! And it's a shame that sometimes people are steered away from it because of philosophical misconceptions. They're missing out. :)
      (7 votes)
  • blobby green style avatar for user Judith joseph
    Why does Big Bang theory exist ?
    (3 votes)
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  • sneak peak blue style avatar for user Kaze Haibara 📴
    if the universe formed 13.8 billion years ago, and started out really hot but then cooled, what will the universe look like in another 13.8 billion years?
    (1 vote)
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  • aqualine sapling style avatar for user Michel Ostiguy
    When they say that the Big Bang happened 13.8 billion years ago, is that assertion based on the current rate of expansion of our universe ? What if the current rate of expansion was different in the past ? If it was, how can we tell ?
    (1 vote)
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  • piceratops seedling style avatar for user Atharva.nigoskar
    I have a question that why did the tiny mass of energy in which the whole universe was stored explode ? I mean that if that mass was infinitely dense and it had enough gravity to overcome the forces of repulsion between the particles then why did it inflate ? We don't see such things happen in black holes but that might be because we can't see them at all !
    (1 vote)
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    • blobby green style avatar for user Daniel Y
      Maybe it is something like quantum tunneling, and the matter making up that universe now is only a tiny fraction of the amount in the tiny dot before the big bang, because anti-matter and matter annialated to leave befhind that matter that forms the whole universe now.
      (1 vote)
  • starky ultimate style avatar for user Thomas
    do we know the properties of the big bang
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Video transcript

I think the real reason I got interested in astrophysics was to understand the Big Bang. That was the first really profound question that I realized was answerable, at least in principle, through mathematics and through scientific observations and that kind of discovery, that you could sit there with your pen and paper and then bring it to an observer and say, "These are the list of possibilities that we've predicted for the Universe." And can you discriminate what's true from what's not true by actually looking at the cosmos? And today, we live in a time where cosmology, the study of the early Universe, is very precise in terms of what we know about the very early Universe, the first few minutes after the Universe began and what we know about the evolution of the Universe since. And we're still surrounded in this bath of light that's left over from the Big Bang. It's cooler now because it's been... the Universe has been expanding in the 14 billion years since and it's cooled down but it's there. It's everywhere around us. And we see galaxies are all moving away from other galaxies, so it's as though the space between them is stretching. And that's evidence that the Universe continues to expand after the initial Big Bang. And yet, there are really profound questions that we can't answer that I study, like, "What happened in the very first moment?" And, "Was there really nothing and then instantaneously something?" And, "When did that happen and why did that happen? Why did the Universe suddenly burst into existence?" Or, "Is that story just wrong? Are we just confused about that? Is it really the case that the Universe existed?" It just looked very different and a small patch of space itself began to expand and grow and evolve and that that's what we mean by the Big Bang, this moment when a little tiny piece of a greater megaverse or multiverse began to expand into our Universe, our observable history. And so, these are deep questions that we're still wrestling with and we don't yet know how to ask for evidence as to which one of these possibilities is true and I just hope that sometime in my, you know, scientific career in my lifetime, that we'll figure out a way to discriminate between these possibilities by actually looking at the Universe that's out there.