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Questions tagged [big-bang-theory]

Questions regarding the currently prevalent cosmological model for the origin of the universe.

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Expansion of space - how do we end up with an unobservable region?

I've just been answering a question on this issue,in physics SE,and realised that my answer conceals a point I don't myself understand. I understand that The expansion of metric isn't affected by ...
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How much helium has been created since the Big Bang?

When I try to find figures for the amount of helium today and just after the Big Bang, I get similar figures. I was expecting that all of the stars since then would have created more helium. Is the ...
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How did the Big Bang occured if before that there was no time? [duplicate]

I am thinking, that if the Big Bang created time, it implies that before the Big Bang there was no time (correct me if I am wrong). My question is that, if there was no time before the Big Bang, how ...
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103 views

How can you verify the theories presented on TV shows like “How the Universe Works” is current and/or valid? [closed]

There are many TV shows such as "How the Universe Works" that explain theories about the origin of the universe such as the Big-Bang Theory. What resources can I access to verify the scientific ...
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How does science knows what is the early universe?

I've read about Hubble seeing the brightest quasar in the early universe. Question is, how does science knows what is early and what is late? Please correct me if I'm wondering, but after the big ...
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122 views

Why more matter still left after collision with anti-matter?

Question implies all, why is that? Why we exist even after equally creation of matter and anti-matter, any possible exception?
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Is there a theory about a collision between a shrinking universe and a new expanding universe?

I recently read a post on a discussion board about the creation of our current universe that stated, and I quote: [T]he shrinkage activity of the old universe and the new Big Bang expansion ...
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How could time only have started with the Big Bang?

I understand that before the Big Bang time (as well as dimensions) didn't exist. But how could this be? If there was no time then nothing could change, and so time itself couldn't come into existence.
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Is it possible that the Universe is expanding due to additional Big Bang events?

Is it theoretically possible that the Universe is expanding due to additional Big Bang events that have occurred at the same location that the original Big Bang occurred at? Perhaps there has been an ...
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How thick is the cosmic microwave background, including the part we cannot see within the observable universe?

What I want to know is how thick the observable universe is from the point of the cosmic microwave background and beyond. It appears the thickness of the cosmic microwave background itself (the part ...
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If the Higgs field only formed after the Big Bang, how was hydrogen formed?

These two statements seem to conflict, but since we're here they can't: Electrically charged particles cannot be massless. Hydrogen was created at the moment of the Big Bang. However, the Higgs ...
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How did space start?

How did this 'black fabric' that we call space start? How was it made? How was the initial singularity formed? How did the first atom come into existence? If it all started from a tiny particle that ...
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440 views

What created the big bang's singularity?

I have heard theories for the big bang like: of another universe existing before the Big Bang, or an unstable white hole that blew up, or our universe detaching from our mother universe, or our ...
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Fundamental axioms in LCDM

What are the axioms (if any) behind the LCDM model of cosmology? NB: axioms, not postulates (e.g., inflation)
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Just after the Big Bang, was the space, in its entirety, filled with Hot gas?

After the Big bang occurred, was the space filled with hot gas totally? If there's any problem in my question please inform me. Thanks!
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calculation of characteristic expansion time of the universe

Hubble's constant is estimated at 15km/s at a distance of million light years, without considering effects of mutual gravity, relativity, etc. I am trying to calculate the characteristic expansion ...
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Location of Big Bang [duplicate]

Can I point to somewhere in the sky where the Big Bang happened? A pathway so to speak on where we (and our progenitor elements) came from?
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Singularity at the time of origins

According to the big Bang Theory, the universe have started from a point and it describes how the universe expanded from a very high-density and high-temperature state.The initial singularity was a ...
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Why Helium could be produced in first minutes of big bang but not heavier elements

At what extent could be sure that no heavier elements than helium could be produced, if we know that matter in universe today is about 25% composed on helium, why could be so sure that the kind of ...
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BIg Bang Happened everywhere

According to the Friedmann equations big bang happened everywhere, but if we account for inflation theory, big bang did not happened everywhere. How ? Anyone please explain. Please see the video for ...
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Is it fruitful to search for a correlation between rates of in-falling matter in black holes and the expansion rate of our universe? [duplicate]

To my understanding, white holes are hypothetical objects that are time-reversed black holes; black holes gravitationally "suck in" matter whereas white holes "spit" matter back out. As such, I think ...
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411 views

How could the universe be a few light years across just 1 second after the big bang?

I was skimming through Neil deGrasse Tyson's book Astrophysics for People in a Hurry when I noticed he says something curious on page 26: "By now, one second of time has passed [since the big bang]. ...
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Was the whole Universe close to Big Bang very small, or just very dense?

I am sorry this question is probably silly for professional astronomers, of which I am not one. I often hear at lectures that immediately after the Big Bang, the universe was small, say, the size of ...
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How the observed deuterium abundance constrains big bang nucleosynthesis?

I know deuterium can be used as a good tracer to constrain the big bang nucleosynthesis. But can anyone tell me the in details how this is actually done?
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How does inflation justify the nonexistence of magnetic monopoles?

It is said that inflation justifies that magnetic monopoles don't exist. Can anyone explain how inflation theory explains the non existence of magnetic monopoles?
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422 views

What is beyond the observable universe? [closed]

What is beyond the edge of the observable universe? Scientists say that the Big Bang is the cause of all creation in the known universe, but it would seem the bang must have happened in the center of ...
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How can the universe be expanding faster than speed of light? [duplicate]

So the story goes like this: A long time ago, 13.799±0.021 billion years to be exact, something happened. It was a big bang, loud explosion and universe came to existence. It grew and grew, and now ...
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Why do we we even exist? [closed]

It came to my mind one day that why does this universe even exist and why do we even exist and like we are enclosed in the so called atmosphere and a floating rock in space called the Earth, so is ...
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Is there a way to know how the magnetic field was at the very beginning of our universe?

I recently read that Gamma-ray bursts are catastrophic events, related to the explosion of massive stars 50 times the size of our sun. If you ranked all the explosions in the universe based on ...
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Was Milky Way formed after Sagittarius A Explosion?

Is it possible that most galaxies (and our galaxy) were formed from leftovers of supernova explosions? In order to have a black hole 4,000,000 x solar mass the initial mass of the star should have ...
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1answer
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Why did the big bang produce a low entropy universe?

In order for the universe to be as it is, containing stars and galaxies, it is a requirement that the early universe was at a relatively low entropy state. Why did the big bang produce this low ...
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1answer
269 views

Does a White hole lies behind a Black hole?

While reading about a White holes, I stumbled upon a question "Where does the matter emitted by a White hole come from?" There seems to be 2 possible candidates: It was the matter engulfed by a ...
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2answers
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How does the earth not continue accelerating? [closed]

I'm not scientist at all so the answer might be obvious but I was pondering about the big bang. I started wondering how is it possible that the earth had to accelerate at some point in history to the ...
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104 views

From where so much of energy would have arrived as was required for such a giant universe to have come into existence? [closed]

If we convert the mass of all the stars and all the planets which must be weighing trillions and trillions of tonnes by the equation E = m.c^2 it gets converted into an unimaginable amount of energy. ...
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Could the big bang have created super massive black holes?

I understand that space was compressed to a single point and that during the big bang all points within that expanded away from each other at phenomenal speeds. I also have heard that during this the ...
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Amount of energy of the Big Bang

What is the currently accepted estimated range of the amount of energy of the Big Bang event? In joules at some estimated size, so a temperature may be calculated. For context, I wonder if the ...
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137 views

Collision of Galaxies

According to the big bang theory, the universe started from a small intial point and is essentially expanding. However, my question is that if the universe is expanding how is it possible for galactic ...
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315 views

Which constellation would appear to revolve around Denab,Vega or Thuban when axis of the earth would point toward them?

We have been calling the star by looking at which we can make out the direction of the North Pole the North Star. This was the only method at the disposal of the sailors during the days when they did ...
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270 views

What existed before the big bang [closed]

What existed before the big bang? What all thing are there inside big bang object ?.
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What made cooler temperatures suitable for atom formation?

I have read in relation to Big Bang theory that after 300,000 years of big Bang temperature was reduced to 4500 Kelvin and this gave rise to Atomic matter.So,my question is why reduction in ...
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How Good Are the Upper Limits on Heavy Elements?

There are between 90 and 254 stable nuclei all the way up to element number 82. In discussions and graphs about big bang nucleosynthesis nothing above lithium is even mentioned. It's a pretty safe bet ...
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Did uncertainty principle triggered big bang? [closed]

So i want to know why world changed from the empty state ( no materials, energy and ...) from to the it's staring state in the big bang shape? based of this answer's to this question: big-bang-thoery-...
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(Thought experiment) if we put a huge mirror into space, could we see back in time to the big bang? [duplicate]

This is an addition to this question which is closed: By putting a mirror in space, would we be able to see into the past? Imagine there is a supernova a hundred years ago. Lots of people see it but ...
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Redshift quantization

A full disclosure to begin with: I'm a PhD student in mathematics and while I understand most of standard cosmological-astronomical terms and I've followed a one semester course on cosmology, I don't ...
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Why didn't the Big Bang produce heavier elements?

Shortly after the Big Bang, temperatures cooled from the Planck temperature. Once temperatures lowered to 116 gigakelvins, nucleosynthesis took place and helium, lithium and trace amounts of other ...
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How could visible light be in pitch-black? Can it be? [closed]

How could visible light be in pitch-black? Can it be?
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On gravitational wave radiation and arrangement of galaxies post- big bang

Orbits of planets and stars decay due to gravitational wave radiation. An elliptical orbit would become more circular with time. This is especially observed well in binary systems. Taking the example ...
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Cosmic microwave background radiation: why did it take so long to get here?

I understand that the universe after the big bang was a super dense cloud of elementary particles, and because of this high density was "not transparent" to light. Then, roughly 400.000 years (380....
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1answer
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What could be past the particle horizon?

Forgive any kind of "dumb" question I may ask as this is a new interest of mine and I know it's purely hypothetical. If one were able to surpass light speed and the expansion of space to go beyond ...
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How can we use hypervelocity stars to determine the origins of the Universe?

I was reading this article finding evidence of Universe's origin, which describes that in 1 trillion years we may lose the ability to determine how the universe was created. The answer seems to be ...