When space and time began

In summary, we don't know exactly what space and time were like before the big bang. Some theories propose a contracting universe with a bounce, but more research is needed to test and confirm these ideas. One particular proposal, the "LambdaCDM bounce," suggests that the laws of physics can help explain the characteristics of the universe we observe today. However, further observations and experiments are necessary to verify this scenario.
  • #1
Emre Deveci
what was space and time before the big bang thank you
 
Astronomy news on Phys.org
  • #3
Emre Deveci said:
what was space and time before the big bang thank you
There are some reasonable guesses and they have to be tested to see which fits new data better.
Here is one proposal which I like. It seems to fit the existing data, collected so far.
Google "LambdaCDM bounce"
The title refers to the standard cosmic model "Lambda Cold Dark Matter" which is the main model currently in use. The authors explore in some detail what results if you run that model in a collapse according to knows physical laws, and then allow it to bounce according to conjectured quantum effects that have been studied quite a bit but not yet proven.
http://arxiv.org/abs/1412.2914
A ΛCDM bounce scenario
Yi-Fu Cai, Edward Wilson-Ewing
(Submitted on 9 Dec 2014)
We study a contracting universe composed of cold dark matter and radiation, and with a positive cosmological constant. As is well known from standard cosmological perturbation theory, under the assumption of initial quantum vacuum fluctuations the Fourier modes of the comoving curvature perturbation that exit the (sound) Hubble radius in such a contracting universe at a time of matter-domination will be nearly scale-invariant. Furthermore, the modes that exit the (sound) Hubble radius when the effective equation of state is slightly negative due to the cosmological constant will have a slight red tilt, in agreement with observations. We assume that loop quantum cosmology captures the correct high-curvature dynamics of the space-time, and this ensures that the big-bang singularity is resolved and is replaced by a bounce. We calculate the evolution of the perturbations through the bounce and find that they remain nearly scale-invariant. We also show that the amplitude of the scalar perturbations in this cosmology depends on a combination of the sound speed of cold dark matter, the Hubble rate in the contracting branch at the time of equality of the energy densities of cold dark matter and radiation, and the curvature scale that the loop quantum cosmology bounce occurs at. Importantly, as this scenario predicts a positive running of the scalar index, observations can potentially differentiate between it and inflationary models. Finally, for a small sound speed of cold dark matter, this scenario predicts a small tensor-to-scalar ratio.
14 pages, 8 figures.
 

1. What is the Big Bang theory and how does it relate to the beginning of space and time?

The Big Bang theory is a scientific explanation for the beginning of our universe. It suggests that about 13.8 billion years ago, all matter and energy in the universe was contained in a single, infinitely dense point known as a singularity. This singularity then expanded rapidly, creating the universe and the laws of physics as we know them. This event is what we refer to as the beginning of both space and time.

2. Is there any evidence to support the idea of a beginning to space and time?

Yes, there is a significant amount of evidence that supports the idea of a beginning to space and time. This includes observations of the cosmic microwave background radiation, the expansion of the universe, and the abundance of light elements in the universe. Additionally, the laws of thermodynamics and general relativity also support the concept of a beginning to the universe.

3. What is the role of dark energy and dark matter in the beginning of space and time?

Dark energy and dark matter are two mysterious components that make up a large portion of our universe. While their exact nature is still not fully understood, they are believed to have played a crucial role in the beginning of space and time. Dark energy is thought to be responsible for the accelerated expansion of the universe, while dark matter is believed to have helped shape the large-scale structure of the universe.

4. Can we ever truly know what happened at the beginning of space and time?

While we may never have a complete understanding of the beginning of space and time, scientists continue to study and gather evidence to piece together the puzzle. As technology and our understanding of the universe improve, we may be able to gain more insights into this mysterious event. However, some aspects may always remain a mystery.

5. How does our understanding of the beginning of space and time impact our current understanding of the universe?

Our understanding of the beginning of space and time has greatly influenced our current understanding of the universe. It has allowed us to develop theories and models that explain the formation and evolution of the universe. It has also led to discoveries such as the expansion of the universe, the existence of dark energy and dark matter, and the concept of space-time. Our understanding of the beginning of space and time continues to shape our understanding of the universe and our place within it.

Similar threads

Replies
4
Views
2K
  • Astronomy and Astrophysics
Replies
7
Views
1K
  • Astronomy and Astrophysics
Replies
24
Views
1K
  • Astronomy and Astrophysics
Replies
3
Views
286
  • Astronomy and Astrophysics
2
Replies
49
Views
7K
  • Astronomy and Astrophysics
Replies
1
Views
8K
  • Astronomy and Astrophysics
Replies
17
Views
2K
  • Astronomy and Astrophysics
Replies
2
Views
1K
Replies
32
Views
3K
  • Astronomy and Astrophysics
Replies
24
Views
3K
Back
Top