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First it is necessary to understand how the early universe evolved according to the big bang model.
Initially the universe was extremely small and extremely hot, comprised of energy rather than material. As the universe began to expand, it also began to cool (more space and less energy means less energy per unit of space). As the universe continued to cool, some of that energy began to condense into quarks which later formed protons and neutrons, and electrons (as well as a myriad other particles we need not concern ourselves with).
Eventually (after about 3 minutes) the universe was now at the temperature where nucleosynthesis could occur. Protons and Neutrons fused together to form heavier nuclei, first heavier hydrogen nuclei, then helium, then lithium. By about 20 minutes after the beginning of the universe, the temperature had fallen too much to allow nuclear fusion, and this process stopped.
For approximately the next 400000 years, the universe was a sea of nuclei and electrons, then the temperature finally dropped to the point that nuclei could capture those electrons, forming neutral atoms.
There is, of course, much more to it than this, but this is sufficient for our purposes.
The three most substantial (there are more) pieces of evidence for the big bang are the Hubble expansion, the cosmic microwave background and the relative abundances of lighter elements.
The Hubble expansion is named for the astronomer Edwin Hubble, who was the first to knowingly observe galaxies beyond the Milky Way. Not only did he discover these galaxies, he discovered that they were all moving away from us. This discovery was achieved by examining their spectra. If an object emitting light or sound is moving relative to an observer, that light or sound is observed at different wavelengths than it is emitted. If the emitter and observer are moving towards each other, the observed wavelength decreases (gets shorter). If the emitter and observer are moving away from each other, the observed wavelength increases (gets longer). You can observe this yourself by listening to the change in sound of vehicle's siren as it approaches, passes, and moves away from you.
This phenomenon is known as Doppler shift, named for Christian Doppler. In the case of light, if the observed wavelength increases, then the light has moved toward the red end of the spectrum and is described as "red shift". Conversely, if the observed wavelength decreases, moving towards the blue end of the spectrum, it is described as "blue shift".
However, Hubble's observations of the red shift of galactic spectra were too extreme be explained by mere Doppler shift. It was not simply that the light was red-shifting as it travelled the distance between the galaxies and Hubble's telescope, but that the actual space between them was expanding, creating a greater distance between the galaxies and us, increasing that red-shift.
Since the light from those galaxies had been travelling for billions of years, it follows that over those billions of years the universe has experienced expansion. This was the first observational evidence of the big bang.
The cosmic microwave background, first observed by Arno Penzias and Robert Wilson in 1964, is a sea of photons in the microwave band which fills the entire observable universe. In whichever direction Penzias and Wilson pointed their telescope they observed this phenomenon, which they initially believed to be caused by an equipment malfunction. Further observations measured this radiation as being a black body spectrum (emitted by an opaque body as a feature of its temperature) with a peak wavelength of 1.873 mm.
Since this radiation is observed everywhere, it must have been emitted everywhere; it could not be a local phenomenon. Logically, this requires the entire universe to have at one time been opaque and suddenly become transparent. When this happened, photons would now be able to move freely through space and - like the light Hubble observed from distance galaxies - red shift as the universe expanded.
There is only one event that could have caused this phenomenon; the spontaneous universal recombination of nuclei and electrons into neutral atoms. When this happened, the universe changed from being a soup of ions constantly interacting with photons to being a somewhat less thick soup of neutral atoms which did not. While neutral atoms can absorb photons, because the universe had cooled so much by this point, the energy of the background photons was several orders of magnitude too low to be absorbed, and so those photons continued on their merry way.
The third significant piece of evidence, the abundance of light elements, is a relic of the period of nucleosynthesis. Since we know what reactions can and therefore would have happened and how long those reactions take, and our model predicts how long the universe would have been at the appropriate temperature to allow those reactions, we can predict the relative abundances of everything up to and including lithium-7.
Our observations of the material composition of the Universe almost exactly match those predictions. At the end of primordial nucleosynthesis, by mass, the universe was approximately 75% hydrogen and 25% helium, with other nuclei making up about 0.01%. Since that time the composition has changed slightly due to stellar nucleosynthesis.
It is important to recognise that the big bang model is constantly being refined as more and better observations can be made. However, the model is extremely robust, and since these discoveries there has been no competing theory.
What else can I help you with?
Astronomers use various tools to gather evidence in support of the Big Bang Theory What are two tools used?
Real scientists do not "gather evidence in support of" any theory. The technical term for that kind of thing is "cherry-picking". Real scientists build a theory to explain the evidence that they have already gathered, and then test the theory to see whether it holds water. The easiest, fastest way to make sure that you are regarded as a wingnut by real scientists is to adopt or invent a theory, and then spend your time trying to prove it.
Although Dalton's atomic theory was rejected at first he used his theory to do what that soon resulted in his theory being accepted by scientists?
Instead of just stating his own personal opinions John Dalton cited evidence to support his atomic theory. The giving of evidence - which could be proved or disproved by others - was what soon resulted in his theory being accepted by scientists.
What was the main counterargument against wegeners evidence?
Many scientists dismissed the theory because it flew in the face of conventional wisdom.
How has molecular evidence affected our understanding of modern evolutionary theory?
It largely supports anatomical evidence and provides more detailed information for specific relationships
What scientist believe provides evidence of the big bang theory?
Scientists do not sit in the coffeeshop and dream up a theory and thengo looking for evidence to support it. Scientists make observations andmeasurements of what IS ... the "evidence" you might say ... and then tryto put together a theory to explain what they see.The "Big Bang" theory is the best explanation so far for the observation that allgalaxies in every direction are receding from us at speeds that are proportionalto their distance from us, and for the observation that all of space is filled withan almost uniform level of electromagnetic radiation with a distribution of wavelengthsthat is characteristic of a blackbody at the temperature of 2.7 K, and for theobservation that on the largest scale, the universe consists of roughly 75%hydrogen and 24% helium.
What is the theory that all the scientists provided evidence for the cell theory?
For their own benefits.
Who were the two scientists that brought forth supporting evidence to wegener's theory?
me and your mom
When would scientists need to change a theory?
Scientists had made observations that did not fit exactly with Dalton's theory. Scientists changed the atomic theory to include this new knowledge. While the modern atomic theory is based on Dalton's theory, it is also very different.
What role does DNA evidence play in modern evolutionary theory?
DNA evidence is crucial in modern evolutionary theory as it provides a molecular blueprint of how species are related. By comparing DNA sequences among different organisms, scientists can trace their evolutionary history, identify genetic variations, and infer how species have evolved over time. This evidence helps support the idea of common ancestry and provides insights into the mechanisms of evolution.
Why were most scientists disagreeing with Alfred Wegeners continental drift theory?
There was no evidence to prove it
If new evidence does not support a scientific theory scientists will most likely?
if new evidence doesn't support a scientific theory, scientists will either revise the theory to accommodate the new evidence or discard the theory altogether in favor of a more accurate explanation. This process is crucial for the progress of science as it ensures that theories are continuously tested and refined to reflect our understanding of the natural world.
A physical representation of an atom is an example of a scientific?
If new evidence does not support a scientific theory, scientists will most likely
What provides the most evidence for the theory of plates tectonic?
The spreading of the sea floor.
Why was wegener's theory not accepted by all scientists?
Wegner's theory was not accept because he didn't have much evidence to support his theory with and scientists thought that there might have been a land bridge between the continents. Another reason to why his theory was rejected was that he was a foreigner, by that; the scientists didn't really take him seriously.
Do you think it's wise for scientists not to accept a theory immediately even if the theory has a lot of evidence to support it?
Each scientists have there own opinion. Some accept theories and some have to have facts.
Why Scientists are most likely to change a scientific theory if?
Scientists are most likely to change a scientific theory if new evidence contradicts the existing theory, if the theory fails to explain new observations accurately, or if a more comprehensive theory emerges that better explains the phenomena in question. Scientific theories are constantly refined and updated based on rigorous testing and evidence.
What do you think scientists would do if they found evidence that did not support the Big Bang theory?
Discard it all.
