Posted on 04/24/2018 10:57:04 AM PDT by ETL
At 13.8 billion years ago, our entire observable universe was the size of a peach and had a temperature of over a trillion degrees.
That's a pretty simple, but very bold statement to make, and it's not a statement that's made lightly or easily. Indeed, even a hundred years ago, it would've sounded downright preposterous, but here we are, saying it like it's no big deal. But as with anything in science, simple statements like this are built from mountains of multiple independent lines of evidence that all point toward the same conclusion — in this case, the Big Bang, our model of the history of our universe.
But, as they say, don't take my word for it. Here are five pieces of evidence for the Big Bang:
#1: The night sky is dark
Imagine for a moment that we lived in a perfectly infinite universe, both in time and space. The glittering collections of stars go on forever in every direction, and the universe simply always has been and always will be. That would mean wherever you looked in the sky — just pick a random direction and stare — you'd be bound to find a star out there, somewhere, at some distance. That's the inevitable result of an infinite universe.
And if that same universe has been around forever, then there's been plenty of time for light from that star, crawling through the cosmos at a relatively sluggish speed of c, to reach your eyeballs. Even the presence of any intervening dust wouldn't diminish the accumulated light from an infinity of stars spread out over an infinitely large cosmos.
Ergo, the sky should be ablaze with the combined light of a multitude of stars. Instead, it's mostly darkness. Emptiness. Void. Blackness. You know, space.
The German physicist Heinrich Olbers may not have been the first person to note this apparent paradox, but his name stuck to the idea: It's known as Olbers' paradox. The simple resolution? Either the universe is not infinite in size or it's not infinite in time. Or maybe it's neither.
#2: Quasars exist
As soon as researchers developed sensitive radio telescopes, in the 1950s and '60s, they noticed weirdly loud radio sources in the sky. Through significant astronomical sleuthing, the scientists determined that these quasi-stellar radio sources, or "quasars," were very distant but uncommonly bright, active galaxies.
What's most important for this discussion is the"very distant" part of that conclusion.
Because light takes time to travel from one place to another, we don't see stars and galaxies as they are now, but as they were thousands, millions or billions of years ago. That means that looking deeper into the universe is also looking deeper into the past. We see a lot of quasars in the distant cosmos, which means these objects were very common billions of years ago. But there are hardly any quasars in our local, up-to-date neighborhood. And they’re common enough in the far-away (that is, young) universe that we should see a lot more in our vicinity.
The simple conclusion: The universe was different in its past than it is today.
#3: It's getting bigger
We live in an expanding universe. On average, galaxies are getting farther away from all other galaxies. Sure, some small local collisions happen from leftover gravitational interactions, like how the Milky Way is going to collide with Andromeda in a few billion years. But at large scales, this simple, expansionary relationship holds true. This is what astronomer Edwin Hubble discovered in the early 20th century, soon after finding that "galaxies" were actually a thing.
In an expanding universe, the rules are simple. Every galaxy is receding from (almost) every other galaxy. Light from distant galaxies will get redshifted — the wavelengths of light they're releasing will get longer, and thus redder, from the perspective of other galaxies. You might be tempted to think that this is due to the motion of individual galaxies speeding around the universe, but the math doesn’t add up.
The amount of redshift for a specific galaxy is related to how far away it is. Closer galaxies will get a certain amount of redshifting. A galaxy twice as far away will get twice that redshift. Four times the distance? That's right, four times the redshift. To explain this with just galaxies zipping around, there has to be a really odd conspiracy where all the galactic citizens of the universe agree to move in this very specific pattern.
Instead, there's a far simpler explanation: The motion of galaxies is due to the stretching of space between those galaxies.
We live in a dynamic, evolving universe. It was smaller in the past and will be bigger in the future.
#4: The relic radiation
Let's play a game. Assume the universe was smaller in the past. That means it would have been both denser and hotter, right? Right — all the content of the cosmos would've been bundled up in a smaller space, and higher densities mean higher temperatures.
At some point, when the universe was, say, a million times smaller than it is now, everything would have been so smashed together that it would be a plasma. In that state, electrons would be unbound from their nuclear hosts and free to swim, all of that matter bathed in intense, high-energy radiation.
But as that infant universe expanded, it would've cooled to a point where, suddenly, electrons could settle comfortably around nuclei, making the first complete atoms of hydrogen and helium. At that moment, the crazy-intense radiation would roam unhindered through the newly thin and transparent universe. And as that universe expanded, light that started out literally white-hot would've cooled, cooled, cooled to a bare few degrees above absolute zero, putting the wavelengths firmly in the microwave range.
#5: It's elemental
Push the clock back even further than the formation of the cosmic microwave background, and at some point, things are so intense, so crazy that not even protons and neutrons exist. It's just a soup of their fundamental parts, the quarks and gluons. But again, as the universe expanded and cooled from the frenetic first few minutes of its existence, the lightest nuclei, like hydrogen and helium, congealed and formed.
We have a pretty decent handle on nuclear physics nowadays, and we can use that knowledge to predict the relative amount of the lightest elements in our universe. The prediction: That congealing soup should have spawned roughly three-fourths hydrogen, one-fourth helium and a smattering of "other."
The challenge then goes to the astronomers, and what do they find? A universe composed of, roughly, three-fourths hydrogen, one-fourth helium and a smaller percentage of "other." Bingo.
There's more evidence, too, of course. But this is just the starting point for our modern Big Bang picture of the cosmos. Multiple independent lines of evidence all point to the same conclusion: Our universe is around 13.8 billion years old, and at one time, it was the size of a peach and had a temperature of over a trillion degrees.
Too much politically “settled science” based on unsubstantiated and unquestioned assumptions blocks alternative explanations.
Observations contradict galaxy size and surface brightness predictions that are based on the expanding universe hypothesis
Eric J Lerner
“An overall comparison of cosmological models requires examining all available data-sets, but for this data-set there is a clear contradiction of predictions based on an expanding universe hypothesis.”
Space/Time itself doesn't need obey the laws of relativity. Space expansion can and actually does proceed at a rate faster than light. According to the Inflationary Big Bang model, the very early universe expanded at a rate many times faster than light. Then it soon after slowed down. Then, some time later, it began to accelerate again. However, this second burst of acceleration was much much slower than that of the inflationary period. In addition, there are supposedly galaxies outside the "observable universe" being carried away from us at speeds faster than light. The further a galaxy is, the faster it recedes, due to universal expansion. And remote galaxies can and do apparently recede at rates greater than light.
Big bang, big shmang. The theory doesn’t explain everything, especially where the fuzzy peach came from!
Exactly what I was thinking? Where was this peach to begin with?-)
In 1980, to explain the conditions observed in the universe, astrophysicist Alan Guth proposed cosmic inflation. The term inflation refers to the explosively rapid expansion of space-time that occurred a tiny fraction of a second after the Big Bang. In another tiny fraction of a second, inflation slowed to a more leisurely expansion that continues to this day and is accelerating.
Major Discovery: 'Smoking Gun' for Universe's Incredible Big Bang Expansion Found
The earliest radiation astronomers can detect is called the Cosmic Microwave Background, or CMB. This is radiation that was released about 380,000 years after the Big Bang.
And all of this was suggested by a Jewish rabbi, Nachmanides, about 900 years ago based on his study of the Bible.
Lol!
So, as our universe expands it is colliding with other universes?
I support the Mobius-strip-shaped universe theory...
Well, if the universe did begin as a singularity, a region of space many times tinier than a single atom, I suppose it had to grow to the size of a peach somewhere along the way.
Lemmings also decide that stampeding over a cliff is the thing to do by multiple small decision all pointing the same way...
To Lemmings, suicide is settled science.
Inflation (cosmology)
Around 1930, Edwin Hubble discovered that light from remote galaxies was redshifted; the more remote, the more shifted. This was quickly interpreted as meaning galaxies were receding from earth.
If earth is not in some special, privileged, central position in the universe, then it would mean all galaxies are moving apart, and the further away, the faster they are moving away. It is now understood that the universe is expanding, carrying the galaxies with it, and causing this observation.
Many other observations agree, and also lead to the same conclusion. However, for many years it was not clear why or how the universe might be expanding, or what it might signify.
Based on a huge amount of experimental observation and theoretical work, it is now believed that the reason for the observation is that space itself is expanding, and that it expanded very rapidly within the first fraction of a second after the Big Bang.
This kind of expansion is known as a “metric” expansion. In the terminology of mathematics and physics, a “metric” is a measure of distance that satisfies a specific list of properties, and the term implies that the sense of distance within the universe is itself changing, although at this time it is far too small an effect to see on less than an intergalactic scale.
The modern explanation for the metric expansion of space was proposed by physicist Alan Guth in 1979, while investigating the problem of why no magnetic monopoles are seen today. He found that if the universe contained a field in a positive-energy false vacuum state, then according to general relativity it would generate an exponential expansion of space.
It was very quickly realized that such an expansion would resolve many other long-standing problems. These problems arise from the observation that to look like it does today, the Universe would have to have started from very finely tuned, or “special” initial conditions at the Big Bang. Inflation theory largely resolves these problems as well, thus making a universe like ours much more likely in the context of Big Bang theory.
No physical field has yet been discovered that is responsible for this inflation. However such a field would be scalar and the first scalar field proven to exist was only discovered in 2012 - 2013 and is still being researched. So it is not seen as problematic that a field responsible for cosmic inflation and the metric expansion of space has not yet been discovered.
The proposed field and its quanta (the subatomic particles related to it) have been named the inflaton. If this field did not exist, scientists would have to propose a different explanation for all the observations that strongly suggest a metric expansion of space has occurred, and is still occurring (much more slowly) today.
https://en.wikipedia.org/wiki/Inflation_(cosmology)#Space_expands
Thanks.
Your question is not meaningful. You're thinking in 3, maybe 4 (space+time) dimensions.
It's like asksing, "Who made God?" That's another question that assumes 4 dimensions.
But scientist don't believe in “faith.”
bkmk
Georgia!
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