Why yall hatin' on physical cosmology?

[Free Soviets]

i got your billions and billions right here, bub

[Drachmar]

I have to admit that's totally above my head.

Essentially, I would believe that if the universe is accelerating faster than it did after the initial expansion, that some sort of bubble effect would occur. In other words, we would see a greater expansion closer to the earth, than was measured closer to the edge of the universe.

We're not accellerating faster than the extremely early universe.

It goes like this (roughly):

Extremely early = inflationary universe, electroweak era, GUT era, etc. expansion was super rapid here

Radiation dominated era: The dark energy density fell off quite a bit after the initial inflation, leading to an immense release of radiation. At this time the universe expanded like the square root of time.

Matter dominated era: Some of the radiation condensed into matter, a lot of the radiation lost its energy due to the expansion of space stretching out the wavelengths of light. (Remember that the energy of light is proportional to the inverse of its wavelength.) At this time, the majority of the energy in the universe was not light, but matter. At this time the universe expanded like the cube root of time squared.

Dark dominated era: Dark energy density is constant, but matter density isn't. As space expands more and more, the density of matter decreases, but the density of dark energy stays the same. This means that the amount of dark energy eventually overtakes the amount of matter energy. At this time, the universe expands exponentially.

Much better description, thanks!

Yes, I was aware that acceleration during the initial expansion of the universe was much much faster. That's why I said after the initial expansion of the big bang. I was hoping you'd catch that.

[Drachmar]

i got your billions and billions right here, bub

You are now taxed at a 90% rate. Your wealth will be redistributed to the poor, huddled masses.

[Errinundera]

If God is suppose to be the one creating and destroying worlds and star systems then why are the black holes (that are at the center of every galaxy) doing it? God is much bigger than trivial things like one universe's little ole big bang.

I guess that means that at the centre of god is a truly gargantuan black hole.

[Drachmar]

If God is suppose to be the one creating and destroying worlds and star systems then why are the black holes (that are at the center of every galaxy) doing it? God is much bigger than trivial things like one universe's little ole big bang.

I guess that means that at the centre of god is a truly gargantuan black hole.

God really sucks.

[UnhealthyTruthseeker]

God really sucks.

My one professor would, at this point, rant about how there's no such thing as a suction force in physics.

[Drachmar]

God really sucks.

My one professor would, at this point, rant about how there's no such thing as a suction force in physics.

Sounds like he left his sense of humor in the departmental office. He should go back and try to find that.

Although I've noticed most professors have quite a distorted sense of humor.

[Allbeama]

Still no proponents of the "God snapped his fingers" theory?

[Infactum]

I have to admit that's totally above my head.

Essentially, I would believe that if the universe is accelerating faster than it did after the initial expansion, that some sort of bubble effect would occur. In other words, we would see a greater expansion closer to the earth, than was measured closer to the edge of the universe.

We're not accellerating faster than the extremely early universe.

It goes like this (roughly):

Extremely early = inflationary universe, electroweak era, GUT era, etc. expansion was super rapid here

Radiation dominated era: The dark energy density fell off quite a bit after the initial inflation, leading to an immense release of radiation. At this time the universe expanded like the square root of time.

Matter dominated era: Some of the radiation condensed into matter, a lot of the radiation lost its energy due to the expansion of space stretching out the wavelengths of light. (Remember that the energy of light is proportional to the inverse of its wavelength.) At this time, the majority of the energy in the universe was not light, but matter. At this time the universe expanded like the cube root of time squared.

Dark dominated era: Dark energy density is constant, but matter density isn't. As space expands more and more, the density of matter decreases, but the density of dark energy stays the same. This means that the amount of dark energy eventually overtakes the amount of matter energy. At this time, the universe expands exponentially.

Interestingly, I know a (Physics) grad student who doesn't really accept the Big Bang/Inflationary universe and all that. His position is that the evidence for what happened before a certain time is much to uncertain to really ascertain what was going on (I get the impression the inflation tends to mess with the precision of the data). I'm not really sure how I feel about that, but it was the most interesting argument against modern cosmology I've heard (Physics/Math major here).

[Dragontide]

Still no proponents of the "God snapped his fingers" theory?

It could be more along the lines of: "One day, billions/trillions of years ago, a scientists walked into a lab and mixed some chemicals in a dish......"
Inquiring minds......may never know.

[UnhealthyTruthseeker]

Interestingly, I know a (Physics) grad student who doesn't really accept the Big Bang/Inflationary universe and all that. His position is that the evidence for what happened before a certain time is much to uncertain to really ascertain what was going on (I get the impression the inflation tends to mess with the precision of the data). I'm not really sure how I feel about that, but it was the most interesting argument against modern cosmology I've heard (Physics/Math major here).

But after that time, things were expanding outward, and there's many good reasons (having to do with the homogeneity and isotropy of the universe as well as other things) to posit that things were expanding before it.

[Christmahanikwanzikah]

I love it, especially as it's classic '...and then a miracle occurred...' physics of the big holes in equations kind. Which is not to dismiss it, I just like the creativity (something sorely lacking in a lot of physics). Tachyons, for example: genius.

Tachyons aren't accepted by most physicists.

I'd say "lol cosmological constant" but I read something recently on that which makes me think about the possibility of one.

Having hour-long mental debates over this stuff is the reason why I avoid this kind of debate in the first place.

[Astralsideria]

Assuming that physical cosmology is what I think it is (ie, trying to ascertain the origins of the Universe), then I don't see there's a problem with it at all, except possibly for the fact that, for all I know, it probably needs more money than it's getting. Even as a person who prayed to three Saints, an Archangel, and the Almighty just to get through the mock exams before Christmas.

EDIT: Please don't use this thread to tell me that that was pointless. I've been told that so often I'm bored of it. I accept that other people disagree with me. I don't need to know exactly how many people.

[Drachmar]

I have to admit that's totally above my head.

Essentially, I would believe that if the universe is accelerating faster than it did after the initial expansion, that some sort of bubble effect would occur. In other words, we would see a greater expansion closer to the earth, than was measured closer to the edge of the universe.

We're not accellerating faster than the extremely early universe.

It goes like this (roughly):

Extremely early = inflationary universe, electroweak era, GUT era, etc. expansion was super rapid here

Radiation dominated era: The dark energy density fell off quite a bit after the initial inflation, leading to an immense release of radiation. At this time the universe expanded like the square root of time.

Matter dominated era: Some of the radiation condensed into matter, a lot of the radiation lost its energy due to the expansion of space stretching out the wavelengths of light. (Remember that the energy of light is proportional to the inverse of its wavelength.) At this time, the majority of the energy in the universe was not light, but matter. At this time the universe expanded like the cube root of time squared.

Dark dominated era: Dark energy density is constant, but matter density isn't. As space expands more and more, the density of matter decreases, but the density of dark energy stays the same. This means that the amount of dark energy eventually overtakes the amount of matter energy. At this time, the universe expands exponentially.

Interestingly, I know a (Physics) grad student who doesn't really accept the Big Bang/Inflationary universe and all that. His position is that the evidence for what happened before a certain time is much to uncertain to really ascertain what was going on (I get the impression the inflation tends to mess with the precision of the data). I'm not really sure how I feel about that, but it was the most interesting argument against modern cosmology I've heard (Physics/Math major here).

Yet from what I understand (relatively simplistically I might add) is that prior to a certain point, most physical theorems breakdown at a certain point in the cosmological theory. More often than not, around the point where the 4 fundamental forces are inherently intertwined together prior to them breaking loose and essentially causing the initial expansion of the universe.

Please note, that I understand I'm talking about theorems and concepts way over my head. I only understand them in some form of basic theoretical understanding. Regardless, I'm quite the firm believer in the big bang theory, regardless of how inaccurate the term "big bang" actually is since it's more a "great expansion" than an actual explosion of energy and matter.

[United Technocrats]

So, are there any people here that have a problem with cosmology? That's what this thread is for.

Sorry, been busy for a while...

I have loads of objections to the modern physical cosmology. First off, it is not unlike the ancient religious theories, where they tried to explain the beginning of the Universe, and as human knowledge expanded and their ideas evolved, the theories became increasingly contrived... I tend to put more of my belief in the instrumentalist, rather than realist approach, where physical theories don't "explain" how something works, but rather, develops its predictory ability.

My second objection is that modern physical cosmology doesn't follow the established scientific method. No experiments can be conceived to verify the theories, it's just the math that fits into itself. And the chief argument is that the math is "elegant". Well, so is my jacket.

Another objection is the obvious bias. Most of the variables cannot be controlled, so, for example, there are two obvious types of bias: (i) the observational bias, and (ii) the observer bias. The observational bias has to do with the fact that we can only observe radiation, that is, we cannot see what is out there, but does not radiate towards us. Since there could be much more stuff out there that we cannot detect and measure, this bias is unacceptably high. The observer bias has to do with the usual notion that the "universe as we know it" can be as it is only if it evolved in a way which would allow for sentient observers, like us, to appear. However, it is just one of a multitude of sets of possible initial conditions, where the one that resulted in sentient observers evolving, would most likely not be the most probable. In other words, the very fact that we're here biases our observations, because we're highly improbable as per known physical laws, so the fundamental constants, which resulted from the initial conditions that led to the evolution of the universe as we see it, is also one of the less probable outcomes. Hence, applying the many-particle model to the macroworld, it would mean that, if parallel universes exist, ours would be one of the least represented (and thus, a highly improbable outcome of a hypothetical independent "universe creating" experiment).

Then, there's the fact that the people who have first realized that there are other galaxies out there, outside the Milky Way, are still alive, meaning that the observations (and hence, the theories too) are so young that they're very likely to be incorrect. And this is not the first time in human history that the humans base their grand ideas on a very limited amount of freshly obtained knowledge. Even in the short history of physics as a science itself, there were numerous claims that "we're almost there, very close to the ultimate truth, the ultimate theory" and it always, invariably proved wrong. The prudent conclusion here would be a high degree of caution: there's no guarantee that the "ultimate theory" is fundamentally simple and easily accessible (albeit there are numerous indications that it exists), and even if we stumble upon it, we will not be able to prove it to be the "final theory". I'm referring, of course, to the candidate theories for "grand unification" as the Standard Model from the '70s is, well, you know what it is...

Visible universe limit - we can only see as far as the light could have travelled in a limited expansion time. Meaning there's more beyond, but we just can't see it.

Problems with time and proper time. How long ago was the Big Bang? Okay, but time (-jt) didn't exist before it, just like the spatial dimensions didn't. Did it flow at the uniform rate? No? So, what exactly the question of the age of the Universe means?

Isotropy - why should I believe the universe is isotropic? The "inflation" could have happened non-uniformly, where our region of space expanded more rapidly than some others, connected to its other constituent parts characterized by different physical conditions through microscale wormholes.

A traditional "litmus test" for new cosmological theories is their ability to predict the fundamental constants. But who says they're constants at all? How do we know it? How do we know they never change?

Dark matter - an ugly patch that accounts for most of the matter in the Universe, but is, as of yet, not experimentally verified. The observed behavior of outer stars in distant galaxies, that do not conform to the known laws of gravity (they should fly apart), could be a consequence of a number of other causes, or a combination thereof. Those causes could include: (i) different behavior of a fundamental force of gravity when acting at long distances (which could also help explain the observed "Pioneer anomaly") which would imply a necessity to tweak the equations a bit; (ii) the existence of more than four fundamental forces, but the "fifth" being too weak to measure in practice; (iii) the "computational universe" hypothesis, where symmetry is not a real law, but rather, a curiosity arising from "programmed" behavior of subatomic particles -- which, in turn, would result in "fundamental constants" being only a result of Nature doing "computations" on individual elementary particles, rather than following the laws of symmetries, which gave rise to all of the known gauge theories...

Uh, oh, I could go on like this for hours. My fingers are aching...

[Acadzia]

I thought this said, "Why yall hatin' on physical cosmetology." Then, I open the thread and you're dithering on about homosexuals, which didn't help. I just want to say, cosmetology is a great career choice, regardless of one's gender or sexual orientation.

[Free Soviets]

God really sucks.

My one professor would, at this point, rant about how there's no such thing as a suction force in physics.

i think the proper response is something about nature abhorring a vacuum.

[The_pantless_hero]

Physical cosmology sounds like the study of sex in outerspace.