Anyone else get a "Access Denied"-error on the Recent speculation and Big Rip links?
The links worked when using a proxy server, so it may be location-related.
Edit: arxiv.org is blocking my ISP as a whole.
Will the Universe End in a Big Rip? (APOD 21 Oct 2007)
Will the Universe End in a Big Rip? (APOD 21 Oct 2007)
Last edited by Case on Fri Oct 26, 2007 12:48 pm, edited 1 time in total.
I have no problem accessing these links. They both pointed to the same aiXiv web page.
As an aside, I wonder how many billion years is a "few billion" years. In 5 billions years from now, two significant events are predicted to happen in this neck of the wood: Dear old sun will become a red giant, possibly engulfing the Earth, AND the Milky Way Galaxy will collide with the Andromeda Galaxy!
Will the Big Rip prevent both events?
As an aside, I wonder how many billion years is a "few billion" years. In 5 billions years from now, two significant events are predicted to happen in this neck of the wood: Dear old sun will become a red giant, possibly engulfing the Earth, AND the Milky Way Galaxy will collide with the Andromeda Galaxy!
Will the Big Rip prevent both events?
Fight ignorance!
The description reminds me of "The Nothing" from The Never Ending Story. Do we see any of this behavior currently in the visible universe?
Last edited by Vision on Mon Oct 22, 2007 6:55 am, edited 1 time in total.
I,d rather have a bottle in front of me, that a frontal lobotomy
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All things unknown will have a multitude of theories, and the more there are, the better the chances we'll have at sorting through and finding the most correct one all the while learning from each, even the ones we consider wrong. I'm surprised someone here would even have this attitude.... on second thought i'm not surprised, given our historyamz wrote:The description makes my stomach churn.
I find it discerning to know that such speculative, fanstasia-like assumptions are being taken seriously by so many in this day and age.
i'm not thinking there will be an antiphoton. a photon occurs with the annhilation of a particle and its' anti. They both dissapear and produce light. So its like the middle ground between the two anti-s.
If a photon and an anti-photon hit each other and annhililated, what would the new form of the energy look like? So I'm not thinking it exists.
If a photon and an anti-photon hit each other and annhililated, what would the new form of the energy look like? So I'm not thinking it exists.
Photons are considered their own antiparticle (although technically, I suppose, an antiphoton is a time-reversed photon, but that's getting into phase conjugation and other weirdness).
If dark matter is made up of the supersymmetric partners of the 'normal' particles, then 'dark light' would be photinos. Otherwise, no, there wouldn't necessarily be a dark matter analogue to light.
If dark matter is made up of the supersymmetric partners of the 'normal' particles, then 'dark light' would be photinos. Otherwise, no, there wouldn't necessarily be a dark matter analogue to light.
Last edited by Qev on Tue Oct 23, 2007 6:32 pm, edited 1 time in total.
Don't just stand there, get that other dog!
Dark photons
I'll have to agree with the previous post. What you are refering to is dark matter, i.e., positron, antiproton, antineutron. Photons are not matter, they are energy which doesn't fall into the same category. Photons are only subject to constructive and destructive intereference and can only be cancelled out in so far as the wavelengths of two photons at the same frequency, but at opposite points in their wavelength, or period if you want to equate their path to a sine wave type trajectory, will negate one another.
The reason that the term dark energy has gained popularity is because it is a new type of energy that we know very little about outside of the effect that it seems to be having on the universe. As of now the current belief is that dark energy has the opposite effect of gravity and repels two objects with mass. The question on most cosmologists minds now is how dark energy will behave, whether its influence increases as the distance between objects increase or whether it will reach some balance with the force of gravity. This is the question left to be answered that will determine whether the big rip is simply an academic exercise and a philosophical ponderance, or a model of the future of our universe.
The reason that the term dark energy has gained popularity is because it is a new type of energy that we know very little about outside of the effect that it seems to be having on the universe. As of now the current belief is that dark energy has the opposite effect of gravity and repels two objects with mass. The question on most cosmologists minds now is how dark energy will behave, whether its influence increases as the distance between objects increase or whether it will reach some balance with the force of gravity. This is the question left to be answered that will determine whether the big rip is simply an academic exercise and a philosophical ponderance, or a model of the future of our universe.
I agreeAll things unknown will have a multitude of theories, and the more there are, the better the chances we'll have at sorting through and finding the most correct one all the while learning from each, even the ones we consider wrong.
However, the lines distinguishing theory from fact are blatantly being crossed, which is concerning.
I'm not really surprised, my comment was in no way directed at anyone in particular here.. or there... or anywhere!I'm surprised someone here would even have this attitude...on second thought I'm not surprised, given our history
Maybe some attitude is necessary and helpful every now and then, indeed... for better or for worse. If only to remind us that our emotions and investments will always be the main obstacle in the advancement of knowledge, in whatever form it takes.
What's concerning... stomach curdling even, is the apparent ability for those individuals in the top tier of hierarchy to pick and choose to their liking who should be granted a career and whose career, life... should be destroyed and buried when the evidence points in another, potentially beneficial direction.
Sounds like you are one of those whose ideas have been rejected by the scientific establishment. Please give us your ideas, backed by data and mathematics and supported by other scientists (real scientist, not psuedo-scientists), not necessarily those "in the top tier of hierarchy", on the ultimate fate of the universe. If you are not a scientist, what motivates you to reject the ideas presented in this APOD? Is it religion? Ideology? I am sure that some of us would be very interested to know what you are thinking.amz wrote: What's concerning... stomach curdling even, is the apparent ability for those individuals in the top tier of hierarchy to pick and choose to their liking who should be granted a career and whose career, life... should be destroyed and buried when the evidence points in another, potentially beneficial direction.
Fight ignorance!
The thing with dark energy is, we don't yet know enough about it to be able to say which theories are definitely more likely than others. With our current observations, we're sort of on a cusp where it could lead to several different outcomes, depending on what its actual nature is. A 'Big Rip' is a viable possibility, if dark energy meets certain conditions. But it's not the only possibility by far.
Don't just stand there, get that other dog!
http://antwrp.gsfc.nasa.gov/apod/ap071021.html
When I read the explanation, I see "speculation", "possibilities", and "controversial scenarios". In no way was the "Big Rip" presented as hard fact. I like seeing alternative theories presented. After all, everything we now hold to be true was at some point pure speculation.
It's all speculation anyway. Everybody knows the earth is flat and at the center of the universe.
When I read the explanation, I see "speculation", "possibilities", and "controversial scenarios". In no way was the "Big Rip" presented as hard fact. I like seeing alternative theories presented. After all, everything we now hold to be true was at some point pure speculation.
It's all speculation anyway. Everybody knows the earth is flat and at the center of the universe.
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
BMAONE23,
Complete destructive interference of photons doesn't have much to do with why the universe over all is a dark place with occasional pin pricks of light from stars and quasars and the such. The reason that the universe appears dark is simply because there is much more "empty space" than there is matter in the universe. In order for our eyes (simply speaking of the visible spectrum of light) to percieve something we need photons to come directly through our pupils. This means that there are only one of two ways to see something, if the light that it emits comes into our eyes (i.e. how we see the sun), or if light reflects off of an object and enters our eyes (i.e. how we see the moon). The simple fact is that they universe is largely devoid of light emiting objects or objects large enough to reflect enough light towards our eyes for us to perceive them.
Complete destructive interference of photons doesn't have much to do with why the universe over all is a dark place with occasional pin pricks of light from stars and quasars and the such. The reason that the universe appears dark is simply because there is much more "empty space" than there is matter in the universe. In order for our eyes (simply speaking of the visible spectrum of light) to percieve something we need photons to come directly through our pupils. This means that there are only one of two ways to see something, if the light that it emits comes into our eyes (i.e. how we see the sun), or if light reflects off of an object and enters our eyes (i.e. how we see the moon). The simple fact is that they universe is largely devoid of light emiting objects or objects large enough to reflect enough light towards our eyes for us to perceive them.
Agreed with that last part!bystander wrote:
When I read the explanation, I see "speculation", "possibilities", and "controversial scenarios". In no way was the "Big Rip" presented as hard fact. I like seeing alternative theories presented. After all, everything we now hold to be true was at some point pure speculation.
It's all speculation anyway. Everybody knows the earth is flat and at the center of the universe.
What you say is true, but the fact remains that the people who made the explanation are professionals in their fields and have access to data (observations and measurements obtained with very expensive instruments). They discuss those observations and measurements with their colleagues and come up with their best ideas for what they find, building on previous findings. They disseminate their ideas in professional journals and conferences all over the world. They will get both praises and brickbats from others for their ideas. Eventually, more data are obtained and presented by the others that may or may not confirm the initial ideas. If confirmed, the findings become parts of the scientific consensus. If not confirmed, someone will come up with new ideas that fit the data better.
Some people for their own reasons will claim that the professionals have to adhere to the scientific orthodoxy if they want to be recognized and get grant monies or awards. Nonsense! The professionals love their work not for the money but for the satisfaction of making a discovery or adding to the body of knowledge.
I object to people who are not experts in th field making claims that the "official" explanations are a bunch of hooey for purely personal reasons without presenting their own data or explanations. And when they do present their own explanations, they fail to provide verifiable evidences.
Fight ignorance!