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New Physics are Needed to Explain the Accelerating Universe by sghill on 24 Feb, 2018 19:28
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Are there engineering concepts that can take advantage of this?
https://www.nasa.gov/feature/goddard/2018/improved-hubble-yardstick-gives-fresh-evidence-for-new-physics-in-the-universe
"Universe
Astronomers have used NASA's Hubble Space Telescope to make the most precise measurements of the expansion rate of the universe since it was first calculated nearly a century ago. Intriguingly, the results are forcing astronomers to consider that they may be seeing evidence of something unexpected at work in the universe.
That's because the latest Hubble finding confirms a nagging discrepancy showing the universe to be expanding faster now than was expected from its trajectory seen shortly after the big bang. Researchers suggest that there may be new physics to explain the inconsistency.
"The community is really grappling with understanding the meaning of this discrepancy," said lead researcher and Nobel Laureate Adam Riess of the Space Telescope Science Institute (STScI) and Johns Hopkins University, both in Baltimore, Maryland.
Riess's team, which includes Stefano Casertano, also of STScI and Johns Hopkins, has been using Hubble over the past six years to refine the measurements of the distances to galaxies, using their stars as milepost markers. Those measurements are used to calculate how fast the universe expands with time, a value known as the Hubble constant. The team’s new study extends the number of stars analyzed to distances up to 10 times farther into space than previous Hubble results.
But Riess's value reinforces the disparity with the expected value derived from observations of the early universe's expansion, 378,000 years after the big bang — the violent event that created the universe roughly 13.8 billion years ago. Those measurements were made by the European Space Agency's Planck satellite, which maps the cosmic microwave background, a relic of the big bang. The difference between the two values is about 9 percent. The new Hubble measurements help reduce the chance that the discrepancy in the values is a coincidence to 1 in 5,000.
Planck's result predicted that the Hubble constant value should now be 67 kilometers per second per megaparsec (3.3 million light-years), and could be no higher than 69 kilometers per second per megaparsec. This means that for every 3.3 million light-years farther away a galaxy is from us, it is moving 67 kilometers per second faster. But Riess's team measured a value of 73 kilometers per second per megaparsec, indicating galaxies are moving at a faster rate than implied by observations of the early universe.
The Hubble data are so precise that astronomers cannot dismiss the gap between the two results as errors in any single measurement or method. "Both results have been tested multiple ways, so barring a series of unrelated mistakes," Riess explained, "it is increasingly likely that this is not a bug but a feature of the universe."
Explaining a Vexing Discrepancy
Riess outlined a few possible explanations for the mismatch, all related to the 95 percent of the universe that is shrouded in darkness. One possibility is that dark energy, already known to be accelerating the cosmos, may be shoving galaxies away from each other with even greater — or growing — strength. This means that the acceleration itself might not have a constant value in the universe but changes over time in the universe. Riess shared a Nobel Prize for the 1998 discovery of the accelerating universe.
Another idea is that the universe contains a new subatomic particle that travels close to the speed of light. Such speedy particles are collectively called "dark radiation" and include previously-known particles like neutrinos, which are created in nuclear reactions and radioactive decays. Unlike a normal neutrino, which interacts by a subatomic force, this new particle would be affected only by gravity and is dubbed a "sterile neutrino."
Yet another attractive possibility is that dark matter (an invisible form of matter not made up of protons, neutrons, and electrons) interacts more strongly with normal matter or radiation than previously assumed.
Any of these scenarios would change the contents of the early universe, leading to inconsistencies in theoretical models. These inconsistencies would result in an incorrect value for the Hubble constant, inferred from observations of the young cosmos. This value would then be at odds with the number derived from the Hubble observations.
Riess and his colleagues don't have any answers yet to this vexing problem, but his team will continue to work on fine-tuning the universe's expansion rate. So far, Riess's team, called the Supernova H0 for the Equation of State (SH0ES), has decreased the uncertainty to 2.3 percent. Before Hubble was launched in 1990, estimates of the Hubble constant varied by a factor of two. One of Hubble's key goals was to help astronomers reduce the value of this uncertainty to within an error of only 10 percent. Since 2005, the group has been on a quest to refine the accuracy of the Hubble constant to a precision that allows for a better understanding of the universe's behavior.
Building a Strong Distance Ladder
The team has been successful in refining the Hubble constant value by streamlining and strengthening the construction of the cosmic distance ladder, which the astronomers use to measure accurate distances to galaxies near to and far from Earth. The researchers have compared those distances with the expansion of space as measured by the stretching of light from receding galaxies. They then have used the apparent outward velocity of galaxies at each distance to calculate the Hubble constant.
But the Hubble constant's value is only as precise as the accuracy of the measurements. Astronomers cannot use a tape measure to gauge the distances between galaxies. Instead, they have selected special classes of stars and supernovae as cosmic yardsticks or milepost markers to precisely measure galactic distances.
Among the most reliable for shorter distances are Cepheid variables, pulsating stars that brighten and dim at rates that correspond to their intrinsic brightness. Their distances, therefore, can be inferred by comparing their intrinsic brightness with their apparent brightness as seen from Earth.
Astronomer Henrietta Leavitt was the first to recognize the utility of Cepheid variables to gauge distances in 1913. But the first step is to measure the distances to Cepheids independent of their brightness, using a basic tool of geometry called parallax. Parallax is the apparent shift of an object's position due to a change in an observer's point of view. This technique was invented by the ancient Greeks who used it to measure the distance from Earth to the Moon.
The latest Hubble result is based on measurements of the parallax of eight newly analyzed Cepheids in our Milky Way galaxy. These stars are about 10 times farther away than any studied previously, residing between 6,000 light-years and 12,000 light-years from Earth, making them more challenging to measure. They pulsate at longer intervals, just like the Cepheids observed by Hubble in distant galaxies containing another reliable yardstick, exploding stars called Type Ia supernovae. This type of supernova flares with uniform brightness and is brilliant enough to be seen from relatively farther away. Previous Hubble observations studied 10 faster-blinking Cepheids located 300 light-years to 1,600 light-years from Earth.
Scanning the Stars
To measure parallax with Hubble, the team had to gauge the apparent tiny wobble of the Cepheids due to Earth's motion around the Sun. These wobbles are the size of just 1/100 of a single pixel on the telescope's camera, which is roughly the apparent size of a grain of sand seen 100 miles away.
Therefore, to ensure the accuracy of the measurements, the astronomers developed a clever method that was not envisioned when Hubble was launched. The researchers invented a scanning technique in which the telescope measured a star's position a thousand times a minute every six months for four years.
The team calibrated the true brightness of the eight slowly pulsating stars and cross-correlated them with their more distant blinking cousins to tighten the inaccuracies in their distance ladder. The researchers then compared the brightness of the Cepheids and supernovae in those galaxies with better confidence, so they could more accurately measure the stars' true brightness, and therefore calculate distances to hundreds of supernovae in far-flung galaxies with more precision.
Another advantage to this study is that the team used the same instrument, Hubble's Wide Field Camera 3, to calibrate the luminosities of both the nearby Cepheids and those in other galaxies, eliminating the systematic errors that are almost unavoidably introduced by comparing those measurements from different telescopes.
"Ordinarily, if every six months you try to measure the change in position of one star relative to another at these distances, you are limited by your ability to figure out exactly where the star is," Casertano explained. Using the new technique, Hubble slowly slews across a stellar target, and captures the image as a streak of light. "This method allows for repeated opportunities to measure the extremely tiny displacements due to parallax," Riess added. "You're measuring the separation between two stars, not just in one place on the camera, but over and over thousands of times, reducing the errors in measurement."
The team's goal is to further reduce the uncertainty by using data from Hubble and the European Space Agency's Gaia space observatory, which will measure the positions and distances of stars with unprecedented precision. "This precision is what it will take to diagnose the cause of this discrepancy," Casertano said.
The team's results have been accepted for publication by The Astrophysical Journal.
The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.
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#1 by colbourne on 21 Mar, 2018 03:08
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I suggest that there are repelling particles (probably 50% of all matter and antimatter) that cause the expansion of the universe.
These particles would mainly have dispersed far from Earth so would be practically invisible to us, but would be very useful if we did manage extract enough to build spacecraft etc. -
#2 by meberbs on 21 Mar, 2018 14:36
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I suggest that there are repelling particles (probably 50% of all matter and antimatter) that cause the expansion of the universe.
The main problem isn't the expansion, but the acceleration of the expansion. I don't think repelling particles explains this very well. In particular, one of the suggested explanations in the article is existence of "sterile neutrinos" which would be a form of dark matter, and increase the mass present, which would slow the expansion when everything was still close together. If you instead add repelling particles, this would have accelerated things more in the early universe, so it does not explain the observations.
These particles would mainly have dispersed far from Earth so would be practically invisible to us, but would be very useful if we did manage extract enough to build spacecraft etc.
Also, the main idea scientists have is dark energy, which they estimate as being 68% of everything.
As for engineering applications, this has been a known area in need of new physics for a while, but the observed effects are on scales that there just isn't a practical use for, and anything useful on an accessible scale would first require us to figure out something about the actual cause. Current hypotheses are too diverse to come to any conclusion. (Also, they are hard to test which makes it impossible to apply practical engineering to them with our current technology.) -
#3 by Khadgars on 21 Mar, 2018 14:49
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Great article and read btw, thank you for sharing.
I suggest that there are repelling particles (probably 50% of all matter and antimatter) that cause the expansion of the universe.
These particles would mainly have dispersed far from Earth so would be practically invisible to us, but would be very useful if we did manage extract enough to build spacecraft etc.
Whats the point of suggesting anything with no evidence or work to back it up? -
#4 by JQP on 21 Mar, 2018 15:35
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The difference between the two values is about 9 percent.
That sounds like a lot. -
#5 by philw1776 on 24 Mar, 2018 16:37
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The difference between the two values is about 9 percent.
That sounds like a lot.
It IS a lot given today's varied means of measurements and their precision.
Back in the "old days" when I was growing up astronomers joked that an order of magnitude signified close agreement.
After Hubble with Cephieds and Planck the astronomical community felt that the Hubble constant would be nailed down precisely with everyone in agreement, within known instrumental error. Now the error bars are tinier than ever but the discrepancy is "large" 9%. -
#6 by Propylox on 25 Oct, 2018 02:21
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https://www.nasa.gov/feature/goddard/2018/improved-hubble-yardstick-gives-fresh-evidence-for-new-physics-in-the-universe
"Dark Energy" definition: There seems to be something there doing something, but we have no idea what it is or what it's doing.
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Explaining a Vexing Discrepancy
Riess outlined a few possible explanations for the mismatch, all related to the 95 percent of the universe that is shrouded in darkness. One possibility is that dark energy, already known to be accelerating the cosmos, may be shoving galaxies away from each other with even greater — or growing — strength. This means that the acceleration itself might not have a constant value in the universe but changes over time in the universe. Riess shared a Nobel Prize for the 1998 discovery of the accelerating universe. ..
For that enlightening "discovery", we already know it's accelerating the cosmos, have handed out Nobel's for the "discovery" and yet are still trying to figure out what that "discovery" was or if it's something else entirely. Guess what - there is no Dark Energy, no force, no nada.
If the distance between two points increases it could mean they're moving apart -or- that the space between them is increasing. If light traveling through this region changes frequency, if more distant objects have a greater change in frequency it's because the space is expanding. To instead conclude the source of the light is moving away shows clear ignorance of how light works - like Hubble and his "constant".
"This means that the acceleration itself might not have a constant value" - No kidding. If space is increasing (likely as a Universal constant in gravity's absence just as space compresses in gravity's presence) than the produced space will continue to produce more space, just like bunnies! Thus the more distant an object, the more space between, the more space that's being created and the greater the redshift. However, to calculate the expansion of space we must quantify the compression of light - the blue shift - as it enters our System (solar or galactic) as well as that of the source star or galaxy.
It's not "New Physics" or undefined naivate like "Dark" energy/matter that's needed, but normal physics done right. -
#7 by meberbs on 25 Oct, 2018 03:48
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"Dark Energy" definition: There seems to be something there doing something, but we have no idea what it is or what it's doing.
The Nobel Prize (actually awarded in 2011, since there is always a lag fro good reason) was for discovering that the expansion of the universe is accelerating. That fact was not "already known" at the time.
For that enlightening "discovery", we already know it's accelerating the cosmos, have handed out Nobel's for the "discovery" and yet are still trying to figure out what that "discovery" was or if it's something else entirely. Guess what - there is no Dark Energy, no force, no nada.
https://www.nobelprize.org/prizes/physics/2011/summary/If the distance between two points increases it could mean they're moving apart -or- that the space between them is increasing. If light traveling through this region changes frequency, if more distant objects have a greater change in frequency it's because the space is expanding. To instead conclude the source of the light is moving away shows clear ignorance of how light works - like Hubble and his "constant".
Astronomers know this and have worked it out through a variety of measurements. It is the space expanding, which means that things are moving away from each other, and since the space itself is expanding the initial Doppler shift is exaggerated as the light travels through expanding space to reach Earth. Dark energy is what is used to explain why space itself is expanding. It is a placeholder, but it is needed to explain why expansion is accelerating. Unless you have a new model of cosmology that can replicate the predictions of GR, but naturally has spacetime with accelerating expansion, then you can't talk about the accelerating expansion and deny the existence of dark energy at the same time."This means that the acceleration itself might not have a constant value" - No kidding. If space is increasing (likely as a Universal constant in gravity's absence just as space compresses in gravity's presence) than the produced space will continue to produce more space, just like bunnies! Thus the more distant an object, the more space between, the more space that's being created and the greater the redshift. However, to calculate the expansion of space we must quantify the compression of light - the blue shift - as it enters our System (solar or galactic) as well as that of the source star or galaxy.
The blueshifts you mention generally cancel out in most cases, since there was also extra redshift from leaving the gravity well of the source. That doesn't change the fact that further away objects are more redshifted.It's not "New Physics" or undefined naivate like "Dark" energy/matter that's needed, but normal physics done right.
What you are doing here is equivalent to asserting that every astronomer on this planet is an idiot. Please think before posting. The astronomers know how to do the math. The data shows that expansion is accelerating, and "normal physics" cannot account for the fact that space itself is expanding at an increasing rate unless you add in an extra term such as dark energy. -
#8 by coypu76 on 25 Oct, 2018 03:59
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(apologies for redundancy with some of the comments already posted)
The Nobel Prize in Physics 2011 was divided, one half awarded to Saul Perlmutter, the other half jointly to Brian P. Schmidt and Adam G. Riess "for the discovery of the accelerating expansion of the Universe through observations of distant supernovae. Perlmutter was mentioned first and got half of the prize because he began his Supernova Cosmology Project in 1988, while Reiss at Johns Hopkins and Schmidt at Australia National University started their project six years later in 1994.
Perlmutter's team at UC Berkeley began working in 1988 to attempt to get a more precise value of Hubble's constant by using a brighter "standard candle" than the Cepheid Variables Hubble used. The specific spectral signature and luminosity curve of the Type 1A supernova made it a superior standard candle to Cepheid variables, which are only usable inside our own galaxy and in our nearest galactic neighbors. The supernovae, orders of magnitude brighter, can be observed and measured by luminosity and redshift in cosmically distant galaxies.
Their findings shocked the astrophysical community to its foundations. George Lemaitre had inferred from Einstein's General Theory of Relativity that the universe must be expanding, else it would collapse. Sir Fred Hoyle, a Steady State adherent, didn't like this idea of an expanding universe, and ridiculed it, saying an expanding universe would, instead of being infinite and eternal, have begun in some sort of messy, ugly "Big Bang". Hoyle had no idea his derisive words would become the sobriquet for the majority report of cosmology to come.
Prior to the Supernova Cosmology Project, it was assumed that the universe's expansion got its initial impetus from the Big Bang. In the seventies, Alan Guth peeked behind the veil of the Big Bang itself and proposed the mechanism of its expansion, which he called Inflation. Inflationary cosmology had to be tuned, but the idea stuck, and Inflationary cosmology was vindicated again and again by increasingly precise measurements of the Cosmic Microwave Background by the COBE and WMAP satellites.
But what would be the ultimate fate of the universe? It was assumed that the mass of all of the galaxies would cause gravitational slowing of its expansion over time, but was there sufficient mass to bring expansion to a halt and cause an eventual collapse, or would it continue to expand forever, having reached something like an escape velocity?
The measurements made by Perlmutter, Reiss and Schmidt were shocking because they showed the expansion of the universe WASN'T slowing down, but was accelerating! And no one knew what was powering that expansion. The energy accelerating the galaxies became known as Dark Energy, not only because we couldn't see it, but also because it was unknown, in epistemological as well as physical darkness.
Cepheid variables show us the local story, but Type 1A supernovae gave us a much larger picture.
We add to that the "Dark Matter" first mentioned in an almost offhand way by Fritz Zwicky in the 1930s in galactic rotation curves, then visited with precision by Vera Rubin and Kent Ford in the seventies, when the Rubin-Ford Effect was the first observational evidence of gravitationally interactive Dark Matter in galaxies, and subsequently observed through gravitational lensing as the light of distant quasars appeared as arcs around interposing galactic clusters, the curvature of the light being a good scale to measure the total mass of the clusters. Dark Matter has been inferred for decades.
But since 2009, when Perlmutter, Reiss and Schmidt published their results, Dark Energy entered the picture. The inferred mass of Dark Matter plus the calculated equivalent mass of the Dark Energy expanding the Universe, calculated according to Einstein's Special Theory of Relativity, came up to an astounding figure: well over 90% of the universe was made of one or the other.
Since then the search for those "New Physics" has been ongoing, and astrophysics has been one of the most fascinating fields to do research in. Most of the Universe is made up of something we have very little understanding of - matter which interacts gravitationally but (apparently) not collisionally nor optically (* except for gravitational lensing).
New physics are needed indeed. But physicists are on the case. I hope we'll get the James Webb scope into orbit as soon as possible to continue observational research. But there is plenty of mathematical and theoretical work to be done to propose candidates for Dark Matter and Dark Energy - some have been proposed, but as yet the proposals are not well verified.
Exciting times!
But at the same time I'm not sure if there will be application of this work to the field of space propulsion or not. That may be a bridge too far. -
#9 by Propylox on 26 Oct, 2018 02:36
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Astronomers know this and have worked it out through a variety of measurements. It is the space expanding, which means that things are moving away from each other..
How can you equate expanding space to objects moving?Quote..and since the space itself is expanding the initial Doppler shift is exaggerated as the light travels through expanding space to reach Earth.
What initial Doppler shift? Doppler is a result of of photons being re-emitted by a body and the kinetic energy of that body altering the wavelength. Light for a star is not re-emitted and thus has no initial Doppler shift. Any matter in the system which may re-emit has zero kinetic energy as its moving with the star, so again - no initial Doppler shift.QuoteThe blueshifts you mention generally cancel out in most cases, since there was also extra redshift from leaving the gravity well of the source. That doesn't change the fact that further away objects are more redshifted.
Why would there be redshift leaving a gravitational well and blueshift when entering if spacetime is contracting in both places? The "fact" further away objects are more redshifted has nothing to do with actual distance, but the amount of empty space it travels through. Yes - there's relation, but not causation.QuoteDark energy is .. a placeholder, but it is needed to explain why expansion is accelerating.
They could just as easily call it "WTF?", but then it wouldn't win a Nobel.QuoteUnless you have a new model of cosmology that can replicate the predictions of GR, but naturally has spacetime with accelerating expansion, then you can't talk about the accelerating expansion and deny the existence of dark energy at the same time.
Pretty sure I did just describe a new model of cosmology while denying the whimsical fancy of Dark Energy.QuoteWhat you are doing here is equivalent to asserting that every astronomer on this planet is an idiot. Please think before posting. The astronomers know how to do the math. The data shows that expansion is accelerating, and "normal physics" cannot account for the fact that space itself is expanding at an increasing rate unless you add in an extra term such as dark energy.
If astronomers can do math, their data shows normal physics cannot account for expanding space and therefor must add a placeholder like "WTF", then obviously something's wrong. I've thought about it plenty, and before posting, and every astronomer on this planet may be a modern Geocentrist describing the Heavens. "Why do Mars and Jupiter retrograde? - We call that Dark Energy." -
#10 by meberbs on 26 Oct, 2018 06:28
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There does not need to be a "re-emission" to have a Doppler shift. You just need to be measuring from a different frame than the initial emission.Astronomers know this and have worked it out through a variety of measurements. It is the space expanding, which means that things are moving away from each other..
How can you equate expanding space to objects moving?
...
What initial Doppler shift? Doppler is a result of of photons being re-emitted by a body and the kinetic energy of that body altering the wavelength. Light for a star is not re-emitted and thus has no initial Doppler shift. Any matter in the system which may re-emit has zero kinetic energy as its moving with the star, so again - no initial Doppler shift.
Go study some basic GR and the effect of light entering or exiting deep gravity wells, it is usually negligible but it is the effect that you appeared to be talking about when you mentioned blueshift. There is nowhere in the universe to our knowledge where space is contracting.QuoteThe blueshifts you mention generally cancel out in most cases, since there was also extra redshift from leaving the gravity well of the source. That doesn't change the fact that further away objects are more redshifted.
Why would there be redshift leaving a gravitational well and blueshift when entering if spacetime is contracting in both places? The "fact" further away objects are more redshifted has nothing to do with actual distance, but the amount of empty space it travels through. Yes - there's relation, but not causation.
Dark Energy did not win a Nobel. Did you even read my previous post?QuoteDark energy is .. a placeholder, but it is needed to explain why expansion is accelerating.
They could just as easily call it "WTF?", but then it wouldn't win a Nobel.
No, you described space itself expanding which is the standard model of cosmology. Your appeal to qualitative words like "whimsical" only shows that you have no real argument, and makes it appear you aren't interested in a logical discussionQuoteUnless you have a new model of cosmology that can replicate the predictions of GR, but naturally has spacetime with accelerating expansion, then you can't talk about the accelerating expansion and deny the existence of dark energy at the same time.
Pretty sure I did just describe a new model of cosmology while denying the whimsical fancy of Dark Energy.
They know something is wrong, that is why they are looking for new physics. If anyone is acting like a geocentrist here it is you, since astronomers were surprised by the data, but accepted it (see coypu76's post.) You are instead stating contradictory nonsense (like spacetime contracting in some places) that indicates you don't have a clue what you are talking about.QuoteWhat you are doing here is equivalent to asserting that every astronomer on this planet is an idiot. Please think before posting. The astronomers know how to do the math. The data shows that expansion is accelerating, and "normal physics" cannot account for the fact that space itself is expanding at an increasing rate unless you add in an extra term such as dark energy.
If astronomers can do math, their data shows normal physics cannot account for expanding space and therefor must add a placeholder like "WTF", then obviously something's wrong. I've thought about it plenty, and before posting, and every astronomer on this planet may be a modern Geocentrist describing the Heavens. "Why do Mars and Jupiter retrograde? - We call that Dark Energy." -
#11 by Propylox on 26 Oct, 2018 09:27
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There does not need to be a "re-emission" to have a Doppler shift.
Actually, that's exactly what causes a Doppler shift. Fire a laser at an object, stationary or in motion, and the Photons impart force. The force is energy transferred by the Photons - basic physics here, folks. If the object is moving away and is accelerated by photons, the re-emitted (or reflected if you prefer the term) photons will have lost energy and frequency. If the object is approaching and slowed by the photons, the re-emitted photons have gained energy and frequency.
And I'm still wondering how can you equate expanding space to objects moving? Again, basic physics.Quote1)..There is nowhere in the universe to our knowledge where space is contracting.
Re1) Considering astronomers have no viable theory of the Universe, nor what's in it - your statement is correct.
2)..(Astronomers) know something is wrong, that is why they are looking for new physics. ..You are instead stating contradictory nonsense (like spacetime contracting in some places) that indicates you don't have a clue what you are talking about.
3)..Your appeal to qualitative words like "whimsical" only shows that you have no real argument, and makes it appear you aren't interested in a logical discussion
Re2) Have you dismissed a comment just for opposing conventional theory, even when those theories admit to being ill-informed, and inaccurate? Yet you mandate "new physics" that would be contrary to conventional theory? Hiding ignorance behind "placeholders" like Dark Energy or "new physics" is such an admittance.
Re3) Did you just dismiss an argument because you didn't like an adjective? I object to your use of the word "nonsense" or "qualitative" as it shows you don't have a clue nor interest in logical discussion.
I'm sensing a pretty clear theme here; I'm wrong for not repeating what Astronomers - who know they're wrong - say while someone who clearly doesn't know basic physics claims GR and runs semantic circles rather than discuss the science. -
#12 by Propylox on 26 Oct, 2018 10:09
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Enough with the fool's banter - What is needed to define redshift, expanding spacetime or an accellerating Universe?
Premise: Spacetime flows toward mass. The observed effect is known as Gravity, though there's actually no real force nor fundamental particle of Gravity. Additionally, the effect of mass on spacetime results in a retardation of time -experimentally proven and quantified.
Empty space is expanding as a fundamental of the Universe and the observed effect is a redshift of light passing through it. To quantify the extent of empty space's expansion we must eliminate our gravitational reference and the distortion it may cause. This distortion may be ...
1) Spacetime is stretched as it flows toward mass. Light traveling in, out, or especially through this well will be redshifted. As such, all light we observe is redshifted by our own system as well as redshifted leaving the initial system. Larger systems will be more redshifted due to their mass and the remaining redshift is from empty space's expansion.
2) Spacetime don't care about its flow. It may move toward mass as a fundamental of the Universe, but it neither stretches nor compresses. As such, all observed redshift is caused by empty space's expansion.
3) Spacetime is compressed as it flows toward mass, just as matter compresses as it accumulates. Light travelling in, out, or through this system will be blueshifted. As such, all light we observe has been significantly redshifted by expanding space to outweight the blueshift of our and the initial system.
Experiment: Compare spectrographic images of the Sun between New Horizons, Dawn and any of the heliocentric solar observatories for variation due to distorion of spacetime over distance. Additionally, compare spectrographic images of Pluto between Hubble and New Horizons as Hubble's light traveled out and back (keeping in mind Hubble's in earth's well). If no variation in spectroscopy is found, the effect is either too small or spacetime isn't distorted, compressed or stretched by systems.
Only after our reference has been quantified can we measure the expansion of empty space. The question then is how/why spacetime is expanding in mass' absence. This may be ...
4) Spacetime's expansion is a consistent fundamental of the Universe. In the same way time moves forward at a specific rate in a vacuum, so does space expand at a specific rate. As a void expands it then has more space in which to expand, thus the expansion will be non-linear.
5) Spacetime's expansion is a result of the Big Bang. As time passes its expansion rate is decreasing, but only when observed from the 4th dimension. From the 3rd, it appears to be accelerating.
ie; Let's say we're 2D beings living on the surface of a Universe that's a 3D sphere. Over a set period of time, the sphere's radius grew from 2 to 4 = our Universe just grew by 151^2 in surface area. Then over the same period of time, the sphere's radius grew at a slower rate of 4 to 5.5 = our Universe just grew by 179^2 surface area.
OMG, it's Dark Energy! Nope, it's decreasing residual energy that appears as acceleration from our reference.
Not sure which is true, or another option, but I do like the 4D Spherical Universe theory as it also explains a cyclical Big Crunch - Big Bang as well as strings, inflation and fundamental formations of a new Universe. -
#13 by SteveKelsey on 26 Oct, 2018 10:29
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#14 by RonM on 26 Oct, 2018 17:30
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There does not need to be a "re-emission" to have a Doppler shift.
Actually, that's exactly what causes a Doppler shift. Fire a laser at an object, stationary or in motion, and the Photons impart force. The force is energy transferred by the Photons - basic physics here, folks. If the object is moving away and is accelerated by photons, the re-emitted (or reflected if you prefer the term) photons will have lost energy and frequency. If the object is approaching and slowed by the photons, the re-emitted photons have gained energy and frequency.
What you have described is how Doppler radar works, an application of the Doppler effect, not the Doppler effect itself. Absorption and emission are not required.
The Doppler effect is the change in frequency of a wave in relation to an observer moving relative to the wave source.
Cosmological redshift looks like the Doppler effect, but it's not. It's due to the expansion of space, not the motion of an individual body. -
#15 by meberbs on 26 Oct, 2018 17:32
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Again, no. No re-emission is needed for there to be a Doppler shift. Paint an object black and you can still measure the effect as the difference between the energy and momentum from the frame of the source to the energy and momentum imparted to the receiver in its own frame.There does not need to be a "re-emission" to have a Doppler shift.
Actually, that's exactly what causes a Doppler shift. Fire a laser at an object, stationary or in motion, and the Photons impart force. The force is energy transferred by the Photons - basic physics here, folks. If the object is moving away and is accelerated by photons, the re-emitted (or reflected if you prefer the term) photons will have lost energy and frequency. If the object is approaching and slowed by the photons, the re-emitted photons have gained energy and frequency.
For applications like radar, where you transmit and receive from the same place with a reflection (not re-emission) in between, the effect is doubled because of shifting frames and then shifting back when going the other direction. (It can of course be described without frame shifts, but I find it more intuitive this way.)
https://en.wikipedia.org/wiki/Doppler_effect
We can agree that this is basic physics, and if you can't be bothered to do basic research to understand it, I don't see any point in trying to explain to you your misunderstandings of the much more complex topics of curved spacetime, and the expansion of space itself.
You aren't making any sense here, giving something a label so you can more easily wave it around like a flag saying specifically what it is that you don't understand is not "hiding" anything. Hiding things would be simply ignoring the data that says that conventional theories do not work. Dark energy is the placeholder name for the new physics that is needed. the position you are taking hear seems to be almost self-contradictory. It seems like you are trying to use the fact that scientists admit that their models do not work without something new to argue that scientists are wrong and therefore their original models are correct.Quote1)..There is nowhere in the universe to our knowledge where space is contracting.
Re1) Considering astronomers have no viable theory of the Universe, nor what's in it - your statement is correct.
2)..(Astronomers) know something is wrong, that is why they are looking for new physics. ..You are instead stating contradictory nonsense (like spacetime contracting in some places) that indicates you don't have a clue what you are talking about.
3)..Your appeal to qualitative words like "whimsical" only shows that you have no real argument, and makes it appear you aren't interested in a logical discussion
Re2) Have you dismissed a comment just for opposing conventional theory, even when those theories admit to being ill-informed, and inaccurate? Yet you mandate "new physics" that would be contrary to conventional theory? Hiding ignorance behind "placeholders" like Dark Energy or "new physics" is such an admittance.Re3) Did you just dismiss an argument because you didn't like an adjective? I object to your use of the word "nonsense" or "qualitative" as it shows you don't have a clue nor interest in logical discussion.
I used nonsense plainly in the sense that what you are saying is contradictory (some compared with actual data, some contradictory with itself) and therefore literally makes no sense. Probably would have been better if I had left off the redundant word nonsense and just said "contradictory statements." It doesn't change that your description of "whimsical fancy" has no place in a scientific discussion.someone who clearly doesn't know basic physics claims GR and runs semantic circles rather than discuss the science.
This is a pretty good description of you, you are the one that clearly doesn't understand basic physics, and you are going in circles of semantic confusion. For example:I'm wrong for not repeating what Astronomers - who know they're wrong - say
What the astronomers know is wrong and what you are disagreeing with them on are different things. Conflating them is literal semantic confusion. I am not entirely clear what you are trying to say, it seems roughly like "they are wrong about being wrong" which simply contradicts the data.Premise: Spacetime flows toward mass. The observed effect is known as Gravity, though there's actually no real force nor fundamental particle of Gravity. Additionally, the effect of mass on spacetime results in a retardation of time -experimentally proven and quantified.
Close, but rather than spacetime "flows towards mass" the general description is "mass curves spacetime" in such a way that objects naturally move towards each other.1) Spacetime is stretched as it flows toward mass. Light traveling in, out, or especially through this well will be redshifted. As such, all light we observe is redshifted by our own system as well as redshifted leaving the initial system. Larger systems will be more redshifted due to their mass and the remaining redshift is from empty space's expansion.
Nope, it has been experimentally measured. Redshift going out of a gravitational well, blue shift going back in.
https://en.wikipedia.org/wiki/Gravitational_redshift
(Wikipedia references some of the relevant experiments)
Most of the rest of your post is just variations on this that indicate you aren't aware of existing experiments.5) Spacetime's expansion is a result of the Big Bang. As time passes its expansion rate is decreasing, but only when observed from the 4th dimension. From the 3rd, it appears to be accelerating.
Physicists do in fact consider options that involve additional dimensions beyond 4 dimensional spacetime like you are suggesting here. (What you are describing would require a 4th spatial dimension, for 5 total dimensions, since you are discussing time separately.) In particular most variations of string theory have multiple extra dimensions. One way or another it is still new physics required to explain the data. -
#16 by meberbs on 26 Oct, 2018 20:10
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https://phys.org/news/2017-03-expansion-universe-dark-energy.html
Interesting results if any other researchers could confirm, but it sounds like they made a mistake somewhere. Dark matter is additional mass, and therefore more reason that everything in the universe should be more attracted to each other, which is the exact opposite of what is needed to explain the universe having accelerating expansion. I only read the news article and not the original, so may be something important got lost in between. -
#17 by Nomadd on 26 Oct, 2018 20:55
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Somebody here .(I'm too polite to say who) is posting the most ridiculous load of scientific crap since the last Flat Earth Society meeting.
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#18 by colbourne on 27 Oct, 2018 02:41
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Great article and read btw, thank you for sharing.
There is plenty of work going on into this mainly at CERN with the AEGIS and GBAR and Alpha experiments.I suggest that there are repelling particles (probably 50% of all matter and antimatter) that cause the expansion of the universe.
These particles would mainly have dispersed far from Earth so would be practically invisible to us, but would be very useful if we did manage extract enough to build spacecraft etc.
Whats the point of suggesting anything with no evidence or work to back it up?
If there are repelling particles they remove the need for dark energy and dark matter. They will also account for the accelerating expansion of the universe as these particles will continue pushing. -
#19 by edzieba on 27 Oct, 2018 06:01
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If there are repelling particles they remove the need for dark energy and dark matter.
My goodness, postulated material that is difficult or impossible to observe due to its weak or nonexistant interaction with the electromagnetic force, but whose existence in inferred from its interaction with the gravitational force? What a novel idea!
Incidentally, scientists investigating that postulated material have already given it a name: 'Dark Energy'. -
#20 by SteveKelsey on 27 Oct, 2018 11:31
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https://phys.org/news/2017-03-expansion-universe-dark-energy.html
Interesting results if any other researchers could confirm, but it sounds like they made a mistake somewhere. Dark matter is additional mass, and therefore more reason that everything in the universe should be more attracted to each other, which is the exact opposite of what is needed to explain the universe having accelerating expansion. I only read the news article and not the original, so may be something important got lost in between.
Yes I agree it needs replication in order to be taken seriously but I am intrigued by the central proposition that if you include the effect of structure on the calculations within the simulation you automatically get a result similar to what we observe without the arbitrary need for Dark Energy, which is not an observed phenomena but, like Inflation, a hypothesis that fits what we observe. Structure is an emergent property of matter and energy and does not require invention. I must admit I was surprised that structure has not been taken into account previously, I appreciate this may be due to a lack of computing power before, but it does seem like a fundamental property which must have a large impact if omitted.
As for the effect of Dark Matter on the Hubble Constant I don't think this has been summarised that well in the précis but as I don't have the math I can't take it much further.
My naive outtake is that both Dark Matter, which is a variable that has to be set subjectively in every case, and Dark Energy, which is not falsifiable, are approximations to solutions that will be revealed in time. I am not expecting any engineering opportunities to arise from them sadly. -
#21 by as58 on 27 Oct, 2018 14:40
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https://phys.org/news/2017-03-expansion-universe-dark-energy.html
Interesting results if any other researchers could confirm, but it sounds like they made a mistake somewhere. Dark matter is additional mass, and therefore more reason that everything in the universe should be more attracted to each other, which is the exact opposite of what is needed to explain the universe having accelerating expansion. I only read the news article and not the original, so may be something important got lost in between.
The paper is about cosmological backreaction, i.e. the effect of inhomogeneity on expansion. It has been argued that such inhomogeneity can lead to apparent accelerating expansion without any dark energy. It's a very difficult question (one needs to deal with the full non-linear GR) and still actively debated. -
#22 by meberbs on 27 Oct, 2018 22:59
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Thanks for the additional info, with that and a bit more research on my end, it seems like it could be a solution, but there is a lot more work that would need to be done to be confident it covers everything, and even more work to show that it should be the new standard. I'll wait for the people who devote their lives to this to work it out.https://phys.org/news/2017-03-expansion-universe-dark-energy.html
Interesting results if any other researchers could confirm, but it sounds like they made a mistake somewhere. Dark matter is additional mass, and therefore more reason that everything in the universe should be more attracted to each other, which is the exact opposite of what is needed to explain the universe having accelerating expansion. I only read the news article and not the original, so may be something important got lost in between.
The paper is about cosmological backreaction, i.e. the effect of inhomogeneity on expansion. It has been argued that such inhomogeneity can lead to apparent accelerating expansion without any dark energy. It's a very difficult question (one needs to deal with the full non-linear GR) and still actively debated. -
#23 by Propylox on 28 Oct, 2018 01:47
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What you have described is how Doppler radar works, an application of the Doppler effect, not the Doppler effect itself. Absorption and emission are not required. The Doppler effect is the change in frequency of a wave in relation to an observer moving relative to the wave source. Cosmological redshift looks like the Doppler effect, but it's not. It's due to the expansion of space, not the motion of an individual body.
The "Doppler Effect", as you've described, is an observation with causes as diverse as the waves. The Doppler Effect with electromagnetic waves is a result of a receiver not being calibrated. Once calibrated, Doppler Radar is possibly by measuring the frequency change of re-emitted energy (there's no such thing as reflecting as a change in energy will always occur). Eliminating re-emittance is the basis of stealth. With photons, re-emittance is required for any frequency change to occur -or- your device hasn't been calibrated and is giving false readings.No re-emission is needed for there to be a Doppler shift. Paint an object black and you can still measure the effect as the difference between the energy and momentum from the frame of the source to the energy and momentum imparted to the receiver in its own frame.
How the heck does "painting something black", assuming it will then absorb all light, become a means to measure a photonic Doppler Effect? And if it "can still be measured", assuming with radar, what was the point of painting it. What are you inferring or attempting to talk about?..
Somebody here .(I'm too polite to say who) is posting the most ridiculous load of scientific crap since the last Flat Earth Society meeting.
I'll say it, its meberbs. I got lost trying to follow his last post of circular, yet contrary and largely indecipherable attempted rebuttal. Yep, it's "qualitative nonsense" word-soup playing as insight just like the term "Dark Energy", but without whimsy to his fancy.
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1) As this thread suggests "New Physics" to explain all conventional theories to date being incapable of describing the Universe, I would suggest correcting the use of existing theories rather than make up fantastic energies or matter to fill the void of ignorance. All science starts with "I don't know", but if that is replaced with mythical, unmeasurable "things" - it's not really science.
2) I would suggest avoiding the crutch of theoretical mathematics. Math is a language with rules. But one can just as easily assemble a meaningless word-soup (as mentioned above) as assemble a meaningless equation of jibberish. This disparity between reality and mathematics doesn't just occur in astronomy, but also subatomic particle physics (often ridiculously renamed "Quantum") and complex systems like fluid dynamics.
I leave some recent wisdom;
"There are many equations because there are many phenomena. They are an attempt to describe mathematically the physical phenomena so that you can solve these problems. Words alone won't solve the problem. .. If you don't use the right model, the rest becomes an exercise in futility. It may be a model that's self-consistent but has no reality," he said. "Of course, the only way you can validate a model is to run experiments and even then, you're introducing another reality into the picture which is the experiment... We use both math and physics in engineering, but within limitations. In physics, we don't always understand what's going on," he said. "That's the case here as well. There are pieces of principles that haven't been resolved. The mathematics are very exact but we tend to shade the equations in terms of what we can solve, rather than what it should be. .."
Quotes by University of Illinois Professor Harry Hilton and his work on aerodynamic modelling.
Oct 23, cut to avoid link - ht tp://ww w.spacedaily.com/re ports/Me rging_mathematical_and_physical_models_toward_building_a_more_perfect_flying_vehicle_999.html -
#24 by ChrisWilson68 on 28 Oct, 2018 02:12
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Somebody here .(I'm too polite to say who) is posting the most ridiculous load of scientific crap since the last Flat Earth Society meeting.
I'll say it, its meberbs.
Incorrect.
meberbs has a very good understanding of physics and is known around here for very good posts on the topic.The Doppler Effect with electromagnetic waves is a result of a receiver not being calibrated.
Incorrect.
This is one of many, many things you've said in this thread that are so completely wrong that most people on this forum will just give up on you and not even try to help you understand where you are wrong.
I admire meberbs for trying to help you understand what you're getting wrong. I wish you were more respectful of that.
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#25 by meberbs on 28 Oct, 2018 06:35
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What you are saying here has no relation to reality. There is a difference between absorption and re-emission (such as what happens in fluorescence, or emission of black body radiation (also 2 different things)) and reflected light. Go look up those terms online if you don't know what they mean.What you have described is how Doppler radar works, an application of the Doppler effect, not the Doppler effect itself. Absorption and emission are not required. The Doppler effect is the change in frequency of a wave in relation to an observer moving relative to the wave source. Cosmological redshift looks like the Doppler effect, but it's not. It's due to the expansion of space, not the motion of an individual body.
The "Doppler Effect", as you've described, is an observation with causes as diverse as the waves. The Doppler Effect with electromagnetic waves is a result of a receiver not being calibrated. Once calibrated, Doppler Radar is possibly by measuring the frequency change of re-emitted energy (there's no such thing as reflecting as a change in energy will always occur). Eliminating re-emittance is the basis of stealth. With photons, re-emittance is required for any frequency change to occur -or- your device hasn't been calibrated and is giving false readings.
You apparently haven't bothered to even read the Wikipedia page on the Doppler effect I linked before, which clearly shows it applies outside the context of radar, and it typically refers to a transmitter and receiver moving at different velocities relative to each other, with no need for any signal returning to the original transmitter to be discussed.
Radar has nothing to do with what I said. You measure the effect, because you are holding the piece of material and you can measure how much energy it received from the incident radiation and how much momentum was transferred to it. This is the basis of how cameras (or your eyes) work. If a camera is moving towards a light source outputting a fixed frequency, it will detect higher frequency light. If it is moving away it detects lower frequency light. No discussion of radar, or re-emission, or reflection is required. (And you know the frequency of the emitted light in the rest frame of the source, because you use something well known and fundamental, such as the emission spectra of specific elements.)No re-emission is needed for there to be a Doppler shift. Paint an object black and you can still measure the effect as the difference between the energy and momentum from the frame of the source to the energy and momentum imparted to the receiver in its own frame.
How the heck does "painting something black", assuming it will then absorb all light, become a means to measure a photonic Doppler Effect? And if it "can still be measured", assuming with radar, what was the point of painting it. What are you inferring or attempting to talk about?1) As this thread suggests "New Physics" to explain all conventional theories to date being incapable of describing the Universe, I would suggest correcting the use of existing theories rather than make up fantastic energies or matter to fill the void of ignorance. All science starts with "I don't know", but if that is replaced with mythical, unmeasurable "things" - it's not really science.
You should correct your own understanding of physics before you try and claim that you understand astronomy better than the people who have devoted their lives to it. Attaching a label to an area of physics that is a "known unknown" is simply a tool to facilitate discussion. Your continued attempts to make fun of scientists are still inappropriate, especially since it is for wanting to not have to say the mouthful "that thing where the universe has accelerating expansion and we aren't sure why" thirty times per conversation. Scientists have given it a name to facilitate discussion, and quantified the correction factor needed to make existing theories match the data. There is nothing mythical about it, the data they measure is real, and it is no secret that the reason for the discrepancy between unmodified theory and measured data is not understood.2) I would suggest avoiding the crutch of theoretical mathematics. Math is a language with rules. But one can just as easily assemble a meaningless word-soup (as mentioned above) as assemble a meaningless equation of jibberish.
What you appear to be saying here is that you don't understand math and won't be bothered to try. Math as a language is a whole lot more rigorous than English, and if you know what you are doing can be used to prove things and communicate with others. If you form gibberish in it, there is also a way to show that it is gibberish.This disparity between reality and mathematics doesn't just occur in astronomy, but also subatomic particle physics (often ridiculously renamed "Quantum") and complex systems like fluid dynamics.
Quantum has a specific meaning, which relates to the quanitzation of physical properties at the level of subatomic particles. Since this is the usually the most important feature of the behavior of particles at the subatomic level, I fail to see how it is "ridiculous" to name the field after the category of effects that dominate it.
I have no idea what your issue is with fluid mechanics, as fluid mechanics equations work despite the complexity (the equations contain the complexity as well, which does make them usually unsolvable in simple closed forms), but you have drifted completely off topic here anyway. -
#26 by colbourne on 03 Nov, 2018 02:55
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New antimatter gravity experiments begin at CERN
https://phys.org/news/2018-11-antimatter-gravity-cern.html?utm_source=nwletter&utm_medium=email&utm_campaign=daily-nwletter -
#27 by Nomadd on 07 Nov, 2018 08:32
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Just saw this.Somebody here .(I'm too polite to say who) is posting the most ridiculous load of scientific crap since the last Flat Earth Society meeting.
I'll say it, its meberbs.
Incorrect.
meberbs has a very good understanding of physics and is known around here for very good posts on the topic.The Doppler Effect with electromagnetic waves is a result of a receiver not being calibrated.
Incorrect.
This is one of many, many things you've said in this thread that are so completely wrong that most people on this forum will just give up on you and not even try to help you understand where you are wrong.
I admire meberbs for trying to help you understand what you're getting wrong. I wish you were more respectful of that.
You better believe incorrect. I respect few people more than meberbs when it comes to understanding and explaining physics. -
#28 by JohnFornaro on 15 Nov, 2018 13:00
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Just saw this.
You better believe incorrect. I respect few people more than meberbs when it comes to understanding and explaining physics.
Hah! I saw the comment "Spacetime flows toward mass" from a few days ago, and got a chuckle. I would have made a correction, but I was too late! Meberbs explanations are very helpful. -
#29 by Star One on 17 Nov, 2018 19:42
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China Plans to Build a Particle Collider Five Times More Powerful Than the LHCQuote
For about a decade, the biggest machine on the planet has been the Large Hadron Collider (LHC), situated on the border between Switzerland and France. The main body of the collider is a giant ring over five miles in diameter and the entire facility employs thousands of people. But according to a new announcement from China’s Institute of High Energy Physics, it might not be the world’s largest machine for long.
The Chinese institute announced plans to build its own particle accelerator over the next decade, and it’s designed to surpass the LHC in every way. According to the report authored by the institute, the upcoming collider will be over five times more powerful and over 20 miles in diameter.