>> Signal in LIGO/Virgo data. Most likely GravitationalWaves from a binary black hole source. Observed a few hours ago!
More at link: https://gracedb.ligo.org/superevents/S200219ac/
Mort Walker wrote:Dyson passed away on Friday 28 FEB 2020. He put the mathematical theoretical work for the development of the Feynman diagrams. It is too bad we've lost Dyson and I can only imagine if Feynman lived another 20 years, what he and Dyson would have uncovered.
Amber G,
My utmost parnam if you were one of Dyson's students.
Vayutuvan wrote:Very sad news. I heard it yesterday on NPR.
I think he should be added to the list of the greats who were overlooked by the Nobel Committee .
A cosmic ray detection experiment has found particles that just could be from outside our universe.The Antarctic Impulsive Transient Antenna (ANITA) researchers used a giant balloon to get electronic antennas high into the cold, dry air above Antarctica to identify cosmic-ray showers.They discovered particles may be moving backwards in time, indicating there is a parallel universe, where the rules of the standard model of physics do not apply.“What we saw is something that looked just like a cosmic ray, as seen in the reflection of the ice sheet, but it wasn't reflected,” Peter Gorham, a physics professor at the University of Hawaii, told Times Now.“It was as if the cosmic ray had come out of the ice itself. A very strange thing.He said the discoveries suggested signals came from upward-moving particles that tunnelled through the earth before erupting from the ice.The simplest explanation for the phenomenon is that at the moment of the Big Bang 13.8 billion years ago, two universes were formed.
Prem wrote:https://www.news.com.au/technology/science/space/nasa-reveals-existence-of-parallel-universe-where-time-runs-backwards/news-story/4ba8516b17d87bc5abd24d45c1aabcbcA cosmic ray detection experiment has found particles that just could be from outside our universe...<snip>
NASA has discovered that y'all should not be getting your news from the new york post
sudarshan wrote:Jalandhar to Dhauladhar - ~200 km. North Bihar to Himalayas - ~200 km.
Take the average scattering coefficient for dry air at various visible wavelengths - violet (0.4 mu-m), blue (0.45 mu-m), green (0.5 mu-m), yellow (0.55 mu-m), red (0.7 mu-m) and calculate how much of the incident energy makes it to a distance of 200 km. Rayleigh scattering (which is the relevant phenomenon here) coefficient decreases with the fourth power of wavelength, so there's a very strong (inverse) dependence on wavelength. This is why sunsets and sunrises are red - the blues and greens get totally scattered away over the long path through the atmosphere.
For 200 km distance, assuming dry air, about 37% of red light, 9% of yellow light, 2.7% of green light, 0.4% of blue light, and 0.012% of violet light can be expected to make it through - the rest is simply scattered away. Even a little bit of water will greatly reduce these numbers. This is why one sees hazy objects through fog. Particulates and pollutants will make that a lot worse - which is why one can't see even a few hundred meters through Delhi smog.
The blues and greens from those Himalayan peaks, making it to the eyes of viewers 200 km away, indicates that the air is practically clean of particulates (also quite dry). In the right circumstances, visible distance is a great semi-quantitative estimator of pollution levels.
Amber G. wrote:Speaking of light scattering.. a question, I often ask to physics students - why far away mountains look blue while sun around sunset is red.
(Blue light has smaller wavelength than red).
sudarshan wrote:What I don't get about this explanation - why should the mountain be a dark object? If it reflects reds at the viewer, and if (according to my above calculation, which I'm pretty confident about) 37% of that reflected red should reach a viewer 200 km away (assuming clean dry air), then the viewer should see that red also. One explanation - the mountain isn't reflecting red, but absorbing it. But this doesn't seem to be true, because when we go close, we do see reds and yellows from the soil on that same mountain.
Atomic scale structure of the single 4-atom acetylene-rotor molecule (grey-white spheres) on the chiral (i.e. having handedness) PdGa surface (blue spheres are Palladium and red spheres are Gallium).
The smallest motor in the world — consisting of just 16 atoms – measures less than one nanometer or about 100,000 times smaller than the diameter of a human hair. The rotor rotates on the surface of the stator and can take up six different positions.
The special feature of the motor is that it moves exactly at the boundary between classical motion and quantum tunneling.
Amber G. wrote:Meanwhile there are reports from Nordic and places (Netherlands who analyzed the data is also reporting this) that there is a increase level of radioactivity - some where in Western Russia there is a damaged fuel element at a nuclear power plant.
SriKumar wrote:Amber G....Any responses to 'why moutains look blue' question posed above?
sudarshan wrote:
What I don't get about this explanation - why should the mountain be a dark object? If it reflects reds at the viewer, and if (according to my above calculation, which I'm pretty confident about) 37% of that reflected red should reach a viewer 200 km away (assuming clean dry air), then the viewer should see that red also. One explanation - the mountain isn't reflecting red, but absorbing it. But this doesn't seem to be true, because when we go close, we do see reds and yellows from the soil on that same mountain.
SriKumar wrote:THanks. Appreciate your explanations. It appears that 'sudarshan' provided the most complete response. A couple of my points were on the right track but without the fundamentals on scattering.
Feel free to post more such questions....
sudarshan wrote:
What I don't get about this explanation - why should the mountain be a dark object? If it reflects reds at the viewer, and if (according to my above calculation, which I'm pretty confident about) 37% of that reflected red should reach a viewer 200 km away (assuming clean dry air), then the viewer should see that red also. One explanation - the mountain isn't reflecting red, but absorbing it. But this doesn't seem to be true, because when we go close, we do see reds and yellows from the soil on that same mountain.
As an interesting aside - a professor (of German origin) told our class group that he went all his life believing Mie was Chinese, but only recently (at that time - I think he was in his fifties) learned that Mie was a fellow German.
Amber G. wrote:To best of our understanding -
Yes heavier elements come from star core's but only up till Iron.
- Elements H, and He were there / got created around big bang...
- Elements from Li to Fe (Iron) are formed inside stars (Carl Sagan's words "We are star stuff")
Elements heavier than elements came from Nova/super Nova/ or Kilonova -- neutron stars collide. {new discovery}
- Theories / observed spectrums of Super Nova explosions accounted for nearly half of heavier metals nicely but not everything fit
-till the recent observation (observed from spectrum) sheds new light. About half of the heavier elements (like Gold, Platinum, Uranium) are from Neutron start collision...
And this discovery is quite important.. very big deal.
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