I read in a book by professor Katie Mack "The End of Everything (Astrophysically Speaking) in chapter 6 titled Vacuum Decay on page 143. A graph of False Vacuum versus True Vacuum energy levels was shown. Before asking Physics Forums for a more detailed explanation, I did look up on Wikipedia...
MOND, as proposed by Prof. Mordecai Milgrom, is an empirical equation. It does correctly predict gravity at stars in the very weak gravitation regions in our Milky Way galaxy and correctly predicts the speeds of their rotation curves. According to Professor Alexander Deur gravitational fields...
Please keep in mind that batteries are correctly tested under a substantial load for that battery. Car repair shops have a meter that draws a substantial percentage of current and then measures voltage. You cannot conclude that your battery is good by measuring voltage while drawing microamps by...
This article cover some theories about the formation of rings https://arxiv.org/abs/0912.3017
This very detailed paper, of 76 pages, discusses different mechanisms for the creation and maintenance of Saturn's many rings. It is amazing how complex planetary astronomy can be. Thanks for referring...
What mechanism pulled small ice and stone particles preferentially into orbiting in the equatorial plane of Saturn? Is there a resonance involved? Wikipedia says that there is no consensus. What are some hypotheses?
After having done some research on carbon sources for renewable synthetic fuels, I would like to report on four sources:
1 Flue-gas emissions from fossil-fuel power plants. The cost here is $7.50 per ton. This is a bridge technology, since it still will emit fossil carbon dioxide. However, it...
The CO2 is removed from seawater, not from the atmosphere. It was stated in the report, that CO2 is much more concentrated in seawater than in air, and therefore cheaper to extract. It was stated in the report that the cost of purchasing and delivering aviation fuel to an aircraft carrier is...
The Sasol plants in South Africa are producing liquid fuels using coal and water as the source of energy and syngas, CO and H2. Some refineries are using natural gas as the starting fuel to produce liquid fuels. Both of these processes are not renewable.
The US Navy has a process to extract CO2...
If the telescope rotates with respect to the sun-shield, then the secondary mirror will be in sunlight. Please explain in detail.
If the telescope tilts, it and the secondary mirror will still be shielded.
I tried finding answers to the below questions on NASA's website and on Wikipedia, but was unable to:
1. How is JWST pointed? There does not appear to be any mechanism, as on a terrestrial telescope. Is the whole telescope with heat shield just rotated and tilted a limited number of degrees? I...
Alexandre Deur is a physics professor at the University of Virginia and a researcher at Jefferson Lab doing nuclear research. I suggest to be more careful in using one's words.
Below is a quotation of the summary of the above paper:
IV. SUMMARY The consistency of the standard Λ-CDM model of the universe in explaining many observations that would be otherwise problematic is a compelling argument for the existence of dark matter and dark energy. Yet, there are good...
After reading professor Deur's latest paper, arXiv:2108.04649v1, I was amazed by his insight into the mathematical similarities between gluon self-interaction in QCD and non-linear General Relativity by expanding the GR Lagraingian.
Prof. Deur's mathematical model fits the astronomical...
Inertia shows itself when you hit a pothole on the road, when you make a sudden turn without slowing down, when a tire is mass unbalanced and rotates. Inertia is a property of mass, but it is shows itself only when that mass is being accelerated.
Do physicists have a deeper understanding of...
Specifically, how would graviton-graviton interactions increase the gravitational binding of matter?
I visualize that the beam of spacetime between two stars is very ordered, in that streams of gravitons from each star flow in very nearly anti-parallel paths. Will these gravitons interact?
Light...
Newton thought of gravity as action at a distance. Einstein showed that gravity is the curvature of space-time. Einstein's General Relativity is the best answer, but neither discusses gravity at the quantum level. I tend to think of gravitational force to be the result of matter interacting with...
If I say that a star on the other side of the galaxy has an almost negligible effect on our Sun. The main gravitational effect is due to Sagittarius. Is this statement correct?
Answering what General Relativity is: General relativity posits that gravity is a geometric property of...
Does intervening mass between two stars decrease the gravitational attraction between these two stars?
Is gravity a local phenomenon in that local mass interacts with the surrounding gravitational field caused by the local star and distant stars?
Please correct my statements: By definition, the ecliptic plane is the path of the Earth around our Sun. Beta of Earth is 0.0000.
The ecliptic is very flat since Jupiter is only 0.5 degrees off the ecliptic.
From Wikipedia: " The ecliptic is actually the apparent path of the Sun throughout the...
Both YouTube videos simulating the evolution of spiral arms were very interesting.
Quote: "Gravity (mostly dark matter) holds the galaxy together."
How is dark matter distributed across the Milky Way galaxy? Is it like a flat pumpkin or a donut? It probably has a more complex shape.
Gravity, inertia, conservation of momentum and angular momentum are some of the forces and conserved quantities that I could think of which will tend to maintain the shape of the Milky Way.
How is the separation of the spiral arms maintained?
Thank you all for your answers.
In the meantime I did more searching at NASA and reviewing in a physics textbook.
As you know, the radiative heat loss is calculated by the Stephan-Boltzmann Law, S = 5.67x10^-8 times (difference in absolute temperature)^4power. Any activity on the Moon or Mars...
Electric power will be needed when man and women settle on the Moon or Mars. I have read read in magazine articles and on the Internet that small nuclear power plants have been proposed to produce electric power.
The main question on this post is: How can heat be removed from such nuclear power...
Heat cannot be removed by liquid-to-gas heat exchangers since there is no substantial atmospheres on the Moon or on Mars. It cannot be dissipated by venting steam since there is a critical water shortage. It cannot be dissipated by rocks or soil since both are essentially thermal insulators. It...
Thanks for the link. I have read the article of the above link, and the observation of doctoral researcher Margharita Bettinelli.
Are radio telescopes more sensitive than optical telescopes since microwaves are less absorbed by clouds and water vapor in the air?
It must take a very...
Thank you for all your answers now and for a similar question during August 2020. I trust your informed answers and your knowledge of astronomy and physics.
Do you have a hypothetical reason to expect such variation?
The hypothetical reason is that light very slightly bends around the gravitational field of our Sun. When viewing Regulus on that date, the light coming from it will bend all around the Sun. Will that have a magnifying effect?
Twice a...
Has any astronomer observed any seasonal changes in the brightness of stars lying close to the ecliptic plane? (Other stars are: d Cnc b=+0.08, mag.=+3.9; d Gem b=-0.18, mag.=+3.5; a Lib b=+0.33, mag.=+2.7.) Once a year these stars are occulted by the Sun. What happens from the date of...
Thank you so much for your detailed explanations.
Since I have time, I will now study up on group theory.
(I read in Wikipedia five or six times a day and contribute monthly.)
Currently, I am reading a textbook on linear algebra.
Also, I have read a book on Special Relativity and have started...
Is gravity as described by Newton considered Abelian? From the above answers: General relativity and graviton self-interactions are non-Abelian. The sequence of transformations make a difference in GR. Are these statements correct?
I have read the paper arXiv:0901.4005v2 by A. Deur (and do not follow most of the mathematics). From my mathematical background, I do know that non-commutative means a x b is not equal to b x a. From Wikipedia, rotating something 90 degrees along one axis and then 90 degrees along a different...
I remember 60 years ago, similar arguments were made about the "unknown" harms of smoking. It stands to reason that smoking your lungs for years cannot lead to a good outcome. However, a belief is not a double-blind experiment. The argument by the tobacco lobby was that there is no scientific...
Janus wrote: "And there are such thing as variable stars. Mira is one example. It has a period of ~332 days, and can actually vary enough in brightness to go from not being visible at all with the unaided eye to being one of the brighter stars in the sky."
How can a star change brightness to...
Since the Earth orbits around the sun and very slightly changes its relative angle and position, does the brightness of a particular star change from season to the season?
I read in a book "Quantum Space" by Jim Baggot, page 290, that the entropy of an object is inversely proportional to its temperature. (He was describing the temperature of a black hole. Does this statement only apply to black holes?) No doubt he is correct, but wouldn't an increase of energy...
Having read many times that there is no theory of quantum gravity, yet physicists at Physics Forums must have some ideas of what a theory of quantum gravity will contain.
Is it allowed to discuss these questions at Physics Forums? Wikipedia does allow some current theoretical work to be...
I did start to read "Gravitation" at a local university library, until it closed to due the corona virus pandemic. (A big black book by Misner, Thorne and Wheeler.) This is absolutely the most difficult book that I have ever read. Among my many deficiencies is the level of mathematics required...