Science topics: AstrophysicsSpace
Science topic

Space - Science topic

Explore the latest questions and answers in Space, and find Space experts.
Questions related to Space
  • asked a question related to Space
Question
33 answers
Human dynasty in its millennium era. We have identified fire from the friction of stones and now we are interacting with Nano robots. Once it was a dream to fly but today all the Premier league, La liga and Serie A players travel in airplane at least twice in a week due to the unprecedented growth of human science. BUT ONE THING IS STILL ELUDING IN THE GLITTERING PROFILE OF HUMAN DYNASTY.
Although we have the gravitation theory, Maxwell's theory of electromagnetism, Max Planck's Quantum mechanics, Einstein's relativity theory and in most recently the Stephen Hawking's Big bang concepts...… Why can't we still revert back and forth into our life?
Any possibilities in future?
if not..
Why? in terms of mathematics, physics and theology??
Relevant answer
Answer
Dear Shuraik Kader,
Given Albert Einstein's theory of relativity, cosmology regarding the development of the universe, quantum mechanics, future technologies for building interplanetary spacecraft, etc., time travel is theoretically possible. But in practice the building of a time machine by humans is impossible. Even if a man would achieve the required technological development in the next several hundred years, unfortunately he would not have enough time for it. First of all, a person must first solve other global problems, such as the necessary one is urgent, i.e. in the perspective of the next max. 2-3 decades of time, stopping or significantly slowing down the progressing global warming process, achieving zero-emission economy and avoiding a global climate catastrophe, which may occur at the end of the current 21st century. In order for man to be able to create new technologies of the future, to be able to build interplanetary manned spacecraft, etc., he must first save the planet's climate, biosphere and biodiversity from the risk of almost total degradation.
Best regards,
Dariusz
  • asked a question related to Space
Question
18 answers
Will man, thanks to technological progress, colonize the orbit of outer space in the 21st century?
Please reply
Best wishes
Relevant answer
Answer
Given the technological progress we are witnessing, I think it's only a matter of time before we reach out for the stars and attempt to make space our new home. Initial human settlements will probably consist of asteroid miners on the moons of earth and Jupiter. Eventually, their will be more humans living off of earth than on it.
  • asked a question related to Space
Question
162 answers
Do you think that man will ever leave our solar system?
Please, answer, comments.
I invite you to the discussion.
Best wishes
Relevant answer
Answer
Well, it seems like a utopia to me, but why not? Primitive man did not imagine that airplanes were created and one day could fly and it was achieved. So perhaps, within centuries, this purpose can be achieved as well.
  • asked a question related to Space
Question
6 answers
Hello everyone,
I want to write an impactful thesis within the real estate and/or the built space but I have a hard time figuring out a decent research topic. I'd like to perform a quantitative dissertation rather than a qualitative study. My interests are:
- proptech and disruptive RE business models
- new asset classes (e.g. data centers etc.)
Also, I want to use this platform to test my idea to write a thesis about Extraterrestrial Real Estate. However, there are not much academic papers to find yet and I can't seem to land a good research question. Any help is welcome!
Relevant answer
Answer
comfort of residents when isolated at home during the covid-19 epidemic.
  • asked a question related to Space
Question
43 answers
Will as a result of the continuation of technological progress in the twenty-first century more perfect telescopes or other astronomical instruments that will allow to know what is on the surface of the nearest exoplanets, and above all the guilty star systems similar to the Earth exoplanets located in other planetary systems circulating around other suns?
Please reply
Best wishes
Relevant answer
Answer
I think may be
  • asked a question related to Space
Question
16 answers
If a black hole swallows an object of mass "m" and the initial mass of the black hole being "M", then does the total mass of black hole be = M + m?
Will the Schwarzschild radius change accordingly?
Relevant answer
Answer
Your explanations about processes in the interior of stars uses terms of ideal gas theory. But actually, nuclear physics terms are needed.
  • asked a question related to Space
Question
14 answers
"THIS IS AN ABSOLUTELY SCIENTIFIC QUESTION"
The US Space Force formed by the administration of previous government is ready to begin its operations and test its weapons. And France, which in 2019 started a space defense program (Army Aerospace) said that by 2025 its program will be active. Looks like we're going to transfer "Cold War" to "Star War".
Now, officially, there are weapons placed in space appear to be a new form of intimidation between great nations. It's like science fiction, but it's not.
Tell us your scientific opinion on what you think about starting space offensives?
PLEASE ANSWER IN ENGLISH ONLY.
VERY IMPORTANT: Participate only if you are original, be yourself give your opinion, do not put links or texts from "Genio Google" or things found out there on the web! No one has any interest in stupid web answers, if that's the case, please be so kind as to ignore this debate! Also, don't post your hurts and hates, and don't deviate from the subject at hand, thanks.
SOURCE LINK:
Relevant answer
Answer
Actually, they are dangerous toys, wasting time, efforts, and money . Instead these efforts, time and money can be used in health sector to fight the diseases , in economic to fight the poverty and in peace against the wars .
  • asked a question related to Space
Question
2 answers
Dear colleagues,
Several scientists are curious and strongly interested to discover any evidences of life on the other planets of the solar system, as well as in the other places of the space. Of course, the scenario of strangers to visit the earth is one of the very exciting scenarios that are dealt with in hollywood. My vision of possible ancient life on Mars is presented in my commentary at the journal "Journal of Astrobiology", and is uploaded at the following link:
This topic is aimed to discuss the different opinions related to this very interesting subject.
Thanks a lot for your comments.
Relevant answer
Answer
You are right, Edgars Alksnis. Let's wait untill we see what will be new in this issue.
  • asked a question related to Space
Question
33 answers
Supposedly Pioneer 10 will fly to the nearest Alfa Centauri constellation for about 10,000 years.
Will humanity manage to build a new generation of space ships that will be able to overcome such huge distances in the galaxy many times faster?
When could this happen?
Please, answer, comments. I invite you to the discussion.
Relevant answer
Answer
Dear Yoshinari Minami,
Thanks for answering the question:
If and when will humans be able to explore other planetary systems?
Thank you very much for providing interesting publications describing important issues of the discussed issues.
Thank you, Regards,
Dariusz Prokopowicz
  • asked a question related to Space
Question
32 answers
Why in spite of the many years of listening to radio waves emitted from various parts of the cosmos, did not there appear such, which would mean the possibility of existence in another cosmos of intelligent creatures?
For several dozen years, various astronomical programs have been running radio-frequency listening programs of various emission ranges to diagnose those that could be a testimony that somewhere in another constellation there is or has existed the civilization of other intelligent beings.
However, up to now, it has not been possible to diagnose such waves that could confirm the existence of other intelligent beings in the cosmos and thus other, developed forms of life.
Why has not it worked so far?
Why in spite of the many years of listening to radio waves emitted from various parts of the cosmos, did not there appear such, which would mean the possibility of existence in another cosmos of intelligent creatures?
Please, answer, comments. I invite you to the discussion.
Relevant answer
Answer
Dear Gerges Francis Tawdrous,
Thanks for the links to interesting publications on the topics discussed in this discussion. Yes, you indicated the key determinants related to the question: What contract can we obtain from other civilizations?
Thank you, Regards,
Dariusz Prokopowicz
  • asked a question related to Space
Question
4 answers
I'm looking for the original articles about magnetosphere physics that is written targeting the fundamentals. I'm highly interested in learning everything there is to know about the magnetosphere and how it interacts with the ionosphere.
Relevant answer
Answer
I think the best thing you can do to understand the basics of magnetospheric physics is to go through the following two books:
(1) Basic Space Plasma Physics By Baumjohann and Treumann
(2) Introduction to Space Physics By Kivelson and Russel
These two books discuss the basics of space physics in a detailed manner. I think it will be helpful to you.
  • asked a question related to Space
Question
54 answers
Relevant answer
Answer
Dear Dr. Filipe Wiltgen , Thank you for this brilliant scientific & technical question.
I think there is one impediment. It is about radiation.
Also, I believe the technology is already there, and some countries have made enough progress on incorporating this technology in their war machinery (as pointed out by Dr. P. Contreras )
Apart from this, I dream, one day I would be driving my bike or car that runs on nuclear fuel.
Best wishes and regards
Yoganandan
  • asked a question related to Space
Question
11 answers
I heard that some storm events can occur without any change in the Dst index. Significant change in solar wind parameters that are triggered by storms events, but, without any change in Dst? Is it true? If yes, can you please suggest some events (or articles) for example? I am really excited to plot them. Moreover, what are the possible reasons behind those effects?
Relevant answer
Answer
Generally a "magnetic storm" is defined by a decrease (negative values) in Dst from its quiet-time, near-zero baseline, something caused by an increase in the strength of the magnetospheric equatorial ring current. Magnetic disturbance can, however, be manifest in different ways, and the field is never completely still. So, you can see very mild levels of disturbance with only small decreases in Dst. Sudden commencements (that often precede storms) are manifest as an increase (positive values) in Dst.
  • asked a question related to Space
Question
68 answers
Space and time are continuous nature quantities. They cannot be changed or deformed. However, the dimensions (length and size) and duration of an object or event can be different depending on the local gravitational field and aging of the universe. Simply because Wu's Unit Length (diameter) and Wu's Unit Time (period) of Wu's Pairs - the building blocks of the universe, are depending on the local gravitational field and aging of the universe. For example, for twin brothers, one is measured 6 Saturn Feet height on Saturn and the other one is measured 6 Earth Feet height on Earth. The one on Saturn is taller, because Saturn Feet is longer than Earth Feet due to Saturn's massive gravity. (This is called Principle of Correspondence - for two corresponding identical objects or events measured by the corresponding identical Units, the amount of the unit quantity remains the same, such as the "6" in the example).
In addition, for the same object or event, subject to the unit length and unit time of the standards used in measurement, the amount of measurement can be different. For example, 2 feet is equal to 24 inches or 52.8 cm. And 6 Saturn Feet could be equal to 8 Earth Feet when measured on Earth.
As a result, the dimensions and duration of an object or event are not only a function of its local gravitational field and aging of the universe, but also the unit length and unit time of the standards used in the measurement which are subject to Wu's Unit Length and Wu's Unit Time of a reference object or event depending on the gravitational field and aging of the universe at the reference point.
In study gravity, there are three important laws. They are:
(1) F = G mM/r2 (Newton's Law of Universal Gravitation)
(2) F = mA (Newton's Second Law of Motion)
(3) dE/dr = A (Einstein's Spacetime with a curvature of acceleration)
Einstein combined (1), (2) and (3) and come out with Einstein's Field Equation:
dE/dr = GM/r2
Where E is an energy function (Einstein's Spacetime) and (1/r) is the curvature.
Einstein used a nonlinear geometry system such as Geodesics system then transformed to a normal Cartesian system on earth to present his fancy field equation.
Ruv -1/2 Rguv +Λ guv = 8π G/C4 Tuv
Where C is the Absolute Light Speed (3x108 m/s) on earth.
I have combined (1) and (2) with Wu's Spacetime Equation and Principle of Correspondence to develop Wu's Field Equation:
A = GM/r2
A = k1 lyy-2 and C = k2 lyy-1/2
tyy = γ lyy3/2
Where tyy is the circulation period of Wu’s Pairs, named “Wu’s Unit Time” of a reference subatomic object, lyy is the size of the circulation orbit of Wu’s Pairs, named “Wu’s Unit Length” of the same reference subatomic object , and γ is Wu’s Spacetime constant. This is called Wu's Spacetime Equation.
I first used local Wu's Spacetime System (a Cartesian system having Wu's Unit Length and Wu's Unit Time of a reference standard at a reference point with local gravitational field and aging of the universe) then transformed to Wu's Spacetime System on Earth (with the reference standard and a reference point on earth with earth gravitational field and aging of the universe).
a0 = δ γ-2 C0-4(GM/R2)
Where a0 is the amount of acceleration and C0 is the Absolute Light Speed on earth.
In comparison, both equations have a term G/C04 on the matter and energy side (right side). However, Einstein use his equation to describe energy and I use my equation to describe acceleration both based on a Cartesian system on earth.
Einstein's spacetime (energy function) is nothing but a continuum shaped function based on a normal earth Cartesian system. Like the dimensions and duration of an object or event, their nature values are dependent on their local gravitational field and aging of the universe and their measured values are further dependent on the reference point and its gravitational field and aging of universe.
Relevant answer
Answer
Saeed Shahsavari , Math's can't curve space! It can only describe the effect on light of space plasma particle interactions (e+/- fermion pairs found in massive abundance at varying densities <1018/cm-3 around massive bodies). In more dense media we call it 'refraction'. Look up 'graded index' lenses, in which we can rotate ('curve') light's optical axis at will. Maths is useful but it provides no physical 'meaning'. Maxwell's Near/Far field Transition Zones (TZ) are 'Two-fluid plasmas' doing the same, and modulating light speed to local c.
If unfamiliar, read Einstein's '52 re-conception of SR, or an intro is here;
  • asked a question related to Space
Question
20 answers
Russian project to explore the moons of Jupiter after 2030 will be based on the nuclear propulsion spacecraft "Nuklon" with an electrical energy power of 0.5 MW. Such energy power gives the opportunity to significantly increase a data transfer performance to Earth. In my opinion, the speed of data transfer can be increase to 100 Mbit/sec. This value will be enough to use 4K Video for the investigation of dynamic processes in the atmosphere of Jupiter and moons. What is your opinion about this?
Relevant answer
Answer
I did confuse confuse bandwidth with delay a bit, but not in recent comments, I think, because I realised I was doing it.
Unless the entangled pairs are prepared on earth and then half are sent to Jupiter on the satellite, which would require coherence lifetimes of years (many orders of magnitude above present lifetimes), a signal has to be sent from Jupiter at lightspeed (for instance a photon entangled with the state on Jupiter) to convey the entanglement information between the two sites before the quantum measurement, so that the half of the entangled state can be set up on earth. This means that the actual data rate is still limited by the bandwidth of the lightspeed signals, even if data can be sent with no delay,
I guess if zero delay was possible, it would still be useful, for things like steering a remote vehicle, or conversation.
I expect that each entangled state will carry 1 bit, one Q-bit.
I am not sure instantaneous communication will ever happen. It may. I don't understand it enough to be sure it can't work. I hope it may be possible. It would also raise lots of interesting problems with relativity. I wouldn't invest my pension on it, but I might invest fun money.
  • asked a question related to Space
Question
6 answers
Anomalies in Orbital Mechanics.
Relevant answer
Answer
Dear Sanjay Rohra , the atmospheric drag is directly connected to the square of the relative velocity of the atmosphere with respect to the satellite (note: orbit velocity is not "alone", you also have winds!). The more drag you have, the more the satellite will experience a force against its velocity and the spacecraft will start decaying. If you go low in altitude, the atmosphere is denser and this drop of altitude is faster. I hope this helps you! Regards
  • asked a question related to Space
Question
7 answers
With an ever-increasing number of known asteroids, it becomes more and more essential to have clear guidance on which objects to study first. To this purpose, estimating an asteroid "importance weight" might be helpful. However, while easy to say, it looks pretty complex to derive such a measure. Do you think this approach is feasible, and if so, what should this index include? Only research aspect or also the relevance of an asteroid from planetary defense and exploitation points of view? Please leave your comments here. Thanks.
Relevant answer
Answer
What about the scientific return of an asteroid mission? Up to now, stony (Eros and Itokawa) and carbonaceous (Bennu and Ryugu) near-Earth asteroids have been studied extensively, while in the main belt Vesta and Ceres have been visited by mission Dawn. Also, in the near future, mission Psyche will visit a metallic asteroid for the first time, and mission Lucy will explore some Jupiter Trojans.
What next? Is there any other type of asteroid to prioritize in order to help answering some important question?
  • asked a question related to Space
Question
5 answers
The current widely accepted relationship between LET and RBE is based on the DNA structure. However, when we want to inactivate an RNA virus such as SARS-CoV-2 with different particles (and different LETs), this model would not be valid as in the case of DNA, the model is based on 20 Angstrom separation between strands and the density of ionization events (attached figure). So, the question is whether a linear model is more appropriate for RNA? I mean, whether higher LET radiations cause higher RBEs in a linear model?
Relevant answer
Answer
My pleasure, Prof. SMJ Mortazavi .
  • asked a question related to Space
Question
6 answers
Countries launch satellites for several valid reasons, but now scenario is that many (in thousands) of these are longer working. Thus acting as space debris, these satellites and their non-working parts can collide with existing functional satellites and create more and more debries. Are we doing the same with space what we have done to our Earth or are some countries are taking some action. Please discuss.
Relevant answer
Answer
Hi Aman, some countries like France have adopted laws to prevent space debris. You will find attached a short presentation of this "French Space Operation Act". The main countries having space activities should adopt the same kind of laws. In addition, some projects are under study to remove debris from space ("Active Debris Removal" missions). Best
  • asked a question related to Space
Question
4 answers
Based on the information from the SpaceX Twitter account can be concluded that the Falcon9 and Starship will be used the Starlink communication antenna as well. What is your opinion about the type of this antenna? I think that it is a Phased antenna array or a digital antenna array. And you?
Relevant answer
Answer
Dear Vadym,
surely there is some paper or article about it, at least with conjectures. In any case I pass you this interesting video where he disembowels the antenna in a quite detailed way. I'm sure it will be of interest to you.
Best regards
  • asked a question related to Space
Question
29 answers
On the surface of the planet Mars are the basic components, organic elements and chemical compounds necessary for the cultivation of terrestrial plants on Mars.
There is water on Mars (saline, it would have to be desalinated) and on the surface of Mars there are elements necessary for the development and cultivation of plants.
There is, however, no atmosphere with the right composition for the earth's plants, which could possibly be cultivated in the future on Mars.
In the next few decades, will human civilization reach such a level of technological development that Mars should begin to grow plants and begin to colonize Mars by building specific stations and cosmic bases there?
In the light of the above, encouraging discussion, I turn to you with the following question: What technologies should be developed on Mars so that plants could be grown on Mars in the future?
Please, answer, comments. I invite you to the discussion.
Relevant answer
Answer
All the conditions necessary for plant survival should be created in Mars.
  • asked a question related to Space
Question
4 answers
Dear all, I'd like to open here a sort of forum for understanding how the geodesists community is moving in view of the X-band SAR satellite constellation. The new constellation will offer new "free, near real-time SAR data" with the "latest information about any spot on the planet within the hour". This will open completely new horizons for InSAR monitoring of ground deformation especially for rapid phenomena such as eruptions and seismic crises. The huge amount of so frequent data acquisitions will open also new needs for rapid and automatic processing. My question are: who knows more? Are you planning a routine use of these data? How?
Relevant answer
Answer
Wow, thank you. I'm looking for understanding their high-frequency repeated interferometry for ground deformation monitoring. Will data be open or should they be bought?
  • asked a question related to Space
Question
5 answers
I don´t have much knowledge about rockets and my short internet research didn´t gave me insights. I´m thinking often about how we could use our solarsystem to reduce environmental problems on earth, for example to dispose our rubbish or take the resources from asteroids.
The basis to any of this ideas have to be greenhouse gas free rockets. What is our current situation and what are the outlooks in the future?
Relevant answer
Answer
Space launch activity cannot be exempt from environmental impact. The problem is not related only to greenhouse gas emission but it is wider. Every technology has its own issue.
Solid propellants emit HCl and alumina particulate. HCl causes acid rain and, in combination with alumina and UV light, local ozone depletion is obtained. Moreover, small particles stay in the stratosphere and contribute to the radiative forcing of the Earth (balance between incoming and outgoing radiation from the outer space).
Liquid propellants (kerosene/oxygen) emit quite large amount of CO and soot. Also in this case, soot participates to radiative forcing of the Earth.
Liquid propellants (hydrogen/oxygen) emit water vapor and a huge amount of unburnt hydrogen. This H2 mixes in the plume with the atmosphere and causes post-combustion, incrementing local temperature as high as 2500 K. Locally, NOx are produced due to high temperature and, again, ozone is locally depleted.
Hybrid rockets emit soot. They are based on a diffusive flame so they are prone to carbon black formation.
Strictly speaking about greehouse gases, probably hydrogen/oxygen are less impactful. Currently, these effects are quite local but in the future we may consider them. this year we have just overcome the number of 100 launches in one year. Current forecasts are predicting a linear increment of launch rate in the next 20 years.
A clearer picture can be obtained reading the works by Marvin Ross, who is working on space launchers environmental impact since long time.
Here you can find one example.
DOI:10.1002/2013EF000160
Best
Filippo
  • asked a question related to Space
Question
4 answers
Dear all,
Which are the most applicable models to analyze the energy effect and thermal comfort?
Models applies especially to occupant-controlled, natural conditioned spaces, where the outdoor climate can actually affect the indoor conditions and so the comfort zone
Many thanks in advance
Elena
Relevant answer
Answer
You can find a good summary of the thermal comfort standards we use in our research in this paper: https://www.mdpi.com/2071-1050/12/22/9630
It includes criteria for naturally and mechanically ventilated, both with fixed threshold and adaptative models.
  • asked a question related to Space
Question
15 answers
Einstein said that energy (or mass) is equivalent to the curvature of the spacetime, based on the Einstein field equations. But I have some questions: What is the effect of energy on the spacetime itself? Are they independent of each other? Does the existence of energy lead to create the spacetime and vice versa in the evolution of the Universe known from the Hot Big Bang model? Is there another physical concept to relate them to each other?
Relevant answer
Answer
As per my arguments ,Energy can not warp space time. That is the main difference between energy and mass. Space time will be warped by mass not by energy. By this nature mass possesses inertia. Inertia is the main difference between mass and energy. Off course, the answer will be in quantum mechanics not in General Relativity.
  • asked a question related to Space
Question
37 answers
How to properly characterize a ten-dimensional space. How does it fit with the modern understanding of the environment.
Relevant answer
Answer
Six-dimensional space is any space that has six dimensions, six degrees of freedom, and that needs six pieces of data, or coordinates, to specify a location in this space. There are an infinite number of these, but those of most interest are simpler ones that model some aspect of the environment. Of particular interest is six-dimensional Euclidean space, in which 6-polytopes and the 5-sphere are constructed. Six-dimensional elliptical space and hyperbolic spaces are also studied, with constant positive and negative curvature.
Formally, six-dimensional Euclidean space, ℝ6, is generated by considering all real 6-tuples as 6-vectors in this space. As such it has the properties of all Euclidean spaces, so it is linear, has a metric and a full set of vector operations. In particular the dot product between two 6-vectors is readily defined and can be used to calculate the metric. 6 × 6 matrices can be used to describe transformations such as rotations that keep the origin fixed.
More generally, any space that can be described locally with six coordinates, not necessarily Euclidean ones, is six-dimensional. One example is the surface of the 6-sphere, S6. This is the set of all points in seven-dimensional space (Euclidean) ℝ7 that are a fixed distance from the origin. This constraint reduces the number of coordinates needed to describe a point on the 6-sphere by one, so it has six dimensions. Such non-Euclidean spaces are far more common than Euclidean spaces, and in six dimensions they have far more applications.
  • asked a question related to Space
Question
98 answers
One of the consequences of relativistic physics is the rejection of the well-known concepts of space and time in science, and replacing them with the new concept of Minkowski space-time or simply space-time.
In classical mechanics, the three spatial dimensions in Cartesian coordinates are usually denoted by x, y and z. The dimensional symbol of each is L. Time is represented by t with the dimensional symbol of T.
In relativistic physics x, y and z are still intactly used for the three spatial dimensions, but time is replaced by ct. It means its dimension has changed from T to L. Therefore, this new time is yet another spatial dimension. One thus wonders where and what is time in space-time?
Probably, due to this awkwardness, ct is not commonly used by physicists as the notion for time after more than a century since its introduction and despite the fact that it applies to any object at any speed.
The root of this manipulation of time comes directly from Lorentz transformations equations. But what are the consequences of this change?
We are told that an observer in any inertial reference frame is allowed to consider its own frame to be stationary. However, the space-time concept tells us that if the same observer does not move at all in the same frame, he or she still moves at the new so-called time dimension with the speed of light! In fact, every object which is apparently moving at a constant speed through space is actually moving with the speed of light in space-time, divided partially in time and partially in spatial directions. The difference is that going at the speed of light in the time direction is disassociated with momentum energy but going at the fraction of that speed in the other three dimensions accumulates substantial momentum energy, reaching infinity when approaching the speed of light.
Relevant answer
Answer
Dear Prof. Ziaedin Shafiei
As a conservative physicist & non-expert in relativity, I would like to answer your question in the following way, as it is elaborated in Landau & Lifschitz classical book: the Classical Theory of Fields. They introduced the idea of the light cone many years ago to described events in space-time in a general way. For them: time is an axis, space is another axis & 1/c the inverse speed of light is the slope of the plot. Hereby, my answer is: t is the time.
  • asked a question related to Space
Question
9 answers
Hello dear academicians,
I control my system with a LQR . My input (u) is torque produced by 3 reaction wheels. These wheels are connected to DC Motors. Reaction wheels inertias are already added as a B matrix without motors. I want to integrate the wheel's DC Motor's dynamic model into the system. But I am confused a lot. You can see my system's Simulink diagram below.
Can you help me please?
Sincerely.
Relevant answer
Answer
Most likely you have solved this problem few months ago. I guess you were confused because the flywheel is driven by the DC motor and both have different inertias. So, you were unsure of how to unify the dynamics for the LQR design. I have uploaded a method. If you are interested, you can find it here:
  • asked a question related to Space
Question
2 answers
Which ozone sensor is perfect for
Balloon-borne Space Exploration project at a altitude of 40 kilometers? Please specify the model no also.
Relevant answer
Answer
Mmm.
At that altitude the concentration is ~10^11 molecules per cc.
I doubt that a COTS ozone sensor designed for use in 1 bar would be useful.
(at rtp there being 10^20 molecules per cc, give or take)
So a sensor would need to have 1ppb as its upper range, and have a resolution ten times better than that at least.
A spectral absorption method appears to be the best bet:
And you may need to 'fold' the optical path a few times to reduce the upper detection limit to the desired value. A Heriott or White cell may help.
The absorption of interest is in the 250nm range:
...and LEDs are available nowadays that can provide significant flux at those wavelengths - so no need to look at D2 or Xe lamps!
  • asked a question related to Space
Question
3 answers
I was once told that stable isotopes of lighter elements such as H, N C , etc are found in stars, planets, etc. Can anyone suggest any literature which talks about the formation of these isotopes?
Relevant answer
Answer
The lightest elements (mainly hydrogen and helium and in trace amounts lithium and beryllium) were formed about 100 seconds after Big Bang through the Big Bang nucleosynthesis (this process lasted up to 20 minutes after Big Bang).
After the formation of stars new elements, from helium to iron, are produced in stellar nucleosynthesis (thermonuclear fusion: CNO cycle, proton–proton chain reaction and triple-alpha process) during stellar evolution.
Elements higher than iron are produced in supernovae through the r-process and s-process.
A very good book about this and generally about properties of stellar interiors and the structure and evolution of stars is: "The Physics of Stars" A. C. Phillips.
About the nuclear physics of stars, you can see also a book of Christian Iliadis "Nuclear Physics of Stars".
  • asked a question related to Space
Question
4 answers
In the immediate future, ( a half century or less) , Mars Adventure will entail robots colonising Mars and the immense benefits, it will accrue to techpreneurs, will be mining Moon for lanthanides or so, will make them king like or trillionaires in the process. Aliens have remotely been encountered, physically, maybe once in 5000 years. If you consider us vs them theory , then it is 1:10000 or so, they should have colonised us long back.The odds are infinitely stacked in their favour. Problems do have a solution, for some, maybe, only in a long term one and so in the immediate scenario, it is impossible. Environmental problems are challenging , hence and some of it is gargantuam and are irreversible. Greta Thunberg has been rightly awarded " Person of the Year 2019" by TIME Magazine and this might instill eco-consciousness of the global society .I have revised special theory of relativity and concluded that: Cosmic Speed is one-third the speed of light.and this could be the reason for the above .Bernie Sanders, emergence as a Presidential contender, awakens the spirit of social consciousness that has been lagging in the past and need not bode well for the future as " Necessity is the mother of invention" . Welfare Economics need not produce or need not result in vibrant Innovative Economies.The Ultimate Adventure of the human species is to become a space- faring civilization could be termed a misadventure. An Endangered Planet's escapist nuances. The same tendencies that can cause extinction of this planet can as well destroy other colonised planets as well .It only needs a momentary lapse of reasoning. Does it mean we are waiting for the apocalypse.?
Relevant answer
Answer
Permanent human habitation on other planets, including Mars, is one of most prevalent themes in science fiction. As technology advances, and concerns about humanity's future on Earth increase, arguments favoring space colonization gain momentum.Other reasons for colonizing space include economic interests, long-term scientific research best carried out by humans as opposed to robotic probes, and sheer curiosity.
  • asked a question related to Space
Question
5 answers
Recently, researchers from Peking University reported large-area perovskite solar cells which were more stable 35 km up than at ground level. The researchers also tested the stability of the devices by sending them to an altitude of 35 km above the Inner Mongolia autonomous region of China using an high-altitude balloon. Scientists from UCL and ISIS also have been testing perovskite solar cells to see how resilient they are to the neutron irradiation they would be exposed to in space. These solar cells maintained good stability in space conditions. Now question is could we use perovskite materials for space applications? could these cells replace existing solar fits?
Relevant answer
I think the main advantage of the peovskite and organic materials that they are molecular in nature, very thin layers. So they can transmit the energetic space radiations rather than absorbing them. Even if they absorb a part of this radiation it will not affect much the carrier collection.
Best wishes
  • asked a question related to Space
Question
8 answers
The idea is to use a large asteroid and impact it again the desert to spread some powder at upper part of the atmosphere and create some shadow to lower Earth temperature some degrees.
Of course it could be done using a small rock to test it before.
ESA could make something useful again Climate Change instead of take measurements of it.
It cost is less to use a large asteroid than shut down all petrol or coal engines and could give some time for fusion and solar and wind generation
Relevant answer
Answer
Any geoengineering with the planet and climate change is terrible and highly dangerous. There is no way to foresee some awful unintended consequences of any human intervention in such a delicate and highly non-linear stochastic system as the Earth climate system (be it an asteroid or missiles spreading particles in stratosphere, or anything else similarly dangerous).
Please leave the planet alone and do not destroy it by any unwise human actions, and it will adapt itself to any changes, be it an atmospheric carbon dioxide or any other factor.
  • asked a question related to Space
Question
9 answers
What I think I need to know is:
1) What is the current accepted shape of the Milky Way galaxy, and its sub-parts, such as core, halo, etc? Some documentation shows a sphere for dark halo, but other documentation shows models suggest some disc shape.
2) What percent of total mass is found in each sub-part, such as core, halo, etc? If this number isn't actually available for the Milky Way, what reference for another galaxy would be appropriate to use as a stand-in until we know?
3) Recent reports suggest that the mass of the entire galaxy is 1.5 Trillion solar masses. Does the mass of dark matter, which might make up 90% of this mass in the dark halo, affect objects within the halo the same as any other lit mass? For instance, does a particle of dark matter pull objects just like a neutron of equal mass?
4) What is the current accepted density of each subpart? Is this somewhat standard for barred spiral and spiral galaxies? Are globular clusters counted in any sub-part, or do they need to be factored separately? I would prefer to have them separate.
5) Can some sub-parts be rounded to homogeneity, or are there very important filamentous regions that must be accounted for? I read that the spiral arms are barely more dense (max 5%) than the region medium in which they exist.
6) Relative to a central black hole, within a relatively circular total circumference of the galaxy, and another reference point in the plane, what is the approximate location of the Sun in the overall X-Y plane of the galactic disk? I'd like for the other reference point defining the general plane to be maybe a globular cluster or important mass feature I need to calculate anyway.
7) I also want to make a map of mass-induced gravitational effect on earth, relative to a person standing anywhere on Earth.
If I model each subpart and define its density in a 3D shape, and then trace a ray through each shape beginning at Earth and ending at the limits of the dark halo, I want to sum the gravitational effect of each section at each of any number of spherical coordinates. Is it sufficient to run an integral though each subsection based on distance and average sub-part density until I reach the next sub-part?
So if my ray passes through one part, the total would be integral of start to end of part, and the formula within the integral would be the gravitational effect associated with mass at the point on the ray. The sum of each sub-part integral should give the total gravitational effect from edge of galaxy to the point of earth, correct? I mean just from mass alone, not from other force interplay, or mass-like effects of photons. I realize almost all mass in the galaxy has zero effect on Earth, or nearly zero, but I need the sum for my model. The sum of that many not-quite-zeros is not zero.
If I do it this way, should I just calculate at an interval of kpc and sum the parts, or take the real integral return?
8) How do I take the Earth as a reference system and project the external mass map or gravity map as a sky? I know the sun is tilted relative to galactic center, and the Earth is tilted relative to the sun.
Assume I have a map of the Milky Way with the equator being the galactic plane, projected onto a sphere (skybox), what angle(s) do I need to apply to a skybox to make it accurate from Earth? Another example: If I have created a mass or gravity map as a sphere with the Earth at the center of the sphere, ignoring daily rotation of the Earth what angle do I rotate the sphere to make the galactic plane match what we see in the sky?
9) A basic calculation suggests that the general projection of the milky way stays generally in the same 1% arc of the sky for 640k years as we move around the galactic center (230Ma orbit time/360°). Is this relatively reasonable? Is a linear account of our changing sky acceptable, or are we much closer to the galactic center at some point of our transit, causing the projection of the Milky Way to change faster on the other side of the galactic orbit?
I love references. So far all the galaxy shape astrometry text and images I've looked at give zero references. Example: https://content-calpoly-edu.s3.amazonaws.com/evolution/1/images/3universe/0MilkyWay/Milky-Way-structure-table.jpg.
Any help with any of the sub-questions, or even just the method itself, is very much appreciated.
Relevant answer
Answer
For your Q8, to map the correct relative inclinations and intersections of the axes/planes/systems, you just need to know the celestial coordinates (RA & Dec) of their 3 "North poles":
  • Earth's spin axis: North Celestial Pole, Dec = +90° [by definition]
  • Earth's orbital plane about the Sun: North Ecliptic Pole, RA = 18h 00m [by definition]; Dec = +66° 33′.
  • Milky Way's Galactic plane: North Galactic Pole, RA = 2h 49m; Dec = +27.4°.
  • asked a question related to Space
Question
3 answers
I can calculate 1 MeV neutron equivalent flux and i want to get this damage in the irradiation test but I dont know how much flux is necessary to get this damage?
Relevant answer
Answer
In order to have a "1-MeV Equivalent Fluence" you will need to specify the material for the damage metric. ASTM Standard E722 provides the damage equivalent metrics at 1-MeV for both silicon and gallium arsenide. As chair of the ASTM E10.07, I produced a report on how the recent changes (2014) would impact the calculation of damage metrics:
"Silicon Damage Response Function Derivation and Verification: Assessment of Impact on ASTM Standard E722"
You can find it in my profile. The Appendices contain the response functions (E/EM cards) for MCNP to convert a fluence to a 1-MeV(Si) equivalent fluence. I recommend examining the E722 standard to grasp what the function is actually doing.
  • asked a question related to Space
Question
7 answers
I am searching about a software for analyzing of electronic and communication boards viewpoint of radiation tolerance. for example the output of this software is 40 krad. it means this boards can tolerate 40 krad in radiation environments.
Relevant answer
Answer
If what you are searching for is the capacity to simulate the damage in boards when irradiated, you could use TCAD for that (through the Sentaurus Workbench). Once the electronics is designed, it allows for a radiation damage model.
  • asked a question related to Space
Question
4 answers
What are the difference between the crystal structure, lattice parameters, and wyckoff positions of atoms in X2YZ system in L21 and B2 phases?
Relevant answer
Answer
You can follow
  • DOI: 10.1007/s10948-015-3149-8
  • asked a question related to Space
Question
8 answers
Hello all,
I am searching for research groups working in the area of space debris. I did some search on web and could only find natioanl sapce agencies/companies working in the field but could not find any pertinent research lab/academic working in the field.
If someone may suggest the same, it would be really kind.
Thanks
Relevant answer
Answer
Prof. Zhang Jingrui in Beijing Institute of Technology works in the field of space debris removal system and mission design. She is head of Distributed Spacecraft Systems Technology Laboratory (DSSTL) in School of Aerospace Engineering.
  • asked a question related to Space
Question
5 answers
We need more information about how the development of the human social repertoire is affected by city life.
Relevant answer
Answer
In the past the agoras in greece and the chowks in india served as social spaces in cities for human interaction .Now the parks serve as spaces for social interaction
  • asked a question related to Space
Question
1 answer
General relativity theory
Relevant answer
Answer
The problem is, pi is not transcendental. it is limited by the Planck length, then Tuv has to be corrected for the Combination elements, [{0,0}, {1,1}, {2,2}, {3,3}] to the permutation.
The reason is imply that the Combination elements do not qualify as representing nor evolving to any 'eigenstate,' and as such, are aberrations in the original [Schwarzschild] derivation, which Einstein never understood.
the result is that the minimal Information Threshold is then {0,1} AS representing the minimal requirement regarded as eigenstate, else evolved from some prior eigenstate. Consequently, when our coin lands heads, that does not mean 'tails' has ceased to exist; that would be the Destruction of Information, and as such forbidden.
Thus, the description for eignstate fails to regard Conservation of Information. Which is why Tuv is incorrectly presented as a Combination, which when presented, is obvious, and 'superposition' seems mystical; resolved upon Conserving Information.
use firefox [chrome does not work, i don;t know why] and try and read:
DESCRIPTIONS HISTORY AND DEFINITIONS OF THE QUANTUM ZENO EFFECT AND ANTI- QUANTUM ZENO EFFECT AS A PROPERTY OF THE EVOLUTION OF THE DESITTER HORIZON IN GENERAL RELATIVITY
  • January 2019
  • DOI:
  • 10.13140/RG.2.2.22174.59204/1
  • asked a question related to Space
Question
19 answers
I do think team working on a subject leading to reliable results more faster than doing research by a single worker. What do you think?
Relevant answer
Answer
Dear Dr. Javan Doloei , Dear all,
I completely agree with you Dear Dr. Javan Doloei . A harmonious team is an ultimate pleasure.
Best regards.
  • asked a question related to Space
Question
15 answers
Currently, sent probes to the planet Mars can provide valuable information. Based on these new information, it will be possible to get answers to particularly important questions.
The most interesting information that can really be obtained during flights to Mars is primarily the answer to the following questions:
- was there any life on Mars?
- if YES is in what forms this life occurred?
- Was there any water, lakes and rivers on Mars?
- Has there ever been a similar or somewhat different atmosphere on Mars, what was its chemical composition?
- whether there were climatic and natural zones similar to Earths on Mars?
e.t.c.
In view of the above, I would like to ask you: What else can you explore on the planet Mars and what questions do you get?
Please, answer, comments. I invite you to the discussion.
Relevant answer
Answer
It is impossible to be the climate on Mars similar to that on Earths, I imagine the climate on this planet is might be contains earthquakes and different circumstances such as temperature and humidity.
regards
  • asked a question related to Space
Question
7 answers
Using coherence band of Interferogram formation is enough for land deformation modelling or the interferometric phase should be unwrapped?
Relevant answer
Answer
Through the phase observations are suggestive of the wide‐area deformation measured, the atmospheric effects are large enough to limit the interpretation of the result. It is difficult to characterize centimeter‐scale deformations spatially distributed over tens of kilometers using differential interferometry without supporting simultaneous, spatially distributed measurements of refractivity along the radar line of sight. So coherence map is just an index but it is not enough.
Different studies imply longer wavelength instruments are more appropriate for studying surfaces by repeat‐pass observations.
  • asked a question related to Space
Question
10 answers
If so, when will new telescopes be constructed, thanks to which you will be able to see what is on the planets of other planetary systems in other constellations?
Every now and then more and more perfect telescopes are being built thanks to which photographs of other constellations and other galaxies are created.
Thanks to these photographs, the cognitive abilities in the field of astronomy are increased, among others the estimated amounts of stars, planetary systems and planets in specific constellations, galaxies.
Besides, thanks to these photographs, more and more perfect maps of the blue vault, collections of galaxies and specific segments of the cosmos are created.
For example, studies conducted in recent years based on new cosmic photographs show with previously unattainable accuracy the distribution of stars in the Milky Way Galaxy, in which there is a solar system with our Earth.
In April 2018, astronomers prepared a much more accurate than the current three-dimensional map of the Milky Way Galaxy.
This was done as part of a research project with a million dollars budget. As part of this research project and thanks to the space mission launched in 2013, the Gaia probe was developed a very accurate map of the Andromeda Galaxy and a new research material was created for the purposes of research into the analysis of the past and future of our Galaxy.
The research project was implemented by the European Space Agency. Based on this research project, the latest astrometric data set containing positions and self-movements of over a billion stars was made available.
Placed on Earth's orbit, the Gaia Probe has two optical telescopes and three scientific instruments that also allow to determine the brightness, temperature and chemical composition of individual stars.
In addition, the latest data set contains star colors that provide vital information about their surface temperature and age.
The Gaia probe also provided new data in the area of ​​13,000. asteroids circulating within the solar system.
In view of the above, the current question is: If so, when will new telescopes be constructed, thanks to which you will be able to see what is on the planets of other planetary systems in other constellations?
Please, answer, comments. I invite you to the discussion.
Relevant answer
Answer
First let me offer a minor correction: "Constellations" are configurations of the stars that appear in the night sky from the surface of the Earth that were grouped together by the ancient Greeks to symbolize mythological and other creatures. Constellations have no physical significance but they are very handy ways to locate astronomical objects in the night sky.
Other than the planets of our own Solar System I doubt that there will every be on planet Earth a telescope capable of resolving the surface of a exoplanet. All we can do is analyze the light we receive directly from the parent star and that reflected by the star's exoplanet.
  • asked a question related to Space
Question
51 answers
particle or a waves
Relevant answer
Reading you I remembered a sufi tale about six blind men and an elephant. keep going, maybe something interesting will come out
  • asked a question related to Space
Question
151 answers
It is well-known that the ground velocity of a plane or helicopter does not depend on relatively fast Earth rotation (~2000 km/h). But a rocket's ground velocity at the high enough altitudes does it increasing if the flying direction is close to the direction of rotation and vice versa.
What is the dependence of such a shifting on altitude?
Relevant answer
Answer
Thierry,
You are wrong. Coriolis and centrifugal forces are named fictitious because they don't exist in a proper inertial frame. If you need to check, look what happens in a rotating vacuum chamber, you will see air is not necessary
for Coriolis force to act.
  • asked a question related to Space
Question
7 answers
brain function and its signals are known to be affected by several things. one of them can obviously be gravity. is it possible that people become smarter on another planet or even have better memory? is brain function dependent on gravity at all?
Relevant answer
Answer
There is a paper in Cognitive Neurodynamics, year 2017 or 2016, that describes gravitational issues in the context of neuronal activity.
  • asked a question related to Space
Question
24 answers
Just imagine we are having to change our planets orbit to another one for reason like reduce its temperature or preventing to crash whit foreign object
How we can do it to survive?
Relevant answer
Answer
Earth's orbital elements oscillate around an essentially fixed mean over very long periods of time (e.g., eccentricity can increase to as much as 6% or decrease to nearly 0 in any given million year period) as a result of orbital interactions with the other planets. However, no conceivable human effort can affect the orbit by any significant amount. But efforts to avoid collisions with smaller objects can be fairly easily done. An asteroid 8 miles in diameter (a little bigger than the one that hit Yucatan about 65 million years ago) has a mass a billion times less than that of the Earth, and can therefore have its orbit changed with a billion times less effort than changing the orbit of the Earth. And the orbital change of the smaller object doesn't need to be very large. Since the Earth orbits the Sun at about 65000 miles per hour, it moves a whole diameter in less than 8 minutes, and half a diameter in less than 4 minutes. So changing the orbit of an impactor just enough to arrive at its original impact site 5 or 6 minutes earlier or later than it would have before changing its orbit is enough to prevent what would have been a direct collision with the Earth. It should be possible to create such orbital changes within a decade or so; the main problem at the moment is calculating the orbit accurately enough to avoid changing an orbit that would have missed the Earth into one that runs into it (as they say in medicine, "first do no harm").
  • asked a question related to Space
Question
20 answers
This works has been made within a project with the CNES (French National Center for Space Studies, during my studies in aeronautic engineer high school), within the project for the study of the sizing of the lauching pad of Ariane 5 project sattelite launcher.
I have made a lot of research to find if this theroem was known or not ?
I had never never found a reference ? May you help me please.
Before the theorem statement, just few recall :
1/ The aerodynamic drag is given (within special domain) traditionaly by : 1/2 Cx ro S v^2
    (ro being the air density, v the velocity (relative to air flow), and Cx the so called penetration coefficient)
    The term of interest in the problem is the S, which is called the "master couple, french traduction of the term used in french" which represents the projection surface of the body on a plan perpendicular to it's trajectory vector.
2/ The theorem I have demonstrated is the following statement :
   " The average master couple for any convex body over all orientations (then integrated over unit sphere, for projection axis) is equal to the "Exterior Surface of the body" divided by 4. "
[this is an evidence for the particular case of the sphere : 4 pi R2 / 4 = pi R2 projected surface equal everywhere]
I know that at the epoch, these formula was used by persons as an heurisic ?
3/ But my definitive questions are :
Is this theorem relevant or not ?
Is it an obvious corollary of convex mathematics ?
(which is from my point of view certainly the case) ?
PS = I have also demonstrated the exact formula for only one particular non convex body (in fact a surface, but this is just a question of factor 2) which is an angular part of a section of a cylinder). This is not really difficult but hardly analysis computational !
and an approximation formula for non convex body (but I do not realy know the quality)
and other few relative theorems (like the result for the union of two convex body creating another convex body)
Thx in advance for any kind of answer ?
Relevant answer
Answer
Dear Herve, I'am interested on your topic: do you have a paper/document on theorem's proof? Thanks.  Gianluca
  • asked a question related to Space
Question
19 answers
Hello, I'm looking for any books, theories, journeys etc about how architecture or/and space or/and materials or/and light affects on people lives or/and moods or/and health?
I would be grateful for any help!
Relevant answer
Answer
The entire architectural structure, from its design (form, structure, color) all have a great impact or influence on the mood and psychological experiences of individuals. 
Glassy architecture, wooden architecture, rattan architecture have a great toll on the residents' mood and experiences. The painting of special colors like the warm colors has been seen to increase the aggression of residents while cool/serene colors like blue calm down tempers.
Multi structures always stir the sensation of fear in some people especially in the local communities in Africa while single structures bolster confidence.
Since the psychological and mood implications vary based on the geographical and ethnological variances of people, care must be taken not to generalize the study of the phenomena among cultures. Therefore, a case/phenomenology approach will be appropriate in such studies.
The attached resource will provide a great deal of insight.
All the best
Dickson Adom
  • asked a question related to Space
Question
26 answers
Given is a finite, homogeneous, isotropic, three dimensional space with constant non zero curvature and a scale facter which is constant in time. Also given is an arbitrary geodesic in that space.
Does another geodesic exist, which at every point has the same nonzero minimal difference to the first geodesic?
If the anwer is no, do we expect consequences for photons with a non zero spatial extension travelling along a geodesic?
Relevant answer
Answer
It doesn't matter-there are boundary contributions, in any case and these ensure invariance under general coordinate transformations. It's this that implies that the notion of parallel geodesics is meaningless in curved spacetime. 
Once more, it's not useful to mix up space and spacetime: spacetime geodesics aren't geodesics on space-like slices.
  • asked a question related to Space
Question
7 answers
i try for finding by using the formula given in attach file but in vain. The reported value for a, b and c is same that i find for 'd'(inter planner spacing) in each case.i want to find a, b, c values by using 'd' in given formula.
Any body can help me....? 
Relevant answer
Answer
thanks all of you for my correction. 
  • asked a question related to Space
Question
3 answers
While I do IHC I could find lot of blank spaces some surrounding the parasite also.What  could be the reason for this and how could I prevent this?
Relevant answer
Answer
In order to properly address your question one should see either the slide (real or scanned) or a picture at the least. If your blank spaces represent unstained tissue areas the Gerald Niedobitek's answer should guide you. Another possibility is a tissue loss during the processing: do you see remaining unstained tissue in these spaces?
  • asked a question related to Space
Question
3 answers
What if we took the uranium atom into space? 
The purpose of the question I want to know is whether it will keep its properties or not ؟؟
Relevant answer
Answer
Yes. It will keep its properties, electronic and nuclear.
  • asked a question related to Space
Question
5 answers
Hi, can I fix a surface to surface contact between two surfaces which are spaces of 0.001 m?
Relevant answer
Answer
Valentina,
Ah, forgive me - I did not see the word 'abaqus'. I am unfamiliar with this tool and am unable to provide help.
  • asked a question related to Space
Question
3 answers
I understand that TOD development can also promote to use the urban transport. I am also curious about creative urban space and related with automobile usages. 
Thanks,
Taryar
Relevant answer
Answer
  • asked a question related to Space
Question
5 answers
If Colombeau's algebras existed, what led to the construction of simplified algebras?
When we are faced with an ordinary or partial differential equation, linear or non-linear, how do I decide to attack the problem by one or the other? How do I decide which one is best for each case?
What function is in the plenums, but is not in the simplified? The space of the continuous functions are not totally immersed in simplified GF?
Is there a differential equation that has a solution in one algebra in the other? Because del-bar is solved in the simplified, can also solve in the plenums?
Relevant answer
Answer
Caro Paolo,
Thank you for rapid answer, I am very happy with your answers.
Best regards,
Antonio Ronaldo.
  • asked a question related to Space
Question
1 answer
I need a new definition for infinite-dimensional vector space that don't admit Hypercyclic Tuples.
Relevant answer
Answer
First, explain what Hypercyclic Tuples are and why you do not want them.
  • asked a question related to Space
Question
3 answers
I'm working on experimental aspect of weak polyelectrolyte (polyacrylic acid). Can anyone please suggest  me whether the average spacing between the monomers  changes by altering pH of the medium? If so, plesae suggest me how to calculate it?
Relevant answer
Answer
You need to determined the degree of charge of your polymer as a function of pH. The easiest thing is to perform a potentiometric titrations. Once you know the fraction of charged units you can easily calculate the mean distance between the charges.
  • asked a question related to Space
Question
2 answers
I have a row of 6 circular pile spaced at 4m.Each pile is suppose to carry 400kN.I want to model this piles as an equivalent wall.How do I get the equivalent wall thickness and the equivalent load to apply to the wall?
Relevant answer
Answer
Not ideal, but you can calculate an equivalent section with the same moment of inertia per metre and together with the load per metre; should give a rough estimate for plain strain conditions.
Good luck 
  • asked a question related to Space
Question
3 answers
Where the border in the space strictly separating the expansion of the space from the expansion within the space. 
Relevant answer
Answer
For objects that are close to us, the expansion velocity due to Universal Expansion is negligible, so their Doppler shift directly corresponds to their motion relative to us and our surroundings. For objects at large distances, where the Universal Expansion is the main component of their Doppler shift z, things are far more difficult. There are techniques that provide redshift-independent estimates of distance, but they usually have large error bars, far greater than any normal "real" motion of an object relative to its neighbors. So in most cases involving distant galaxies we probably can't measure the "real" Doppler shift that you are talking about.
There is an exception, however. In rich clusters of galaxies, the individual galaxies may have real motions relative to their neighbors in excess of 1000 km/sec, so that some of the galaxies appear to be receding from us as much as 2000 km/sec faster than others (the difference between those going away from us relative to their neighbors, and those coming toward us relative to their neighbors). I recall seeing a visual representation of the distribution of galaxies in space done about twenty years ago, which had many linear structures pointing directly toward us, as though the galaxies in that region were lined up with our position. What was really happening was that the average position of the linear structures represented the probable location of a cluster of galaxies, and the linear structure was caused by the galaxies moving toward us being interpreted as being closer to us, and the ones moving away from us being interpreted as being further from us. So for a rich cluster of galaxies you can measure the radial motions of the galaxies relative to the cluster as a whole by comparing their recessional velocities to the average recessional velocity of the cluster. That still doesn't tell you their actual motion relative to us, unless the overall motion of the cluster itself can be independently determined; but it does yield something close to what you are looking for.
  • asked a question related to Space
Question
4 answers
Methods to study the behavior of people in urban spaces
The impact on the behavior of people in urban spaces
What is a behavior patterns?
  • asked a question related to Space
Question
7 answers
What is space of function s.t. D^{alpha}J^{alpha}=J^{alpha}D^{alpha} where D^{alpha} and J^{alpha} are fractional differential and Integral operator.
Relevant answer
Answer
Dear Joachim,
Thank you for your comments regarding the domain for the  commutator D^{alpha}J^{alpha}=J^{alpha}D^{alpha} with alpha being fractional.  
Since the domain contains the set of polynomials, it may extend to the set of analytic functions along with appropriate closure, which will depend on how to compute the commutator [D^{alpha}, J^{alpha}] in certain integral form.
The review article "A Review of Definitions for Fractional Derivatives and Integral" also gives detailed exposition about the calculus-wise origin for the definition of the fractional derivatives.
Best Regards, Shijun 
  • asked a question related to Space
Question
2 answers
My question relates to the implicit assumption that topologically associating domains(TAD) have to be contiguous along the genome.  This seems odd to me given that the DNA molecule exists in a 3D space while this contiguity criteria relates only to the 1D genome coordinate, which might not be appropriate to delimit interactions in a 3D space.
Consequently I am wondering if I'm missing anything obvious to impose such a criteria to characterise TADs.
Thanking you in advance.
Relevant answer
Answer
Hey Nouratan Singh ,
Your answer doesn't seem to tackle directly the necessity for contiguity, though it does highlight that current method for detecting TADs rely on pairing up 'borders' regions that display distinct genomic features like expression activity, suggesting that this contiguity appears to be more of a technical convenience for interpreting those border regions?  Your example with centromere and origins of replication concerns a minority of TADs hence I don't know if this justification can be used as a rule for all TADs.
  • asked a question related to Space
Question
4 answers
Hello,
I need to know what is the benefict of using the graph theory for solving some mathematic problems,  ( when we projected them in this space) and what's the best references of graph theory and its applications.
Relevant answer
Answer
Ok, you would need to tell us more exactly.  I am a bit puzzled by your questions. Graph theory is part of combinatorics. It is often studied in under-graduate modules in mathematics degree. 
As you do not provide more information. I would recommend you to look at Cartesian Genetic programming. It can solve some mathematical problems by using evolution on a graph-based encoding scheme. 
  • asked a question related to Space
Question
6 answers
I have published an overview of a theory, but want to seek advice for publishing further details related to this. The original publication was a broad overview, and there is substantial detail (including constructs not previously mentioned) that could not be provided due to space constraints. Does anyone have experience or advice publishing this kind of material? Any thoughts much appreciated.
Relevant answer
Answer
Hello,
Without knowing all the details about how the second publication might differ from the first publication it is difficult to offer advice. However, definitely read the APA manual on the issues of dual publication, least publishable unit, etc. When submitting to a journal be sure to alert the editor in your cover letter and the readers that your submission/article is an extension of the prior publication. The APA and the journal editor will want transparency so being upfront is important.
  • asked a question related to Space
Question
8 answers
How to find out the hkl values and phase corresponding to the smaller d spacing (below 1,eg.0.279) obtained from SAED pattern analysis?
Relevant answer
Answer
Thank you sir..
  • asked a question related to Space
Question
2 answers
Hi friends.
Can you give structural positions of Sm2O3 with P-43n as the space group
Relevant answer
Answer
Mr. Samuel,
For the requested space group you have to dispose 13 atoms Sms and Os with ratio 5:7.5, because of the main composition is SmO1.5. The space system is cubic and the transformation can be found here (Cubic space system, space group 215):
You should place 5 full occupied positions to Sm atoms; and 7 full occupied positions to O atoms. The 8th position of O should be half-occupied (or 1/2). The total number of occupied positions should be kept (13). 'Half-occupied position' means '1/2 electron density', computing properties of such as system.
For example, if the oxidation states of your ions are:
Sm3+ and O2-
Full occupied position means:
Sm3+ with electronic configuration [Xe]6s24f3 (59 electrons)
O2- with electronic configuration [He]2s22p6 (10 electrons)
Half-occupied position means:
1/2O2- with preliminary unknown electronic configuration (most probably [He]2s22p1), but with 5 electrons around one isolated in the 3D space O-nucleus.
  • asked a question related to Space
Question
3 answers
Coherence of two electromagnetic waves takes place if their phase difference is: (i)Constant in time (ii) Constant in space (iii)Constant in time and space
Relevant answer
Answer
iii
  • asked a question related to Space
Question
6 answers
If the space is the same why the Relativity Teory doesn't connect with quantum mecanics?
Relevant answer
Answer
Yes I do.
See eq. 22 in the following note https://arxiv.org/abs/1609.06208 
It derives from a fundamental and Euclidean approach, independent by Relativity Theory, and it can be applied to a newtonian system as well as a electrodynamic system
  • asked a question related to Space
Question
3 answers
Solar atmosphere causes difficulties in communication during opposition (when Mars is almost behind the sun w.r.t. Earth).
The question is: is it possible to define an extended radius for the sun, which the Earth-Mars line of sight should never pass through it? if there is, how much is it, in terms of angular separation?
I've read in some mainstream and NASA news that there is a two week blackout period during each synodic period of Earth-Mars. But I want to know the exact numbers. I'd appreciate any answer with technical references.
Relevant answer