Questions tagged [estimation]
A rough calculation or an approximation of the value, number, quantity, or extent of something so that it is usable for some purpose even if the input data may be incomplete or uncertain.
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How accurate does the ISS's velocity and altitude need to be to maintain orbit?
We know the the ISS is not drifting weightless in space, but rather is constantly falling as it circles the Earth. To do this it must be at a specific altitude and moving with a specific velocity. ...
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Boat floatation load [closed]
I was reading about boats, from what i was reading a qubic meter of air should be able to float a 1 ton boat
so as far as i understand the equalibrium point will be if a boat wight is 1 ton - 1 qubic ...
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Is there an estimate for how many monopoles would be produced in the very early universe?
The question really hits it with this one. I haven't really found some good numbers other than the whole “It'd be so many (per Hubble vol) to recollapse the universe”. I don't know if that comes of as ...
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Does the Host Rock of This Mexican Hyalite Show Signs of Uranium Minerals? I Previously Cut It and Am Now Concerned
I previously cut a Hyalite specimen from Zacatecas, Mexico. Using a Geiger counter, I measured a slightly higher level of radioactivity on the cut surface compared to the environment. Although I know ...
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Does life erode Earth's mass over time?
Since life converts matter to energy, and there's no natural process that does the opposite (aside from supernovas), does this mean that the mass of our planet is gradually diminishing? I asked ...
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Bound states between neutrinos using Schrödinger's equation?
I would like to see if it's possible that neutrinos (with sufficiently slow velocities) could form bound states in a universe with matter (such as ours)
There is a cosmic neutrino background in the ...
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How many photons pass through us every second?
I just read this answer https://physics.stackexchange.com/a/229374, which says that, when a magnet rotates, photons are emitted with wavelength $λ=c/f$, where $f$ is the frequency of rotation. And ...
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How can I find the distance between planet and black hole?
With the movie Interstellar how I can find time dilation of the Miller's planet? Do I need find the distance between the planet and the black hole? Then I can find the time dilation?
If not, please ...
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Why can we use $|p| \approx\hbar /\langle x\rangle$ as an approximation?
In our lecture, the approximation for the zeeman energy shift is
$$\frac{2e \vec{p} \vec{A}}{2m} \approx \frac{e \hbar B}{m}.$$
Here, symmetric gauge was used (therefore $A \approx r B$) and my ...
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What percentage of light gets scattered by a mirror?
Sunlight strikes a mirror at a 45 degree angle. The vast majority of light will be reflected about the normal. Some light will be absorbed by the mirror. Some light will be transmitted through the ...
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Accelerating Expansion of Universe - Why Not Caused by Radiation?
As I understand it, dark matter and dark energy are used as an 'explanation' for how universe expansion is accelerating; because without it gravity would be expected to cause a long term shrinking.
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How many photons are received per bit transmitted from Voyager 1?
As of 2024, according to https://voyager.jpl.nasa.gov/ , Voyager 1 is around one light·day away from Earth and still in radio contact. When Voyager 1 sends messages to Earth, roughly how many photons ...
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Acceleration at peak of a gravitational wave
The amplitude of the strongest gravitational wave signal detected by LIGO sofar can maybe be expressed as an acceleration? If so, what would the numerical value be (in m/s^2)? I would like to compare ...
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Are these levels of RF radiation harmful?
I live on the top floor of a building that has four 5G antennas on the roof. The house is curved, and from my viewpoint, I can partially see one of the antennas pointing towards me. Curious about the ...
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Will a nuclear blast just above the surface of an asteroid push it, or just heat it and maybe produce outgassing?
Will a nuclear blast just above the surface of an asteroid push/nudge it, or just heat it and maybe produce outgassing? In other words, would nukes be actually useful to deflect asteroids?
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