eshaya
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Does the Earth orbiting around the Earth-Moon barycenter cause a measurable centrifugal force?
2 votes

The Earth and Moon are in orbit about each other, which means that the centrifugal (outward inertial) force $M_iV_i^2/d_i$ is balanced with the centripetal (real inward force), ie $GM_{\oplus}M_{\...

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Deriving Dark Matter; specifically looking for a table of stellar speed versus distance from center of galaxy to derive dark matter
2 votes

It is very difficult to measure Galactic orbital speeds of stars in our galaxy for several reasons. We are moving with them and do not have a reliable measurement yet of even our own orbital motion. ...

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Can a Neutron Star become charged?
2 votes

The pressures are so great in a neutron star that most of the electrons combine with protons and become neutrons. A statistical equilibrium is set up in which neutrons, because they are unstable, ...

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If a rocky world is large enough (not a gas or ice giant) can it have helium from the primordial disk in its atmosphere?
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2 votes

The snow line is the inner radius from the star where the water condenses onto dust and larger particles as ice (ie snowballs). The hydrogen and helium never freezes out. Planets start forming by ...

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What complementary observation campaigns have looked at Kepler's field of view?
2 votes

The Kepler Field had been covered in the near IR by the 2MASS catalog since that covered the entire northern sky. There was also a Smithsonian Institute program called the Kepler Input Catalog ...

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Photodetector Question: Does converting an RGB image to grayscale produce the same result as using a grayscale image detector?
2 votes

Really, all cameras/detectors are greyscale detectors. Every pixel in a CCD detector puts out a single number for the number of photons it detected. To create an RGB image you need three filters. If ...

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Are there events in universe which we receive first from their neutrino's instead of their photons?
2 votes

Yes. When a core collapse supernova happens, it takes a few hours for the shock wave to reach the surface and "break out" (when we first "see" it). Meanwhile, the neutrinos can escape nearly directly ...

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Is the diameter of the observable universe a relative quantity?
2 votes

What would an observer see if they were moving at nearly the speed of light? They would see distances along the direction of motion appear shorter, but perpendicular to that direction distances would ...

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Question about total absolute magnitudes of galaxies - negative or not?
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2 votes

The morphological properties of galaxies between 21 mag < I < 25 mag in the Hubble Deep Field are investigated using a quantitative classification system based on mea- surements of the ...

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For how many bodies can there be a stable orbit with no very heavy central body?
2 votes

It is not unusual to have pairs of pairs or even more complex stellar systems. Two stars make a stable pair. A pair of these make a stable system and a pair of these would also make a stable system. ...

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What are the arguments against the Feng and Gallo thin disk explanation of galactic rotation curves?
2 votes

Feng and Gallo and others before them ask the question, what is the expected mass distribution derived from the rotation profile, assuming that the matter is distributed entirely in the disk (ie. in a ...

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What is the explanation for rapid inflation just after the big bang?
2 votes

With normal matter, the strength of gravity depends on the stress-energy tensor, which, in an isotropic homogeneous universe, has trace of $\rho + 3p$. Note that the pressure from relativistic ...

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What is the degree of ionization is the solar photosphere?
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2 votes

The degree of ionization in the photosphere varies with depth of course, but overall it is small. Table 1 of the Bilderberg Continuum Atmosphere (Solar Physics, 3, 5, 1968) gives the pressure and ...

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How is the universe bordered?
2 votes

Your intuition is correct. It does not really make any sense for the universe to have a border. Would it be an unbreakable wall? What would be on the other side? Models with a finite universe would ...

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Accretion of in-falling material for a young main sequence star
2 votes

At the end of the protostar phase a vigorous outflow from the star develops called the T-Tauri Wind and this could cut off accretion. Eventually, it develops into a normal star and the strong wind ...

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Is there a paper on galaxy mergers in clusters of galaxies?
2 votes

Galaxy mergers in clusters explain the large central galaxies in clusters. In fact, the centers of clusters often host a special type of galaxy called a cD which is usually extremely massive because ...

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What is a hard spectral state vs. a soft spectral state?
1 votes

Active galaxies are known to change state as seen by a change in slope of their X-ray and gamma-ray spectra. We say that a spectrum has become harder (or changed to its hard state) when the slope ...

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What is the antonym of "closest approach"?
1 votes

Historically, astronomers focused on the easier to measure conjunctions, since getting distances is very hard, so knowing exactly when greatest distance occurs was not possible. Planets interior to ...

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How well is Earth’s motion through the universe quantified?
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1 votes

Surprisingly, we will soon be able to do this well enough to go back several hundred million years and place ourselves, if not in the solar system, inside the Galaxy and roughly in the right part of ...

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Sunlight intensity during a day
1 votes

The sunlight intensity is the cosine of the sun's elevation angle $\alpha$. How to calculate the position of the sun is described simply at PVEducation.com. To summarize the relevant equations: $\...

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Units of integrated flux density (irradiance) along longitudes
Accepted answer
1 votes

You could say "MJ in bins of x degrees in l" where x is the degrees spanned by a pixel. Or, you could divide the fluxes by the steradians in each column and keep it MJ/sr or "Mean MJ/sr within ...

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Why is NEOWISE used for galactic observation?
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1 votes

After WISE ran out of cryogens to cool its detectors it was re-purposed to look for asteroids. This was possible because the detectors for 3.4 microns and 4.6 microns could work at higher ...

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Star systems forming when large gravitational force is applied
1 votes

Most binary stars are believed to have formed together as they condensed out of a common rotating dense cloud of gas and dust. A few more form when, coincidentally, two are ejected from a cluster at ...

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How did Bradley arrive at the +/- correct speed of light when he calculated it?
1 votes

The velocity of the Earth going around the Sun changes such that the sign changes every six months. Therefore, the part of the aberration due solely to the Earth's motion about the Sun also changes ...

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Does our current understanding of the mass of black hole only allow for it to be located at the singularity?
Accepted answer
1 votes

As a star or neutron star collapses to form a blackhole there will, of course, be a moment when the matter is distributed everywhere within the event horizon. So, there may not be a singularity ...

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Is TESS replaceable by gound-based-small-telescope arrays?
1 votes

I think the biggest issue is the precision of the photometry. The atmospheric turbulence limits ground-based photometric precision to 1%. In space, Kepler achieved about 0.001% on bright stars over ...

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Question regarding the Milky Way when calculating galactic space velocities for galaxies
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1 votes

v$_r$ and μ are radial velocities and proper motion as seen from the Sun (ie heliocentric) and the equations in the appendix convert to v in the $S_o$ frame which is the center of the Galaxy. So, ...

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Which moons have cold traps? (i.e. low ecliptic inclination in orbital and rotational axes)
1 votes

Many of the moons of Jupiter and Saturn are tidally locked and probably move ice from their equatorial regions to their polar regions. Ganymede is the best example where you see bright polar ice caps ...

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Reasoning questions on eclipses
1 votes

Let me put it this way. If the Moon's orbital plane where exactly aligned with the Earth's orbital plane (which, by the way, includes the sun, not surprisingly) then there would be a solar eclipse on ...

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Stellarium 0.10.4: planet orbits change over time?
1 votes

Probably this is due to the fact that orbits of the Earth and Mars are inclined to the ecliptic differently so our viewing angle of the orbit of Mars changes slightly over the year. The program is ...

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