# All Questions

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18 views

### Black hole collision animation: What are these extrusions?

In this video uploaded by LIGO Lab Caltech, two inspiraling black holes are depicted. The video's description explains what is shown and can be summarized by: The colored surface is the space of ...
12 views

### What is the least dense exoplanet?

An exoplanet with density 0.31 grams per cubic centimeter has been found. Is this the least dense exoplanet we know of?
17 views

### How was lunar eclipse proven using the scientific method?

I read a few articles about lunar eclipses and while they explain the science behind them, they do not describe who explained it and how it was explained using the scientific method. Some of them ...
5 views

### Creating a 2D matrix from 2 FITS images of unequal dimensions for Radio/FIR correlation

I have two images of NGC 6946: ...
42 views

### Is world flat according to Einstein? [on hold]

I didnt understand how to apply general relativity to earth. If there is no such a thing as gravity but space-time bending.
46 views

### Ecliptic line data

I would like to get the data of ecliptic line with respect to celestial equator for a particular day. Is there any specific URL that can give me this. I only have data for declination of Sun and the ...
463 views

### Ross 128 (What does the number mean?)

I see that there are a number of stars that have a number at the end of them. Ross 128 is an example. What does this number mean?
60 views

### Hot Jupiters around heavy stars?

Hot Jupiters are giant planets that are very close to their host star. How many Hot Jupiter exoplanets have been found around stars more massive than our Sun? Has the number of Hot Jupiters ...
77 views

### Are there only a set number of atoms in this universe?

As per the title, are there only a set number of atoms in the universe? Or does the universe make more atoms, and if so, how does it work? I'm a high school student that just had a question during ...
4k views

### Is Earth's Surface “In orbit”?

I'm having trouble understanding relative angular/tangential speeds at increasing altitudes above Earth's surface. In particular, I find this comparison of tangential velocities on Wikipedia very ...
86 views

### How can a star be “thrown out of the Milky Way” by Sagittarius A*?

A recent publication reports that a hypervelocity star on course to leave the galaxy was found, likely accelerated by the black hole at the center of the Milky Way in a process predicted by Jack G. ...
31 views

### How to calculate the Subsolar's Latitude and Longitude for a given Date and Time from RA and Declination? [on hold]

I think that the latitude is equal to the declination. How to calculate the longitude from the RA?
62 views

### How much starlight do black holes absorb?

Can it be calculated how much light from other stars a black hole of certain sizes would absorb? And how long will it take for the number of active stars to decrease to the point where Hawking ...
21 views

### Could we detect an extraterrestrial signal with the SKA radio telescope?

As I have not seen this question answered and, following the rules: https://stackoverflow.blog/2011/07/01/its-ok-to-ask-and-answer-your-own-questions/ , I would like to answer this important question. ...
74 views

### how is it possible to see the sun and the moon at the same time? [duplicate]

I once saw the sun and the moon at the same time once. How is this possible? Im from london england U.K and this probably some time in 2017 autumn time at around 6pm any Ideas.
75 views

### How to determine the orbital period of an asteroid using Kepler laws given its orbit's radius?

Given that the mean distance of an asteroid from the Sun is $450 \times 10^6$ km is it possible that the asteroid completes one rotation around the Sun in two years? According to the third law of ...
2k views

### What are the minimum element requirements for a star?

What elements would be essential for a star to exist? From what I understand our sun is made of mostly hydrogen and helium and most stars have small amounts of heavier elements like carbon, nitrogen,...
144 views

### If a star were travelling at 99% of the speed of light, directly at Earth would we see it?

Stars being flung from black holes in the news made me question if something were heading directly for us at the speed of light, would we even know? Update: Since it's impossible for a star to travel ...
49 views

### What exactly is the relationship between the orbits of Neptune's moons Naiad and Thalassa?

Scitechdaily's Wild Orbits of Neptune Moons a ‘Dance of Avoidance’ [Video] links to the YouTube video Neptune Moon Dance (Naiad and Thalassa) and says: In this perpetual choreography, Naiad swirls ...
79 views

### Earth's magnetic field vs. refrigerator magnet

According to this article: The Earth's field ranges between approximately 25,000 and 65,000 nT (0.25–0.65 G). By comparison, a strong refrigerator magnet has a field of about 10,000,000 ...
23 views

### Does The ISW Effect Predict Net Redshift Over Distance?

The Integrated Sachs–Wolfe (ISW) effect is concerned primarily with the study of the Cosmic Background Microwave Radiation (CMBR), but seems to demonstrate that photons passing through voids suffer a ...
46 views

### What will happen to a object if it somehow crosses universal speed limit? [on hold]

Speed of light, ( 299792458 m/s ) is considered to be the universal speed limit. Let us hypothesize that we found an object with the ability to go beyond light. So what are the things that the object ...
35 views

### Why is earth a giant magnet? [on hold]

If it is a giant magnet then will it produce a flow of electrons due to the magnetic flux effect or not?
327 views

### Are the orbits of all triple star systems at least technically unstable?

Background: In the Circular Restricted Three Body Problem (CR3BP, CRTBP) some halo orbits are mathematically stable. That means that the orbit of the third body is closed, periodic, and stable ...
4k views

### Why are there so many binary systems?

Most star systems are binary, but why is that? Why would new stars form close to others, and not (relatively) evenly spread? And even if they are clustered close together, why are the majority binary? ...
103 views

### When do radio and tv signals become indistinguishable from background noise of the universe?

I understand the rate an EM signal broadcast uniformly from the Earth will decrease in its power is governed by the inverse square law. How far from Earth will radio and tv signals become ...
104 views

### Hills' mechanism for making Hypervelocity Stars

In Hill’s mechanism, the gravitational tidal force of a single MBH disrupts an approaching binary. One star is captured on an eccentric orbit around the MBH and, by conservation of energy, the ...
19 views

### How to determine Az-El pointing of a telescope spiral scan?

I am writing a simulation of an automated telescope observation program. One part of this is to run a spiral scan pattern on and around objects of interest. I would like to tile this scan pattern so ...
85 views

### If we've only observed Oumuamua as a single pixel, how can we know its shape?

On a separate Oumuamua question (Oumuamua alien space junk?), I was confused how shape could be inferred from a single pixel, per another user's (@Uwe) comment. It was suggested I ask this question ...
41 views

### Beneficial astronomical uses of satellite constellations like Starlink?

Has any thought been given to software that would use predictable occultations by Earth-orbiting satellites to improve (rather than degrade) astronomical observations? Potential challenges I could ...
86 views

### Will the conditions that allow life to evolve still be around in a trillion years?

Some billions of years ago, systems like the Earth couldn't emerge and therefore life couldn't arise, because not enough of the heavy elements had formed yet. Assuming there'll neither be a big ...
19 views

### How to estimate the uncertainty of the average velocity of a galaxy given the uncertainty of its flux?

I am doing an experiment about the Tully-Fisher relation. I found the Flux density of the galaxy for different velocities, using DS9. I estimated the uncertainty in the flux due to the background ...
62 views

### Could S5-HVS1 conceivably still hold on to any planets?

If the star (S5-HVS1) has been accelerated to 1,700 km/s by a close encounter with the super massive black hole at the centre of our galaxy (Sagittarius A*) what would happen to any planets orbiting ...
109 views

### Is the sun flipped on the other side of the world?

As the orientation of the moon is different in the northern and the southern hemisphere, is the orientation of the sun different in both hemisphere? Does a sunspot appearing in the Sun northern ...
25 views

### who use the GADGET-2 pack for simulation? can I do it with my PC?

I want to do hydrodynamic simulatin for universe at vary redshifts. How can I do it? or how can I find an simulation of universe for use my work?
92 views

### Accuracy of Mercury transit calculations

What is the error range for calculations for the time of 1st-4th contacts for a given GPS coordinate on Earth? I observed through a telescope the 3rd and 4th contacts and compared against SkySafari ...
78 views

### Weird lights in the sky following me [closed]

So I was walking home after work one day and there was a light above me going in circular motions l, but it was following me... any ideas?
42 views

### How official is TNO 486958, 2014 MU69's new name Arrokoth?

The Trans-Neptunian object 486958 or 2014 MU69 has had several designations and nicknames. According to Phys.org's NASA renames faraway ice world 'Arrokoth' after backlash Ultima Thule, the ...
23 views

### Will the Magdalena Ridge Optical Interferometer be able to image extended objects like the surface of the Moon?

Inspired by several questions: When will a moon landing site be visible via telescope? Could the E.H.T. produce an image of the human artifacts on the moon? Picture of equipment left on the Moon? ...
43 views

### Moon Photo from Apollo 12 mission

Can anyone explain why the Moon looks so small and dark in photos taken from cislunar space during the Apollo 12 mission? AS12-53-7887 found at https://www.lpi.usra.edu/resources/apollo/frame/?AS12-53-...
51 views

### Could different views of the universe simply be different points in time?

I'm not sure if this is the correct stackexchange site for this question. I've been reading this article on Vice Motherboard There’s Growing Evidence That the Universe Is Connected by Giant ...
55 views

### Troop of moving stars through a straight line [duplicate]

Last night,I and my brother suddenly saw that some(50-60) dots of light( exactly like stars) were moving through a straight line(from NW to SE) above us with same velocity and towards exactly same ...
24 views

### How can I check if we can observe a certain star (given its equatorial coordinates) from a certain location on Earth (given its DMS coordinates)?

I am given the equatorial coordinates of a star (e.g. Sirius has RA: 6h45m8.9s and Dec = -16°42'52.1"). Now my question is: can we observe this star from a specific location on Earth (e.g. from ...
28 views

### Date and Time of Year given Sun's Right Ascension

Can anyone tell me how to calculate date of year given a specific sun's Right ascension (RA)? I know RA at Vernox (21 March 00hh:00mm:00ss)is 0 degrees. How can I get date and time for a given RA, ...
61 views

### Can I use the Tokyo Skytree as clock?

After my observation today at the Skytree in Tokyo, I am wondering if this building could be used as a giant sundial? As an aside, it would be interesting to consider how the Skytree might be used ...
17 views

### Series of Star Looking Objects Moving in a Perfect Straight Line [duplicate]

I was out and the moon was shining. I looked at the sky just because of the moon, because the light of moon was making things visible. I just looked at the sky. What I saw was spectacular. I don't ...
4k views

### Does the sun cross other spiral arms in its movement around the galaxy's center?

Today, Ansa.it released an article that states: [...]. In questo suo peregrinare galattico, il Sole ha attraversato anche i due bracci della Via Lattea Perseo e Centauro. "Sono zone di alta ...
118 views

### Based off of the study that found the universe has a positive curvature, how big would the whole universe be?

This study found that the universe has a positive curvature https://www.nature.com/articles/s41550-019-0906-9. I didn't really want to buy it and see if it says how big the universe might be. I know ...