0
votes
1answer
61 views

Description of Henyey tracks on wikipedia incorrect?

So, if you search for Henyey tracks on wikipedia (I know, the shame of it!) you will come across this statement: The Henyey track is characterized by a slow collapse in near hydrostatic ...
3
votes
2answers
165 views

What are the advantages and disadvantages of a 2-inch eyepiece versus a 1.25-inch eyepiece?

I'm considering picking up some new eyepieces for my telescope and am interested in comparing 2-inch and 1.25-inch eyepieces. Are there any disadvantages to 2-inch eyepieces? Are 2-inch eyepieces only ...
0
votes
1answer
50 views

Stellar data for data mining [closed]

Where could I find detailed data from stars? Like spectrum, x ray and so on ? Because I would like to do some data analysis on it.
2
votes
1answer
49 views

In what manner is the spectrum of a black body really a continuum?

Usually they say the spectrum of a black body is a continuum and emits radiation at every frequency. Is it really a continuum like a line or are there (small) intervals? For example, can a body emit ...
8
votes
2answers
80 views

How to configure Celestia to work with a spherical mirror projection on a dome

I find hints around the web, e.g. http://www.cosmodome.net/mirrordome.php that Celestia can be projected on a dome using a spherical mirror projection configuration. The problem is that I can't find ...
3
votes
2answers
146 views

When you travel fast around a black hole, do you experience high speed yourself?

When an object in the space comes close to a massive body (like a black hole or a neutron star), we see from Earth that its speed significantly increases while it is close to the body. As we know, ...
10
votes
1answer
184 views

Will gravitational waves too far away ever reach us?

Gravity is the curvature of spacetime, and its effects travel at lightspeed. However, space is expanding; eventually, light from distant galaxies will become more and more redshifted, and we will no ...
-1
votes
2answers
63 views

Size of the Universe [duplicate]

The number of atoms in the whole Universe seems to be finite, yet the Universe is infinite in dimensions? How it is possible in the Universe?
1
vote
1answer
61 views

Procession of the Equinox

I just learned about procession of the equinox, i.e. the Earth's axis tilts one degree every 72 years. And it takes 72 years/degree x 360 degrees = 25,920 There are many theories to this, i.e. ...
2
votes
2answers
125 views

When was visible light for the first time created?

"A few minutes into the expansion, when the temperature was about a billion (one thousand million) kelvin and the density was about that of air, neutrons combined with protons to form the universe's ...
2
votes
1answer
66 views

Could science be lost if a phenomena is observed before predicted? [closed]

An observation could validate the predictions made by a previous theory. If something unpredicted is observed, then a new theory which is compatible with the observation should make predictions which ...
-3
votes
1answer
49 views

Origin of the Universe [closed]

I heard on a you tube video that a new theory came out in 2015 . The theory is that there was no "Big Bang" and that the Universe has no beginning .
-1
votes
1answer
44 views

How to figure out a moon phase for July 1937

I would like to know how to figure out the moon's phase for July 4, 1937 at 9:34 pm. Thank you.
6
votes
1answer
56 views

Is there a variation of ISO 8601 for julian calendar dates?

If I want to write a date in the Gregorian calendar, I can write it in the ISO 8601 format; today would be 2016-02-20. The advantage is that there are many parsers available to let computers read in ...
-2
votes
2answers
85 views

What is the current state of gravity in the vacuum of space? [closed]

Is Gravity in the vaccum of space decelerating or exspanding? please explain why,when and how in detail, Along with a credible reference. If Science has not concluded either please give a reference as ...
4
votes
1answer
77 views

Where is the flaw in this hypothetical concept of escaping event horizon using another's blackhole flyby?

imagine two black holes approaching each other in a way that they will perform just very close flyby. You have a spaceship just below the event horizon of one black hole in line between centers of ...
0
votes
1answer
48 views

Astronomy Olympiad Gravitation Qn

Question: Approximately once in 5 years people on Earth can observe bright comets whose nuclei have radius about 1km. The orbits of such comets are close to parabolic. Assuming that these nuclei are ...
6
votes
5answers
435 views

Are black holes really singularities?

Can't black holes just be super dense objects? They could still be black (having the color of black never really required special physics, after all) and have a really strong gravitational field. If ...
3
votes
1answer
79 views

Earth's Versus Catastrophic Meteor

How evasive is the Earth to Catastrophic Meteors? Google says the Earth is approximately 92.96 million miles from the Sun. It also says the suns radius is 432,474 miles. Therefore, it is 93,392,474 ...
3
votes
1answer
37 views

What is the formulat to compute King tracking rate for a given set of topocentric coordinates?

Canbury Tech has a good background on King tracking rate, which approximates the average sidereal motion of a refracted star across the sky. Most amateur telescope mounts have some sort of notion of ...
1
vote
2answers
64 views

Table of absolute magnitudes of stars by spectral type and photometric band

I would like to find a table where I can, say, look for K5 dwarfs and read off that stars of that type have on average an absolute magnitude of X.XX in the infrared L band and Y.YY in the G band. I've ...
5
votes
2answers
290 views

Does natural satellite(s) of a planet affects its orbital velocity around a star?

Please excuse me for a lay question. As we know, to calculate the orbital velocity, we take the mass of the orbiting body, the mass of the body being orbited and the distance between the two bodies ...
6
votes
1answer
103 views

Does LIGO have a blind spot?

If I understand the principle of operation of operation of LIGO, it detects relative distortions of the two perpendicular arms. So if both arms are distorted the same way, nothing would be spotted. ...
1
vote
1answer
89 views

Special Relativity as Applied to an Interstellar Starship?

I'm once again confused by the twin paradox. Let's say I am on an interstellar starship flying at 0.6c from a star 30 light years away from Earth to a star 50 light years away from Earth and 40 light ...
3
votes
1answer
43 views

what is the percentage of stars with planetary systems?

I'm having hard times understanding the equation of Drake, i can´t find the number of the variable that refers to the stars with planetary systems (fp)
2
votes
2answers
91 views

How fast can and do gravitational waves travel?

I was thrilled by the recent announcement of the detection of gravitational waves. The media has done a great job explaining them and the theory behind them and I get the concept fairly well. But if ...
2
votes
0answers
19 views

Telescope optical tolerance from central axis

I sometimes encounter telescopes/binoculars with a decent objective diameter but are very difficult to use because they only work when the eye is looking down the central axis (i.e. in the centre of ...
0
votes
1answer
72 views

Create Position-Velocity diagram from a velocity field

Can someone explain to me how I can generate a Position-Velocity (PV) diagram from a galaxy's radial velocity field? I understand that usually PV diagrams are generated across the major axis of the ...
1
vote
1answer
146 views

Do black hole singularities actually merge?

new questioner here so please be gentle. Do the singularities of merging black holes actually merge together? I mean there are 2 infinitely small objects (singularities) that are trying to find each ...
11
votes
3answers
130 views

Frequency of gravitational wave detection

You may have heard in the news that the LIGO experiment recently detected a gravitational wave. Though I'm not an astronomer, the paper is a good read and mostly accessible. The detection of the ...
-1
votes
1answer
75 views

Is the flat curvature of the universe in the 5th dimension?

It is hard to imagine that the universe could have a flat curvature while I've read that it is at this moment the most likely. When you look around the universe is expanding in all directions, so it ...
1
vote
1answer
62 views

How early/late is the human race as intelligent life in the universe/milkyway? [closed]

In the history of the universe, there has been a time, where intelligent life had no chance to develop (e.g. in the early universe, when no habitable planets have formed) and there is a time today ...
1
vote
1answer
140 views

How did LIGO verify that the gravitational waves originated 1.3 billion years ago from two specific black hole collision? [duplicate]

So they finally found gravitational waves. That's cool and I trust is the case, but how did they confirm it originated 1.3 billion years ago and that two blackholes merging caused it and what ...
4
votes
1answer
158 views

Could a pair of binary black holes form within a star?

After the discovery of gravitational waves by LIGO last week the team behind the Fermi gamma-ray telescope released a paper that showed a soft gamma ray burst was detected only 0.4s after the ...
2
votes
2answers
112 views

Is phys.org/space-news reliable source?

I found this page: http://phys.org/space-news/ . It seems to me pretty good page with interesting news and so on and I like that it is free. But I noticed in comments people arguing about the validity ...
2
votes
1answer
49 views

What methods exist to calculate the ellipticity of galaxies

What methods exist to calculate the ellipticity of galaxies and what are their drawbacks? I have asked this question about ellipticity in the SDSS but I want to know about general methods for cases ...
28
votes
6answers
6k views

What did LIGO Actually See? (Gravitational waves discovery)

I am trying to find an original video/image of what LIGO actually saw, but all I can find is artist renditions of gravitational waves.
2
votes
2answers
129 views

Could gravity waves be used to confirm the existence of a ninth planet?

Shortly after the news of the discovery of gravity waves, my physics professor explained the significance of the discovery by comparing it to a medical X-ray machine. He said that gravity waves can be ...
1
vote
2answers
69 views

visualisation of galaxy density

If I had a long stick that was millions of light years long, and with a width of about the Sun, and I then swiped it through the center of the milky way galaxy, what would the probability be of me ...
3
votes
1answer
88 views

Sundial (solar clock) in a binary star system

What would a sundial look like in a binary star system? What is the path drawn by the shadows? It probably depends on the system, the sizes of the stars, their distance... If you know a binary star ...
4
votes
1answer
36 views

Problem with denoising the BICEP2 data?

This question pertains to this article which talks about why the BICEP2 measurements of B-mode polarization in Cosmic microwave background radiation turned out to be noise from galactic stardust. They ...
0
votes
1answer
31 views

Angular distance/apparent separation between AE Aurigae and Orion's belt

The title perhaps gives the question away, but would anyone know/be able to roughly approximate the angular distance/apparent separation between AE Aurigae and Orion's belt. I have the value of $42^\...
1
vote
1answer
83 views

The effect of gravitational wave is like tidal forces?

What would happen if a strong gravitational wave passed through a human body or any other kind of material? The shape of the human body would change? Would the human body be distorted apart? If ...
2
votes
1answer
69 views

How far should the source be, for the gravitation waves to be visible on Earth?

If I understand it well enough, gravitational waves cause ripples in the space-time fabric. To our eyes, that would look like those rippling-effects on amateur videos. Where does a source have to be,...
0
votes
2answers
38 views

Reference for broader spectral lines?

I'm looking for some reference listing spectral lines outside the visible spectrum. (In particular, I'm looking for an element or compound that emits strongly in the 700-900nm range.)
0
votes
1answer
31 views

Minimum Mass Solar Nebulae Scaling Factors

I'm attempting to build a MMSN, I've been trying for about... a week to get an intuition on the scaling factors for calculating the mass of the disks, I'm not entirely sure how to think about it. I ...
4
votes
1answer
69 views

How to determine the ellipticity of galaxies in SDSS

What is the best approach to determine the ellipticity of galaxies in the SDSS DR12. I have read this page. Are those really good methods? Do flux-weighted second moments (as given in the stokes ...
1
vote
2answers
69 views

Why can't different regions of the universe be the same as they have the same origin?

The horizon problem states that because of the speed of information can't be faster than light and the distances between far regions are too big there is a problem because they look quite the same. ...
0
votes
0answers
11 views

SDSS ImgCutout webservice returns black image for dr12

The SDSS (Sloan Digital Sky Survey) ImgCutout webservice should return jpeg images for a given field that is defined by the parameters. The service can be tested here: http://skyservice.pha.jhu.edu/...
0
votes
1answer
75 views

Does the event horizon of a black hole increase or decrease by adding mass?

So a black hole is a something that has enormous gravity, therefore mass accelerates faster towards it. But if the black hole double it's mass, will it's event horizon increase in length , or will it ...

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