7
votes
3answers
65 views

Eclipse Cycle Calculations Needed

I am writing a work of fiction about a world where: The length of a year is 335 days. The world has two Moons. Moon A is Larger and further away with a 78 day lunar orbit. Moon B is smaller and ...
1
vote
1answer
90 views

Local Standard Time Meridian - LSTM (Units)

I was just wondering what units I could scale down to (or or shouldn't) for working out values like Local Solar Times, or Local Time etc... From the papers I'm looking at, I can't see any mention of ...
1
vote
2answers
185 views

Dish antenna as parabolic mirror for OPTICAL telescope?

Can i use a chrome painted dish tv antenna as a parabolic reflector for my Optical telescope ? Given that glass mirrors are quite expensive, i am thinking of using a Dish TV antenna and coating its ...
3
votes
1answer
71 views

Is it practical to hand grind a convex parabolic or hyperbolic mirror?

I know it's practical to hand grind a convex spherical mirror and that it's practical to make a concave parabolic mirror from a spherical one. But as I understand it, the procedure for doing so depend ...
1
vote
2answers
129 views

How can a supernova cause a gravitational wave?

With the recent results of LIGO, I read a lot how limited the detection capabilities where and how one could only expect to measure the most extreme events like black hole mergers and supernovae. I ...
5
votes
1answer
244 views

Is it safe to watch solar eclipse's reflection in water?

There will be a solar eclipse soon at my area... naturally I want to watch this with my son. Is it safe for us to watch the solar eclipse's reflection in the water? There is a swimming pool near my ...
-8
votes
2answers
124 views

Can there be life in black hole? [closed]

Can there be life inside a black hole is it possible that we are living inside a massive black hole right now? This is because i see no reason why we cant be inside a super massive black hole the only ...
3
votes
2answers
78 views

Oxygen in a methane atmosphere akin to methane in oxygen atmosphere?

If we assume a planet the size of Earth with an equally dense atmosphere of nitrogen and methane, rather than oxygen, and it's in the goldilocks zone. Would a hypothetical alien species be able to use ...
-3
votes
1answer
84 views

Does planets revolves around all the 88 constellations? [closed]

I am a beginner / novice and I have got very little knowledge about astronomy Please tell me whether 'Planets' revolves around all the 80+ constellations or not
1
vote
2answers
72 views

What are gravitational waves actually? [duplicate]

I read about the LIGo experiment recently, but i didn't understand their significance. Although, it's clear to me that the gravitational waves do exist and are caused by large accelerating bodies in ...
5
votes
1answer
56 views

Can visible wavelength spectroscopy study an exoplanet's chemical composition directly?

I know spectroscopy of light in visible wavelengths is very effective for studying and determining the chemical composition of bodies within the solar system and bright objects outside of it. However, ...
2
votes
2answers
59 views

Would humans hear gravity waves from a binary BH fusion nearby?

The frequency of the gravity waves detected by aLIGO recently were in the audible sound spectra. Actually spanning over half of the keys of a piano, I've been told, during 2/10 or so seconds. Would a ...
1
vote
1answer
86 views

Physical laws in other universes

In the theory of multi-verses, we can imagine countless other universes where the constants of nature, including the amount of dark energy in a volume of space and possibly even shapes of hidden ...
7
votes
2answers
80 views

Would Adaptive Optics be Useful in Radio Astronomy?

This Question and Answer got me thinking. If atmospheric seeing at visible wavelengths is the result of refractive index inhomogeneity, would it also be a similar problem for mm to cm wavelengths? ...
5
votes
1answer
70 views

Does the accelerating expansion of spacetime mean that the pace of time is changing?

Space expands everywhere, also here. And time is inseparable from space. Does this mean that time also "expands" as in changing its pace? Is the changing rate of time also astronomically observable? ...
7
votes
1answer
72 views

What is the schedule for science runs of aLIGO (and VIRGO)?

Advanced LIGO seems to operate only intermittently. Is there a schedule for at what times it will be able to register new gravity waves? Even if no formal schedule is available, what main factors ...
1
vote
1answer
48 views

How useful are filters for spotting nebulae?

Recently I've been trying to spot a couple of nebulae, IC59 and IC1318. The skies at the site are modestly dark (4.5 on the Bortle scale), I'm using an 8" scope, and I've slowly scanned around the ...
4
votes
2answers
56 views

Do massive bolide entries coincide with meteor showers?

Are exceptionally large, bright, meteors (such as Tunguska or Chelyabinsk) more common during common meteor showers like the Perseids, or the Leonids? If not, why is that? Do the meteor showers ...
5
votes
3answers
84 views

Distinction between metric expansion and objects just moving apart from each other?

I see explanations likes this: Galaxies and other sources, then, are not strictly expanding away from each other but rather are attached to the fixed grid on the expanding fabric of spacetime. ...
4
votes
1answer
56 views

Why is this video showing radio waves transmitted from a radio telescope?

I saw this video at Space.com and I noticed that at 00:05 the animation illustrates waves propagating from space into The Dish at Parks Observatory, but at 00:50 the direction of propagation is ...
0
votes
2answers
65 views

What would harnessing of gravitational waves look like?

We have harnessed and learned to generate and control sound waves, light waves, water waves, and electromagnetic waves in general. What would be needed for science to be able to generate and use ...
9
votes
1answer
482 views

How much of a difference do good lenses make?

I recently purchased a Celestron PowerSeeker 114EQ and with it I got three lenses (which I assume are low quality), a 4mm, a 20mm and a 3 x Barlow. I can get pretty decent views of the moon but a ...
4
votes
2answers
103 views

Rate of Mass Loss from the Solar Wind

This is problem 1-4 from Principles of Stellar Evolution and Nucleosynthesis by Clayton: Assuming at the Earth a characteristic velocity of 400km/s and density of 10amu/cm$^{3}$ for the solar wind, ...
4
votes
1answer
41 views

How are the element abundances calculated for a meteorite in the Hydrogen log10 scale?

In astronomy, solar abundances are often calculated or tabulated per $10^{12}$ H atoms. I understand that in case of the Sun this can be done because H atoms are in majority or are present for a scale ...
4
votes
1answer
107 views

How often do meteorites hit earth

I heard of one that occurred in 2008 in the Nubian Desert in sudan, how often does it happen? Is there a catalogue of all hits or is it very rare? Related link (This is what inspired my interest not ...
2
votes
1answer
111 views

What exactly is meant by “expanding universe”? [duplicate]

What exactly is meant when we say the universe is expanding? I understand stars and galaxies are getting farther and farther away from us, but are individual particles (atoms, molecules, anything ...
0
votes
1answer
33 views

SDSS. Google Sky and DeCaLs

(1) Please go through following image Possible Super Red Giant? However sdss shows it as galaxy! Am I missing something. (2) Google Sky shows object in latitude and logitude format like this. Is ...
5
votes
3answers
323 views

What happens to the information on the event horizons of two merging black holes?

What happens to the hairiness/information on the horizons of two black holes if they collide? After Hawkin the information of the matter which has fallen into the blackhole is encoded on the surface ...
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
156 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
59 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
43 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
431 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
78 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
62 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 ...

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