5
votes
1answer
66 views

Where did the grand design spiral galaxy designation come from?

What is the history behind the name that we gave to that class of galaxies?
1
vote
1answer
63 views

How well supported are the theories of black-holes containing their own universes?

The thought crossed kidnapped my mind one night almost a year ago. I was laying down, but I was very interested in thinking about the secrets of a black-hole. Nat. Geo. - News article What does the ...
1
vote
0answers
38 views

Hubble Space Telescope #2 cost

If a second Hubble Space Telescope (with lessons learned) was to be made and sent up, what would the cost be compared to the original cost (um, original cost back then including second mission to ...
0
votes
0answers
7 views

Do things get dirty in space? [migrated]

I'm writing a computer game involving space exploration, where the player will come across space ships/stations that are hundreds/thousands/tens of thousands of years old. I'm also trying to make it ...
3
votes
1answer
74 views

If a hot Jupiter collides with the parent star, does it enhance or reduce the life of the star?

Suppose a hot Jupiter is collided into parent star due to tidal force, does the life of the star becomes longer due to extra hydrogen, or becomes shorter due to extra mass?
1
vote
1answer
42 views

Has anyone filmed a total lunar eclipse from the Moon's perspective?

With all of the footage we have of total lunar eclipses, has NASA, ESA, or any other space program ever taken a photo or video of it from the Moon itself?
0
votes
1answer
56 views

Can one calculate the size (i.e. the radius) of our universe? [closed]

If one can estimate the mass of our universe, might one also calculate its ultimate size, (after it fully expands), based on the Schwarzschild formula for the radius of a black hole? Please note that ...
1
vote
1answer
63 views

Are there any reliable optical measurements of the radius of a neutron star?

I know that there is plenty of theory to predict the size of a neutron star: my question is whether or not there are any reliable size estimates based on observation. Please note that, to be reliable,...
3
votes
1answer
71 views

Do planets form around lone stars, multiple stars, or both? Do we know this yet?

Since about 1990 astronomers been able to detect planets around other stars, using a couple different techniques, which is amazing. By this point, do we know whether planets form only around single ...
5
votes
1answer
57 views

How does 2015 RR245 compare to the other KBOs predicting “Planet 9”?

2015 RR245 was recently announced, in a highly eccentric orbit in the KBO. From what I understand, the so called "Planet 9" was predicted because these objects tended to be pointed in a particular ...
4
votes
1answer
45 views

Spherical Accretion (Bondi Model)

I have a question. I studied Bondi's model for spherical accretion. I know the assumptions made in the model are big and that they are rarely representative of what happens in astrophysics. What I ...
5
votes
1answer
71 views

Was the use of silver on 'optical' telescope mirrors more common in the past? Why?

In the past, weren't many astronomical telescope mirrors periodically removed and 'resilvered', and wasn't this actually done using silver? I'm guessing that this is much less common now - new ...
6
votes
1answer
173 views

Why are Saturn bands much fainter than Jupiter's?

The atmospheric composition of both planets are very similar. Then why are Jupiter's bands more visible (North and South equatorial belt, etc.): Whilst Saturn's are not: (except for the storm of ...
1
vote
1answer
85 views

Solar Eclipse: How it occurs

In relation to the image above, although the topic relates to math, how can I visualise the situation described in the final equation presented, i.e., the declinations, ascensions, solar and lunar ...
0
votes
1answer
37 views

Why aren't planetary bodies static? [duplicate]

Why are planets moving in the first place? Gravity causes them to orbit, but why move at all? note: this is not a question on why planets orbit each other, I know the reason for that is gravity. ...
1
vote
1answer
205 views

Could a cross-ringed planet exist?

My title doesn't do my question justice in explaining, but the kind of satellite system I'm thinking of is two rings on two separate axis, much like (if you've seen it) the film 'Treasure Planet' ...
5
votes
1answer
234 views

Why is there a supermassive black hole at the center of every galaxy?

According to https://en.wikipedia.org/wiki/Sphere_of_influence_(black_hole) the gravitational sphere of influence of a supermassive black hole is really limited compared to the size of its hosting ...
4
votes
2answers
435 views

Will Saturn's Moons be destroyed?

I heard that Saturn has 62 moons with confirmed orbits, 53 of which have names and only 13 of which have diameters larger than 50 kilometers. Some come within 1km of each other. How do these moons ...
-1
votes
1answer
62 views

What are the small things, look like stars, moving in the sky? [duplicate]

I have always been observing something that looks like a star but not as bright as a star moving from south to north at the same time every night. What is it? It cannot be a star because I know ...
0
votes
2answers
60 views

Kepler's second law of motion

Planets sweeps out equal areas in equal times. Is the area being calculated here the area of a triangle? You draw a straight line from the center of the sun to the earth at point A. The Earth moves ...
3
votes
0answers
40 views

Why do so few satellites pass over the poles, and why do so many focus on the equator? [migrated]

The following screenshots from the website Stuff in Space, which tracks satellites and man-made debris orbiting the earth show us a few things: Very few satellites (or pieces of debris) pass over ...
0
votes
2answers
62 views

Data reduction and photometry without IRAF?

The IRAF package is old. I've been looking around for a more modern software to replace it in the processes of CCD data reduction and photometry, but haven't been able to find any. The closest I've ...
1
vote
1answer
81 views

How massive can a cold solid object be?

I understand that a neutron star is dense enough that adding more matter will increase the amount of degenerate matter directly, and the limit to its size is about 1.4 solar masses. But if an object ...
1
vote
1answer
18 views

Future redshifting and effect on the 'pitch' of CMB radiation

After discovering this question exploring the sound of a blackbody, I started wondering about the sound of the Cosmic Microwave Background radiation from the Big Bang, specifically what the current ...
1
vote
1answer
56 views

Why aren't stars like Eternally Collapsing Objects?

We know that stellar radiation pressure balances the gravitational compressive forced of a star. Are there other factors which resist such a collapse? Also, if radiation pressure balances ...
1
vote
2answers
61 views

Can a tidally-locked planet maintain an obliquity

If a planet is tidally-locked, can it have an obliquity? e.g. the Earth's rotation is being slowed by tidal forces. A long way in the future it will be tidally locked. As it slows, will the ...
0
votes
2answers
60 views

Is the lower mass limit of a neutron star the same as the upper mass limit of a white dwarf?

If not, when can a white dwarf be more massive than a neutron star?
0
votes
1answer
47 views

Inverse of the sunrise equation - finding locations with a given sunrise time on a given day

I'm working on a project for fun where I represent some sleep data geographically. For a given day, I have a date, a time for falling asleep that night, and a time for waking up the next day. The idea ...
2
votes
1answer
114 views

Has the velocity of photons coming from black holes already been measured?

Has the velocity of photons, which are coming from black holes, already been measured? I am not aware of such measurements. The reason for the question is the following: If space-time near black ...
4
votes
0answers
117 views

When can we (public) expect to see the first optical images of Jupiter from the Juno spacecraft? [migrated]

As many of us know, Juno spacecraft achieved orbit of Jupiter yesterday (July 4, 2016). Does anyone have an educated guess on approximately when we might see the first optical images from Juno in ...
5
votes
3answers
164 views

How fast would Earth need to rotate to fling someone off due to centrifugal force?

If Earth started spinning fast enough, would the centrifugal force eventually overcome Earth's gravity enough enough to fling someone (let's assume 75 kg) into orbit or into space? If so, how fast ...
1
vote
2answers
30 views

lunar calendar accuracy for predicting new moons

I wonder, how accurate the lunar calendar is? Can we predict the new moons precisely for tens of years in future? If we know all factors that affects the movement of the moon, then why it is not ...
1
vote
1answer
50 views

What solar features would I see at 10x magnification?

I have a pair of binoculars with 10x magnification, 50mm objective diameter, and 6.5 degree (real) angular field of view. I'm looking into buying solar filters for it (something like these) so I can ...
1
vote
2answers
54 views

What is the most distant observable White Dwarf known?

I attended a talk last week about Type 1a supernovae with the focus being on double-degenerate systems as potential progenitors for them. We were shown a graph of White Dwarf (WD) mass distribution ...
5
votes
1answer
82 views

Do other planets with a magnetic field also have two Van Allen belts?

On Jupiter and Saturn, aurora is seen around the planet's poles, so that implies that there must be a kind of magnetic field around those planets. Perhaps even the moon Europa could have a magnetic ...
3
votes
1answer
98 views

What may be the period and speed of revolution of the star that is closes to galactic centre?

The Sun moves at the speed of 220km/s around the galactic center in a circular orbit. The sun is located at about 30,000 light years from the galactic center. The Sun orbits around the center of the ...
0
votes
1answer
59 views

Could dark matter be “inside-out” reality?

Where we are, and in the conventional galaxies etc. that we see, there is a whole lot of relatively uniform space but in isolated places within that space, there are pockets of concentrated "mass" ...
1
vote
2answers
165 views

Has NASA confirmed earth now has a second moon orbiting the planet?

Several sites claim NASA has confirmed a second moon orbiting earth. This is the Asteroid 2016 HO3. One source states The newfound quasi-satellite/moon-2016 HO3, is likely larger than 120 feet (40 m) ...
0
votes
1answer
48 views

Would we be able to feel the acceleration of a planet with a highly eccentric orbit?

Even though our Earth moves on average 67,000 miles per hour around the Sun, we cannot feel its movement since its speed is fairly constant. More precisely, its change in speed is very low and our ...
0
votes
1answer
41 views

Converting ångströms to km/s

I have a spectral cube (in FITS format) whose spectral dimension is in ångströms. The sampling along the spectral dimension is 0.28A (CDELT=0.28). The observation in the cube is Ha emission of a ...
0
votes
1answer
29 views

The Three Elements in the Milankovitch Cycles

According to the Serbian geophysicist Milutin Milankovitch, there are three elements that make an ice age possible: Eccentricity (orbital shape): Varying between 0.000055 and 0.0679 over the course ...
2
votes
2answers
88 views

What color is earthshine?

What color is earthshine (e.g the average color of earth that shines on the moon)? I am making a solar system exploration game, and would like to know this for the lighting of my moon level at night, ...
1
vote
4answers
133 views

What are the exact causes that differences in sunrises are shorter around june and december but long in march and september?

The changes of the sunrise and sunset times not expire regularly in a straight line but according to a sinusoid. Around the solstice (summer solstice on June 21st and winter solstice on December 21), ...
2
votes
0answers
50 views

Juno Mission. How better resolution will the optical images be to previous missions? [migrated]

Resolution in km/pixel at: (i) the closest approach and (ii) typical when in close to Jupiter part of the eccentric orbit.
0
votes
2answers
56 views

Is this picture of a digital camera being oversaturated by bright light source i.e. the Sun? [closed]

Is this picture of a digital camera being oversaturated by bright light source i.e. the Sun? http://farm4.staticflickr.com/3110/3147227521_396e16bcfc.jpg
1
vote
3answers
109 views

Can you still see Polaris even if you are in the south pole?

I haven't been to south pole but can the Polaris still be viewed if the viewer is in the south pole? Or this question makes no sense at all?
3
votes
4answers
135 views

Would space-based telescopes need to remain in the shadow of Earth to avoid light interference from the sun?

So I am thinking about orbiting telescopes tonight and I was thinking that it would probably be beneficial to keep them in the shadow of the Earth or some other space body to avoid light interference. ...
1
vote
0answers
27 views

What did New Horizons photograph that was close enough to be out of focus? [migrated]

The picture below shows a Kuiper Belt object and a number of stars. It was recently taken by the New Horizons probe and published by NASA. The arrow points at the KBO and the rest of the bright ...
0
votes
3answers
62 views

Are we moving faster than the Cosmic microwave background radiation?

if the Cosmic microwave background radiation is coming towards us in the speed of light and all matter and energy was singular at the big bang, doesn't that mean we somehow moved faster than the speed ...
0
votes
0answers
25 views

Replacing the tripod on a Celestron Travel Scope 70

I have a Celestron Travel Scope 70. The tripod seems incredibly wobbly, making it very difficult to view anything without the whole system bobbing up and down. I was thinking about replacing it with ...

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