5
votes
3answers
171 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
31 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
51 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
61 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
171 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
91 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
120 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
63 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
27 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 ...
1
vote
1answer
89 views

Which lens and magnification is best to see planets?

I just bought a Celestron Travel Scope 70 and it comes with a 20mm and a 10mm eyepiece. I get a good view of the Moon but I am not able to see Jupiter, Saturn or Mars as expected. I read about the ...
0
votes
2answers
74 views

Does the retrograde movement affect the true angular distance between 2 planets?

I need to calculate the relative angular path between two planets in the geocentric view or in other words the number of degrees of a circle one planet travels away from another planet around the ...
1
vote
1answer
61 views

What is the reason the Chinese want to measure the <30Mhz radiation behind the moon?

On the Earth it is difficult to detect radiation below 30MHz from space due to our atmosphere. But why do they want to measure this radiation behind the moon? It has something to do with the big bang, ...
3
votes
2answers
296 views

Could the earth become a star if more mass was added?

I've heard that the only difference between a star and a planet is mass, meaning that if planets accredited enough mass they would too become stars. Does this mean that the star started off as a ...
4
votes
2answers
105 views

Are white dwarf stars supported by proton degeneracy as well?

In general, fermions form a degenerate gas under high density or extremely low temperature. It's clear that white dwarf stars are supported by electron degeneracy pressure. However, there are still a ...
6
votes
1answer
1k views

Have there been successful attempts at spotting Neptune with the naked eye?

As pointed out here, the limit of naked eye visibility for people with extremely good night vision is about magnitude 8.5. Neptune at opposition is much brighter at magnitude 7.7, so it should be ...
8
votes
1answer
636 views

Is Universe Sandbox 2 realistic?

Universe Sandbox 2 is the second installment of Universe Sandbox that is available on Steam. It is an educational simulation game based on astronomy and anything space, it ranges from supernova ...
3
votes
1answer
74 views

Star formation: When a nebula collapses, is it only the gasses that form the star?

A nebula is made of dust (elements heavier than He and H) and gas (H and He). Stars are made when nebulae's collapse and hydrogen begins to fuse. 99% of nebula material goes into making the star. The ...
1
vote
0answers
64 views

What is the shape (along the plane, not up-down) of stellar orbits in flat spiral galaxies

What I mean is, with a central mass orbits are relatively simple, but orbits around the galaxy are different, in essence as the star orbits through the dark matter halo, the further it moves away from ...
1
vote
0answers
45 views

What is the word for space that is in the solar system, but outside the heliopause?

Wikipedia says the definition of interplanetary space is the region dominated by the interplanetary medium, which extends out to the heliopause where the influence of the galactic environment ...
3
votes
1answer
74 views

Is Planet Nine observable in principle?

Is so-called Planet Nine (given it exists) observable in principle? By "observable in principle", I mean "if we knew exactly where to look, would we be able (from a technological standpoint) to get an ...
2
votes
2answers
52 views

Is the composition of stars in future made of more and more heavy elements?

In the beginning stars only consisted of the hydrogen element and due to nuclear fusion of those elements in stars and supernova's more heavy elements were created. Because of that, like our Sun, the ...
15
votes
2answers
4k views

Why do the planets orbit in the same direction?

Theoretically, planets would have an approximately equal chance of going one way in their orbit or another but in reality, this is not the case (at least in our solar system). Why is this?
1
vote
1answer
92 views

How does the sun move within the galaxy [closed]

I am trying to know what is the exact movement of the sun. I saw article like this one http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question18.html and from it I understand that the sun ...
3
votes
1answer
75 views

Why the light curve goes down when the planet is behind the star?

There is a video explaing the transiting exoplanet light curve — https://www.youtube.com/watch?v=RrusIZaWDW8 It is clear to my why the curve goes down when the planet is between the observer and the ...
3
votes
1answer
65 views

Why don't globular clusters flatten with a galactic disc?

Globular clusters lie in the galactic halo, outside of the disc. However, galaxies are more or less a collection of material and objects — why is it, then, that most stars form a plane due to the ...
0
votes
2answers
110 views

Two moons and one Earth? [closed]

Can any one explain to me What will happen to Earth if its has two moons? Same Distance & two sides of earth (North & south)? Will it be good for humans or bad?
1
vote
1answer
20 views

Eyepiece projection photography [closed]

Nothing is showing up in the viewfinder of camera when I try to do eyepiece projection photography.could I have something set up wrong?
1
vote
2answers
54 views

a random distribution of RA&Dec

How to make random positions in Equatorial coordinate system? If I divide Dec between -90 and 90 evenly, the space distribution is not random.
0
votes
1answer
54 views

Why is the CMB not simply travelling parallel to us? [closed]

When we look to the distant farthest reaches of the universe we see light that was emitted at the big bang 14 billion years ago. But the universe was tiny back then so that light, which is only ...
0
votes
1answer
70 views

How can black holes be sometimes so gaseous?

One of the most massive Supermassive Black Hole observed is the one at the centre of the galaxy NGC1600 with a mass of 17 billion suns. It would have a density of ∼0.01kg/m^3, or one part in 100,000 ...
0
votes
1answer
42 views

How do astronomers distinguish the spectral lines?

As a black body a star emits a continuous spectrum of light and other radiation. I've learned they are capable of knowing of what elements the stars are made of because of the spectral lines. But how ...
0
votes
1answer
54 views

How would seasons at the equator be if the Earth were tilted 90 degrees? [duplicate]

If Earth's axis of rotation were tilted 90 degrees, what type of seasons would be observed at the equator. My prediction is that there would be no seasons, as the orientation of the equator would be ...
1
vote
1answer
69 views

How close would merging black holes have to be to feel gravitational waves? [duplicate]

Recently LIGO discovered gravitational waves caused by two black holes that were orbiting each other, and then collapsed into one black hole. A few months later, we find out that this actually happens ...
0
votes
1answer
38 views

an exercise from Spherical Astronomy by Smart

I want to solve this exercise from Spherical Astronomy by Smart: Prove that, in latitude 45°, the interval between the moment at which a star's azimuth is 90° east and the moment of setting is ...
1
vote
1answer
37 views

Unable to achieve focus

I feel like this is going to be a duplicate of this question, Astrophotography - Unable to achieve focus with current setup. However, the suggestions to go to a straight adapter doesn't apply in my ...
0
votes
0answers
49 views

Send a rocket against orbit around the sun [migrated]

I presume it's a bit simplified, but ... What if we launch a rocket, the same speed but opposite direction of the orbit of our planet around the sun. Will that rocket fall into the sun?
0
votes
1answer
55 views

Distance and orbital period for terrestrial binary planets

This article, http://phys.org/news/2014-12-binary-terrestrial-planets.html, suggests binary planets could orbit each other at a distance of only three planet radii. For two earth-like planets, that is ...
8
votes
1answer
594 views

What is the Galactic Latitude and Galactic Longitude? How is different from the latitude and longitude we use on Earth?

It has to something with the positioning of sun and galactic center of the milky way but I wasn't able to understand how for a given star, its co-ordinates are calculated. Some explanation would be ...
1
vote
2answers
42 views

Having some weird issues with my tracking (Advanced VX)

I need your help! I am having some weird tracking issues with my tripod (Advanced VX). When I setup and calibrated my scope yesterday I took this picture of NGC6888 (90s exposure): As you can see ...

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