1
vote
1answer
45 views

How to get error out of astropy constants

How do I get the error value out of an astropy.constants quantity? ...
8
votes
3answers
200 views

Perceiving movement of stars

Are there any stars visible to the naked eye whose position, over a normal human lifetime, can be seen to have changed (relative to other stars in the vicinity)?
3
votes
1answer
142 views

What does the orbit of multiple star systems look like?

How can I find simulations of trinary, 4-nary.. etc. star systems? What do they look like? For example the Alpha Centauri system has 3 stars and possible planets. What does that orbit look like? I ...
1
vote
1answer
22 views

accretion discs in h/lmxbs

High mass x-ray binaries necessarily accrete via wind, no disc accretion? What makes the difference between a hmxb and a lmxb? In what kind of circumstances does an accretion disc form? How does it ...
3
votes
1answer
98 views

The colour of saturn as it appears to the naked eye

I have started to watch the skies in order to learn stars, constellations planets etc. The few references I checked state that Saturn presents itself to the naked eye as a pale yellow tiny little ball,...
3
votes
2answers
85 views

How to interpret this old degree notation?

I'm trying to follow the calculations in this paper on page 5 (see image below). The paper is describing traditional methods of calculation for a luni-solar calendar. The math is not hard, but I can'...
2
votes
1answer
175 views

Venus presents same face toward Earth at closest approach. What do you make of that?

Is reference 6 in this Wikipedia article "dubious" and this passage in need of excising or clarifying? Venus's 583.92-day interval between successive close approaches to Earth is equal to 5.001444 ...
3
votes
2answers
65 views

Are micrometeorites cosmic dust?

Are micrometeorites just dust grains at high relative speed, or is there some difference between them and cosmic or interstellar or solar nebula dust? Dust as in the clouds which obscure parts of the ...
0
votes
1answer
93 views

Do bigger telescopes equal better results?

There are many large reflecting/optical telescopes around the world, just to name a few: the Very Large Telescope, Large Zenith Telescope, and European Extremely Large Telescope. My question is does ...
2
votes
1answer
73 views

Travelling at light speed(inside water) [closed]

It is a said fact that 299792458 m/s is the speed limit,nothing can go faster than this speed, or it will take an infinite amount of energy for propulsion.What we perforce in vacuum is one thing.Can ...
3
votes
1answer
101 views

What do we know about the characteristics of stellar objects, 13,3 billion light years away from us?

To receive light from objects like MACS0647-JD, I suppose, it has to has extraordinary dimensions and intensity of electromagnetic radiation. What are the mass, the dimensions and other ...
2
votes
4answers
101 views

If I were to point into the sky, how many galaxies would be in this line?

If I point in the sky and draw a line from the tip of my finger to the end of the universe, how many galaxies would this line cross? I had a discussion with my dad and he said due to the universe ...
4
votes
1answer
378 views

Why Earth does not have rings?

Why does the Earth not have rings like Saturn or Uranus?
1
vote
1answer
36 views

Amount of EM radiation (and particles) Earth “receives” from other planets in our solar system?

Can it be (or has it been already?) measured how much and what kind of EM radiation (apart from visible light)/particles Earth "receives" from a specific planet in our solar system? Can other planets ...
3
votes
1answer
107 views

Supermoon Lunar Eclipse?

I recently read this article: http://www.cbsnews.com/news/supermoon-lunar-eclipse-coming-this-month/ I'm having some trouble understanding how a "supermoon" lunar eclipse is possible. Judging from ...
4
votes
1answer
170 views

Does the universe expand at the same rate everywhere in the universe?

Specifically, I am wondering if some areas of the universe expand faster than other areas and whether the faster expanding areas diffuse the expansion through the slower expanding areas or does the ...
4
votes
1answer
112 views

Determining North-South Line Via Watch Method: Theory & Reason

I recently read that if you're in the northern hemisphere and have an analog watch, then you can point the hour hand at the sun and know that a south line lies between (bisection) the hour hand and ...
4
votes
2answers
85 views

When a neutron star accretes matter, will its mass increase?

When a nova gets matter, the outcome is that it may lose more matter because of eruptions. Only some kind of nova's masses can increase stably. A white dwarf may become a supernova after it exceeds ...
2
votes
1answer
329 views

What are iron stars?

I have a question about iron stars. I was fascinated about the theory about the inability of protons to decay, and it led me to a point where I read something about some special kind of star called an ...
2
votes
1answer
120 views

Spicules vs Prominences/filaments

What is the difference between spicules and prominences/filaments. I know that they are both in the chromosphere, and I know the difference between provinces and filaments (depends on the view), but ...
5
votes
1answer
732 views

Astrophotography - Unable to achieve focus with current setup

I am new to astrophotography and am looking for guidance. I have the following equipment: Orion StarBlast 9814 4.5" Altazimuth Reflector Tabletop telescope 1.25in Telescope Adapter Extension Tube T ...
2
votes
1answer
113 views

Roll, Pitch and Yaw of Orbital Planes

I have been reading about celestial mechanics and particularly about planetary orbits. I understand that a planet's orbit can be tilted (pitched) with respect to the Earth's ecliptic and that it might ...
1
vote
1answer
58 views

Finding the suns position in the sky anywhere at any time

What am I looking for? from any point Latitude, Longitude and date D I want to know where the sun is in the sky at any given time anywhere on our planet. I even don't know what the outcome will be ...
4
votes
1answer
104 views

Were parts of the Universe deflating during Inflation?

I was reading about the history of the early universe in Carroll & Ostlie and specifically looking at Inflation, which, as I understand, occurred because our [observable] part of the universe ...
1
vote
2answers
74 views

Real-time position of a distant celestial body

How might it be possible to determine (via some specific online empemeris or via some well-understood algorithm) the observed position of some distant celestial body (e.g. Betelgeuse)? To be concrete:...
-2
votes
1answer
98 views

What if the earth stopped rotating and revolving at the same time? [closed]

What will happen to us are we going to move in a tangential direction with earth axis of rotation ?
1
vote
1answer
89 views

What is a Seyfert galaxy?

I know Seyfert galaxies are types of active galaxies, but I do not understand what separates them from other types of active galaxies. Are they brighter/not as bright as other types of active ...
4
votes
1answer
156 views

What causes the aurora of other planets to have different colors?

All I could come up with is it depends on the atmospheric composition of the planet as they will interact with the charged solar particles which might be true but is there is there a definite reason ...
2
votes
1answer
48 views

stellar metallicity

I saw a talk recently mentioning that another factor that may determine a star's metallicity (besides age) may be how far from the center of its "birth cluster" it is when the short lived hot central ...
3
votes
2answers
226 views

Can the Sun become a big ball of gold atoms?

The atoms inside the core of sun are continuously fusing and forming other atoms. Can this continuous fusing make gold atoms?
2
votes
1answer
238 views

The dark side of the moon [duplicate]

I encountered this statement that the dark side of the moon is hidden from our sights. Could someone please explain?
5
votes
2answers
130 views

Do most planetary systems have fewer planets than the solar system?

It is my impression that most planetary systems have, at most, three to four planets. Is that real? Or is it just that we lack the ability to detect most planets?
2
votes
1answer
80 views

Sun's apparent motion above the arctic circle during summer solstice

I'm having difficulty with an apparent contradiction about the sun's motion during the summer solstice above the arctic circle. The YouTube video The North Pole Entire Summer of never ending sun ...
5
votes
3answers
97 views

International Space Station

Recently, I have been going out to observe the ISS when it is within sight of my location. I have noticed that the ISS, based on the time that I have to observe the space station during any given ...
3
votes
2answers
493 views

Can things move faster than light inside the event horizon of a black hole?

Black Holes are regions of space where things get weird [Citation Needed]. Past the event horizon of a black hole, any moving particle instantaneously experiences a gravitational acceleration towards ...
6
votes
2answers
59 views

Is the Astronomy community still concerned about the lumpyness of matter distribution in the universe?

A decade or so ago, when I was still a science undergrad, one of the open questions in astrophysics was to explain the uneven distribution of galaxies in the observable universe. That is, why did the ...
10
votes
2answers
2k views

Is it possible to witness a star's death?

Given that the stars' distances to Earth are measured in light-years (for example, Sirius is 8.6 light-years away from Earth), what we are seeing as Sirius now is actually its state 8.6 years ago, ...
2
votes
1answer
63 views

Why are there no Oe or Ae stars?

The unique characteristics of Be stars are mainly because of their circumstellar discs. I wonder what makes Be stars special that only they have unique characteristics? Which kind of stars have discs ...
0
votes
1answer
32 views

Road map for a faster spaceship [closed]

New Horizons, speediest yet, is currently running at about 15 km/sec relative to the sun. What is the roadmap for future ? How is it possible to reach much faster speeds ?
2
votes
1answer
66 views

Does tidal heating imply orbit degradation?

What compensate the energy loss in tidal heating? Is it orbital decay?
1
vote
2answers
34 views

Simulating location of the moon

I'm researching high altitude photography and want to know a schedule for taking pictures of the moon. Preferably I want a picture of the (full) moon on the horizon. How would I go about scheduling ...
3
votes
1answer
66 views

Ultra Low Cost Telescope Project

A few years or so ago there was a project that distributed small very low cost telescopes (perhaps around US$20). What was the name of (and links to) that project?
0
votes
0answers
27 views

Units of angular power spectrum

I am not sure whether this question might be better suited for crossvalidated or stackoverflow, but I will give it a try here: I have a map of the full sky in in the healpix format, units are $\rm ...
2
votes
1answer
81 views

How long will it take to reach the closest earth like planet

Using the engines today how long will take humanity to reach earth like planets?
2
votes
1answer
38 views

IAU Dwarf planet definition Point 2.b - is not a satellite

I am a bit confused with point 2.d of the IAU's resolution on dwarf planets. (2) A "dwarf planet" is a celestial body that (a) is in orbit around the Sun (b) has sufficient mass for its ...
1
vote
1answer
98 views

What is the largest possible size for a brown dwarf?

What is the largest possible size for a brown dwarf before it has enough mass, capable of sustained fusion, thus becoming a star?
0
votes
2answers
6k views

Star like light moving in the sky, what could it be?

I was camping this weekend away from the city, so my friends and I decided to spend one of the nights watching the sky, since it's impossible to see anything around where we live. After a little while,...
2
votes
1answer
78 views

Why are there no more images revealed by New Horizon?

Since a few days after the flyby there are no more images published on the NASA page. Why is NASA waiting to publish any more images for some reason? Or is there something happened to New Horizon?
2
votes
1answer
34 views

how to assess a periodical signal?

After folding a light curve, we may get some kind of shape. How to tell whether there is a real periodical signal quantifiably? The fluctuation may be small, and the folded shape may not be perfect.
7
votes
2answers
898 views

How is a non-rotating black hole created

How are non-rotating black holes formed? I guess that non-rotating black holes are formed from non-rotating stars but I couldn't find any proof that such a star exists on the internet. If this is ...

15 30 50 per page