0
votes
2answers
31 views

How do astronomer measures the size of any celestial objects?

What techniques and tools are available to the astronomers to measure the size of any celestial objects such as, stars or perhaps black holes that doesn't emit light nor reflects starlight?
1
vote
2answers
69 views

What triggers solar flares?

The sun is a big ball of hot plasma which contains free electrons. However, how does the absence of metallic elements in the sun generate the magnetic field to orchestrate these free electrons to ...
0
votes
1answer
38 views

Do astronomers and astrophysicists more often use diameters or radii when discussing about planets, dwarf planets, exoplanets and stars?

Mathematicians much more often use radii over diameters when discussing about circles and spheres, because in mathematics the radius is more fundamental than the diameter (the sphere is defined using ...
1
vote
1answer
66 views

What came first: the Sun shining or the existence of helium?

This seems to be a chicken and egg problem, the sun begins shining due to hydrogen becoming helium, but it's odd that there was no helium initially without the stars. Is my logic flawed? (Note: ...
0
votes
1answer
44 views

Will the Universe end by time stopping?

I know there are several theories as to how the universe might end, if it does. Is it possible for it to end by time stopping? A friend of mine told me about this theory, but her explanation that it ...
3
votes
1answer
99 views

How many arms does the Milky Way galaxy have?

How many arms does the Milky Way galaxy have and how is it determined?
1
vote
1answer
39 views

Shadows of Light = Space or Dark Matter?

Perhaps my title is misleading. but here is my understanding and I'm looking for confirmation. You cannot have dark without light. The only thing faster than light is darkness (i.e. shadows) Stars ...
3
votes
0answers
104 views

Why do dark objects look white from a distance? (Moon, Ceres, but not Earth!)

What makes the Moon shine white in the sky, although it seems to be as dark as asphalt? Earth's average albedo is 3 and 4 times that of the Moon and Ceres respectively (0.37 vs 0.12 and 0.09). But ...
1
vote
2answers
60 views

What type of star does theory predict should be the most massive?

The most massive known stars are Wolf-Rayet stars. However, as Wolf-Rayet stars do not appear to be the first stage of any star's lifecycle, I infer that whatever these Wolf-Rayet stars used to be ...
1
vote
2answers
34 views

How does one measure velocities of far-off, bright objects

As the title already says, I want to know how one measures velocities of far-off, bright objects, e.g. when the mean parallax drift isn't measurable with current apparatus (this means when there is ...
1
vote
1answer
27 views

Simulation packages or theory to work with gravitational collapse of massive molecular clouds?

So, I am getting interested in gravitational collapse of large molecular clouds that fragment and collapse into multiple stars. Are there well-known popular academic simulation packages that simulate ...
0
votes
0answers
43 views

Statistics to prove handedness of the universe

There are some papers discussing a potential handedness of the universe: GalaxyZoo: the large-scale spin statistics of spiral galaxies in the SDSS, Longo with Detection of a Dipole in the Handedness ...
2
votes
2answers
103 views

In theory, is there anywhere in the universe where velocity=0?

Earth is traveling at a certain velocity. Earth orbits the Sun at velocity X. The sun is orbiting the center of our galaxy at velocity Y. The galaxy is orbiting (something?) at velocity Z. On and ...
1
vote
1answer
28 views

What do cosmologists mean when they talk about “the running of the spectral index”?

All I know is that the spectral index is related to the CMB, and that it has to be slightly less than 1 to favor inflation.
0
votes
0answers
13 views

LIGO and Fabry–Pérot interferometer

I was currently reading about how LIGO works, it uses the basic principle of a Michelson interferometer, and the laser it uses is infrared laser with 1064nm. so from what I know about interference and ...
0
votes
1answer
48 views

What will the mass of the new galaxy be?

When the Milky Way galaxy collides with the Andromeda galaxy, what will the mass and volume of the new galaxy be?
0
votes
1answer
33 views

axial tilt of uranus [duplicate]

Simple question: I read that the axial tilt of Uranus is 97.77 degrees. I don't understand why it would be this instead of 82.23 degrees the other way. It seems like saying that the Earth's axial tilt ...
-1
votes
1answer
35 views

What's the cheapest research-level telescope?

Like the title says, what is the most low-powered (cheapest) research-level telescope there is? Is there any in the consumer price range (e.g. at the cost of a new car)? Of course, scientists probably ...
1
vote
1answer
31 views

Why do astronomers use supernova to measure distance in space?

Why can't the distances between our Sun and the celestial objects be measured directly and instead had to rely on looking around for supernova? Is these events frequent, evenly distributed and lasting ...
0
votes
0answers
8 views

North Pole Right Ascension/Declination to axial tilt conversion

Wikipedia , on several asteroid articles, claims that right ascension and declination of the North Pole can give you the axial tilt of the object. What formula is used to convert these 2 values into ...
0
votes
1answer
49 views

Why are the high density regions in outer space black holes?

The escape velocity of an object is given by the following formula. $$v_e=\sqrt{\frac{2GM}{r}}=\sqrt{\frac{2 \mu}{r}}= \sqrt{2gr}$$ As far as I am aware, the mass of the star which formed the black ...
2
votes
3answers
70 views

Is dark energy evenly spaced throughout Universe?

Are there certain parts of the Universe that are expanding faster than others? Is there anyway to definitively measure this?
2
votes
2answers
61 views

Is there a connection between black holes and dark matter/energy?

Is there a spatial or gravitational relationship between black holes and dark matter/energy?
1
vote
0answers
42 views

What mechanism could have formed the Moon's Oceanus Procellarum rift-like gravity anomalies?

According to the NASA JPL web-report, Gravity Gradients Frame Oceanus Procellarum, a rift-like ring structure surrounding the Moon's Oceanus Procellarum has been detected as a gravity anomaly by the ...
1
vote
2answers
120 views

Is it possible that the Sun has a binary partner (the Nemesis Theory) that has eluded detection?

I just recently learned about the theory that our Sun has a small companion star with a 26 million year orbit. This theory came about when it was realized that mass extinction events happened ...
1
vote
1answer
57 views

Are galaxies moving away from us faster than before?

Are all galaxies moving away from us at constant speed even those that may be moving in our direction as the space is being formed? How does nothingness appear to push matter? A black hole sucks as ...
1
vote
2answers
33 views

Expansion of Space

If Space is expanding between the Galaxies then why isn't it also expanding between the Stars within the Galaxies as well ? In fact why isn't Space expanding within our Solar System ?
-3
votes
1answer
49 views

Does “Dark Matter” really exist?

Does dark matter really exist or is just a made-up theory in order to cover up the loopholes in the Big Bang theory, and also to explain why universe is expanding at an accelerated rate?
0
votes
0answers
15 views

Orbital resonances and position of planets

I am interested in quick generation of planetary systems for programs similar to Space Engine or Pioneer Space Simulator. As far as I understand, formation of planets is a complex process and the ...
1
vote
1answer
60 views

How to calculate the expected surface temperature of a planet

I'm writing a program to generate solar systems but I'm having trouble calculating the expected temperature of a planet. I have found a formula to calculate this, but I haven't been able to get a ...
1
vote
2answers
40 views

Could we detect an earth-like planet around another star?

Could we detect an earth-like planet (e.g. similar distance from star, and similar size) with current planet finding techniques? If an earth-like planet were orbiting our nearest star, excluding the ...
1
vote
0answers
33 views

Is it likely OMG particle (and those like it) originate from alien spacecraft propulsion systems?

Is it likely that Ultra High Energy Cosmic Rays (UHECRs) like the OMG particle come from alien spacecraft propulsion systems? I realize this is a bit "out there", but my reasoning behind it is that ...
4
votes
1answer
62 views

Is there any way a planet could form independent of a star?

I just recently heard that there are currently no theoretical models that support planet formation without a star, but I can't remember where. So, I thought I would request all of your expertises. ...
1
vote
0answers
19 views

How do the orbits of Nu Scorpii and AR Cassiopeiae work?

I apologize for the way this question is worded but I don't think I know the proper verbiage. Basically, I want to know how the stars orbit one another in the two septuple star systems. For example, ...
2
votes
1answer
39 views

brown dwarfs and planets

As far as I know, a brown dwarf is a 'star' whose core never underwent a fusion reaction, so it never became a star. So I was wondering if, appart from orbiting a star, is there any difference between ...
1
vote
1answer
31 views

app to locate star by coordinates

I've named a star and would love to be able to find it in the sky - is there an app I can use to locate stars given a specific coordinate?
2
votes
1answer
38 views

visualisation of the universe's expansion

in physics we were learning about the universe and the big bang. we were being told that everything came from one point and 'exploded' outwards, and is continuing to expand. I felt that this ...
0
votes
0answers
23 views

How to calculate the new orbit after a instantaneous change in a well defined initial one?

Say one has a simple two body system (and one body is much more massive than the other, for example a star, planet system) where all the quantities about it are know, that is the eccentricity, masses, ...
6
votes
0answers
40 views

Statistics of elements abundance in exoplanets

Recently, I encountered the concept of carbon planets - planets, which would be, unlike the Earth, formed mostly by carbon, instead of oxygen, silicon and magnesium. (I am not counting iron, which is ...
2
votes
1answer
310 views

Why are Hubble images “Cut”

Whenever you take a look at a photo that is taken by hubble, Lets say M87 or Eagle Nebula or maybe Ultra Deep space field, The Image is always "Cut" Like this : or this I want to know reason ...
2
votes
1answer
70 views

Why is there so much methane in space?

In school I learned that methane is organic matter and that it is a possible product of crude oil refinement. However, recently I read that Uranus has huge methane storms and the Saturn moon Titan ...
4
votes
2answers
78 views

Does rotation affect gravitational lines of force

I was reading about rotating pulsars and other more-massive objects spinning at absurd speeds (hundreds of revolutions per second), and there was one point of which I was not clear. Does a rotation ...
1
vote
2answers
75 views

Looking for help in understanding how black holes can move

I'm looking for help in understanding how black holes can move through space. This is probably a trivial question for anyone who knows astronomy, but probably due to my lack of education on the topic, ...
1
vote
0answers
30 views

Who discovered what set of factors is responsible for visibility of celestial bodies on Earth's daytime sky?

Visibility of a celestial body on the sky during the day depends on a number of factors - if I recall correctly: the body's magnitude, Seeing, Sky brightness, and probably some others I have missed. ...
2
votes
1answer
71 views

How long does it take Dawn to orbit Ceres?

I haven´t been able to find the orbit time of Dawn around Ceres. Do you know how long it takes?
0
votes
0answers
12 views

How can we see the Milky Way Galaxy when we are already in it? [duplicate]

How can we see the Milky Way Galaxy when we are already in it? I have seen lots of pictures of Milky way galaxy. Consider yourself being in a room, how can you see it from out when you are already ...
0
votes
2answers
106 views

Supernova explosion nearby

A nearby star has crossed Chandrasekhar's limit. How do we come to know when it will undergo supernova explosion? Or has it already undergone supernova explosion?
1
vote
0answers
40 views

Angular momentum in planetary disk formation

Reading about the formation of planetary disks, one of the major problems, it seems like, is the evacuation of angular momentum. Aparently planets can't form with the amount o angular momentum the ...
1
vote
0answers
34 views

Calculating Postition of ISS / Hubble in space

How do I calculate the positions of above satellite in space ?
1
vote
2answers
43 views

What is the term for astronomical objects outside the solar system that are smaller than dwarf planets?

Asteroids and comets only seem to refer to masses within the solar system, and it seems unclear whether planetesimal does.

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