9
votes
2answers
105 views

Relativistic effects in stellar dynamical systems

I am curious, if anybody knows of any stellar dynamical systems/environments, where relativistic effects could play a dynamical role on the motion of these stellar systems? As a subquestion - are ...
7
votes
2answers
66 views

What is the difference between asteroids, comets and meteors?

Some celestial objects seem to be referred to as asteroids, some as comets, and some as meteors or meteorites. What is the distinction between all of these different objects? Are any of them the ...
11
votes
2answers
173 views

What physical features determine if a planet is a major, minor or dwarf planet?

Like many, when I was growing up, we always were taught, hence always learned that there were 9 planets. However, recently, decisions were made and all of a sudden there were 8 major planets and a ...
9
votes
1answer
71 views

How is it known that Callisto has no core?

My Astronomy book claims that scientists have discovered that Callisto, a moon of Jupiter, has no hot inner core. In fact, it says, Callisto has a core much like the nucleus of a comet. Is this still ...
11
votes
2answers
68 views

Near-Earth supernova

There are 51 stars within 17 light years of the Earth (source). If one of these stars was to become a supernova, how would they effect the Earth?
5
votes
1answer
81 views

What is the current accepted hypothesis of what caused Triton's retrograde orbit around Neptune?

According to the NASA overview about Triton, this, the largest satellite of Neptune is unique in that it has a retrograde orbit around Neptune. The page also suggests that Triton is a captured Kuiper ...
6
votes
1answer
148 views

Why does the moon sometimes appear giant and a orange red color near the horizon?

I've read various ideas about why the moon looks larger on the horizon. The most reasonable one in my opinion is that it is due to how our brain calculates (perceives) distance, with objects high ...
6
votes
1answer
31 views

Is the Apophis asteroid a concern?

I was watching the TED lecture How to defend Earth from asteroids , and the speaker Phil Plait spoke of the possibility of this asteroid hitting Earth. Is this really a concern?
6
votes
1answer
56 views

What percent of planets are in the position that they could be viewed edge-on from Earth? (and thus able to undergo transits)

Star number 12644769 from the Kepler Input Catalog was identified as an eclipsing binary with a 41-day period, from the detection of its mutual eclipses (9). Eclipses occur because the orbital ...
7
votes
1answer
46 views

What are Trojan Asteroids and where are they located?

Asides from the main Asteroid Belt, there are Trojan Asteroids - what are these and where are they located?
3
votes
2answers
64 views

What is a wormhole?

I have learned that there are white holes and black holes in the universe, but I am confused as to what a wormhole is. Is it a tunnel that connects black and white holes?
3
votes
2answers
130 views

How long does it take to produce a star? Why does it take that long?

I wonder, why stars take a really long time to become stars? Is it because it needs to gain mass? Or heat up? Something like that? And could it be sped up at all?
10
votes
1answer
792 views

How can I collimate a dobsonian telescope with a laser collimator?

I've had a dobsonian telescope for a while now, but I've never been able to collimate it. I thought I had it collimated once, but when I looked through it the star didn't look right, it looked kind ...
3
votes
4answers
125 views

Do all objects get larger in an “expanding universe”?

I'm envisioning an analogy of the universe as a plane with marbles in that plane to represent different planets. Now, if this plane expands how does this work? I assume that it is not like 'nothing' ...
14
votes
1answer
313 views

Milky Way Galaxy from Earth

I've seen a lot of beautiful pictures of the Milky Way from Earth such as this: ...but I can't understand what the cloudy ribbon at the bottom the horizon is. Is it a super-large nebula? Or is it ...
30
votes
2answers
654 views

Does the Sun rotate?

The planets rotate as an after effect of their creation, the dust clouds that compressed span as they did so and the inertia has kept it rotating ever since. It's fairly easy to prove that planetary ...
8
votes
1answer
63 views

What is a White Hole?

White holes are purely hypothetical at this point and are considered only because it is assumed something like it could exist as the balance to black-holes. Reading this article seems mostly writers ...
7
votes
3answers
61 views

Are there ways other than the collapse of a star which have been observed to form black holes?

Every time I hear about a black hole, it's always in conjunction with the collapse of a star. Have any other processes been observed to create a black hole?
9
votes
1answer
436 views

Is the moon moving further away from Earth and closer to the Sun? Why?

According to The NASA Moon Facts page: The moon is actually moving away from earth at a rate of 1.5 inches per year. Why is the moon moving further away from the Earth? Is this a result of the ...
8
votes
1answer
160 views

Why do the planets in our solar system orbit in the same plane?

(Yes I'm excluding Pluto from this the same way it was excluded for not being a planet) Observing the planets orbit of the Sun they all seem relatively planar and roughly all orbit along the same ...
6
votes
2answers
59 views

What are the Earth-like features of Titan?

This NASA site says that hidden beneath the smog of Titan are Cirrus like clouds and This space article describes how Titan's atmosphere is similar to Earth's too. What other features does Titan ...
5
votes
2answers
146 views

Do parallel universes exist?

Do other universes like ours exist? If they exist, how do we know that they exist when we have even not seen the ends of our own universe?
9
votes
2answers
101 views

How hot must a star get before it is considered to be a star?

How hot must a star get before it actually becomes a star? Why does it need to get so hot? Please find an official site to quote from, if you can.
5
votes
3answers
64 views

What qualifies as a good place for stargazing, i.e. with least light pollution?

I know that minimal light pollution is a must for stargazing, and a place which is away from civilization is better. Does altitude of a place matter for light pollution? Does it affect the quality ...
4
votes
1answer
51 views

What proportion of planetary systems have been found with 'Hot Jupiters'

According to the NASA website "The strange attraction of Hot Jupiters", one of the main types of exoplanets that have been detected are Hot Jupiters, which are These are behemoth worlds that ...
9
votes
1answer
95 views

On what scale does the universe expand?

According to the theory (or my understanding of it), the universe is not only expanding, but speeding up. If the galaxies are moving apart, are the solar systems within them also moving apart from ...
6
votes
1answer
40 views

What are the metrics of observation conditions?

How do professional astronomers measure and describe (ambient) observation conditions? I know smog, light contamination from the city lights, fog, clouds, rain/snow, humidity etc all contribute ...
6
votes
2answers
119 views

What causes a neutron star to become a pulsar?

Leading on from this pulsar question, what criteria/processes make neutron stars become pulsars, do all neutron stars become pulsars?
9
votes
2answers
116 views

How many galaxies have been discovered?

I know Andromeda is our nearest galaxy. But how many known galaxies have been discovered and what are they?
17
votes
2answers
251 views

What is a parsec and how is it measured?

Astronomical units of measurement are mostly pretty straight-forward: Astronomical Units refer to the mean Earth-Sun distance (~150 million km or 93 million miles) Light years are the distance light ...
14
votes
1answer
167 views

How distances are measured in the Solar System, in the Galaxy, and in the Universe?

Distances in our universe can be calculated in several ways: Stellar Parallax Standard Candles Redshift How are these methods linked, and how they are actually used to calculate distances are ...
6
votes
2answers
64 views

What is the current estimation for how much time the Sun will function properly?

Eventually, the Sun will run out of fuel, go dark, and other bad things will happen. About how much long is it predicted that we will have a sun functioning as it is currently?
5
votes
1answer
39 views

What are the main differences between solar flares and coronal mass ejections?

Specifically, what causes them, what sort of damage can they cause, and what are the differences in their composition?
10
votes
1answer
47 views

What is the naming convention for newly discovered objects?

Often, a newly discovered star is identified by a seemingly random string of letters and numbers. I'm sure that there is some order to it, though. What is the naming convention for newly discovered ...
7
votes
1answer
94 views

What is the current accepted theory for Neptune's immense wind speed?

According to "Neptune: The Other Blue Planet in Our Solar System" (Choi, 2010), Neptune, despite its great distance from the sun, is the windiest planet in the solar system, with winds reaching ...
8
votes
2answers
96 views

What is the upper and lower limit of temperatures found on stars?

What are the most extreme temperatures (both hot and cold) stars have been detected at? Is there an upper and lower limit for the detected temperature of stars?
12
votes
4answers
126 views

What is Gravitational Lensing?

What is the effect known as gravitational lensing? How does it work? What objects would be able to cause this effect?
8
votes
1answer
59 views

Will an observer falling into a black hole be able to witness any future events in the universe outside the black hole?

I know someone or something sucked into a black hole could not survive, but is the bending of light so immense that an observer falling into a black hole will be able to witness any future events in ...
6
votes
2answers
85 views

If nothing travels at the speed of light, except light, how can a black hole also pull light into itself?

Is it because it has super massive gravity and energy? Or is it some sort of an anti-light component in it because it used to be a star?
8
votes
2answers
65 views

Do the orbits of planets change sometimes?

Do planets sometimes wobble and get off their paths? What if an asteroid were to hit it?
11
votes
3answers
336 views

Do all the objects in the universe exert force on all other objects?

Do all the objects in the universe exert force on all other objects? Like a type of gravity; also, how much does it decrease as it gets farther away?
6
votes
1answer
64 views

How many stars can stay close to each other without collapsing?

Is it possible for two stars to exist close to each other? "Close" is relative; let's assume that two stars are close to each other if they are at the center of the same solar system. It's ...
10
votes
1answer
74 views

How hot can a planet be?

Given that some exoplanets, particular "Hot Jupiters", orbit very closely to their parent star, how hot can these planets become? What is the hottest exoplanet discovered so far?
7
votes
1answer
44 views

How would the pocket cellular clock work?

In a museum in Lviv, I saw a pocket cellular clock. I don't have a photo, but it was a small disc that had 2 or 3 filaments in it which were pointed at the stars (one of them was Andromeda, I think). ...
16
votes
1answer
155 views

What causes a star to become a pulsar?

What processes does a star undergo to become a pulsar? Does it take a very specific star with a certain set of qualities such as "Just the right mass, diameter, and composition," or is it a freak ...
4
votes
2answers
118 views

How to calculate the movement of the object passing near other object in space?

Assume object A is moving through the space and is passing near the other object (B). Assume the gravitational influence of other objects can be ignored. How to find the equation describing the ...
10
votes
1answer
118 views

What is the accepted theory as to why Uranus' axis is tilted so severely?

The planet Uranus is another solar system anomaly, where according to the NASA profile has an axial tilt of 97.8 degrees, also considered to be retrograde. This NASA summary "Uranus" suggests the ...
8
votes
1answer
73 views

Navigation using moon phases

How to navigate with possible maximal precision using moon phases? The Moon is the brightest celestial body seen in the night sky, and it is possible to find even through moderate clouds. So it's a ...
11
votes
4answers
139 views

What are the differences between a Black Hole and a Supermassive Black Hole

From what I understand, the mass of a black hole should be nearly infinite, how much more massive can something get? Is the name to be literally interpreted such that a Supermassive Black Hole just ...
8
votes
1answer
84 views

Can any information leave a black hole?

Referring to this question, is there any information that can leave black holes? Are they causing a permanent information loss in our universe?

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