4
votes
1answer
105 views

What is driving the expansion of the Universe?

Is it just the momentum from the Big Bang? If yes, how can it account for the acceleration of the expansion? Why isn't the collective gravitational force slowing it down? What part does dark energy ...
2
votes
2answers
37 views

Is the colour of a wave from a far galaxy the same for us as for a galaxy which lies between?

Because of the expansion of the universe, light from a far galaxy is redshifted. The expansion of the universe will make the wavelength of light longer. But is the colour of such light the same for us,...
3
votes
2answers
170 views

Why is it said that the far side of the moon's crust is thicker?

This video states that NASA has determined that the far side of the moon's crust is thicker than the near side's crust. How did they determine this? Please note I'm not asking for theories or ...
4
votes
2answers
127 views

Why do planets move in an elliptical orbit? [duplicate]

I am a student of class 9 and recently came to know about kepler's law of planetary motion and got confused about the foci and elliptical orbits of planets and some stars.
3
votes
1answer
360 views

Where do new stars get their hydrogen from? [duplicate]

When stars run out of hydrogen, they explode (though they also use heavier elements for some time) and form nebulae. In the nebulae, new stars are born which use hydrogen as their fuel. So, my ...
5
votes
1answer
268 views

What do gravitational waves allow us to understand?

Before reading this question, you should read this paper. From what I understood, we managed to detect gravitational waves for the first time. Is this discovery going to help us understand ...
6
votes
1answer
491 views

How do star densities work?

If we take a look at stars more massive than the Sun, their densities vary a lot. UY Scuti is an extremely low-density star that's only 8.5x more massive than the Sun, but is 1000-2000x its size. ...
1
vote
0answers
33 views

What would we not know without spectroscopy?

What do we depend on spectroscopy to know about in astrophysics? Or, without spectroscopy, what would remain unknown to us? I want to know how important it is. My wife is studying spectroscopy in ...
0
votes
0answers
9 views

Convert axis display in ds9

I have a fits file of an echellogram with the axes showing the pixel indices. However, I would like to convert my horizontal axis from pixel to wavelength given that I have a conversion formula for ...
4
votes
1answer
74 views

Why do pre-main sequence stars show lithium in absorption?

This paper and this paper state without discussion that the presence of lithium absorption in the stars they observe as strong evidence of these stars being pre-main sequence stars. Because they state ...
1
vote
2answers
69 views

Determining distance from semi-major axis and eccentricity

I am trying to obtain the distance covered by an object in orbit around the earth within a specified amount of time past its perigee passage. The object is in an elliptical orbit with eccentricity 0.2 ...
3
votes
2answers
98 views

Why does mass naturally move closer toward's the center of other masses?

If general relativity is understood to mean that mass curves space such that objects are still traveling in a straight line, why does mass naturally move closer toward's the center of other masses?
7
votes
2answers
94 views

What conditions would lead to this event around the black hole in the Pictor A galaxy?

This is a picture of a jet of particles exiting the supermassive black hole in the center of Pictor A galaxy at nearly the speed of light. Source This event is supposedly created from a black hole of ...
-1
votes
2answers
59 views

Is parallel universe possible [duplicate]

Does parallel universe really exists or just science fiction which ain't possible? Can we ever know ?
0
votes
1answer
38 views

What was the entity/particle/state at the time of the Big bang?

At the time of the big bang if there was an original entity, what were it's attributes(if applicable) - mass, electric charge, color charge or spin? Can the current matter and dark energy together ...
1
vote
0answers
35 views

Is there any support for the Big Crunch Theory? Could there have been a partial Big Crunch in the past?

Is there proof in either the CMB or other observed astronomical phenomena for Big Crunch? Could there have been a partial Big Crunch maybe like a cluster of Black Holes colluding to create a ...
0
votes
2answers
89 views

Are there any studies that prove/disprove the Oscillating Universe Theory?

Is there any evidence that supports or disproves the Oscillating Universe theory? What kind of observations could provide this evidence?
1
vote
0answers
24 views

Is it observable what is the north and what is the south pole of magnetic fields of stars and black holes?

The question is related to this about Are there collected data about the direction of rotation of black holes and the direction of the magnetic field?. Perhaps it is observable for pulsars?
2
votes
2answers
49 views

Are any other planetary bodies warming up as well in the Solar System?

Do we have a few decades worth of surface temperature data to compare?
12
votes
3answers
1k views

Existence of gravitons?

For a lot of my uninformed life, I have doubted the existence of gravitons or even that gravity is an actual "force" (like electromagnetism). This is because my vision of general relativity was that ...
1
vote
1answer
79 views

What would be the outcome for life in our galaxy if the merger of the Milky Way and Andromeda creates a Quasar?

If predictions are correct, the Milky Way and Andromeda are set to collide in around 4 billion years. If, when this occurs, a Quasar is formed by matter being accreted to the common galactic center (...
2
votes
4answers
125 views

What planet is better than earth to infer solar system configuration?

The mankind had to work some centuries to infer the real configuration of solar system, starting from greeks, Ptolemeus, until Copernicus, Galilei, Kepler, Newton etc. Is there any planet where we ...
1
vote
1answer
96 views

Are we so sure global warming is a result of humans burning fossil fuels? [duplicate]

The Sun is a fiery mass of colliding particles. We still know very little about what it is. Could it possibly be the output of the sun fluctuates, like our weather, from one extreme to another. ...
1
vote
0answers
29 views

Are there collected data about the direction of rotation of black holes and the direction of the magnetic field?

Is there a relation between the direction of rotation of black holes or neutron stars and the magnetic dipole moment of BH or neutron stars? BTW, are there different directions of this two parameters ...
1
vote
0answers
21 views

Eclipse in sun-synchronous orbits

I am trying to figure out the eclipse periods of a satellite orbiting the Earth. The satellite is placed on a circular sun-synchronous orbit at 800 km height. The LTAN (local time of ascending node) ...
-2
votes
2answers
66 views

Large hadron collider [closed]

Whether the collision of particle will lead to a massive WORMHOLE or if BLACKHOLE is also possible? How much I know is that it's created for einstien's E=mc^2 ,conservation of energy from mass and ...
4
votes
0answers
37 views

Orbital eccentricity variation of the other planets?

On Earth, it's fairly well published, mostly in climate change related articles, that the Earth's orbital eccentricity operates on a 413,000 year cycle with roughly 90,000 - 125,000 year variation ...
1
vote
1answer
65 views

Is it ever possible that the graviation from the mass of kinetic rotational energy will overcome centrifugal force?

This is, I think, somewhat intuitively obvious, but this comment got me thinking about this: what is gravitational force? "Rotation speed can create centrifugal force opposing gravity and making ...
7
votes
3answers
98 views

Precision of geocentric gravitational constant

I am looking for an answer as to why the geocentric gravitational constant, μ, defined as the product of the gravitational constant, G, and the mass of a body (earth in this case), M, can be ...
2
votes
1answer
31 views

Does earth's Umbra reach Sun-Earth L2?

Moon can be fully eclipsed by the virtue of being fairly close to Earth. Any body distant enough will not be eclipsed fully, Earth's disc not fully covering Sun's disc. How's that for anything at the ...
0
votes
3answers
103 views

Distance of a planet to the star?

QUESTION: Suppose we discover a planet orbiting a nearby star. The distance to the star is 3 pc. We observe the angular radius of the planet’s orbit to be 0.1 arc sec. How many AU from the star is ...
1
vote
1answer
25 views

How to see other celestial things using stars for direction?

I have a simple question. I can see orion constellation clearly in the night sky. I read it somewhere on this website that gemini is on the left-hand side of orion constellation. I was able to spot ...
1
vote
0answers
10 views

Tools and algorithms for angles-only orbit estimation

I've seen discussion threads where amateur astronomers estimate a satellite's orbital parameters from angles-only telescope observation. Are there any community tools or algorithms to help with this ...
1
vote
1answer
57 views

Why is it strange that outer stars are travelling with the same speed as inner while the total mass is also increasing?

Astronomers say that it's strange that the outer stars of a gallaxy are travelling with the same speed as the inner stars. Therefor they introduced dark matter to solve this strangeness. The theory ...
0
votes
1answer
33 views

Is their any clue where gravitons come from?

Everything which has mass has gravity. Some theories hypothesis that gravitons are responsible for that, but do they have any clue where they come from? Like gluons are interacting between quarks and ...
5
votes
1answer
75 views

How does an accreting black hole acquire magnetic fields?

There is actually a similar question on this site: Can magnetism escape a black hole?, however the answers do not focus on accretion, which is my main concern, so I start a new one. In Kip Thorne's ...
2
votes
1answer
47 views

Since the Universe is expanding, is it accurate to say that a galaxy is 5 billion light years away?

Isn't it better to say that the light from the galaxy took 5 billion light years to reach us and it is a very old picture of it? However, if light travelled back to the galaxy at the constant speed ...
2
votes
2answers
97 views

What happened just before the Big bang? [duplicate]

Does the CMB contain any clues to what caused the Big Bang? Does a mathematical model theorize it?
0
votes
1answer
118 views

what is gravitational force?

Gravitational force is particle or wave? I know that gravitation depend of the mass and the rotation speed but what is the transmission medium of this wave the same like transmission medium of the ...
1
vote
0answers
45 views

Is Planet Nine shepherding the Kuiper Belt?

Is it possible Planet Nine is shepherding the Kuiper Belt similar to the way Jupiter shepherds the asteroid belt? I understand that very little is actually known about Planet Nine at this point, but ...
0
votes
2answers
55 views

How probably is it that galaxies will extinguish?

In the nebulaes of galaxies are stars born, but the gasses and dust they are made of comes from exploded stars (fe supernovas). So it looks like these processes can go on continuesly. But is that ...
-6
votes
1answer
115 views

Is this Universe scenario correct? [closed]

I will try to give you my reasoning behind my scenario. Ok I've researched and found That 95 percent of the galaxy has been formed already, And the other 5 percent is still to come.http://www....
0
votes
1answer
44 views

Is our supercluster part of a galaxy filament?

It was discovered recently that the Milky Way galaxy lies inside a supercluster named Laniakea Supercluster. On the other hand, wikipedia says that galaxy filaments are "the largest known structures ...
1
vote
2answers
448 views

Why can we observe the Cosmic Microwave Background no matter the direction we look?

I often read that the CMB was released from everywhere in the Universe, in every direction. If that statement is true, can someone elaborate what "everywhere in the universe, in every direction" ...
1
vote
1answer
76 views

highspeed black holes or neutron stars on (almost) head-on collision course and kinetic energy

First: I don't think this is a duplicate question. There are related question on mergers of black holes that orbit around each other etc., so please read on. I'm having a hard time picturing what ...
-1
votes
1answer
47 views

Can a drastic change in a stars cycle cause harm or affect a nearby star system?

If Alpha Centauri A our neighboring star happens to shift into a Red Giant or a Planetary Nebula, Will our star system be affected? And if so is there a ripple effect throughout the galaxy causing a ...
1
vote
2answers
164 views

Have any planets been discovered in Orion constellation?

Orion constellation is a very famous constellation. It can be seen throughout the earth. Orion looks like a warrior with a weapon and skirt. I see this constellation daily and wonder, if there is a ...
1
vote
2answers
108 views

Does every object in the Universe have gravity? Space has no gravity, why?

My science teacher told me that every object in Universe has gravity but space is a part of Universe too, so, why does the space have no gravity?
2
votes
1answer
64 views

What was “space” like before big bang?

I have a simple question which I think about often but have no answer. If The Big Bang is true, than if the whole space was just a point 14 billion years ago, then what was around that point, some ...
3
votes
1answer
103 views

How do we know the current state of the universe by observing it from Earth?

Since light travels at the constant speed and takes more than a billion years to travel from the distant parts of the Universe, how do we know the state of the distant regions? Do those still exist or ...

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