1
vote
0answers
4 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 ...
0
votes
2answers
46 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 ...
0
votes
0answers
2 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
1answer
12 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
58 views

Would a satellite in geosynchronous orbit between the earth and moon track across the sky together?

On Nov. 25 at 2:30a.m. from southern California while viewing the moon with a 70mm D x 400mm F telescope a point of light was seen at about the 7 o'clock position below the moon. As viewed the point ...
0
votes
1answer
9 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 ...
-5
votes
1answer
49 views

Is this Universe scenario correct?

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 ...
3
votes
1answer
17 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 ...
0
votes
0answers
21 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 ...
1
vote
1answer
16 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
12 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 ...
0
votes
0answers
15 views
1
vote
0answers
6 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
20 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 and ...
3
votes
4answers
106 views

Compared with similar stars, does the sun itself have properties that make life on Earth possible?

We often hear our solar system has properties for life. For example, it is far away from the center of Galaxy. It has Jupiter far away to protect us from asteroids. It has optimum size of territorial ...
8
votes
5answers
303 views

Using the Sun as a Gravitational Lens

Can the Sun be used as a gravitational lens to achieve better telescopic viewing? Can this effect be practically used to view celestial objects?
1
vote
0answers
19 views

What happened just before the Big bang?

Does the CMB contain any clues to what caused the Big Bang? Does a mathematical model theorize it?
1
vote
2answers
43 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
votes
2answers
31 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 ...
0
votes
2answers
35 views

Can “dark matter” be the additional mass from the speed of the Galactic Cluster?

Considering that the Earth orbits the Sun at 100 000 km/h and that the Sun orbits the Milky Way at almost 1 000 000 km/h, could it be possible that the galactic cluster orbits some super cluster at ...
0
votes
2answers
29 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 ...
1
vote
1answer
59 views

What part of the milky way do we see from earth?

When looking up at the night sky, we can sometimes observe a bright band of stars stretching across it. I know this is our galaxy but exactly what are we looking at? Could we look at the centre of ...
1
vote
2answers
352 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" ...
0
votes
1answer
21 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 ...
0
votes
0answers
31 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
vote
1answer
48 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 ...
1
vote
2answers
71 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?
1
vote
1answer
32 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 ...
2
votes
4answers
117 views

What is spacetime 'made' of?

General relativity is often explained as saying spacetime is curved by gravity, what does this mean? How could we perceive a curve in spacetime when there is no external "straight" reference frame for ...
5
votes
3answers
180 views

Does the Sun impose back it's tidal forces onto the Earth (such as the Earth's to the Moon)?

It is known that each year the Moon is moving away from the Earth due to tidal forces. What about the Earth relative to the Sun?
1
vote
2answers
28 views

How to calculate when the moon is highest in the sky to the earthbound observer?

Like when is the new moon highest in the sky? Or third quarter? How do I know this for any general moon phase? Thanks.
5
votes
1answer
781 views

How many earths fit in the observable universe?

I was pondering our insignificance, when I wondered - how how much smaller is our planet then the (observable) universe? And being as I dont know how to do the math, I'm asking it here. So how many ...
6
votes
3answers
298 views

How does light affect the universe?

When light is emitted by for example a star, that star loses energy - which causes it to reduce its gravity. Then that energy begins a journey for potentially billions of years, until it reaches some ...
3
votes
1answer
84 views

Is there a photo that shows a iron meteor or asteroid in space in raw form having no layers of fusion crust?

A raw iron meteor or asteroid in outer space should be in its raw form having no signs of fusion crust from the friction of atmospheric entry and should therefore show distinctive signs like the ...
0
votes
0answers
18 views

plane of moons orbit, self spin with respect to earth's self spin and orbit around the sun? [on hold]

is there an image of plane of moons orbit, self spin with respect to earth's self spin and orbit around the sun? is that Geodesy related or Astronomy related?
0
votes
1answer
58 views

Is there sufficient evidence to confirm additional Planet in solar system

I have watched this scishow episode where Hank says that astronomers believe there is another planet in our solar system. Link He says that it's because how asteroids and comments are being pushed ...
4
votes
1answer
32 views

Calculating longitude from star culmination

Here is the problem: I need to calculate longitude of observing place. And I know time (in UTC+1) of star culmination (Sirius) and star altitude. I also know RA (right ascension) and Dec (declination) ...
5
votes
1answer
97 views

Why do planets tend to rotate in the same direction although they have formed from tumbling asteroids?

The axial tilts of asteroids seem to vary randomly (let me know if this premise is wrong), while the planets have a strong tendency to rotate in the same way. If planets were formed by colliding ...
4
votes
2answers
87 views

Why are stars more metallic closer as you move closer to the galactic bulge?

As I see it, most of the stars in the galactic bulge are Population I stars. However, as one moves farther from the galactic bulge, star metallicity decreases. In fact, halo stars are almost entirely ...
1
vote
1answer
33 views

Red dwarf variation in Luminosity

I recently saw this video. The creator of the video says that one of the reasons for non-existence of life on planets around red dwarfs might be that these stars can increase luminosity roughly by a ...
0
votes
0answers
6 views

Is there really no difference between up and down in ISS? [migrated]

ISS is actionally falling towards the earth and therefor they don't feel gravity. But ISS is falling in a direction towards the earth. So the astronauts living in ISS probably live in ISS in a manner ...
1
vote
0answers
55 views

How can a naked singularity be possible?

How can we have a singularity, without a black hole around it? How would one form? What does it do?
2
votes
0answers
22 views

Astronomy Jokes [migrated]

Disclaimer: I battled with myself for a few days over whether it would be a good idea to post this question on Astronomy SE. Inspired by Jon Skeet Facts question on Meta SO, I decided to go for it. ...
3
votes
3answers
56 views

Good textbooks for a descriptive astronomy course

Brief tale of woe My department at a small public university in the US has decided to begin offering a descriptive astronomy general education course for the first time in a couple of decades and we ...
6
votes
1answer
113 views

Could an impact have resurfaced Venus 300 million years ago?

Venus surface isn't older than about 300 million years. The only explanation I've come across is that some kind of global volcanism resurfaced the planet. But couldn't it have been an impact event? A ...
0
votes
0answers
29 views

Angular Separation

Two stars A and B are located on the celestial equator. The RA of star A is 02h 0m 00s and that of star B is RA 07h 00m 00s. What is the angualar seperation between star A and B?
4
votes
1answer
83 views

Could Venus or Mercury have a moon that we haven't detected?

Let's consider Mars' two moons for a moment. They're small, not even spherical, and most likely are captured asteroids. They weren't discovered until the late 1800's. Telescopes are much more powerful ...
5
votes
2answers
71 views

Why argon instead of another noble gas?

I noticed that the atmospheres of Earth and Mars have a little bit of argon in them (1% to 2%). I checked Venus, too, which has 0.007% argon, but that's still more than any other noble gas in the ...
10
votes
7answers
9k views

Did atoms in human body indeed come from stars?

I think I am not alone who saw videos about that we (humans) are made of same atoms which someday were in stars. In other words, some atoms in our bodies are from stars which exploded billions of ...
11
votes
4answers
3k views

Is the Earth going to evolve towards Mars' fate or Venus' fate?

Upon reading on this site (and many others), one can think that Mars might have supported life in a distant past (discovery of liquid water, valleys, mountains...). On the other hand, Venus is the ...

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