All Questions

0
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0answers
6 views

What is the reason for high lithium concentrations in Sun-like stars?

In reading the European Space Organisation paper Lithium depletion in solar-like stars: no planet connection (Baumann et al. 2010), several conclusions based on their observations include: Lithium ...
0
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0answers
12 views

time on earth compared to completely stationary in space

I recently started trying to understand the theory of relativity and I have the following question. Because earth is orbiting the sun at approx 67,000 mph (and its my understanding time slows down ...
0
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1answer
17 views

How many meteors hit the moon every day or in how many days does a new meteor hit the moon?

What is the frequency of meteor strikes on the moon per day?
1
vote
1answer
16 views

Why does Jupiter break comets apart?

I understand that there are magnificent tidal forces that come with getting too close to Jupiter, but what is causing comets like Shoemaker-Levy to get torn apart? I wouldn't expect that the ...
0
votes
1answer
23 views

What would happen if a Black Hole and White Hole Collided?

Given our understanding of both black holes and white holes, what would be the outcome if they were both to suddenly collide? Black Holes: A black hole is a region of spacetime from which gravity ...
0
votes
2answers
19 views

Are humans going to end up living in other planets? [on hold]

Are humans going to live on something like Titan or not, in about 4 billion years (if they still exist then). If the sun is going to be expanding much bigger then, Earth will obviously heat up, so we ...
2
votes
2answers
34 views

Is the white hole a myth or not?

I've been doing some research on white holes, and there has not been enough information to provide the answer. Some websites are saying that they might exist, but it is not yet proven. So, is it true ...
1
vote
0answers
22 views

What are the color progression of a typical sunrise?

"Dawn simulators" are used to simulate a natural sunrise, or at least the physiological effects of one. What temporal sequence of color values (e.g., hue, saturation, brightness, and timing) ...
2
votes
0answers
16 views

Energetics of Titans Tholin haze

So, I've googled and wiki'd on this, but no clue, so I turn my question to the community: Given Titan's nice orange haze that is supposedly composed of Tholins and strangely coincides with its ...
1
vote
0answers
47 views

Why don't small stars end up as a black holes?

I've recently done some research about black holes, and I realized that big stars form black holes and small ones don't. Is it because the gravity isn't strong enough for it to fall in on itself, or ...
0
votes
1answer
36 views

Companion Sun the cause of comet impacts with Earth

On television, I heard a scientist who believes that our Sun has a companion (brown dwarf) Sun, that is responsible for comets destroying life here on Earth every 26 million years. He proposed the ...
2
votes
1answer
57 views

Could we fly/drive through Jupiter?

If Jupiter is made of gas, could we fly or drive through it or would its center be too dense?
5
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1answer
57 views

Why does this graph for sunlight intensity on land has a steeper slope during sunrise as compared to sunset?

I got this image while checking weather data for a city in North India using Mathematica's Wolfram Alpha query I noticed one feature in the graph which i could not explain . Why does the encircled ...
16
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4answers
4k views

If Jupiter is a gas-giant then why don't its features change?

A naive question. When we look at Jupiter, we see that its features didn't change largely over many years, for instance, the red-spot. If it is composed of gases and liquids, then why aren't the ...
4
votes
1answer
67 views

Exercise: 2D orbital mechanics simulation (python)

Just a little disclaimer beforehand: I have never studied astronomy or any sciences for that matter, so I am trying to fill this gap by self-education. Astronomy is one of the areas that has captured ...
1
vote
3answers
90 views

What happens to photons that don't interact with something?

Say a photon left one of the first stars ever created in our universe. This photon has been traveling for 13+billion years through the vastness of space without ever hitting anything. Sure, it's ...
2
votes
4answers
70 views

Is the Drake Equation an accurate way of finding the probability of life on planets?

I was interested in finding out if there was life on any planets or moons. I saw ReNiSh A R's question, and I saw the answer about there being life on Europa, but it didn't accurately answer what I ...
0
votes
1answer
39 views

What will happen to our solar system if the milky way collided with Andromeda galaxy, would any planets survive? [duplicate]

Is there a chance if any planets in our solar system survive when the milky way and Andromeda collide?
2
votes
1answer
65 views

Black Holes, how do they form?

Do black holes form by when the massive star dies and all the gravity falls in on itself, or something else. Please let me know, I'm really desperate!!
1
vote
0answers
34 views

What is brighter/more powerful, a gamma ray burst or a supernova?

What is brighter or more powerful, gamma ray bursts or supernovae?
2
votes
1answer
75 views

What causes the bright white area in this photo of the earth?

Regarding the photo of the earth described here, I know that the green tinge on the left hand side is to do with the aurora borealis. What's causing the bright white light on the right hand side?
1
vote
1answer
38 views

How would Special relativity explain past-present-future if thinking about 13-billion-light-years distanced objects

Halo. I'm interested in how would Special relativity comment on this: Suppose there are 2 objects, A and B. They are 13 billion light years away from each other. When the light from the B object ...
1
vote
0answers
21 views

Python 2D Jean Instability in Spiral Galaxy Simulation

I have ~1000 snapshots of a spiral galaxy simulation (from Molecular cloud perturbations t=0 to t>1Gyr. What I need to do is determine whether any position at any of the snapshot times meets criteria ...
4
votes
3answers
95 views

Is it possible to break apart a neutron star?

I was inspired by this question on Physics, as well as this question right here on Astronomy. Neutron stars are tightly bound together as neutron degenerate matter. They're very massive and have a ...
2
votes
0answers
15 views

How to determine scalar-to-tensor ratio r from CMB polarization spectrum?

CMB polarization spectrum can tell us about the primordial scalar and tensor perturbation. By analyze B and E mode angular spectrum power spectrum and temperature power spectrum we can determine the ...
2
votes
1answer
73 views

What is the ratio of “real” stars in the sky?

When you look at the sky without any utilities like binocular or telescope, what is the rough ratio of "real" stars to other objects like planets, the moon, asteroids, satellites? 90% stars - 10 % ...
2
votes
1answer
104 views

Viewing a solar eclipse through a leafy tree

Viewing my Facebook feed today, my local news station posted regarding a solar eclipse taking place today: Note the line about using a leafy tree as a filter: Scientists say NOT to directly ...
1
vote
2answers
63 views

Is there a standard mapping of symbols to terms for celestial and orbital mechanics

Is there a standard mapping of symbols to terms for celestial and orbital mechanics (and physics in general)? For example here are some ambiguities Angular Momentum: L, H, J, $\Gamma$, Orbital ...
0
votes
1answer
27 views

Declination and Ascension - the Sun and Andromeda

If Andromeda is overhead at midnight, what is the right ascension of the sun? (andromeda is ar RA =1hr, Dec = +40). I thought I understood what Dec and RA were, but I can't think of how to start this ...
1
vote
3answers
30 views

Does naked eye miss a lot between local stars and distant milkiness?

When I look at the night sky I seem to resolve points which are local stars and milkiness at further regions of the galaxy. But what is between? I think there must be a lot of stars which are too ...
3
votes
1answer
167 views

Pictures of a curious astronomical phenomenon

In a recent holiday, a friend made the following picture. It contains a curious green "thing" in the nightsky. The picture was made in Ladakh, India, 6weeks ago. The "thing" only appeared in one of ...
3
votes
1answer
89 views

Evidence behind Giant Impact hypthesis

The giant impact hypothesis is a theory to explain how the moon was formed. What evidence is there that supports the theory and led us to find the current theory?
0
votes
2answers
42 views

Do extraterrestrial landscapes or planets count as nature?

If I am talking about the surface of Mars, is this still nature, comparable to uninhabited places on earth, or does nature exclusively describe not man-made things on earth. I am asking this ...
4
votes
0answers
23 views

How to compute satellite coordinates (lat,long) given antenna's coordinates, angles and satellite height

Given an Earth station (antenna) coordinates (in lat,long) ant its Elevation (El) and Azimuth (Az), how to compute the satellite coordinates (lat,long), known its height? For simplification purposes, ...
1
vote
1answer
30 views

How are stellar elemental abundances quoted?

Close to the bottom of page 4 of this article (marked as page 164 in the upper left corner) states Values are given in the logarithmic scale usually adopted by astronomers, A$_{e\ell}$ = log ...
2
votes
1answer
41 views

Is there light on the surface of Venus?

A simple question: is there light on the surface of Venus?
0
votes
3answers
76 views

Mass of sun's core

It is estimated that the sun's core is about 1/5 of the radius of the sun (from Wikipedia). I know that the density of the plasma increases substantially the near the center, and that the volume of ...
1
vote
1answer
68 views

Is it accurate to say that we have a gravitational attraction towards all objects in the known universe?

Its probably small, but is there a theoretical gravitational attraction between all objects in the universe? Light can move pretty far, so does that mean gravity can as well, and is the gravity ...
0
votes
2answers
64 views

What is the angular diameter of Earth as seen from the Moon?

...today I must have left my brain home. I know it's a simple calculation but I keep failing simplest calculations today. What is the angular diameter of Earth as seen from the surface of the Moon?
9
votes
1answer
169 views

Do we get any benefit from being in a galaxy?

If our solar system were to somehow be created outside of a galaxy as a single star in the vast nothingness between galaxies, would life on Earth change any? Does being a member of a galaxy actually ...
5
votes
2answers
68 views

How did the Mars satellites “take cover” from the recent comet flyby?

After comet Sliding Spring's Oct. 19, 2014 close flyby of Mars, NASA reports that All three NASA orbiters around Mars confirmed their healthy status Sunday after each took shelter behind Mars ...
0
votes
3answers
37 views

How near to Earth do comets pass?

Siding Spring now passes about 10 Earth diameters away from Mars. What are the estimates of how often comets fly by Earth at different distances? Are the distances to some famous historical comets ...
3
votes
2answers
246 views

Diameter of any galaxy

I've been trying to figure out how to find the diameter in kpc of any galaxy given that one knows the distance to it in Mpc (d) and also the angular diameter/size (A) in arcsec. I had a formula before ...
2
votes
1answer
101 views

What would be the dynamics of a double-planet system, similar to Earth / Moon, but with both bodies nearly Earth-sized?

Researching a sci-fi story involving a "twin-planet" system. Is such an arrangement (however unlikely) physically possible? And if so, must they be tidally locked with each other, similar to the moon, ...
18
votes
2answers
1k views

Do all stars have an oort cloud or is it a rare occurance?

Do all stars have an oort cloud like ours that will be filled with comets and other objects? If not, why are they not around every star?
1
vote
1answer
41 views

Star class according to initial mass

Studying the stars classes for my homework (school) i learned that stars are classified by the spectral types (Harvard) and luminosity class (MKK) .. So the sun is a star class ...
2
votes
3answers
117 views

How much would you weigh if Earth stopped orbiting the Sun? [on hold]

I have a curious question. The reason why astronauts are weightless in space is because they are orbiting Earth. If they suddenly stopped orbiting they would fall directly into Earth. Earth is doing ...
3
votes
1answer
77 views

Is early life required for life?

I was watching the new Cosmos and Neil DeGrasse Tyson said something that made me go hmmm... He mentioned that the only reason that the Earth did not experience the runaway greenhouse effect like ...
5
votes
2answers
114 views

Planets and Pluto? Neptune?

If one of the rules to be a planet is that it needs to clear ALL objects from their orbit, does this also make Neptune a non-planet? Since it has thus far failed to clear Pluto (and based on an answer ...
3
votes
1answer
101 views

What is the correct ratio of Newtonian to General Relativistic gravitational effects for Sun + single planet orbital system

For a hypothetical orbital system (Sun + single planet) the Newtonian model and the General Relativity (GR) model produce different expressions for the gravitational effect of the Sun on the planet. ...

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