2
votes
2answers
80 views

What happens if you fail to reach escape velocity for the galaxy?

I was listening to Skeptics Guide to the Universe the other day, and Steve Novella mentioned that the escape velocity for the galaxy is 544 km/s. If an object fails to reach escape velocity on Earth, ...
8
votes
1answer
63 views

How far apart is the dust in the Sombrero Galaxy's dust lane?

In his answer to this question, TildalWave made this remark: I think that first, we have to properly appreciate the size of the Sombrero Galaxy. It is roughly 50,000 light years (15 kilo parsecs) ...
1
vote
2answers
23 views

How do I find the RA of sunset and sunrise in a specific location?

I want to make some observations with a telescope in Hawaii on Mauna Kea but I am living somewhere else (not Hawaii) and I want to plan a night's viewing on the Hawaiian telescope. How do I find the ...
5
votes
1answer
93 views

Composition of planets' core

It is often possible to find a list of the materials that compose the cores and the mantle of plantes (often they are iron and/or nickel). How can these materials be determined in our Solar system? ...
5
votes
3answers
190 views

I'd like to become an astronomer. What experience do I need? [closed]

I think I'd like to become an astronomer. What degrees and training/experience do I need to become one? I've heard I should take science and mathematics, but I don't know which specific courses I ...
1
vote
0answers
25 views

Synthesising types of galaxies using various stellar spectra

I have asked this on Physics Stack Exchange but Astronomy is probably more appropriate. I have been given the task of synthesising an elliptical galaxy, a starburst galaxy and a spiral galaxy ...
0
votes
2answers
65 views

Is gravity a source of infinite energy at a cosmological scale

As I understand it, gravity cannot be attenuated by any medium (in the way that EM radiation can be, for instance). Does this, then, not make it a source (theoretically, I am not talking of ...
4
votes
2answers
72 views

Can a gas giant have an other gas planet as satellite?

Is it possible for a gas giant (A very big one) to have an other smaller gas planet as satellite?
1
vote
1answer
44 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
2answers
103 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 ...
-1
votes
1answer
99 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 ...
1
vote
2answers
73 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 ...
-2
votes
2answers
88 views

why quantum gravity doesnot exist?

I am not an astrophysicist and not its student.All my knowledge about astronomy comes from you tube videos and discovery channel.From them i knew that to solve the mysteries of black hole both ...
-2
votes
1answer
43 views
2
votes
1answer
45 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 ...
13
votes
3answers
118 views

When will we be able to detect Earth-sized exoplanets?

I have heard that the only planets able to be seen outside the Solar system are Jovian-sized planets with the occasional detection of planets three times the Earth's size. But, as far as I know, we ...
0
votes
4answers
89 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 ...
11
votes
5answers
6k views

What will happen to life on Earth when Andromeda and Milky Way galaxies collide?

It is said that, Andromeda and Milky way galaxies are coming close to each other with the speed of approx $400000 \ km/hours$. They will be together in the next $4 \ billion years$. What will ...
2
votes
1answer
75 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?
6
votes
1answer
79 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 ...
0
votes
1answer
45 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 ...
1
vote
1answer
48 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 ...
-2
votes
1answer
94 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
3answers
95 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 ...
0
votes
1answer
53 views

Is the location that published calendars use to calculate the seasons one specific location on the earth?

All the calendars in my house say the fall equinox is Tuesday the 23rd. All the astronomical programs and astronomical sources say it is it is Monday the 22nd in Ohio. Since the time given is 10:29 ...
5
votes
1answer
127 views

How can we tell if the asteroid 2013 TV135 will hit Earth in 2032?

Some astronomers in Ukraine have estimated that there is a small likelihood (1 in 63,000) that the asteroid 2013 TV135 will strike Earth in 2032. (source) Don Yeoman of NASA JPL says: with more ...
1
vote
0answers
29 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 ...
9
votes
4answers
1k views

Is Pluto still a dwarf planet?

Recent news seem to suggest that astronomers are arguing about whether Pluto should become a planet again. However, I cannot find an official source for this. Is this actually true?
0
votes
1answer
47 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
84 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?
9
votes
2answers
95 views

What is the current accepted theory as to why Titan has retained its atmosphere?

Titan (moon of Saturn) is unique in that it possesses a very thick atmosphere. However, Titan is certainly is not the largest of the moons - Ganymede being larger. What is the current accepted ...
2
votes
2answers
392 views

What would happen if Jupiter and Earth were at the same distance as the Moon is from Earth?

If Spock came with a super machine capable of moving planets, and placed Earth so close to Jupiter as the Earth's moon, the gravity of Jupiter would make us fall into it?
2
votes
0answers
18 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 ...
4
votes
1answer
65 views

Is it conceivable that the presence of chlorophyll (or similar) could be distinguishable from other chemicals on an exoplanet?

If an Earth-like exoplanet had a sufficiently extensive plant biosphere (i.e large forests, aquatic algal mats etc), is it at all conceivable that scientists could spectroscopically detect the ...
3
votes
1answer
93 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?
10
votes
1answer
193 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 ...
2
votes
1answer
112 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 ...
2
votes
1answer
82 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
387 views

In 2016, the summer solstice will coincide with a full moon. How often does this happen?

I found that the solstices work on a 400 year cycle based on this. I can't find anything similar for the lunar cycle. Is there a formula I can use to calculate the date of the full moon?
5
votes
2answers
174 views

Statistically, what would the average distance of the closest black hole be?

The closest confirmed black hole is several thousand light years away from earth. Our galaxy has about 100 billion stars. I didn't find any reliable information on the black hole count of ratio versus ...
1
vote
2answers
76 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 ...
1
vote
1answer
31 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 ...
0
votes
3answers
79 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
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
177 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 ...
0
votes
2answers
79 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?
0
votes
2answers
43 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 ...
1
vote
1answer
70 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 ...
2
votes
2answers
63 views

Is Mars expected to go through the tail of Comet Siding?

This question will likely be answered "in retrospect" in about 8 days. So it's a great opportunity to "lay it out there" and then let reality prove you right/wrong. On the 19th of October, Comet ...
2
votes
1answer
113 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, ...

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