All Questions

5
votes
1answer
162 views

How much of an effect does the moon have on Earth's liquid mantle?

The gravitational pull of the moon is enough to create tidal forces of large bodies of liquid, i.e the sea. I was having a conversation the other day about how to terraform Mars, and someone ...
8
votes
1answer
123 views

How old is our sun in galactic years?

A year is measured as the amount of time it takes Earth to orbit the sun once, a galactic year is the time it takes our sun to make one full orbit of the center of the galaxy. In galactic years, how ...
6
votes
1answer
171 views

Why does Pluto's Orbit underlap Neptune's Orbit

Why does Pluto's Orbit underlap inside of Neptunes Orbit. Clearly Neptunes Orbit is not overlapping on Pluto's. Yet, they fail to maintain the symmetric banding appearance all the other Planets ...
4
votes
2answers
76 views

What is the furthest object in the observable universe?

My question is about furthest object in the observable universe except Сosmic microwave background.
8
votes
1answer
67 views

How Does Cosmology Constrain the Number of Neutrino Species?

I've asked this question already on the Physics SE, but I felt it would be worth posting here as well. I know that based upon theories of structure formation cosmologists can constrain the sum of the ...
11
votes
1answer
782 views

How does neutron star collapse into black hole?

We know the spectacular explosions of supernovae, that when heavy enough, form black holes. The explosive emission of both electromagnetic radiation and massive amounts of matter is clearly observable ...
3
votes
1answer
30 views

Is there any evidence that the Gas Giant planets in our solar system are experiencing orbital migration?

Planetary migration is defined by Lubow and Ida (2010) in their article Planet Migration as the process by which a planet’s orbital radius changes in time. The main agent for causing gas giant ...
5
votes
2answers
112 views

Why are some planets so close to their star?

"Kepler-10b orbits its parent star once every 0.84 days, which means it is more than 20 times closer to its star than Mercury is to our sun" space.com Are there any accepted theories that ...
9
votes
3answers
214 views

How to detect emission lines in optical spectra?

Is there any handy module to detect emission lines in a spectrum like one we get from the Sloan Digital Sky Survey (SDSS)? You can see there are many emission lines like Ha,OI in the spectrum below. ...
13
votes
1answer
241 views

How dense are Saturn's rings?

I assume that the A ring is the densest, but I might be wrong. Nevertheless, I failed to find any explicit information over the net about the minimum and maximum of densities for the different rings. ...
7
votes
1answer
58 views

Sources of Turbulence in the ISM

What sources of turbulence exist within the Interstellar medium (ISM)? Which ones are physically the most important for newly forming stellar systems?
5
votes
1answer
40 views

How can I observe the Orionid Meteor Shower?

I would like to see the orionids sometime this week (October 20-26, 2013). What is the best way for me to observe them by naked eye? Also, would I be benefitted by trying to look at them with a ...
7
votes
2answers
443 views

How long until we cannot see any stars from other galaxies?

Since all the galaxies are moving further away from each other at a faster and faster rate, eventually we won't be able to see stars from other galaxies. How long until we can't see stars from other ...
7
votes
1answer
54 views

Crab Nebula Time Period

I've learned that the time period for a rotating neutron star, i.e., a pulsar is very accurate and can be used as an interstellar clock. But according to Walter Lewin's 8.01 Lec 19 on classical ...
10
votes
1answer
105 views

Which came first: black holes or galaxies?

In other terms, did galaxies grow around black holes at their center?
9
votes
1answer
43 views

Loss of atmosphere on Mars

If the atmosphere on Mars was once much thicker, how was it likely lost? Was it due to interaction with the solar wind, the small size of the planet, both, or something else, and approximately how ...
8
votes
2answers
166 views

Why is the Earth's center still hot after millions of years? [closed]

Why didn't the center of the earth cool after millions or billions of years? What keeps it hot?
4
votes
3answers
261 views

Very bright star in the east at northern hemisphere. What it is ?

From some time now (few weeks as far as I can remember), there is a very bright star in the eastern sky. I first thought it was Venus, but according to this link, Venus is in the western sky and ...
5
votes
1answer
119 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 ...
6
votes
2answers
155 views

Why don't Neutron Stars form event horizon?

Trying to compare density of Black Holes and Neutron Stars I came up with the following: A typical neutron star has a mass between about 1.4 and 3.2 solar masses1[3] (see Chandrasekhar Limit), ...
5
votes
1answer
318 views

Why does Titan's atmosphere not start to burn?

If Titan has a methane atmosphere and seas of methane, then why doesn't some meteoroid / chemical reaction ignite and blow the whole thing?
1
vote
0answers
44 views

Is the moon rotation at complete standstill? [duplicate]

Moon always faces Earth with one side, its spin period equal its orbital period - this is what we learn at school. But I know Nature rarely operates in absolutes. I'd find it hard to believe Moon ...
7
votes
1answer
250 views

What reason is there to doubt the existence of the hypothesised planet Tyche in the far distant solar system?

Please note, I do not necessarily believe in its existence, just after a scientific (hence, non-Wikipedia) reasoning to doubt the planet's existence, other than the "we would have seen it" argument. ...
5
votes
1answer
145 views

Are Barlow lenses stackable for bright objects?

I'm back to the refractor that I own, and I want to maximize the zoom capacity. I realized today that I own more than one barlow lens, and I was wondering if I could stack them together for looking at ...
5
votes
1answer
44 views

Who or what will the Arecibo message reach?

The Arecibo Message was aimed at the globular star cluster M13, but as far as I read, M13 will move out of the original position and thus not be able to receive it. So, who or what will be able to ...
12
votes
3answers
103 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 ...
6
votes
1answer
143 views

In what timeframe is W26 expected to go supernova?

All the news-articles say that it is expected to "eventually" explode. Which doesn't really tell me much. When is "eventually"? Also, considering this is the largest star in the known universe and 16k ...
6
votes
1answer
51 views

How does interstellar matter density vary?

Answer to my question partially answers this one, about density of intergalactic matter and matter within galaxy: But it is mostly a hot, ionized void. How void? The density of the intergalactic ...
7
votes
1answer
41 views

Does the Reflection Method for Looking at the Sun Work For Refractors?

I own a newtonian reflector and occasionally use it (using the reflection method with paper) for looking at the sun. I happen to also own a refractor, but I'm not exactly sure if the reflection method ...
9
votes
1answer
138 views

How Does a Refractor Telescope Work?

As I understand it, the difference between a reflector and a refractor is that a reflector uses mirrors on the back to reflect the light to the secondary mirror then the secondary mirror reflects the ...
8
votes
1answer
98 views

Age of the universe

We know that the universe is approximately 13.7 billion years old. What methods did we use to discover this? How sure are we about its accuracy?
10
votes
3answers
353 views

How do we know dark matter/dark energy exists?

I've never quite understood the theory behind why dark matter and dark energy exist. I know it has something to do with gravitational pull being stronger than what we calculate it SHOULD be, could ...
0
votes
1answer
56 views

What do shape of universe mean? [closed]

What shape does a three dimensional universe have ? and how did scientists determined that it is flat and not curved.
12
votes
5answers
311 views

What is in the center of the universe?

If the universe has formed & originated by a Big Bang Explosion, then there must be empty space left in the center of the explosion site, as all the matter is travelling at tremendous speeds away ...
24
votes
3answers
1k views

How powerful a telescope would allow me to view the astronauts aboard ISS do a space-walk?

This arose from a comment posted against a question elsewhere on the stackexchange How powerful a telescope/binoculars would allow me to view the astronauts aboard the ISS do a space-walk? Aperture? ...
6
votes
2answers
64 views

Are we moving ever closer to the center of our Galaxy due to a super massive black hole?

I've seen in documentaries that at the center of each galaxy is a super massive black hole which holds the galaxy together. Since black holes have such a strong pull, are we slowly being pulled in ...
3
votes
1answer
74 views

What study profiles could land me the job of Astronomer?

I realize there are very few to none universities that offer direct specialization of Astronomy. If I aspired to be make astronomy my career choice, I'd likely have to pick something like physics and ...
7
votes
1answer
94 views

What is the Lyman Alpha forest Used For?

The Lyman-alpha forest is an interesting feature found in the spectra of sufficiently distant objects. This series of absorption lines extends over a range of frequencies, and are a result of the ...
6
votes
1answer
36 views

Long term development of Comets

When an exocomet passes by our Sun in a trajectory that leads it to establish a Solar Orbit what eventually happens to it? In addition to its original inertia and vector being altered what are the ...
7
votes
1answer
86 views

Have we observed any rogue/wandering stars?

Do we know (have we observed and cataloged) any rogue star, being not part of galaxy, but drifting somewhere in inter-galactic space? I know that determining if a star is a part of galaxy or not is a ...
8
votes
1answer
174 views

How do we detect if a planet has a liquid core?

In case of Earth, we have many hints about the internal structure of our planet, from what I know, the most important of which is analyzing seismic waves. Do we have any instruments to detect if ...
3
votes
0answers
45 views

Which are the consequences of Uranus' high rotation axis angle? [closed]

The rotation axis of Uranus is 90 degrees away from vertical, there are some theories about its reason.. But which are the consequences of this? Which are the unique features of Uranus that happened ...
7
votes
1answer
88 views

What was the greatest spatial extent of the Asteroid Belt prior to the Late Heavy Bombardment?

Reading the article On the asteroid belt’s orbital and size distribution (Gladman et al. 2009), there is an interest point made: asteroids a few kilometers and smaller in size are recent ...
11
votes
1answer
214 views

Inflation cosmology: slow-roll inflation versus tunneling between two vacua

In slow-roll inflation models, the early inflation of the universe is driven by the flat non-zero part of the inflaton potential, and it ends as the ball rolls down the cliff and the potential energy ...
12
votes
4answers
665 views

Is the light we see from stars extremely old?

Our nearest star Proxima Centauri is 4.243 light years away from Earth. Does that mean we are seeing light that is 4.243 years old everyday?
4
votes
0answers
148 views

Day and night temperature on an earthlike planet with longer rotational period [closed]

I'm trying to understand the climatic effects of the far future scenario of an Earth-like planet with a reduced rotational speed caused by tidal locking with the moon (day-night period of 28 days, one ...
10
votes
2answers
264 views

How exactly is our universe mapped?

Watching this youtube video shows that our planet is nothing more than dust in the wind. At the 2:50 mark in the video, you will see a view of the whole Milky Way. At the bottom you will see this ...
11
votes
1answer
288 views

Why has Venus's atmosphere not been stripped away by solar wind?

This answer on Space Exploration to a question about Mars says that one reason Mars has such a thin atmosphere is because it lacks a magnetic field to protect it from the effect of double solar winds. ...
8
votes
1answer
288 views

Determining effect of small variable force on planetary perihelion precession

Is there an analytical technique for determining the effect of a small variable transverse acceleration upon the rate of aspides precession (strictly not a precession but rotation of the line of ...
5
votes
1answer
272 views

From which country or area is the new moon visible first?

Being able to see the Moon is dependant on various factors like sunset timing etc. Considering all these factors, which country or area of the world sees the new moon first? I am asking about the new ...

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