1
vote
1answer
27 views

Adaptive Optics?

I get the general idea of adaptive optics. The light from an object distorted by differences in the earth's atmosphere, and a telescope with AO tries to compensate for this distortion by various ...
4
votes
2answers
183 views

Is it possible that a ultra-large portion of the space we live in is already inside a black hole? How could we refute this?

Trying to wrap my head around some concepts involving the very large gravitational fields of black holes, and what the gravitational gradients look like on a cosmic scale. I'm familiar with the Great ...
1
vote
1answer
58 views

what is the metal distribution in our universe

Most of the metals are located in ISM,IGM, or stars? Maybe different metals have different distributions? For one kind of metal element, what is its distribution? Let's classify the metals according ...
5
votes
1answer
67 views

Objects entering or leaving the observable universe

Have there been any observations of objects entering or leaving the observable universe? When looking at the physical limit of observing something like this I will to assume that the "object" would ...
2
votes
1answer
65 views

Is there a term for stars without any planets?

Quite simply, is there any used term for stars that don't have any planets? While contemplating this and doing numerous searches to no avail, I think I found my own answer, but I'm asking here for ...
4
votes
1answer
96 views

What can a lunar-based telescope do?

What can a lunar-based telescope do? If the band is ultraviolet and it can do high time sampling exposure, maybe it can be used to get distance for a star with stable pulses. However, the star should ...
2
votes
4answers
129 views

Milky Way Formation

Is the Milky Way a collection of merged galaxies, or has it only been one galaxy that was created from the interstellar media?
4
votes
1answer
114 views

When will the Milky Way “arrive” at the Great Attractor, and what all happen then?

The Great Attractor is described as a location to towards which the Milky Way, along with all other galaxies in the Laniakea Supercluster are moving. How long will it take for the Milky Way to ...
1
vote
1answer
26 views

What is the radius of observable universe- 46 billion LY or 200 yottameters?

I have found two answers for the radius of the observable universe. Wikipedia (and other places, including this site) say approximately 46 billion LY. I am researching this to study for the National ...
3
votes
1answer
58 views

Hypothetical scenario, two nearby black holes

I've always wondered what would happen if a hypothetical scenario, two black holes meet, with similar proportions: Maybe one swallow the other one? Or would make a bigger one between them.
4
votes
1answer
155 views

Is there a 'South Star'?

The star Polaris is commonly known as the Northern Star because it always points North. This being said is there a South star that always points south?
6
votes
2answers
244 views

Why does the Moon never set in Svalbard, Norway?

I heard in a documentary that, in Svalbard (Spitsberg), Norwegian archipelago in the Arctic Ocean, the Moon never sets. Why? A drawing would certainly help.
4
votes
2answers
144 views

How was the Earth-Sun distance originally calculated?

AFAIK it was possible long before the first interplanetary probes. Who did it?
3
votes
1answer
22 views

Save current state in ds9?

After fooling around with a FITS file(s) (e.g. setting scale, changing color) is it possible to save the session such that there is a file associated with all those tweaks the next time I open it up? ...
2
votes
2answers
34 views

Why is sodium such a common ion for in ion tails?

I was doing research about ion tails of planetary bodies and noticed that ion tails composed of sodium were common. For example, Mercury and the Moon both have ion tails made of sodium. Why is sodium, ...
1
vote
1answer
27 views

During what time of the year can Centaurus be seen from Tokyo?

During exactly what dates of the year can the Centaurus constellation be seen from Tokyo, Japan? And what is the ideal date for viewing it from Tokyo? I found on a website that it can been seen ...
1
vote
2answers
48 views

Birthdate differences calculation relative to earths orbit duration

I have got a question as i am trying to figure out what the real difference between the birthdate of my friend and me is. I am born on 1983 6th February 7 am. My Friend is born on 1984 7th February 1 ...
3
votes
1answer
26 views

meaning of p-wave charmonia

What exactly does p-wave mean when referring to particles, like charmonia states. For example, see the following reference: http://arxiv.org/abs/hep-ph/9208254 My doubt is - p wave in scattering ...
0
votes
3answers
45 views

Could the universe have evolved differently?

Given the initial conditions at the Big Bang, could our universe have evolved any differently? In other words, did the initial conditions predetermine every stage in the evolution of the universe to ...
1
vote
1answer
74 views

Mechanism for Brown Dwarf Fusion

I've read (at here, among other places: http://deepblue.lib.umich.edu/bitstream/handle/2027.42/55288/index.html?sequence=1) that during the Degenerate Era, star formation will end and the last stars ...
2
votes
1answer
31 views

How LOFAR pass through the ionosphere?

The LOFAR project open a new window in the universe's study because it allows to receive low frequences of the universe that we could not get because of the ionosphere. But I'm wondering how can ...
6
votes
1answer
69 views

How to identify stars in photographs?

I can look at a star chart and identify things like constellations in the sky. But if I take a picture with my DSLR camera (35mm with a decent zoom lens, no astronomy specific optics), I run into ...
9
votes
3answers
402 views

Questions about spiral galaxy arms

I have 2 questions related to spiral galaxies. Firstly, how did the arms form? Why would the stars accumulate into those specific areas? And secondly, why are they still intact? The inner parts of ...
2
votes
2answers
92 views

Why aren't the farthest objects close to each other?

The last years we find some objects like this : MACS0647-JD which are more than 13 billion light-years away from us. This means that the picture we get was created only some million years after the ...
3
votes
1answer
51 views

Can the martian dichotomy (SIH) and the moon's formation (GIH) be related?

If we assume that the Single Impact Hypothesis regarding the martian dichotomy (wikipedia) and the Giant Impact Hypothesis regarding the Moon's formation (wikipedia) are true, then is it possible that ...
0
votes
1answer
79 views

Thought experiment about the outskirts of the universe [closed]

Suppose I aim at some object that is 13 billion light years away from Earth. Let's assume I have a twin that pilots a ship that travels in infinite speed, meaning that he can reach that object and ...
2
votes
2answers
75 views

Fate of the Spiral Arms of the Milky Way and Andromeda

In a few billion years, the Milky Way and Andromeda will collide. Chances are, there won't be many spectacular stellar collisions, and there's a pretty good chance that the Solar system (and most ...
1
vote
1answer
34 views

What is the exact position of the Large Magellanic Cloud?

I am not able to visualize the position of the LMC and have not found a satisfactory explanation... Can someone please answer it this way? Relative to a ray joining the Earth to the ...
1
vote
3answers
197 views

What is the relative time difference between us and a star system in outer layer of our galaxy?

Just curious to know what will be the time difference between someone living on the outer layer of our galaxy and us, considering the known facts that Time is relative to gravity Our sun goes around ...
4
votes
2answers
187 views

Are there stars that don't emit visible light?

Are there stars that do not emit any light in the visible part of the EM spectrum?
1
vote
1answer
45 views

World line coordinate finiteness

If you trace two particles' world line backwards in time, according to current theory, both objects should converge at big bang. Would both objects arrive there simultaneously? Another way of asking ...
3
votes
1answer
60 views

Time after sunset until star can be seen

Given a star's apparent location and apparent magnitude, how how many degrees below the horizon must the sun be for the star to be visible to the naked eye for an observer on Earth at a specified ...
7
votes
1answer
83 views

Is there a paper on galaxy mergers in clusters of galaxies?

I'm looking for something to cite about galaxy mergers in clusters of galaxies. I need numbers on the frequency of mergers in the outer parts of galaxy clusters vs. the cluster center. In the center ...
1
vote
1answer
93 views

How many light years away is Earth from the closest outer edge of the black hole at the center of the Milky Way?

How many light years is Earth away from the closest outer edge of the supermassive black hole in Sagittarius A* at the center of the Milky Way? I don't mean the distance to the center of the galaxy, ...
1
vote
1answer
62 views

Which spiral arm of the Milky Way is Kepler-62 in?

I am trying to find out which spiral arm of the Milky Way the star Kepler-62 and its planetary system are in. All I can find by Google searching is that it is part of the Lyra constellation, but I ...
1
vote
1answer
36 views

Star System Formation questions

I'm making a game in which I'd like to randomly generate star systems. Which is cool. The trouble I'm having is working out exactly what limits I need to place on the generation. So far, the ...
1
vote
2answers
107 views

How do black holes evaporate?

Will black holes evaporate, if they evaporate? When and why do they evaporate? What are the conditions for evaporation? Under what principle do they evaporate?
7
votes
1answer
120 views

Can we see the Big Bang happen if we look far enough?

The observable universe is constantly expanding as more light from the Big Bang reaches us. This light has been travelling for billions of years, so we are looking at the universe as it was a few ...
6
votes
4answers
161 views

The Existence of Natural Satellites in Geostationary Orbits

While browsing through Physics SE, I noticed a question about satellites in geostationary orbit (unrelated to the one I'm asking here), and for a moment I interpreted it as referring to natural ...
5
votes
2answers
73 views

Can the Gaia telescope detect small temporarily captured asteroids near its Lagrange orbit?

The Gaia space telescope is in a Lissajous orbit around the Sun-Earth Lagrange point 2. The orbit period is about 180 days and the size of the orbit is 263,000 x 707,000 x 370,000 km. It has been ...
11
votes
3answers
289 views

Why do (most of) the planets rotate counterclockwise, i.e. the same way the Sun does?

Referring to the mechanisms explaining the solar system formation and to the initial rotation of the gaseous cloud that collapsed, I understand easily why the planets orbit the Sun the same way this ...
6
votes
1answer
111 views

Would bagging an asteroid destroy valuable science about it?

NASA has a plan called "Asteroid Redirect Mission option A". It would robotically put an asteroid of a few meters diameter in a bag and push it into reach of astronauts for thorough examination. 44 ...
1
vote
0answers
70 views

Multiple apparent lunar eclipses last night

I saw something very strange last night that I'm hoping someone can help me explain. I was sitting on my roof with a night-cap at about 3am last night. The moon, about the last quarter, was low in the ...
2
votes
1answer
65 views

What type of energy is escaping from black-hole's poles?

Following this article, it is stated that: As a star drifts too close to a supermassive black hole, intense tidal stresses rip the star to shreds. As this happens, the shredded material will ...
1
vote
2answers
170 views

Why don't planets give off their own light? [closed]

Why don't the planets glow like stars?
3
votes
5answers
241 views

Why aren't there galaxy-sized balls of iron out there?

Since we know that stars burn out, collapse, or blow up when too many of their atoms fuse inti iron, then how come, with all the ancient galaxies we've been observing, there isn't one galaxy whose ...
3
votes
2answers
57 views

Why do some celestial bodies have atmospheres, and not others?

Question is rather self-explanatory. An answer touching upon how/why atmospheres are formed in the first place would be ideal as well. An example of such astral bodies would be The Earth and it's ...
1
vote
2answers
115 views

How was an infrared picture of the entire universe taken?

(click to enlarge) How was this picture of the supposed entire universe taken in infrared? Also, why does it seem as though almost all of the matter is in a line formation over the center? It makes ...
1
vote
1answer
43 views

the length of second, minute or hour, what defines the time of exo planetary bodies

we measure time based on earth and earth mass\gravity plays a role in the measurement ? so how and what would be time if not earth time on other exo planets since they will be having different ...
2
votes
2answers
75 views

The face of the moon at moonset

It appears that the face of the moon "rotates" clockwise from the time the moon rises to the time it sets. Tycho's crater seems more to the left and the "Rabbits head" looks like it's facing down ...

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