8
votes
1answer
83 views

What implications do younger Earth and Moon have on Late Heavy Bombardment genesis hypotheses?

The Late Heavy Bombardment (LHB) or the Lunar Cataclysm is when the inner solar system, including the Earth and the Moon, underwent multiple and sustained heavy impacts early in their history (around ...
3
votes
3answers
98 views

Did big bang happen only one time or it might happen again somewhere million time away from our observable universe?

We know, everything is in existence due to big bang from singularity. Time also started from that big bang point. So, did big bang happen only once or it might happen again somewhere million time ...
9
votes
3answers
298 views

How do we know the big bang didn't happen in an existing universe?

I understand the evidence for the big bang (expansion, background radiation, etc), but how do we know that it was the start of the universe? Why couldn't it have occurred in an existing, but very ...
-2
votes
2answers
77 views

Nuetrino interaction with plasma and electromagnetism [closed]

Following question enter link description here After watching the Thunderbolt Project on Youtube I have a very very very fresh perspective on the universe - the electric universe. From the electric ...
3
votes
1answer
82 views

Time dilation on an object circling earth

How would a receiver on Earth hear a radio transmission from an object circling earth at 99% of the speed of light for 24 hours. The transmission from the object circulating would be non-stop. ...
5
votes
1answer
134 views

Computing the Sérsic profile of a galaxy from jpg images

I am trying to calculate the Sérsic profile of various galaxies from the SDSS based on the images provided by the galaxy zoo site. I am doing this as part of a kaggle competition on using machine ...
3
votes
1answer
125 views

Can we calculate the average temperature of the Heliosphere?

It is to my understanding that one can measure the temperature of the universe by measuring cosmic microwave background radiation. Could we also use this method for calculating the average temperature ...
6
votes
1answer
120 views

Asteroids between Mars and Jupiter

Is the cluster of asteroids between Mars and Jupiter two dimensional as seen in every model of solar system shown in books or television? Or is it three dimensional as i think it should be?
8
votes
2answers
197 views

Will saturn rings become a moon?

Planets form from disks of matter orbiting around a star as well as some moons form from disks of matter orbiting a planet. If this is going to happen, aproximately how much time will it take?
4
votes
1answer
135 views

What distance has the moon been from earth at the closest?

For every year, the moon is orbiting further away from earth. What distance has the moon been from earth at the closest?
3
votes
2answers
83 views

Expansion again: where does the energy come from?

Is it sensible to ask for the overall increase in potential energy when looking at the baryonic mass in the universe moving away from each other, that is, moving against the direction of the force ...
6
votes
2answers
66 views

Neutrino interaction with dense molecular structures

Would dense molecular structures on heavier planets (crystalline or other compounds which are generally unknown to us) allow neutrinos to pass through as easily as on Earth?
4
votes
2answers
98 views

How many minutes does a sundial change every day?

I'm planning to create a sundial in Ghana (10° 28.852', 0° 26.032') in July 2014. I will stay there for about 3 weeks. Do I need to adjust the numbers anywhere in these 3 weeks? I know the shadow's ...
0
votes
2answers
96 views

Length contraction of a star

Something moving toward or away from us will be contracted in length according to special relativity. As the M31 galaxy is moving toward us at great speed it's "depth" should appear slightly ...
3
votes
1answer
85 views

Recommended papers

I am highly interested in how the moon originated. Theories suggest that the moon is a chunk of the earth, or rather, both were at one point one celestial body. Is there any literature out there with ...
2
votes
1answer
112 views

What if the black hole in the center of the galaxy grew faster?

Imagine that hypothetically the black hole in the center of the milky way gradually increased in mass by for example 50% every year. That is exponential increase in mass. Which visual effects would ...
4
votes
2answers
65 views

What happens to the energy from a GRB?

A gamma ray burst produces somewhere around 1044 J of energy, according to Wikipedia. Only a small portion of that energy will be absorbed by other objects. The rest of that energy will go on to ...
3
votes
1answer
90 views

Do all moons orbit their planets on the ecliptic?

Do all moons orbit their planets on the ecliptic? Do they all follow this same process as the moon that orbits Earth, or is their some random distribution with some even having extreme polar orbits.
5
votes
1answer
94 views

SPH simulations

Are there any simulations that can be obtained that use smooth particle hydrodynamics and can be configured to include different initial conditions? I wish to simulate planetary collisions and their ...
12
votes
1answer
1k views

Can I see “my own hand” in the void space?

If I were floating in a void (far away from any galaxy or cluster), would the light from these objects at such distances be enough to see for example, my hand?
-1
votes
1answer
162 views

Is it possible that we see our solar system as a star?

A few days ago I just read here that our galaxies (one of which we are part of) move or expand faster than light, And read here that light we see from stars is extremely old, maybe more than several ...
1
vote
1answer
140 views

How Far Are We From the Edge of the Universe? [duplicate]

Following the Big Bang the Universe continues to expand, presumably and roughly equally in all directions. It is understood that the Big Bang occurred 13.798 ± 0.037 billion years ago. Is there ...
1
vote
2answers
89 views

Relation between black hole mass and radius, and our universe's

Is there a graph of known black holes, with their estimated mass in the X axis and their estimated radius in the Y axis? If so, where can we find it? I would like to know if a black whole with the ...
0
votes
1answer
92 views

Spacetime curvature illustration accuracy

When a particle travels through spacetime, this is sometimes illustrated moving in flat grid with various depths. How accurate is this way of imagining gravity? Can the gravity well be infinitely ...
3
votes
1answer
62 views

Periodic behavior of Venus

After a couple months of watching a very bright Venus appear at dusk and set soon after the Sun, I've noticed that it seems to have temporarily disappeared to the naked eye. I used a virtual sky ...
3
votes
1answer
75 views

How to estimate age of asteroid family Erigon

I have one problem: On picture below we can see Erigone family asteroids in plane semimajor axis - absolute magnitude. Based on V-type as a consequence of Yarkovsky effect, estimate age of this ...
14
votes
3answers
264 views

Are we made of the stuff of one star or more stars?

[T]his coincidence enabled stars in the late stages of their lives to turn helium into carbon, oxygen and most of the other atoms that you and I are made of. [...] [W]e're made of star stuff. Max ...
5
votes
1answer
105 views

Could the earth's atmosphere have been partially stripped by a passing rogue planet?

I am involved in the fight between palaeontologists and aerodynamicists on the theoretical flight capabilities of the largest pterosaurs (who reached their climax in the Cretaceous and then ...
1
vote
2answers
92 views

Could dark matter particles be unstable?

Is it possible that dark matter particles are unstable and the existing dark matter will decay in the long run and turn into hydrogen, for example? What would be possible mechanisms for such a decay? ...
3
votes
1answer
66 views

Did time pass more slowly in the past?

13 billion years ago, the universe was about 600 million years old according to many scientists. At that time, all matter in the universe would have to be closer, or in other words denser. Did time ...
3
votes
2answers
35 views

what is the highest throughput astronomy project in pixels?

I was having a discussing about big scientific projects with colleagues, and I postulated that astronomy is still one of the scientific fields with biggest projects per amount of data dealt with, ...
4
votes
1answer
67 views

Pictures of large galaxies

The Andromeda Galaxy is tens of thousands of light years in diameter. That suggests that the most distant stars in the Andromeda galaxy is up to tens of thousands of years "behind" in their orbit ...
7
votes
2answers
137 views

How often does Earth cross the galaxy regions with higher supernovae activity?

According to Summa Technologiae, a book by a Polish author Stanisław Lem that based his science fiction novels on scientific research of the era, the Earth crossed in the moment of forming of life the ...
17
votes
2answers
148 views

Amateur observing targets for binary star systems?

Are there any easily resolvable, binary star, observing targets visible from ~N40°? I'd like to be able to show, in one observing session, Mizar and Alcor (naked eye resolvable), another with ...
2
votes
2answers
73 views

Where can I find good places to watch stars? [duplicate]

Where can I find good places to watch stars near me? I live in Leicestershire, England and am looking for good places to watch the sky nearby.
3
votes
0answers
98 views

Magnetic fields of peculiar HgMn A type stars

Are HgMn (peculiar A type) stars really possess global magnetic fields? See, for example, paper Hubrig et al. 2012: http://arxiv.org/abs/1208.2910
8
votes
5answers
174 views

Orbiting around a black hole

Is it possible (for either a satellite or a planet) to orbit around a black hole? Do they attract everything around themselves into the center? Or they just affect gravitational force just like stars? ...
5
votes
3answers
168 views

Does gravity slow or speed light up?

The speed of light in a vacuum is presumably the fastest speed possible. if gravity bends the course of light, does this imply that gravity the retards light so it is moving at a slower speed? If ...
9
votes
2answers
186 views

Will new stars stop forming at some point of time?

New stars keep forming in the universe thanks to all the nebulae. Now, we need Hydrogen to form stars and there would a time when all the hydrogen will get exhausted, and no more star formation will ...
4
votes
2answers
200 views

How to plot orbit of binary star and calculate its orbital elements?

I have a set of dates, position angles ($\theta$) and angular separations ($\rho$) for visual binary star. For example: ...
0
votes
1answer
105 views

Can you identify this telescope in a desert? [closed]

It should be in a desert. 5-15 similar lens cones are binded together,small size(about 30 cm?),same direction. The purpose is to find exoplanet? It is like WASP below. It is in a desert and lower ...
2
votes
1answer
20 views

In India, what is the best time to view the geminid meteor shower in 2013

As of the time of writing this question, the meteors should have appeared, but so far I haven't seen any. What time would be the best to view them?
7
votes
1answer
136 views

Emulation of an Orrery

Orrery is a clockwork model of the solar system. I am trying to emulate one in 2D. Now, to emulate, I need to know what goes on inside. Can someone please explain the basic principle behind the ...
4
votes
2answers
123 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 ...
0
votes
1answer
69 views

Age and relativity [closed]

This is a question, where I start with some assertions: Try to consider the universe as a four-coordinate system, x,y,z,t where t is time and where we view a change in t as a change in position, and ...
6
votes
1answer
59 views

How can the life time of a multiple star system, such as for example the trinary system PSR J0337+1715 be derived?

As for example explained at the beginning of this blog post, the trinary system consists of a millisecond pulsar ($1.438$ times the mass of the sun) orbited by two white dwarfs. One of the white ...
7
votes
3answers
149 views

Why are planets spherical?

I am a complete novice when it comes to astronomy, but someone asked me the above question casually. It seems as though planets are all roughly spherical, whereas other celestial bodies aren't ...
5
votes
2answers
42 views

apparent size of an astronomical body

What's the name of the measure of apparent (visible) size of a body? e.g. the Sun and the Moon appear to be roughly the same size, despite the Sun being vastly bigger - because the Moon is much ...
3
votes
2answers
67 views

Does gravity propagate?

Gravity is sometimes described as a curvature in space-time. Due to relativity, doesn't this imply that gravity doesn't propagate? A thought experiment. If you are moving toward a black hole, this ...
5
votes
1answer
115 views

When we say a galaxy is 200 million light years away, does this account for the expansion of space in the time it took it's light to reach us?

When we see a distant galaxy, the light we are watching started it's journey millions of years ago. In all that time, space has been expanding, so if the initial distance was A, right now the distance ...

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