6
votes
2answers
59 views

Is the Astronomy community still concerned about the lumpyness of matter distribution in the universe?

A decade or so ago, when I was still a science undergrad, one of the open questions in astrophysics was to explain the uneven distribution of galaxies in the observable universe. That is, why did the ...
6
votes
2answers
273 views

Has the conjunction between Venus, Jupiter, and Regulus only occurred twice in 2,000 years?

I recently heard the claim that mid-July, the "Star of Bethlehem" formed for the first time in 2,000 years, where the Star of Bethlehem is a three-way conjunction between Venus, Jupiter, and Regulus. ...
6
votes
1answer
86 views

Are trojans in L5 more likely than in L4?

Mars has much more trojans in L5. Does it reflect a common pattern?
6
votes
3answers
143 views

How/where to check where the Sun is (constellation)?

I would like to check in which constellation the Sun was in at some time in the past, any recommendations how to do that?
6
votes
1answer
165 views

What are the last images from the Galileo orbiter before impacting Jupiter?

NASA's Galileo orbiter at Jupiter ended its mission in 2003 by intentionally dive into the gas planet. Did it take and transmit any close up images before it ceased to function? If not, why? Are there ...
6
votes
2answers
167 views

How do I calculate the positions of objects in orbit?

In a model of the solar system, given the Sun is at the point $(0, 0, 0)$, an given the six orbital elements for each object in orbit ($a$, $\epsilon$, $i$, $\Omega$, $\omega$, $M_0$), how can I ...
6
votes
1answer
93 views

Time period in which a planet rotates

I notice that Wikipedia give two contradictory terms for the time period in which a planet rotates in relation to an infinitely-distant object. In one place this is called a "sidereal day" and in ...
6
votes
2answers
265 views

Sky Glow calculations

I am leading a project for my High School NASA Club, and am looking for some advice. The goal of our project is to use a Raspberry Pi to control a camera that takes photos of the sky, and uses the ...
6
votes
1answer
121 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 ...
6
votes
2answers
431 views

Is it possible for a person to not see the new moon at different places on earth?

It is known that theoretically we see the same moon phase everywhere on the earth, but practically I see that people are unable to observe the 0.8% waxing crescent at different places on earth. This ...
6
votes
2answers
132 views

On analogies between gas and stellar systems

Analogies between (typically) ideal gas and stellar systems are not only intuitively valid to some extent, but have been established and used in the studies of stellar clusters and galactic systems, ...
6
votes
1answer
279 views

What is the direction of a comet's dust tail before and after perihelion?

I recently created a visualisation of comet ISON's orbit. However, I received a critique that the dust tail of the comet should be pointing away from the Sun after perihelion. As far as I know, the ...
6
votes
1answer
64 views

What does observational evidence say about the number of protoplanets believed to exist in the early solar system?

Currently, the solar system has 8 major planets, a handful of dwarf planets and a plethora of asteroids, comets and natural debris, and of course, a rather locally dominant star (the Sun). There are ...
6
votes
1answer
83 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 ...
6
votes
1answer
51 views

How much oxygen did the Warwick/Cambridge study find in the rocky debris around white dwarf GD 61?

There are several articles out saying that a Warwick/Cambridge study of ultraviolet spectroscopy data from the Cosmic Origins Spectrograph on the Hubble Space Telescope found a large amount of oxygen ...
6
votes
1answer
64 views

Current limitations in radio-astronomical spectrometry analysis of local interstellar cloud's hyperfine structures

I've been trying to wrap my head around capabilities of current radio-astronomical spectrometry technology to isolate not too distant tenuous sources, say, chemical composition and density of the the ...
6
votes
1answer
56 views

Is there a variation of ISO 8601 for julian calendar dates?

If I want to write a date in the Gregorian calendar, I can write it in the ISO 8601 format; today would be 2016-02-20. The advantage is that there are many parsers available to let computers read in ...
6
votes
1answer
338 views

why does pluto have a high orbital inclination

Pluto has a high orbital inclination compared to the planets in our solar system. What has caused Pluto to have such a different orbit -- was it always like this, or did something happen to make it ...
6
votes
1answer
192 views

Lack of planets in the Oort Cloud

With the current news about the possibility of a planet in the Oort cloud, I was thinking, why is the matter in the Oort cloud distributed so? It makes sense that inside the planet region there is not ...
6
votes
1answer
90 views

Orbital resonances and position of planets

I am interested in quick generation of planetary systems for programs similar to Space Engine or Pioneer Space Simulator. As far as I understand, formation of planets is a complex process and the ...
6
votes
1answer
78 views

Do star systems stripped from galaxies have different expected behavior?

Another way of stating this question: Does the fact that a star system (or comparable concentrated mass) exists in a galaxy affect its long-term evolution, in terms of expansion, contraction, ...
6
votes
1answer
68 views

To what extent are structure formations unexplained?

I hear conflicting claims about our understanding of the structure formation in our universe. I heard that ΛCDM explaines well the large scale structure of the universe i.e. Comparison of the ...
6
votes
1answer
409 views

If we were to see the Sun with our naked eyes from the Orion belt, would all planets be encompassed inside the star? Is this calculable?

When we see a star it looks much bigger in diameter to us than it really is, this picture (extracted from here) explains what I mean: Notice that the point we see in the skynight, represented by ...
6
votes
1answer
1k views

Calculate angle of inclination for a certain angle in a planet's orbit?

The background is that I'm trying to write a computer program to show at what angles each planet would be able to be seen transiting in front of the sun from an observer outside our solar system. My ...
6
votes
1answer
137 views

What are some theories that explain the 11 year solar cycle?

The Sun exhibits a periodic cycle for solar activity as manifested by solar activity (e.g. sunspots, solar flares). This activity is related to magnetic fields which emerge from the interior of the ...
6
votes
1answer
124 views

How to tell a pulsar is rotation-powered or accretion-powered?

We need to calculate P/Pdot? A pulsar may switch between theses two states. For a rotation powered pulsar, it can pulse and, the pulsed Lx can be much larger than the luminosity given by its ...
6
votes
1answer
86 views

What's the bleeding-edge model for how Population III stars are born and evolve?

I'm trying to do a brief literature review to find out what the best current models for population III stellar evolution are. I was hoping that someone with more expertise in the area could perhaps ...
6
votes
1answer
99 views

What is the brightest star (relative magnitude) in M31?

I am wondering what the brightest individual star is in M31, the Andromeda Galaxy. Specifically, brightest as seen from Earth (so relative magnitude).
6
votes
1answer
77 views

What are the most valuable meteorites and asteroids in terms of precious metals?

There were some suggestions that asteroids could one day be mined for precious metals. I have found an outdated study that says that some siderites contain as much as 0.001% of gold: ...
6
votes
4answers
196 views

Image sets for testing stacking algorithms?

I am looking for sets of astronomical images for testing different kinds of stacking algorithms. The idea is simple: if one has $N$ images of the same object, the signal-to-noise ratio of the ...
6
votes
1answer
80 views

Astronomical databases for machine learning?

I was reading this question about open problems in astronomy. The bounty-receiving answer says that I have just left the field where some colleagues are trying to develop some software to use ...
6
votes
1answer
44 views

How does radio bandwidth restrict the choice and use of science payload on interplanetary probes?

I asked a question here about returning to Earth a physical memory capsule along with soil samples, as a complement to radio operations as today. This might return a much larger amount of data ...
6
votes
2answers
153 views

Likelihood of a stable system with a dwarf planet's orbit inside that of a gas giant

I keep thinking of various planetary system configurations, and would like to know: What are the fundamental references based on Monte Carlo long-term simulation of planetary systems' evolution that ...
6
votes
1answer
337 views

Given a date obtain latitude and longitude where is the sun zenith

Searching is easy to find terminator line (frontier between day and night) or the position of the sun in the sky given a position on the earth and a time; but I can't find how to obtain where is the ...
6
votes
1answer
521 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, ...
6
votes
1answer
51 views

When do Mercury/Venus reach greatest elevation at sunset/twilight for a given location?

On what day does Mercury reach its greatest elevation (in degrees from the horizon) at sunset a given location? The obvious answer is the day of Mercury's greatest elongation from the Sun, but, ...
6
votes
1answer
55 views

Going from the second moments of an object to its ellipticities and half-light-radius

I am studying ellipticity distributions of galaxies and am having trouble moving from the second central moment matrix (covariance matrix) to properties for an object such as its half-light radius. I ...
6
votes
1answer
454 views

is there any theory or observational evidence that our universe is electrically neutral or not?

It seems our universe is neutral in large scale. There is CP violationwiki problem about matter and dark matter. Similarly is there any theory about whether our universe is electrically neutral? ...
6
votes
1answer
104 views

Exoplanet naming conventions

I'm looking for any exoplanet nomenclature, official, semi-official, proposed, or just a good idea, beyond what can already be found on Wikipedia at ...
6
votes
2answers
177 views

Would being ejected from the Milky Way Galaxy have any major impact on life on Earth? [duplicate]

I was reading about the impending collision of our galaxy with the Andromeda galaxy, and learned that there is a small possibility that our solar system could be ejected during the collision. ...
6
votes
2answers
164 views

Is ours the first universe?

I see here that after a very long time into the future, "Estimated time for random quantum fluctuations to generate a new Big Bang". This begs the question, do we speculate that our big bang was the ...
6
votes
2answers
109 views

Does the shape of a supernova remnant depend on the progenitor star's magnetic field?

The magnetic field activity in a star can be very chaotic and my question is are they somehow related?
6
votes
0answers
122 views

Questions about a fictional binary system, and habitability [closed]

Note: Questions are at the bottom. The rest had simply been written in a format to better organize my thoughts. The formulas used to construct this fictional solar system, had been borrowed from ...
6
votes
0answers
54 views

What implications does younger volcanism have on the Moon's thermal evolution?

In the paper Evidence for basaltic volcanism on the Moon within the past 100 million years (Braden et al. 2014), suggest that features such as Ina (image below) represent a far more recent age of ...
6
votes
0answers
146 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 ...
6
votes
0answers
110 views

Is it possible to have two objects moving by sum speed of light (c) in the opposite direction? [closed]

I am puzzled by this question, because by the laws between the two object the relative gravitation force should be infinite. Anyways we can take two objects where the sum of speeds are equaling c ...
5
votes
2answers
6k views

Is there any planet/star bigger than VY Canis Majoris?

Compared to VY Canis Majoris, our Sun is more like a speck of space dust. Is there any planet or star which is known to us that is bigger than the VY Canis Majoris?
5
votes
3answers
557 views

What would the night sky look like if Earth orbited an intergalactic star?

If the Earth and its host star were located exactly in-between the Milky Way and Andromeda would the night sky be completely void of light? Would stars be visible to the unaided eye? So there could ...
5
votes
3answers
974 views

Why are all quasars so far away?

Why are all quasars so far away? If the universe is homogeneous, we could expect to have a homogeneous distribution of quasars, but all of then seem to be far away from Earth. Why is that?
5
votes
3answers
430 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 ...

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