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8
votes
5answers
1k views

Are the stars in constellation located in a plane or they are in different distances

Are the stars in constellation located in a plane or they are in different distances from each other and when we observe them from the Earth we think they are all in a plane?
3
votes
1answer
400 views

Can Jupiter's bands be made out using a 15x70 pair of binoculars? [closed]

I have been getting mixed opinions on this. I have a 15x70 Pair of Binoculars. I have tried staring at Jupiter for several minutes with it, I was able to see the Galilean moons, in fact the last time ...
3
votes
1answer
141 views

Smallest body that can be observed from Earth?

What is the minimum size of an object that can be observed from Earth with our most powerful telescope? I understand that the answer depends on how far the object is from Earth. For the sake of ...
23
votes
3answers
4k views

Does the Earth have another moon?

I was just wondering what are the chances that there is a small object (say less than 1 km but more than few meters) that orbits the Earth but has remained undetected by us? Are we actually ...
3
votes
1answer
1k views

Look up current positions and velocities of solar system objects

I am working on an orbital dynamics code and, for fun, I would like to model the Sun-Earth-Moon system with my code. I can look up the masses of each object just fine, as well as average distances ...
7
votes
2answers
2k views

Is there anywhere I can find some kind of database on all known stars and their properties (mass, surface temperature, radius, and luminosity)?

I have been looking for some kind of collection of all known stars and their individual respective mass/radius/temperature/and luminosity, can you link me to one if it exists? My goal is to write an ...
5
votes
2answers
2k views

What is the orbit of Earth around the Sun?

According to wikipedia and other sources, a planet and a star always move in a circular orbit around the common center of mass of the both bodies, in case of Earth and sun, this center of mass lies ...
7
votes
1answer
173 views

What determines the configuration of orbits in a binary system?

There are essentially two configurations of orbits a system with two bodies can have: A configuration where the paths do not cross: A configuation where the paths cross: Note: Size of the bodies ...
1
vote
2answers
165 views

How would vehicles travel through the interstellar medium with its such low density?

I've heard from a number of different places that the density in the interstellar medium can have an average of 1 atom per centimeter cubed. Perhaps I have a wrong understanding of what 'nothing' is (...
2
votes
3answers
240 views

Stable polar solar orbit with the Earth continuously observable

Is there a stable polar solar orbit such that the Earth is always in view and not eclipsed by the Sun?
2
votes
1answer
197 views

Data for Sun's Orbit

The planets approximately orbit the sun, but a more precise statement is that the planets and the sun all orbit around a common barycenter. Because the sun is so massive, this barycenter is very ...
6
votes
1answer
3k views

Accretion disks - why are they disk-shaped, rather than spherical?

So, the theory (briefly) about accretion disks is that stuff falling into the black hole will most likely not fall straight into it but will miss it and go into orbit, perhaps for a long time, perhaps ...
11
votes
0answers
275 views

Method to determine the amount of reflected starlight necessary for an exoplanet to be visible from a given distance/angle? [closed]

What is the method to determine the amount of reflected starlight necessary for an exoplanet to be visible from a given distance/angle? (Not from occlusion but actually visible on its own.) Further, ...
2
votes
1answer
92 views

How often and over what period is Earth’s rotation averaged to compute UT1?

I understand that UT1 (and for that matter UT0, UT2, etc.) are based on averages of actual earth rotation, and serve as a form of mean solar time. However it’s not clear to me when these averages are ...
1
vote
1answer
377 views

Orbital elements: Difference between longitude of perihelion and argument of perifocus

I am learning orbital elements and one thing isn't clear to me. When I look at the Horizon's ephemeris data for Mars, this gives me argument of perifocus equal to roughly 286.53 degrees on epoch J2000....
0
votes
1answer
895 views

Can an observer on Earth only see half of the sky?

Is this the following statement true? An observer on earth only may see half of sky from the northern or southern hemisphere, and even if the observer stands on the equator on top of a very high ...
4
votes
1answer
446 views

Solar System formation, considering its and the universe's age

It is known that the Sun is 4.6 billion years old, and the complete Solar System is of a similar age. The class of stars to which the Sun belongs seems to be quite common. Stars of its class can live ...
4
votes
1answer
364 views

Is it possible to steer the sight of a Liquid Mirror Telescope using a plain mirror scheme? If yes, why hasn't it been done?

I have read about Liquid Mirror Telescopes in a number of places, and according to these sources, a major disadvantage of these telescopes is that they can only "see" straight up. In a nutshell, the ...
3
votes
3answers
4k views

Do planets repel?

I know gravity is the result of mass. Gravity is nothing but the attractive force on a body due to its mass. I have a question that may be silly. In magnetism we have attraction and repulsion. Earth ...
19
votes
4answers
10k views

Is Jupiter made entirely out of gas?

I heard that Jupiter is made out of gas. But in school I learned that Jupiter has gravity which is 2.5 times that of Earth (Gravity that can tear apart a comet) and gravity is proportional to mass. ...
4
votes
3answers
1k views

Why, in the Solar System, all the mass seems to be concentrated at the centre?

Is this a consequence of planet formation in accretion disks ?
6
votes
2answers
122 views

Deriving Dark Matter; specifically looking for a table of stellar speed versus distance from center of galaxy to derive dark matter

I'm trying to find some data that I can use to derive dark matter (in a loosey-goosey sort of way, I won't be too rigorous). I'm helping a friend out with a final project for his astronomy course and ...
1
vote
1answer
120 views

What is the line of light in galaxy cluster MACS J1206?

I noticed this in a thread from world building, what is the continuous line of light in MACS J1206 slightly right of center in this picture? The only thing I could think of would be the side view of a ...
6
votes
1answer
52 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 ...
0
votes
1answer
86 views

Where can I find the image of MY Camelopardalis?

In this news article, it says The image captured by the telescope at the Calar Alto Observatory in southern Spain, reveal the physical properties of each of the stars including temperature and ...
9
votes
3answers
4k views

Why are stars so far apart?

So, this is mere musing, but it seems that stars are quite extremely far apart. I tried to determine the mean distance between nearest neighbors for stars (in just our galaxy) but I'm not sure what it ...
7
votes
1answer
366 views

How is it known that Pillars of Creation are destroyed?

We can observe Pillars of Creation with 7000 years delay, but it is destroyed only 6000 years ago. How do we know that? How the information about explosion reached the Earth before light do?
2
votes
1answer
294 views

where is the boundary between dark night and grey night

Is there a clear cut between them? How long and how bright will the moon be for a dark night? I googled but could not find a definition for them. People just talk about them empirically?
2
votes
1answer
136 views

Do/did the asteroids contain enough water to create Earth's oceans?

It seems from the recent Science paper by Altwegg et al (2014) that the commonly accepted source of Earth's water being the comets might not be (completely) true. Their study suggest that the water in ...
9
votes
1answer
146 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 ...
5
votes
2answers
200 views

Are there stars in the first photo from space?

Wikipedia has this photo (see below) labelled "First photo from space" which was taken in 1946 from a U.S. launched German V-2 rocket. Approximately two thirds of the image is a section of the Earth ...
14
votes
1answer
951 views

Do Pluto and Charon have unusual Lagrange points?

The usual examples of Lagrange points one most commonly encounters, Sun-Earth and Earth-Moon Lagrange points, are examples of 3-body problems where $M_1\gg M_2\gg M_3$. The Pluto-Charon system, ...
-2
votes
2answers
225 views

Lack of contact with Aliens [closed]

Lack of contact could be due to one of three things ? Interstellar space travel is just not possible . There is no other Alien Life in the Galaxy . There exists Alien life and interstellar space ...
3
votes
4answers
1k views

What is the most oblate astronomical object known?

There are some very vast spinning objects out there. How high can the eccentricity get, or, which I think is easier to understand, how small can the ratio between the polar and equatorial diameter ...
12
votes
4answers
2k views

Why is there a black stripe in the Hubble images of Pluto?

While reading reports about the New Horizons misson, I noticed an odd vertical, black stripe in the images of Pluto. Here is an example: Source: Hubble Discovers a Fifth Moon Orbiting Pluto (07.11....
1
vote
3answers
89 views

The name of a particular low extinction region

There is a region called Baade's window. I remember there is a similar region called "somebody's window", which also has a low amount of dust. Does anyone know the name?
5
votes
1answer
439 views

Is there a star simulation software that can handle mass ejections and supernovae?

I use MESA right now to play around with stellar dynamics, but it can't do mass ejections and therefore, I can't think of a way to let the simulated stars explode as supernovae. What simulation ...
5
votes
2answers
563 views

What are the arguments against the Feng and Gallo thin disk explanation of galactic rotation curves?

The well-known galaxy rotation problem is described here. Basically (as one moves outward from the galactic centre, $R$ increasing) the observed pattern of variation in orbital speed $V$ is very ...
8
votes
2answers
440 views

Typical wavelength of solar flare

I read that solar flares are customarily viewed in H-alpha light, as a temporary brightening of a small portion of chromosphere. What all can be interpreted from this? Is it because, energy of the ...
2
votes
3answers
983 views

Visibility of earth from moon during day-time of moon

Inspired by this question. I am curious whether earth, besides being nearly fixed on one place on the moon's sky, is it visible during the day-time on moon too? My understanding is that earth should ...
2
votes
1answer
70 views

How to convert a gravitational force to speed and direction

I am doing some calculations, and I wanted to know that after using the gravity equation, $$F = G \frac{m_1m_2}{r^2}$$ if you can use $F$ and convert it into a speed, such as km/year, and also a ...
2
votes
1answer
99 views

Voyager spacecrafts

Will the Voyager space crafts actually reach another Star System in 63,000 years? If the answer is yes, what will be powering the crafts to keep them going for so long?
4
votes
1answer
57 views

Spectra of electromagnetic radiation emitted during solar flare

During solar flare, electromagnetic energy is released at a wide range of wavelengths but the most dominating are x-rays and extreme ultraviolet rays. Why is that intensity of these wavelengths is ...
3
votes
1answer
78 views

Exploiting symmetry in the axisymmetric Jeans equations

I'm solving the axisymmetric Jeans equations to determine the initial conditions for an exponential disk inside an NFW halo. The density profiles of the two components are \begin{equation} \rho_d(R,z)...
1
vote
1answer
6k views

Distance between Earth and where The Big Bang's happened? [duplicate]

The universe is around 13.8 billion years old. We know how fast the light is. We also know how fast our galaxy moving around inside observable universe. Is it possible to calculating distance between ...
8
votes
3answers
346 views

How should one rationally deal with the issue of space travelling alien civilizations?

What kind of reasoning is appropriate to understand the as of today unanswered question of whether there are (other) interstellar space travelling civilizations in the Milky Way? We have already sent ...
21
votes
3answers
3k views

how far away could we detect that Earth has life?

My guess is that life bearing planets are too far apart to be detected. I think we can only find the ones within a sphere around our planet that is 100s of light years in diameter but I suspect life ...
7
votes
2answers
172 views

Could the Philae comet lander be recharged by laser?

Could the Philae comet lander be recharged with a laser (or possibly many lasers) from earth? My thought would be to aim one or more powerful lasers from earth at the Philae lander to recharge it ...
6
votes
2answers
142 views

Are our 'observations' of or near a black hole affected by gravity induced time dilation?

This answer made me wonder if matter/energy/events near a black hole are viewed (by us) in a very different time frame, how might that affect our measurements? ...
2
votes
1answer
60 views

Could discoid galaxies be expanding?

I understand that astronomers once thought that the material in the disc of a galaxy was moving around the galactic centre (where most of the mass was thought to be) in roughly circular orbits. The ...

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