1
vote
1answer
55 views

Whats to be gained from the New Horizons mission once its beyond the Kuiper Belt?

Now that we have seen what Pluto has to offer and New Horizons is headed to the Kuiper Belt, is there anything we can gain from the mission in interstellar space after it travels beyond the Kuiper ...
0
votes
2answers
114 views

Precessing of the Earth

It's been known that the Earth's axial tilt varies from 22.5 to 24.5. Does this result in a wobbling while the value of the tilt varies about these two limits? If so, how does it affect the mechanics ...
6
votes
3answers
135 views

Why are radio telescopes shaped so differently than optical telescopes?

Why are radio telescopes typically only a dish with a receiver above it, while optical telescopes have a primary, plus secondary and sometimes even a tertiary mirror? In other words, why do radio ...
1
vote
1answer
75 views

How do I get from Star Atlas to real life?

This question is about finding the elevation and bearing of a given star at a particular time at Latitude 52N. I look up the RA and Declination of my star. How do I calculate its RA and elevation at ...
2
votes
1answer
121 views

Real images (not “artist concept”) by NASA

Does NASA make publicly available real images of missions in an organized manner? What I mean is: Say I'm looking for the images taken by New Horizons - a simple list of the images in chronological ...
4
votes
1answer
66 views

which pulsar has the longest spin period so far?

Vela X-1 has a 283s spin period, while this one may have a 2.7hr spin period. However neither of them is included in ATNF catalog. They are not included in $p-\dot{p}$ diagram either. The longest ...
0
votes
1answer
78 views

How can they tell no asteriods will hit earth in the next hundreds years?

It has come to my mind this interrogation : How can they tell no asteroids (big enough to create damage) will hit earth in the next hundreds years? Because, so far, we were unable to get a clear ...
0
votes
2answers
54 views

Calculate time when star is above altitude 30°

To find the best observation time for an object, I'd like to calculate the time when it is 30° or more above the horizon. Local Sideral Time would be sufficient. To include that in my program, I need ...
2
votes
2answers
43 views

How many nested stable (1 Mio years) orbits are theoretically possible?

If we look at our solar system we have the sun which has planet orbits and planets have moon orbits. If we look at the possible size difference from hypergiants to small asteroids why shouldn't it be ...
1
vote
1answer
46 views

Problem with Dobsonian reflector telescope

I'm not sure whether I should ask this question here but I'll give it a shot. I have a XT8 Dobsonian Reflector telescope and it works fine. But recently when I use the focuser to focus the image when ...
16
votes
3answers
1k views

Where does the solar system end?

This is a question I've heard many times in the past, and a quick search of the site says it hasn't been asked here, so I figured I might as well ask (and answer) it. I know that it is rare for ...
5
votes
2answers
86 views

Official Definition of Satellite?

So I had an argument with a friend, which was about whether the Moon is a planet or a satellite. IAU 2006 Resolution B5 gives definitions on what it is to be a planet, but there is a vagueness, as I ...
3
votes
1answer
40 views

Speed of light through the ISM and Wavelength

Articles written about fast radio bursts describe the signal's short-wavelength components arriving before its longer-wavelength components, suggesting energy-dependent time delays in the interstellar ...
4
votes
1answer
169 views

What is the bluest narrow band filter mounted on ground based telescopes?

If we want to check a QSO's lyman alpha narrow band image, could a ground based telescope do that? I mean under the circumstance that its lyman alpha shifts to 3300A.
2
votes
0answers
67 views

Why are retrograde orbits more stable than prograde ones?

Regarding solar system dynamics, i.e. planets in stellar systems and moons in planetary systems, this is often mentioned in the literature, but it is difficult to find a good analysis/explanation of ...
2
votes
2answers
109 views

Can stellar black holes cancel each other?

Hypothetical question: when a pair of identical stellar black holes are very close to one another wouldn't the side facing each other experience lower gravitational force? How is this logic un/sound?
1
vote
1answer
47 views

Planets and moons positions in cartesian coordinates?

Is there freely available and reliable source, where one can find positions of planets and moons of the Solar system at given time in cartesian coordinates? (I am writing a simple gravity simulator ...
0
votes
1answer
25 views

Historical astronomical lunar tables

I hope this is the right place to ask this question, and I apologise if not. I've come across a date written in an old book, but it is written using what seems to be a lunar/zodiac system. Below is a ...
0
votes
1answer
69 views

Is the Universe really expanding at an increasing rate?

Here's what I just read from Wikipedia's page on the Hubble Space Telescope: While Hubble helped to refine estimates of the age of the universe, it also cast doubt on theories about its future. ...
6
votes
3answers
2k views

If Venus and Mars changed places, would we then have 3 habitable planets?

This is the supposition: Venus is too hot, Mars is too cold. If they switched places then Solar energy would change to make both more Earth like. We might as well have had three instead of just one ...
3
votes
1answer
67 views

Which kind of properties can we get for cosmic ray particles hitting on an optical ccd?

It is very common that we meet cosmic ray particles in optical images recorded by CCDs. You can see the "snowflakes" in the hubble images below: Generally we should remove them in order to get ...
3
votes
0answers
52 views

How to calculate the moon phase

I need a way of to calculate the moon phase. Do you know resources for research the theory from behind this? I basically have searched in Google, but the results were not very satisfactory. Exists a ...
7
votes
0answers
121 views

How has the Earth's orbit changed over hundreds of millions or billion of years?

First, I know that modeling orbital mechanics of 8 planets is hard, but there are some theories out there, for example, Jupiter is thought to have moved in towards the sun then started moving away. ...
1
vote
0answers
57 views

Energy required for light speed [closed]

It is said that in order for us to travel at the speed of light, there has to be an infinite amount of energy. Light is made up of photons but photons themselves do not have an infinite amount of ...
33
votes
3answers
2k views

How many planets are there in this solar system?

So, in school (that's a long time age) they have been teaching us there are 9 planets in our solar system. Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune Pluto But every now and then I ...
17
votes
2answers
1k views

Can you see man-made lights on the dark side of the Earth from the surface of the moon with the naked eye?

This question is prompted from a comment on this answer: Could a person on the surface of the moon see man-made lights on the dark side of the Earth with the naked eye? If not, how much magnification ...
1
vote
1answer
52 views

When is Gamma Draconis closest to the zenith in London on April 4th

I am reading Roobert Hooke's paper An attempt to prove the motion of the earth from observations (1674, faksimile). Hooke writes The principal dayes of doing which will be about the 4 of April, ...
1
vote
1answer
64 views

How to calculate a planet's current position within the solar system

I'm making an application that needs to calculate a planet's current position within the solar system - I don't want to calculate its position in the sky. For example, what I want to do is exactly ...
2
votes
1answer
33 views

How significant and accessible is modern Chinese astronomy?

Is China fully integrated in the international astronomical community, or does military secrecy and language problems and sanctions (ITAR) or something else stand in the way? Does China have valuable ...
4
votes
2answers
74 views

Is there a mechanism that makes small moons more rounded than comets?

67P/Churyumov–Gerasimenko has a highly irregular dumbbell shape. But the sample of comet shapes observed is very small, so I wonder if irregular shape is the norm for comets and for small moons. Many ...
0
votes
1answer
107 views

what planet is the most radioactive?

So as I understand it the source of most geothermal energy on Earth is due to radioactive decay. Jupiter is the most massive planet but if the bulk of it's mass comes from gaseous elements instead of ...
0
votes
1answer
13 views

What does the BinTableHDU store?

I'm just getting started with very primitive analysis of FITS data, and I have a 'raw' FITS file which I don't know how to get different wavebands of data from (if this is even possible). ...
7
votes
2answers
559 views

Visibility of Apollo 11 module

I wasn't around when man landed on the moon in 1969. When I see the moon, I always wonder, were people able to see the rocket? Yesterday, I looked at the moon in daylight and wondered again. My ...
7
votes
2answers
2k views

Why don't we see the galaxy center?

When we look at the sky, and see the Milky Way, we mainly see a band, with no real center. On a more accurate picture we can guess the center of the galaxy (see this picture), but we still don't see ...
1
vote
1answer
42 views

Who invented the blink comparator?

The Wikipedia page for the blink comparator fails to mention who invented it. Many other pages extol the importance of the device, but we cannot find any mention of an inventor. Wikipedia does ...
3
votes
3answers
343 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 ...
1
vote
1answer
103 views

What will the last days of Earth be like?

The sun is a main-sequence star; as I understand it the sun will expand into a red giant in a few billion years. I have heard conflicting reports of what this entails - some sources I found say the ...
4
votes
1answer
116 views

Will the Sun rotate slower in red giant form?

When the Sun runs out of hydrogen to fuse it will grow bigger in size and my question is does it rotate more slowly, like a spinning ice skater extending their arms to reduce angular velocity? What ...
2
votes
3answers
333 views

Appropriate battery for overnight viewing to drive telescope and GOTO?

I have a Plettstone 18" Dobsonian telescope with GOTO and clock drive that runs off a 12 volt cigarette lighter adapter. What is an appropriate battery to use to run this overnight while viewing all ...
4
votes
1answer
146 views

How long until the Earth and Moon become a binary planet?

With the rate at which the moon is further receding into a higher orbit, how long until the barycentre between us and the moon leaves the earth, and going by the IAUs 2006 definition update, we become ...
2
votes
0answers
30 views

Are trojans in L5 more likely than in L4?

Mars has much more trojans in L5. Does it reflect a common pattern?
0
votes
0answers
3 views

Does astronauts only perform spacewalks while space-station is on night side of the earth? [migrated]

Does astronauts have to perform spacewalks on space-station while its not facing sun directly? If so, I'm curious about the reason behind it. Is it only because they would be shielded from solar winds ...
1
vote
1answer
40 views

Suns Orbital speed and escape velocity question

This is a homework question and I don't want an answer but just want to understand what its asking for. We are given that a star with a mass of x solar masses in ...
5
votes
4answers
508 views

Can magnetism escape a black hole?

I know light, and practically nothing but gravity can escape a black hole. My question is: can magnetism escape a black hole? A couple things that convince me it can are: Jupiter's magnetic ...
0
votes
0answers
8 views

Semimajor axis variations in co-orbital moons

I've been playing with simulations of co-orbital bodies similar to Saturn's moons Janus & Epimetheus- horseshoe orbits where the two bodies are of comparable mass- and I'm seeing some very odd ...
0
votes
1answer
26 views

Is it possible to get the distance to a star in the IPHAS DR2 catalog?

I'm looking at the IPHAS DR2 catalog. It has the Right Ascension and Declination but I'm not seeing any distance information (lightyears or parsecs). I'm wondering, given the columns in the dataset, ...
4
votes
1answer
74 views

Radio Astronomy and Imaging

So, I've been starting to investigate radio astronomy, and am wondering about if certain things are possible from an amateur standpoint. I was looking at this powerpoint(that discusses building a tiny ...
1
vote
2answers
80 views

How clearly would I be able to see a galaxy with the naked eye if viewed from a “close” distance?

In images of other galaxies they look very bright and vivid against the blackness of space (example). If I was located a few tens of thousands of lightyears away from a galaxy, would I see something ...
1
vote
1answer
48 views

How far away would a supernucleus comet be visible?

If an instrument like LSST quickly spots something as soon as it reaches magnitude 24½, how far away would a 60km first-time visitor from the Oort cloud be when it is spotted? I'm thinking that a ...
2
votes
1answer
38 views

Could martian meteorites come from Olympus Mons?

Could Olympus Mons have thrown ejecta out of Mars' orbit when it was active? Does it fit with the composition and dating of meteorites with martian origin?

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