Jeremy
  • Member for 8 years, 4 months
  • Last seen more than 1 year ago
Why don't we feel the speed of earth moving
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13 votes

In a car, you have a perception of speed because of (a) the "wind" passing by as you rush through the air which is not moving at the same speed as the vehicle, and (b) you perceive the stationary ...

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What is the difference between Sphere of Influence and Hill sphere?
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11 votes

The two terms are used in answering different questions. Hill Sphere: given a large mass (eg Sun) and a small mass (eg Earth), can a tiny mass (eg Moon) find a stable orbit around the small mass? (...

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What's the furthest object observable by the naked eye from earth?
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11 votes

This is partly a question of 'limiting magnitude' - the faintest magnitude that is visible using a particular instrument, or in this case, just the eye. +6 - maybe +6.5 - magnitude is sometimes used ...

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Earth's gravitational pull on ISS
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11 votes

Your question presumes that the ISS is beyond Earth's gravity, that it has escaped earth's gravitational pull. This is not correct. All objects with mass in the universe affect all other things with ...

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The face of the moon at moonset
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10 votes

Actually, it is rotating relative to your perspective. (The other answer relating to liberation occurs over a longer period of time). Here is a simulation from Sky Safari for later tonight (moonrise)...

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How do telescopes "zoom" and change angle of view?
10 votes

Telescopes tend to have a fixed focal length. What changes is the size of the sensor in the instrument used. If a small sensor is used, then a smaller section of the field of view is exposed, ...

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Present distances between planet. How can I find them?
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10 votes

Ask Wolfram Alpha. Here is an example.

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What limits the usable focal length of telescopes currently?
10 votes

To answer the question reworded as: "What limits the quality of telescopes currently?" The answer is mostly: money. It used to be: atmosphere. But with advances in adaptive optics, ground-based ...

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Outside of a Universe and its origin
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8 votes

You are making the mistake of thinking that there was a single spot in space that everything expanded from. Rather, the expansion was not of things in space, it was space that expanded. It was an ...

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What qualifies as a good place for stargazing, i.e. with least light pollution?
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8 votes

A good question, and in the early 2000s John Bortle published a categorization of a variety of conditions, with descriptions for each category. It is the commonly used scale to describe to others the ...

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What is the difference between LMC and SMC?
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7 votes

The LMC has an apparent size of about 645x550 arc mins, the SMC 320x205. Both contain several hundred million stars each. The LMC is about 14000ly in size, and is about 10 billion solar masses; the ...

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Time after sunset until star can be seen
7 votes

It depends on the star's brightness. Astronomical darkness (full night, essentially) begins when the sun is 18 degrees below the horizon. Then, you can see all of the ones you're going to be able to ...

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How can a planet not rotate at all and yet have 1 year that is day and 1 year that is night?
6 votes

Your premise is incorrect. We used to think Mercury was tidally locked, but since 1965 we now know it is in a 3:2 spin-orbit resonance, which gives it (long) days. Anything you read that says it is ...

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Why does iron consume more energy in the fusion process than it produces?
6 votes

It would be good if you referenced your sources, because you may be misunderstanding them. We'd be able to see what they actually say, and help you understand them. Nucleosynthesis of iron does not ...

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What are the objects that are visible from a city?
6 votes

We can't know this without knowing what the sky is like for your city. However, you can determine what the limiting magnitude is for your location, then you can set planetarium software to only ...

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Is Mars visible from naked-eye from Michigan (47N, 88W) these days?
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6 votes

On 16 June 2014 at 11:45pm, it was up not far from 220az 30alt. It was actually 232az, 27alt, almost level and to the right of Spica. It would have been easily seen without binoculars being -0.2 ...

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Why did the moon abruptly change positions in the sky?
6 votes

The moon didn't abruptly change position, it is gradually and continually changing position. You've obviously never really noticed what it is doing until now. You would really benefit from getting a ...

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Why is the Solar Helical (Vortex) model wrong?
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6 votes

It isn't correct, because a vortex is not a helix, and so while the planets do trace a helical path as they move through the galaxy, this is not evidence of a vortex. Yes, the sun actually is moving ...

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How and when did we learn about the universe?
6 votes

Throughout man's history, we have been learning things about the universe we live in. Probably one of the most interesting discoveries that let us know how amazingly large the universe really is was ...

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Will the UK be able to witness the tetrad in April 2014?
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6 votes

It is great that you have an interest in astronomy. Unfortunately, the UK will be on the wrong side of the Earth to see the lunar eclipse on April 15. If you you want to experiment with various ...

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What is Gravitational Lensing?
6 votes

One star passes in front of another from our perspective. Instead of just blocking the light from the distant star, the light from the distant star that was previously directed to one side, the other ...

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Aren't there more naked-eye-visible stars in the Milky Way plane?
5 votes

Firstly, the galaxy is only about 1000ly thick. We are fairly close to the galactic plane, maybe around 65 ly 'above' it if we call the direction we are moving away from 'down'. So on your assumption ...

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Schmidt-Cassegrain telescope
5 votes

There are many other variations on telescope designs others than the ones you have mentioned. They differ in the light path, the shape of the optics utilised, the use of mirrors and/or lenses, and the ...

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Do the orbits of planets change sometimes?
5 votes

The orbits of the planets and other bodies are changing all the time, because of the influence of other bodies. Yes, planets can change orbit significantly because of the influence of other planets. ...

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Why do rocks on other solar system bodies that have an atmosphere seem to be flat?
4 votes

I would say that your initial observation is flawed, so the question is moot. Huygens landing site, Titan:

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Calculation of Horizontal Coordinates
4 votes

You can't, not with that information. However if you also have the date and time, you'll be good to go: there are plenty of sites in the web with this information, such as: RA and DEC to ALT and AZ

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Build a high quality telescope from scratch
4 votes

Amateur telescope making (ATM) is a popular past-time for astronomers. You can grind your own mirror, or you can buy ready-made mirrors. You can coat your mirrors with silver using chemical ...

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Location on (or in) the celestial sphere
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4 votes

Well, at least you did some thinking and proposed a couple of personal thoughts instead of just asking for the answer to a homework question. Both observations you make are pertinent. Remember, a ...

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How to calculate the movement of the object passing near other object in space?
4 votes

It isn't clear to me if you are merely interested in the equation so that you can plug numbers in and figure it out, or instead would like to understand how the equation is derived. Either way, is ...

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2SB mixer in radio astronomy?
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3 votes

2SB is Dual Sideband, as opposed to DSB - Double Sideband. Here are a couple of papers you might find relevant and interesting: a 2SB upgrade replacing a DSB a paper that mentions the advantages of ...

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