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B Why is ancient astronomy right?

  1. Jul 23, 2016 #1
    Let's be honest...Why were planets visible to the ancient people and not to us humans any longer? Is it because the planets distanced? How can some planets distance themselves while others don't? It's said that light pollution has affected the visibility of planets in the sky, whereas there still reports of people seeing at least one planet in the sky. So how come ancient astrology was on right before the telescopes?
     
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  3. Jul 23, 2016 #2

    Orodruin

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    This is an incorrect supposition. Many planets are visible to the naked eye - brighter than the stars. Most notably Venus and Mars, but I regularly see Mercury, Jupiter, and Saturn too.

    It is unclear what you mean by this. The planets all have different orbits, resulting in different periods and therefore varying distances.

    You have to separate astrology from astronomy. The latter is an empirical science, the former is hokum.

    Ancient astronomers could easily measure the movement of the planets. Saturn and closer planets are visible to the eye without problem. Uranus was not discovered until the 18th century and Neptune 19th.
     
  4. Jul 23, 2016 #3
    How come i haven't been capable of pointing out any planets on my own? and the only one planet that i was pointed to looked allot like a normal star in the same white seeming color. What colors do you see the planets you pointed out in?
     
  5. Jul 23, 2016 #4

    phinds

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    I don't see how you can expect us to know why you fail to do what most of the rest of us do easily.
     
  6. Jul 23, 2016 #5

    mfb

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    To the naked eye, planets look very similar to bright stars. The most notable difference is their position in the sky which varies a bit from day to day. They also tend to flicker a bit less in turbulent air.
     
  7. Jul 23, 2016 #6
    Im being honest i don't see any planet and the only one shown to me didn't look like a planet it looked more like a star I don't need your insult at all....how long does one have to look in the sky without a telescope until they notice the orbit of a planet?
     
  8. Jul 23, 2016 #7

    1oldman2

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  9. Jul 23, 2016 #8

    fresh_42

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    Light pollution plays a crucial role. Especially if you live in an urban area. And other than phinds, I doubt that I could find or see Mercury. Venus isn't difficult. She is a little brighter than stars and changes position within hours. Sometimes Mars is easy, too, if it can be seen at all, because it really appears to be a little orange and as Venus, is slowly moving. I haven't seen Jupiter or Saturn either, although I tried. But I guess my main problem (beside light pollution) was, that I didn't knew very well where to search for. And this might be another essential point. You have to know where and also when to look at. If you have plenty of time, as your ancient astronomers probably had, you could watch and see which points are slowly moving (differences between half an hour or so). In addition you have to rule out high flying aircrafts, ISS, and some other man made satellites.
     
  10. Jul 23, 2016 #9

    Astronuc

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    As Orodruin mentioned, the planets, notably Venus and Mars, as well as Mercury, Jupiter, and Saturn are readily visible. It helps when they are on our side of the sun. Mercury might be a challenge given it's proximity to the sun, but Venus and Mars are readily visible.

    If Venus is visible, it's readily apparent. Venus has been incorrectly called the 'Evening Star' or 'Morning Star'. It is very bright, and as mfb indicated, the planets do not flicker like the stars do.

    https://stardate.org/astro-guide/ssguide/venus

    There are numerous astronomical resources, which provide information on the planets, their positions and when they are visible.

    For example,
    http://earthsky.org/astronomy-essentials/visible-planets-tonight-mars-jupiter-venus-saturn-mercury
    http://earthsky.org/astronomy-essen...onight-mars-jupiter-venus-saturn-mercury#mars
     
  11. Jul 23, 2016 #10
    before i do that answer my question...how long does it take for anyone to measure the orbit of a planet without telescope?
     
  12. Jul 23, 2016 #11

    Astronuc

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    One would have to take several measurements over days for Venus, and perhaps weeks for Mars to months for Jupiter and Saturn, keeping careful note of date and time, and positions with respect to the coordinate system.

    There are plenty of astronomical resources that map the planets' orbits. Why would one bother to repeat such measurements?

    One should study some basic astronomy, including understanding about the ecliptic.
    http://earthsky.org/space/what-is-the-ecliptic
     
  13. Jul 23, 2016 #12

    fresh_42

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    I would say it took Copernicus half a lifetime. There have been column after column of notes on positions, entire fully written books.
    I don't know whether it would be easier today as we know Kepler's laws.
     
  14. Jul 23, 2016 #13
    Yep...Yet it seems very tiresome to me to do all that work. Do you possess any links to the first and all records left behind by ancient people about jupiter, venus, saturn...etc?
     
  15. Jul 23, 2016 #14

    1oldman2

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    :headbang:
     
  16. Jul 23, 2016 #15

    Astronuc

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    I don't know about ancient data sources, but current sources are available from various national observatories. In the US, the US Naval Observatory publishes data on the moon and planets.

    Depending on where one lives, one could probably contact a local (regional or national, that is) and see if they offer a publication (either hard copy or pdf) or software to determine the position or orbits of the planets.

    https://en.wikipedia.org/wiki/List_of_astronomical_observatories
     
    Last edited: Jul 23, 2016
  17. Jul 23, 2016 #16

    russ_watters

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    For the brightest planet, Venus, you really can't miss it since it is the brightest object in the night sky that isn't the moon. And if you are paying attention, you should be able to notice its movement over a period of a few weeks (or even a few days if you are really paying attention). So the problem is, quite simply, that you are spending very little time looking at the sky.
    [edit]
    About every other year, Jupiter and Venus are very close to each other in the sky. For an ancient with nothing else to look at at night that isn't lit by a campfire, they'd pretty much have to be blind not to notice them changing position from one day to the next:

    Venus-Jupiter-Mars_Oct-24-25-26_big-630x360.jpg

    Jupiter, Mars, Venus and Mercury are so bright and therefore so noticeable that the ancients simply couldn't help but realize they weren't stars, what with Pokemon Go and Must See TV not being available yet to occupy their time at night.
     
  18. Jul 23, 2016 #17

    1oldman2

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    Those were the days. :cool:
     
  19. Jul 23, 2016 #18

    fresh_42

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    I have also the problem, that I don't have a horizon nearby and it's difficult to see objects that don't rise very far in the sky. Plus light pollution is bigger the closer it comes to human housing. So sometimes it is not as easy as simply look out of the window.
     
  20. Jul 23, 2016 #19

    fresh_42

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  21. Jul 24, 2016 #20

    davenn

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    Mars ranges from easy to that flaming bright you cant miss it, as it has been for the recent months
    has also been very easy to see its motion relative to the background stars. It has just finished doing a big loop into the constellation of Scorpio and back out


    Dave
     
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