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7月在北半球冬季吗?谁能解释一下吗?

2007年7月出版的《国家地理杂志》用了数页“气候变化”和“全球变暖”。作者详细地解释了地球的运动和他们如何引发巨大的气候变化。“摆动”是列出的四个动作之一,描述如下:

“地球慢慢摇摆像一顶轴旋转时,大约每20000年来回变化。结果:大约11000年后,北半球的冬至日将在7月份。

虽然我知道最高是什么,以及它如何旋转,我很难理解摆动预计将带来这一预测。

谁能解释更多didatically这种转变将如何发生的呢?摇摆运动是如何做的?
这样的天文现象无疑被科学家们所接受吗?
冬天预计将在11000年7月从现在和现在这种转变正在进行,这是否意味着冬天北半球正慢慢走向7月,也许,从现在开始的5000年冬至会3月吗?

谢谢你！

回答

>谁能解释更多didatically这种转变将>怎么发生的?摇摆运动是如何做的?首先,它可能是一个糟糕的方法把它看作一个转变。这是一个旋转。类似于一个旋转的陀螺。(这叫做岁差。][1]它一直都在那儿——(这么说)。这是地球运动的一部分。地球是够庞大和空间、空有有效零电阻和地球的进动是永久性的,很大程度上是一致的。(不像一个顶级,减缓由于摩擦从地面和空气阻力)。 Earth's precession shifts a tiny bit due to the sun, moon and gravity from other planets but those adjustments are very slow and not relevant to your question. As Earth's precession completes one rotation every 22,000 years (give or take), over a human lifetime that's about 1.5 degrees or 1.5 days, which is pretty small and easily missed by anyone not taking very careful measurements. That doesn't affect calendars however. Calendars are a little complicated, and I'm not sure it's necessary to go into that in detail for your question. Calendars also can be adjusted to match Earth's orbit. Any un-adjusted calendar will eventually mess things up like putting July in winter, but that has nothing to do with the 22,000 year precession. 365.25 days (a leap year every 4 years), was inaccurate enough to lead to [the year that lost 11 days][2] in the UK in 1752. 365.25 days (Julian calendar) is much more accurate than 365 days (which loses a day every 4 years (in effect, a 365 day year would put July in winter in 720 years, not 11,000). Any movement of winter across the calendar depends on how good the calendar is, **NOT** earth's precession. 365.242 days ([Gregorian calendar][3]), or 97 leap years every 400 years is better than the Julian (1 every 4). Having an accurate accounting of leap years and being able to add or remove one as needed, will keep winter in the winter months for as long as we need to, much longer than 11,000 years. What changes with Earths precession is the position of the stars. The sky will shift depending on where Earth is in it's 22,000 year wobble. Similarly, the North star won't always be the North star. The night sky will look shifted by about 46 degrees in 11,000 years (some of the stars will have moved over that time-frame as well, but lets ignore that for now). You've herd the term "Age of Aquarius". [The astrological ages][4] each last about 1,800-2,000 years, and the cycle of 12 ages corresponds to Earth's 22,000 year wobble. Note, that article says 25,860 years and your quoted 22,000 years. The solar system also wobbles, so how those wobbles add up can give different estimates. If you use 22,000 or 25,860 or 25,771 or 26,000 or 23,000 on average, the different numbers don't change the answer to this question. [This explains the variation in the numbers used][5]. > Is such an astronomic phenomenon accepted by scientists > unquestionably? Absolutely, 100%, unquestionably yes. This is accepted, measured, confirmed and can be modeled and explained. It's 100% accepted science. Even [the ancients were able to observe this][6] with careful measurement, though they couldn't accurately explain it. > If winter is expected to be in July 11,000 years from now and such a > shift is under way right now, does it mean that winter in the NH is > slowly moving towards July and that, perhaps, 5,000 years from now > winter solstice will be in March As the assumption is flawed, then both no and yes. With an imperfect calendar, then this would happen and the rate would depend on the accuracy of the calendar as noted above (not precession). Because we use a very accurate calendar that allows for adding and removing a leap year as needed, no "drifting" of the solstices across the months will happen. There will be some yearly variation as the solstice is a precise point in Earth's orbit, so it happens not only on a day but at a precise time, it might be December 21 one year and December 22 the next year, but every year our calendar gets "messed up" by about 6 hours, and every 4 years, that 6 hour error is mostly corrected. Jupiter also accelerates or decelerates the Earth in it's orbit and Earth's orbital speed varies depending on how close to perihelion and aphelion, so there's some variation year to year, but there's no movement across the calendar over 11,000 years. [1]: http://hyperphysics.phy-astr.gsu.edu/hbase/top.html [2]: https://www.historic-uk.com/HistoryUK/HistoryofBritain/Give-us-our-eleven-days/ [3]: https://en.wikipedia.org/wiki/Gregorian_calendar [4]: https://en.wikipedia.org/wiki/Astrological_age [5]: https://en.wikipedia.org/wiki/Milankovitch_cycles#Apsidal_precession [6]: http://www.crystalinks.com/precession.html

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\ begingroup美元伟大的回答。你确定知道你的主题。我收集的人写道,NGM段落不是一位科学家。或者他们想要煽情说,冬天将在7月份。谢谢你！ \ endgroup美元
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2018年4月22日12:00

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