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12 votes

How long does a magnetic pole reversal take to complete?

The entire process appears to take 3,000-4,000 years, according to Valet and Fournier's May 2016 review article "Deciphering records of geomagnetic reversals," which was published in AGU's Reviews of ...
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  • 2,803
10 votes

Least populated time-zones

There is one timezone that is completely uninhabited: the UTC-12:00. It covers only two islands: Baker Island and Howland Island that are both uninhabited (owned by US). Because of the weird way ...
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  • 1,043
10 votes
Accepted

Changes in Earth's orbital and rotation speeds

The Earth moves faster around the Sun when it is near its perihelion (the closest point of its orbit to the Sun). And it moves slower when it is further away (aphelion), just as Kepler realized quite ...
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8 votes

Is there any DST to ST transition happening at the end of the day?

Per Wikipedia, several countries switch to daylight savings time at midnight. Time jumps from midnight to 1:00 AM in these countries on the date of the switch to daylight savings time. Only Chile, ...
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6 votes
Accepted

Why does the earth rotate in correlation with it's rotation around the sun to such precision?

I find it bizarre that the earth rotates at nearly exactly 365 1/4 times per year, requiring an extra day every 4 years. The Earth does not rotate nearly exactly 365 1/4 times per year. That's the ...
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5 votes

Why do the earth sciences use mega-annum instead of mega-year?

annum (ka, Ma, Ga) Time before present. A point of time in the geological past, measured backwards from now. Often, “now” is defined as the year 1950. year (kyr, Myr, Gyr) A measure of duration, ...
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5 votes
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Are the length of seasons the same globally?

As has been noted in a comment, it depends on how you define seasons (see https://earthscience.stackexchange.com/a/2603/111). If seasons are defined in astronomical terms, then they have the same ...
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5 votes
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Seeming correlation between time of day and earthquakes

As noted by Barry Carter, you could take a look at https://www.emsc-csem.org/Earthquake/Map/zoom.php?key=75&typ=NAM#5 to see the earthquakes around San Francisco, with a table below giving the ...
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  • 1,959
5 votes

What are the farthest Time Zone locations?

The original wording of your question revealed that you are missing something about what time zones are, and how they are defined. So let me start from the begin. If you are impatient, you can jump ...
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5 votes

Will the definition of the second be changed?

Someday in future, the length of a day will be longer than 86400 atomic seconds. Then what should future human do? Having a time standard that works well with the ever improving capabilities of ...
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4 votes

Perihelion Vs Aphelion position of Earth

Why is the length of the apparent solar day less at aphelion than when compared to perihelion? The TL;DR version: There's a simple answer to this question, which is that the Earth is orbiting the Sun ...
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4 votes
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What happens when the North and South poles flip?

First of all I will try to explain what a geomagnetic pole reversal is. A magnetic pole reversal happens when the magnetic field weakens until it can no longer sustain itself. This can take 1000-3000 ...
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  • 1,820
4 votes

What does "rapid" mean in terms of igneous rock formation?

Obsidian is volcanic glass of felsic composition (i.e. SiO2-rich) whereas basalt is a volcanic rock which may or may not be (partially) glassy of mafic composition (i.e. SiO2-poor). So when you're ...
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4 votes

How long does a magnetic pole reversal take to complete?

As per our numerical calculations it takes about ~1000 years to completely flip the dynamo, that being said the current models are not even close to the actual parameters in the earth's core because ...
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4 votes
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How much of one day can be considered nighttime, on average?

To further clarify, assume we are on the equator, I want to know how long a time, as a percentage, you could consider to be nighttime on Earth, with the points in time separating night and day being ...
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3 votes

Why do the earth sciences use mega-annum instead of mega-year?

Annum and year are not the exact same thing. The exact length of a year depends on what exactly you are measuring, whether distance between perihelions, distance between solstices, etc. It also varies ...
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  • 31
2 votes

Why would moving the prime meridian hasten the time when it would be necessary to drop a day from the calendar?

There is no basis in logic to have to subtract a day due to a change in the prime meridian. Both the Julian & Gregorian calendars require days to be added, not subtracted. It's why we have leap ...
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  • 20.2k
2 votes

Oldest to Newest Bedrock in the USA "road trip"

If you were hoping for a smooth succession from Archean all the way down to Quaternary, you're going to be disappointed. Geology is messier than rocks being serenely laid down continuously through ...
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  • 3,028
2 votes

which are the two countries with the flight time between them and time zone differences are equal

I'm not going to look for examples, but there will be some. More interesting is to consider the underlying geometry: At one extreme, if you fly from north to south (or vice versa) you'll experience ...
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1 vote

What are the farthest Time Zone locations?

Given you are in the UK, ignoring daylight savings, Tonga and Tokelau are in time zones that are 13 hours ahead of the UK (i.e. to the east). To the west, the largest difference in time is 10 hours ...
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  • 20.2k
1 vote

Precession & Time

I believe the source of your confusion is that you are confusing a sidereal year with a tropical year. The sidereal year, which is the definition most often cited as the standard definition of a year, ...
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  • 2,137
1 vote

which are the two countries with the flight time between them and time zone differences are equal

If you flew from Warsaw, Poland to Lviv, Ukraine the flight time would be one hour and the time difference the two is one hour.
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  • 20.2k
1 vote

The sun rises up at 7:30 in 25°E, What time will the sun rise up in 15°E?

Your maths is not detailed, but you have the correct answer. The Earth rotates at 15 degrees per hour (360 degrees/24 hours). The time required to rotate 10 degrees is 10/15 = 0.666 hours, which is ...
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  • 20.2k
1 vote

Adding time dimension and corresponding new variable to a netcdf file

There are two issues (and one optimization) with/for the code above: Array indexing starts with 0 (not 1) in Python. Therefore, ...
1 vote

Least populated time-zones

Communisty has done a good job of giving the winners in various categories, but I think it's also worth mentioning the runner-up UTC+12:45, which is only used by the Chatham Islands, population 600. ...
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  • 5,370
1 vote
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Why would moving the prime meridian hasten the time when it would be necessary to drop a day from the calendar?

I don't know the book and the quality of fiction are rarely in the facts. However, it is always nice to think about the spinning of our planet and how our theories and methods relate to the actual ...
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  • 5,896
1 vote

Why would moving the prime meridian hasten the time when it would be necessary to drop a day from the calendar?

To give a fuller explanation, the current calendar is the Gregorian calendar, which was introduced in 1582 to address the inaccuracies of the older Julian calendar. The Julian calendar gains a day ...
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  • 3,294

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