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Earth's tilt 2: Land of the midnight sun
How can you tell when to go to bed when the sun never sets? Ask a reindeer from Norway. License: Creative Commons BY-NC-SA More information at http://k12videos.mit.edu/terms-conditions. Created by MIT+K12.
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On the Equator is each and every day of the year the exact same length of time?(12 votes)
From what I researched quickly, each day on the equator has practically the same amount of daylight, so the answer to your question is yes!
Also, interestingly, it is not quite 12hrs day and 12hrs night.
Apparently on the equator the day is slightly longer than the night (very slight, less than 10 minutes). The atmosphere of the earth refracts the sunlight a bit. According to the website (http://www.timeanddate.com/astronomy/equinox-not-equal.html) the edge of the sun is visible for about 6 minutes before the sun actually breaks the horizon giving the impression of about 12hr 6min of day and about 11hr 54min of night.(15 votes)
June solstice? Not the summer solstice?(4 votes)- She didn't say summer solstice because she was talking about north and south. In June in the north it is the summer solstice but in the south it is the winter solstice.(3 votes)
Why is there so much snow during summer in Norway even though it is really close to the Sun?(2 votes)
There isn´t a lot of snow in Norway during the summer. The only places you find snow is on a few glaciers, which are located in high-altitude areas. However, we do have high days with warnings of high UV-radiation during the summer.(5 votes)
- Why don't they focus on Alaska too? Isn't it the same thing for Alaska?(3 votes)
They have to pick someplace. If they did Alaska someone would ask why not Norway? You are right, though, it is the same thing for Alaska.(1 vote)
- is it easy sleeping in so much sun?(2 votes)
It may not be that easy, but you can survive by having the right things to help keep yourself healthy, keep your body hydrated, and cool. Some equipment includes coolers and big freezing bottles of a lot of water to stay healthy and throat infections from staying away, as well as hydration in your body.(1 vote)
- Around4:38she said that there are 24 hours sunlight in Arctic circle & 24 hours on darkness in Antarctic circle..then what kind of vegetation is there in these places??Do they really have intense sunlight for 24 hours??(2 votes)
yes the earth rotates with a tilt causing the north and south to experience these drastic condition and no vegetation doesn't grow that is why most creature don't inhabit that area(1 vote)
what does the begening sign me(2 votes)
It is the logo for MIT - Massachusetts Institute of Technology. They are the ones who recorded the video for the KA.(1 vote)
Who has the longest days in the summer or winter?(2 votes)- Aren't the poles sometimes always sunny in summer or always dark in the winter? How long does it last?(2 votes)
- Could we jump to the conclusion that the tilt of the Earth also affects the shape of the moon we see in the sky for example during the solstices of December and June?(2 votes)
While somebody at different latitudes would see the moon from a different rotation [i.e. The northern hemisphere would see ( but the southern hemisphere would see ) ] the phases of the moon-- ( or O or ) --have nothing to do with the tilt of the earth. Instead, the phases are caused by the moon's orbit changing what side the sun shines on it.
For more information on what effect latitudes have on moon viewing see: http://curious.astro.cornell.edu/question.php?number=775(1 vote)
4:38Video transcript
Imagine that you live
in North America, and one day you call up
your friend in Norway, up by the North Pole. You guys are talking,
and you make plans to go visit him next summer. So any time next
summer works for you? Yep. Any time is good for me. OK, how about June? That's summer for you, right? Of course. In a few months,
June rolls around, and you hop on the plane
for your Norwegian vacation. You guys are hanging out
one night, when he says-- I think I'm going
to head to bed. And you say-- Come on, man. The Sun's still up. You can't go to sleep. And your friend is like-- But it's Midnight. What? I don't get this. Why is the Sun still up
in the middle of the night here in Norway? That's a great question. I think we can help
you out with that. If we take a look at the
Earth's orbit from the side, we see that the Earth
revolves around the Sun in this orbital plane,
once every year. Remember that Earth is tilted
at an angle of 23.5 degrees, and it's rotating on
its axis once every day. At this point in the
Earth's revolution, the Southern Hemispheres is
at its maximum inclination towards the Sun. This is called the
December solstice. At this point in the
Earth's revolution, the Northern Hemisphere is
at its maximum inclination towards the Sun. This is called
the June solstice. Let's put a line
through the Earth that's perpendicular
to the orbital plane. We know that this angle
here is 23.5 degrees. That means that this angle
here between our vertical line and the equator is 90
minus 23.5 degrees. That's 66.5 degrees. We can draw a circle around
the Earth at the point where the line perpendicular
to the orbital plane touches the Earth's surface. This circle is 66.5 degrees of
latitude north of the equator. Wait. Latitude, what's that? Latitude is the measure of
how far north or south you are from the Earth's equator. If you're zero
degrees, then you're right here on the equator. If you're 90 degrees
north or south, you're on one of the poles. And if you're 66.5
degrees north, like we just talked
about, you're at what's called
the Arctic Circle. We can do the same thing
on the Southern Hemisphere. We draw a circle is
66.5 degrees south. This is called the
Antarctic Circle. OK, but how does that
keep the Sun from setting during the summer in Norway. I think it's best if we explain
this through an experiment. Here we have a
globe of the Earth, tilted at about 23.5 degrees. And we're using a flashlight
to stimulate the Sun. We're wondering about
summer in Norway, so we have the Northern
Hemisphere tilted towards our flashlight Sun. Hmm, I don't think that
flashlight is powerful enough for this experiment. Yeah, there we go. We can see that the half of
the Earth that's facing the Sun is lit up. It's daytime on this half, and
nighttime on the other half. We'll put a little flag here
in the northern part of Norway, which is above
the Arctic Circle. And we'll put another
little flag here in the US, which is
below the Arctic Circle. If we start rotating
the globe, we see that there's a point where
the Sun is no longer shining on the US. We experience this as sunset. However, the Sun continues
to shine on Norway. It's so far north that
it's always in sunlight. Oh, awesome. That's so cool, 24
hours of sunlight. So much time for fun stuff. Skiing, hiking,
[GASP] mini-golf. Not in the winter. What do you mean? Let's take a look at
Norway in the winter. During this season,
the Northern Hemisphere is tilted away from the Sun. So if we rotate
the Earth, we see that the US is in periods
of sunlight and darkness. But we can't see the
Norwegian flag at all. That means-- Twenty-four hours of darkness. Sad, but true. Oh, man. That stinks. It sure does. The same thing happens
between the Antarctic circle and the South Pole too. During their summer, they
have 24 hours of sunlight, and during their winter, they
have 24 hours of darkness. So that's crazy. Even if you don't live far north
or south, the tilt of the Earth still affects the
length of the day. If it's the June
solstice, we have 24 hours of sunlight here
above the Arctic Circle, and 24 hours of darkness here
below the Antarctic Circle. Huh. So if we were to go a
little south to the US, between the equator
and the Arctic Circle, how many hours of daylight
do you think we'll have? Less than 24. Right, it's the longest day
of the year in the Northern Hemisphere. If we continue south until
we get to the equator, halfway between the poles,
here we have 12 hours of light and 12 hours of darkness. If we go even further
south to Australia, between the equator and
the Antarctic Circle, how many hours of
daylight will we have? Less than 12. Exactly. This is the shortest day
of the year in the Southern Hemisphere. The effect is reversed
during the December solstice. There's more than 12 hours of
daylight below the equator, and less than 12 hours
of daylight above it. So now you know how
the tilt of the Earth causes both the seasons and the
length of the day to change. So it's the tilt
of the Earth that gives us longer days in summer
and shorter days in winter. Right. Awesome. I think it's time for some
celebratory summer Midnight mini-golf. Right, Martin? [SNORING] Martin? Martin, are you awake?