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Why Does It Get Lighter In February

Sabresonic

Sabresonic

Justified & Ancient
Joined
Feb 11, 2020
Messages
1,230
I live on the Tyne in a block of flats and at 5.15 everyday the DFDS ferry goes past on its why too Amsterdam and today I noticed how bright it was when it past yet 2 weeks ago in was pitch black when the ferry past????
 
This is to do with the tilt of the Earth. In December the Earth is tilted away from the Sun so that Newcastle is buried deeply in its shadow, while in February the Earth is beginning to tilt back again. By March 21 the Earth will be tilted so that Newcastle (and everywhere else on Earth) experiences half day and half night, and in the summer the Earth tilts towards the Sun so that the days are longer than the nights.

The rate of change in day length changes too. At this time of year the day length is getting longer more rapidly, with the Sun setting five minutes later each day. But in midwinter and midsummer the day length changes very slowly, by a minute a day or less. This is why we notice this sort of thing more in February and March than in the middle of winter.
 
Also a lot depends on how bright the day is. If it's a cloudy, overcast day then it will get dark earlier than on a clear, bright day. Today I was out with the dog at twenty past five and it was still (fairly) bright daylight. A couple of days ago it was raining most of the afternoon and it was dark by five.
 
It's t'light nights startin'. ;)
 
I don't think this phenomenon is entirely intuitive. The fact that the rate of change in day length itself changes over time is not obvious, or widely known, but it does definitely get faster around this time of year.

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I seem to remember being taught many many years ago that there is a point in the year when each day the mornings are still get light earlier but the evenings are getting dark also earlier but by less minutes each day than the mornings. Or visa versa. Or something like that.
 
kesavaross said:
I seem to remember being taught many many years ago that there is a point in the year when each day the mornings are still get light earlier but the evenings are getting dark also earlier but by less minutes each day than the mornings. Or visa versa. Or something like that.
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I can't remember exactly, but someone will look it up, but you're basically correct. The darkness doesn't simply creep in at both ends of the day until the winter solstice, then start receding until the summer solstice.

The winter solstice is the point of balance where one end of the day has already begun to get lighter (the evenings, I think), but only slowly, and the other end of the day (the morning, I think) is still getting darker but slowing down.
 
PeteByrdie said:
I can't remember exactly, but someone will look it up, but you're basically correct. The darkness doesn't simply creep in at both ends of the day until the winter solstice, then start receding until the summer solstice.

The winter solstice is the point of balance where one end of the day has already begun to get lighter (the evenings, I think), but only slowly, and the other end of the day (the morning, I think) is still getting darker but slowing down.
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Thanks. You put it a lot better than me and that has clarified it for me.

After the winter solstice one end of the day is getting lighter while the other end of the day is still getting darker. It's that the end that is getting lighter is doing it each day by more minutes than the end that is getting darker. The over all net effect though is that the days are getting longer.
 
eburacum said:
I don't think this phenomenon is entirely intuitive. The fact that the rate of change in day length itself changes over time is not obvious, or widely known, but it does definitely get faster around this time of year.

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I've also only realised since I've lived in the mountains that the trajectory of the sun as days get shorter is different to when days get longer - it hides just below the ridge to the south of the house for longer in Feb than it does in December even though the days are now quite a bit longer.
 
The pattern the Sun makes in the sky over a year is called the analemma; if you take a picture of the sun at the same time each day you get a strange 'figure-of-eight' pattern that follows a very different path in spring and autumn.
analemma.jpg
 
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Ahhh I see - they really should teach this sort of stuff at school.
 
This was covered at length in an episode of QI, in which they also informed us (despite it seeming to be a ridiculous assertion), that the shortest day is not within the adjacent 24 hours to the longest night, thanks to a number of factors to do with the earths spin, it's orbit, and the tilt of the axis.
As such the shortest day is usually about 3 or 4 days adrift of the longest night.
The same happens mid-summer with the longest day/shortest night.
 
eburacum said:
This is to do with the tilt of the Earth. In December the Earth is tilted away from the Sun so that Newcastle is buried deeply in its shadow, while in February the Earth is beginning to tilt back again. By March 21 the Earth will be tilted so that Newcastle (and everywhere else on Earth) experiences half day and half night, and in the summer the Earth tilts towards the Sun so that the days are longer than the nights.

The rate of change in day length changes too. At this time of year the day length is getting longer more rapidly, with the Sun setting five minutes later each day. But in midwinter and midsummer the day length changes very slowly, by a minute a day or less. This is why we notice this sort of thing more in February and March than in the middle of winter.
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Excellent reply eburacum and I forgot to put the ferry passing by at 5.15pm:clap:
 
eburacum said:
The pattern the Sun makes in the sky over a year is called the analemma
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Just be careful when doing a Google search for "analemma". Don't ask me how I know, but Emma seems a very accommodating girl.

The length of daylight each day mapped across a year roughly works out as a sinewave. Around the solstices, the rate of change is slow, and around the equinoxes, it is rapid.

On a pedantic point, the tilt of the Earth's axis remains more or less constant, but it's tilt relative to the Sun changes as the Earth proceeds around it's orbit.
 
I've noticed changes around June 21th and December 21th are approx. 1 minute a day. A month before and after it's approx. 2 - 3 minutes a day.
 
The In House GP likens it to the turning of the tide. When the tide is very high or very low you barely notice the change but once it's halfway, the difference is obvious.
 
Absolute piffle, it's because the Sun is pulled across the sky by magic goats (or something), they get up a bit earlier each day but they sometimes get distracted by space herbage and suchlike that's why it can vary. Toward the end of the year they get tired so spend more time in their spacebeds.
 
It gets lighter in February because it needs to get a bloody move on! We have to get to about 16 hours of daylight in a few weeks. Chop-chop!
 
eburacum said:
The pattern the Sun makes in the sky over a year is called the analemma; if you take a picture of the sun at the same time each day you get a strange 'figure-of-eight' pattern that follows a very different path in spring and autumn.
analemma.jpg
Click to expand...
When I first saw this, I thought it might be the origin of the infinity sign, but after looking it up, they seem to be completely unrelated, in which case it's an amazing coincidence!
 
Bullseye said:
Absolute piffle, it's because the Sun is pulled across the sky by magic goats (or something), they get up a bit earlier each day but they sometimes get distracted by space herbage and suchlike that's why it can vary. Toward the end of the year they get tired so spend more time in their spacebeds.
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Look, I'm sure you know, that the first rule of Magic Goats is not to talk about Magic Goats!
The 'normies' will get suspicious.
 
kesavaross said:
I seem to remember being taught many many years ago that there is a point in the year when each day the mornings are still get light earlier but the evenings are getting dark also earlier but by less minutes each day than the mornings. Or visa versa. Or something like that.
Click to expand...
Yeah, there's some weirdness there-- if you look up sunrise/sunset times for late december/early in the new year, you will notice that the hours of sunlight are getting longer, but the time the sun rises is still creeping a hair later relative to the day before, for a while.
 
Bullseye said:
Absolute piffle, it's because the Sun is pulled across the sky by magic goats (or something), they get up a bit earlier each day but they sometimes get distracted by space herbage and suchlike that's why it can vary. Toward the end of the year they get tired so spend more time in their spacebeds.
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Heresy! The sun is a giant hamster wheel and the increases and decreases in speed are when sparkie builds up a head of steam or gets knackered.
 
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