Ant Sinclair Posted February 16, 2015 Share Posted February 16, 2015 I don't know if this has been asked before, but if the Earth didn't have an inclination of 23.5° would our day length be any longer? Link to comment Share on other sites More sharing options...
John Cuthber Posted February 16, 2015 Share Posted February 16, 2015 If the Earth's axis wasn't tilted, the day would be longer in Winter. It would be shorter in Summer. (All other things being equal, the day would be 12 hours (very nearly) all year round and the seasons would be much less noticeable). There would still be some "season" effect because the Earth's orbit isn't a circle. Link to comment Share on other sites More sharing options...
Ant Sinclair Posted February 16, 2015 Author Share Posted February 16, 2015 (edited) Thanks for replying John, the reason I asked the question( and now see I should have been more precise ) is that I was wondering if Our planets magnetic field, if it were "up-right", would it have more "drag" on it due to Our stars magnetic field crossing its path so to speak?, possibly lengthening Our day slightly. Edited February 16, 2015 by Ant Sinclair Link to comment Share on other sites More sharing options...
Janus Posted February 16, 2015 Share Posted February 16, 2015 One thing you have to realize is the the Earth's magnetic field isn't really affixed to the Earth. It doesn't even line up with the Earth's axis of rotation nor does it stay in the same place. Presently, the North Magnetic pole is some 4 degrees away from the physcial North pole, but it moves some 55-60 km every year and at the turn of the 20th century it was in Northern Canada and some 30 degrees from the North pole. If the orientation of the Earth's magnetic field had any significant effect on the the Earth's rotation rate and the length of the day, we would have noticed over the last 100 yrs or so. Link to comment Share on other sites More sharing options...
Ant Sinclair Posted February 16, 2015 Author Share Posted February 16, 2015 Thanks Janus for Your reply, if say the Earth did swing from 23.5° to 0° would its' magnetic field follow in any way or would it stay where it was? Link to comment Share on other sites More sharing options...
Ant Sinclair Posted February 25, 2015 Author Share Posted February 25, 2015 Can anybody point Me to material that may lead Me to finding information on the last question on this thread, as I have searched but found nothing of relevance to date. Link to comment Share on other sites More sharing options...
swansont Posted February 25, 2015 Share Posted February 25, 2015 You have not put any constraints on how the tilt occurs, so I'm not surprised nobody has answered. The best you could say is "it depends". Link to comment Share on other sites More sharing options...
Acme Posted February 25, 2015 Share Posted February 25, 2015 (edited) I don't know if this has been asked before, but if the Earth didn't have an inclination of 23.5° would our day length be any longer? Day length would be equal. If the Earth's axis wasn't tilted, the day would be longer in Winter. It would be shorter in Summer. (All other things being equal, the day would be 12 hours (very nearly) all year round and the seasons would be much less noticeable). There would still be some "season" effect because the Earth's orbit isn't a circle. Day length would be equal [12 hours] with 0 inclination. The shape of Earth's orbit has no effect on day length. One thing you have to realize is the the Earth's magnetic field isn't really affixed to the Earth. It doesn't even line up with the Earth's axis of rotation nor does it stay in the same place. Presently, the North Magnetic pole is some 4 degrees away from the physcial North pole, but it moves some 55-60 km every year and at the turn of the 20th century it was in Northern Canada and some 30 degrees from the North pole. If the orientation of the Earth's magnetic field had any significant effect on the the Earth's rotation rate and the length of the day, we would have noticed over the last 100 yrs or so. I agree the magnetic field has no effect on day length, however just because it moves relative to the geographic pole does not mean it is not affixed to Earth. Your arm is affixed to your body but moves relative to your long axis. Thanks Janus for Your reply, if say the Earth did swing from 23.5° to 0° would its' magnetic field follow in any way or would it stay where it was? First, Earth will not 'swing' as you describe. Nonetheless, the orientation of the magnetic field is described relative to the geographic poles so IF Earth swang to zero then yes, the magnetic field orientation would follow. So if the magnetic pole were at 72.21°W longitude and 80.08°N latitude before the swing, it would be at that same location after Earth swang. Edited February 25, 2015 by Acme Link to comment Share on other sites More sharing options...
swansont Posted February 25, 2015 Share Posted February 25, 2015 Day length would be equal [12 hours] with 0 inclination. The shape of Earth's orbit has no effect on day length. On the contrary, the shape of our orbit has an effect. The speed of the earth varies with its distance, and a solar day is reckoned from solar noon to solar noon (sun is on the line going overhead) so the earth has to rotate a little more than 360º in a day. When the earth is moving faster in its orbit, that angle is incrementally larger, so the day is longer, and shorter when slower. The length of the solar day varies about ±15 minutes from the average over the course of the year, and about half of that is due to the eccentricity. http://en.wikipedia.org/wiki/Equation_of_time 1 Link to comment Share on other sites More sharing options...
Acme Posted February 25, 2015 Share Posted February 25, 2015 On the contrary, the shape of our orbit has an effect. The speed of the earth varies with its distance, and a solar day is reckoned from solar noon to solar noon (sun is on the line going overhead) so the earth has to rotate a little more than 360º in a day. When the earth is moving faster in its orbit, that angle is incrementally larger, so the day is longer, and shorter when slower. The length of the solar day varies about ±15 minutes from the average over the course of the year, and about half of that is due to the eccentricity. http://en.wikipedia.org/wiki/Equation_of_time I should have specified 'mean' solar time. Even so, this difference in day length would not create seasons as John stated. We should also add -and you are expertly qualified to comment- that 'day' length is a relative measure tied to the period of Earth's rotation and that today's day length is ever-so-slightly more than yesterday's day length as Earth slows due to the Moon's tidal drag. Oui? Link to comment Share on other sites More sharing options...
John Cuthber Posted February 25, 2015 Share Posted February 25, 2015 I should have specified 'mean' solar time. Even so, this difference in day length would not create seasons as John stated. We should also add -and you are expertly qualified to comment- that 'day' length is a relative measure tied to the period of Earth's rotation and that today's day length is ever-so-slightly more than yesterday's day length as Earth slows due to the Moon's tidal drag. Oui? Yep. http://en.wikipedia.org/wiki/Leap_second Well, the tidal drag is the biggest factor... Link to comment Share on other sites More sharing options...
Harold Squared Posted March 26, 2015 Share Posted March 26, 2015 Agreed. I am surprised that no one has mentioned precession, the "wobble" of the planet's axis of rotation, a small and slow but detectable phenomenon. The reversal of the magnetic poles remain a fascinating enigma and one of great relevance to our technology, worthy of more scrutiny, or would you agree? Link to comment Share on other sites More sharing options...
swansont Posted March 26, 2015 Share Posted March 26, 2015 Agreed. I am surprised that no one has mentioned precession, the "wobble" of the planet's axis of rotation, a small and slow but detectable phenomenon. The reversal of the magnetic poles remain a fascinating enigma and one of great relevance to our technology, worthy of more scrutiny, or would you agree? Maybe because they are not answers to the question that was asked Link to comment Share on other sites More sharing options...
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