This is from NASA latest solar image “movies” available here. This shows a 48 hour time lapse of the surface of the sun, 15 October to 17 October 2018. The surface of the sun is currently “spotless” in that there are no “sunspots.” But as you can see, it is hardly featureless; in fact a coronal hole pointed our way may cause visible aurora if you live in a dark place close enough to the poles.
Showing posts with label inquiring minds need to know. Show all posts
Showing posts with label inquiring minds need to know. Show all posts
10/17/2018
Our 'Spotless' Sun
This is from NASA latest solar image “movies” available here. This shows a 48 hour time lapse of the surface of the sun, 15 October to 17 October 2018. The surface of the sun is currently “spotless” in that there are no “sunspots.” But as you can see, it is hardly featureless; in fact a coronal hole pointed our way may cause visible aurora if you live in a dark place close enough to the poles.
9/23/2015
Equi-Nox means [Day] Equals Night -- Right?
Wrap this around your mental astronomical-phenomena spindle and see if you can make of it more of a skein than a snarl:
Where I live on the west coast of the U.S.A., astronomical equinox is at 1:20AM Pacific Daylight Time on Wednesday 23 September 2015. The time from sunrise to sunset should be equal to the time from sunset to sunrise, right?
Doesn't work that way.
Wednesday actually has six more minutes of daylight than Friday. On Friday 25 September we actually get 12 hours zero minutes between sunrise and sunset.
Why?
First, the astronomical definition of equinox is at the moment the earth in its orbit around the sun crosses a particular point in reference to what astronomers call the fixed stars. We know that point wanders with respect to the earth's axis-wobble and the earth's elliptical orbit (precession of the equinox) -- ve-e-e-r-r-y s-slo-o-o-owly! But can it make a difference of a day or two?
Second, there's the spin of the earth. Does the spin, added to the round-the-sun motion, make a difference?
I admit I haven't done the research. But hey, give me some credit for finding the conundrum.
Where I live on the west coast of the U.S.A., astronomical equinox is at 1:20AM Pacific Daylight Time on Wednesday 23 September 2015. The time from sunrise to sunset should be equal to the time from sunset to sunrise, right?
Doesn't work that way.
Wednesday actually has six more minutes of daylight than Friday. On Friday 25 September we actually get 12 hours zero minutes between sunrise and sunset.
Why?
First, the astronomical definition of equinox is at the moment the earth in its orbit around the sun crosses a particular point in reference to what astronomers call the fixed stars. We know that point wanders with respect to the earth's axis-wobble and the earth's elliptical orbit (precession of the equinox) -- ve-e-e-r-r-y s-slo-o-o-owly! But can it make a difference of a day or two?
Second, there's the spin of the earth. Does the spin, added to the round-the-sun motion, make a difference?
I admit I haven't done the research. But hey, give me some credit for finding the conundrum.
7/17/2014
Wiki Wander 17 July 2014
It was work related! Honest!
Started with the label of a purple gasket replacement gel containing the descriptor THIXOTROPIC.
By the time I gave up, I had visited
RHEOPECTY
DILATANT fluid
BINGHAM PLASTIC
NON-NEWTONIAN FLUID
and FLOCCULATION.
Special guest appearances by science and math!
Started with the label of a purple gasket replacement gel containing the descriptor THIXOTROPIC.
By the time I gave up, I had visited
RHEOPECTY
DILATANT fluid
BINGHAM PLASTIC
NON-NEWTONIAN FLUID
and FLOCCULATION.
Special guest appearances by science and math!
"Oh, the places you'll go! There is fun to be done!
There are points to be scored. There are games to be won.
And the magical things you can do with that ball
will make you the winning-est winner of all."
-- Dr. Seuss
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