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Earthshine

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500 years ago, Leonardo da Vinci explained the phenomenon when he realized that both Earth and the Moon reflect sunlight. The dim light is reflected from the Earth to the Moon and back to the Earth as Earthshine. The bright crescent is plain ole moonshine.

As seen this evening

has20birds, askliu, and 50 other people added this photo to their favorites.

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  1. TheAlieness GiselaGiardino²³ 88 months ago | reply

    Sister, don´t kill yourself.. Venus will still be there for you to have its picture taken for a long time.

    Because it´s the planet of Love. It will never turn you down. =)

  2. Sister72 88 months ago | reply

    Thank you TAGG23, you saved me! ;-)

  3. biotron 88 months ago | reply

    it´s like perspective when you go on a roadtrip and the farther objects close to the horizon "seem" to move slowly or slower or not to move at all - yeah, but those farther objects you refer to are presumably not ones that move in the first place, ie mountains etc.

    it's all in the tail. while there is great velocity involved, the tail implies extreme motion and makes it seem faster relative to the frame of the sky against which we see it. it's very hard to find earth-based analogies, because rarely are we in a fixed position observing fast-moving distant objects that are massive enough to appear even temporarily motionless! certain high cirrus clouds might be a rough approximation of the effect if their form were to remain fixed rather than fluid over time...

    we should probably also mention the fact that - whether the comet is inbound or outbound - the dust tail extends away from the sun (approximately, and curving... if McNaught had an ion tail as visible as Hale-Bopp's, that would point directly away from the sun) - so there's something else which isn't as it first might appear. apart from the closest few days approaching perihelion (and depending upon the eccentricity of the orbit) the comet is generally moving toward or away from us, rather than laterally across the night sky - despite the tail - and so "moves" even less than one might imagine (or notice if the earth's rotation were to be stopped for a few weeks to observe it constantly at dusk :) )

    when you consider that the tail can be millions upon millions of kilometers long, and that the head (while very bright) is usually less than 50km across, it becomes clearer that for anything to appear to move across the night sky it is either much closer to earth, or travelling many times faster than the speed of light!

    but no explanation lessens the sheer wonder of staring at something so beautiful and relatively rare.... and it is fun to have senses deceived by empirical observation... plenty of scientists wake up each morning "knowing" the sun has risen :)

    maybe we should throw a Sereda cat in amongst the physics pigeons?

    and then, to counteract some of the bunkum contained therein, return to Earth with a solid recommendation to read this cracking little book if the chance arises.

    poor Steve has had his lovely Earthshine pic and related comments eclipsed by McNaught and beyond - sorry!

  4. biotron 88 months ago | reply

    nb it is hard to take Sereda seriously when he includes so many typos, including the absolute cracker : "if we follow any pint (sic) in the 4 dimensions over time, from half a second to 250 million years...." etc - unless of course he means to speak of the curved wave-path of the antigravity UFO i just dropped into the large and timeless Guinness sitting in front of me...?

    i digress. for anyone who wants to see Comet McNaught satisfyingly in motion - here is the link to a movie taken by the permanently sun-facing Solar & Heliospheric Observatory.

    the brightness makes it appear far closer than it actually is, a result of SOHO's exposure tuning for faint solar corona.

    but this is the best example i've ever seen of a comet "swinging by" the sun - check it out!

  5. jurvetson 88 months ago | reply

    all very interesting! The SOHO video links are fantastic. Are the comets large enough to have any effect on the Sun's magnetic field and flare activity?

    Sereda's crop circles around p.42. cracked me up. But they are also a bit poignant. Sometimes, when people become unglued, you see archetypal extremes of embedded mental traps, such as the search for "meaning"

  6. biotron 88 months ago | reply

    good! glad you liked them. i guess you asked that question because of the enormous coronal mass ejection that takes place just after Comet 96P/Machholz swings by its perihelion in the second video? it's amazing, isn't it?!

    i always presumed their nuclei could never have great enough mass / density to have any influence on something as large as the sun, so in this case just assumed it was a wonderful coincidence.

    spot on about Sereda too - a shame that something which might act as an interesting thought experiment and (in places) has apparently sound overviews of known physical processes unhinges itself so completely in the name of Jesus Christ and the deep mystical import of his leaden aphorisms.

    the Strange Attractor "Field Guide" to crop-circle making really is a classic, and a good deal of the book revels at the lengths to which some people will go to find "meaning" and avoid admission of error. a fantastic little read.

    nature abhors a vacuum, and the "unglued" are often willingly sucked in :)

  7. patisfaction ~ censored [deleted] 88 months ago | reply

    ooh kewl yr Earthshine!
    & even on buzz' b-day!
    ;)

  8. TheAlieness GiselaGiardino²³ 88 months ago | reply

    wow, i am right now bookmarking this page... there´s so much to go through here!!! Thank you, biotron, again. I really appreciate that you take time to explain this to me (and to all other bystanders ;-) And steve, thx too.

    (hey that "2 sec timer trick" to avoid the moves from clicking... that was neat! I found myself trying it successfully, and giggling and thinking: "This steve... jeez, smart guy." (as if I need further proof whatsoever of that!) :D

  9. RJM Images 88 months ago | reply

    Very, very nice.

  10. rg250871 88 months ago | reply

    I enjoyed that one.

  11. Brian Nordlund 88 months ago | reply

    Fantastic photo and a lot of interesting info too

    --
    Seen in 1-2-3 (?)

  12. _sarchi 88 months ago | reply

    ..as I mentioned to gi_ it's problematical to the average picture taker.. but CL's tutorial for hdr from 1 .jpeg_ might show interesting details next time it arises for me.. any thoughts?

    --
    https://www.flickr.com/photos/jurvetson/ (?)

  13. aaardvaark 88 months ago | reply

    This is a great moon shot - your lens (100-400?) has done a pretty good job of handling the contrast, I must try this.

  14. Anna Sunny Day 88 months ago | reply

    This is so neat!

  15. melcir.meri 86 months ago | reply

    Like a smile of de-light! It is invited to "FIRST - THE EARTH!" Photo-ART Competition, CAT. #1 -'THE MOON', via this link - www.flickr.com/groups/348618@N21/discuss/72157600036294015/ . For details and a glimpse [& do send me this in 75x75 html, please], of the 'Invite Only' Competition Group see EXHIBITION page - www.flickr.com/people/melcir-selfportraits-2006/ . - Mel

  16. MONKEY50 83 months ago | reply

    GREAT SHOT!!!!!
    Seen in the group;I Saw The Light

  17. Donna62 80 months ago | reply

    Beautiful shot.
    A1-App-FTE-455531011_7dfad6f375_m

    A great image, much admired by Donna62 --,
    a "FIRST - THE EARTH!" member
    You are invited to add it to our group pool!
    www.flickr.com/groups/first-the-earth/

  18. ComputerHotline 76 months ago | reply

    Thanks for licensing this image as CC "by" !
    Your photo is uploaded here :
    commons.wikimedia.org/wiki/Image:Jurvetson_-_Earthshine_(...
    under the terms of the Creative Commons "by" license.

    --
    http://flickrcc.bluemountains.net/index.php?terms=moon&edit=yes&com=yes&page=1 (?)

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