APOD: Lunation (2012 Feb 05)

Comments and questions about the APOD on the main view screen.
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APOD: Lunation (2012 Feb 05)

Post by APOD Robot » Sun Feb 05, 2012 5:06 am

Image Lunation

Explanation: Our Moon's appearance changes nightly. This time-lapse sequence shows what our Moon looks like during a lunation, a complete lunar cycle. As the Moon orbits the Earth, the half illuminated by the Sun first becomes increasingly visible, then decreasingly visible. The Moon always keeps the same face toward the Earth. The Moon's apparent size changes slightly, though, and a slight wobble called a libration is discernible as it progresses along its elliptical orbit. During the cycle, sunlight reflects from the Moon at different angles, and so illuminates different features differently. A full lunation takes about 29.5 days, just under a month (moon-th).

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Re: APOD: Lunation (2012 Feb 05)

Post by Beyond » Sun Feb 05, 2012 5:38 am

I think that taking the square root of '2' to 10 million places, is definitely 'irrational', and should take quite a few (moon)ths, to do it by hand.
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Re: APOD: Lunation (2012 Feb 05)

Post by Boomer12k » Sun Feb 05, 2012 1:17 pm

Cool animation....

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Bulwersator

Re: APOD: Lunation (2012 Feb 05)

Post by Bulwersator » Sun Feb 05, 2012 4:34 pm

http://commons.wikimedia.org/wiki/File: ... 012%29.ogv is in higher quality and is in the public domain

noriyosan73

Re: APOD: Lunation (2012 Feb 05)

Post by noriyosan73 » Sun Feb 05, 2012 4:39 pm

This may be an easy question for many, but is the animation the same as viewed from Australia? If it is different, is it possible to have a side by side animation?

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Loon Nation

Post by neufer » Sun Feb 05, 2012 5:06 pm

http://videocafe.crooksandliars.com/david/gingrich-promises-moon-base-could-become-51s wrote:
Gingrich Promises Moon Base That Could Become 51st State
January 25, 2012 06:05 PM

<<Republican presidential candidate Newt Gingrich on Wednesday vowed to build a lunar colony that he said could eventually become the 51st state. Speaking to Republicans on Florida's Space Coast, the former House Speaker explained that the "grandiose" idea would be possible because the government would fuel innovation by awarding prizes and incentives to private businesses.

"At one point early in my career, I introduced the Northwest Ordinance for Space," Gingrich recalled, referring to it as the "weirdest thing" he'd ever done. "I said when we got -- I think the number is 13,000 -- when we have 13,000 Americans living on the moon, they can petition to become a state."

"By the end of my second term, we will have the first permanent base on the moon and it will be American," the candidate insisted. "We will have commercial near-Earth activities that included science, tourism and manufacturing."

"I accept the charge that I am an American and Americans are instinctively grandiose because we believe in a bigger future!" he exclaimed. "I want you to help me both in Florida and across the country so that you can someday say you were here the day it was announce that of course we'd have commercial space and near space. Of course we'd have a man colony on the moon that flew an American flag."

http://videocafe.crooksandliars.com/hea ... -colony-pr

Gingrich later joked to reporters about his chances with voters stationed at the lunar colony. "I think the moon primary would come late in the season," he said.>>
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Re: APOD: Lunation (2012 Feb 05)

Post by Wolf kotenberg » Sun Feb 05, 2012 5:08 pm

If you were stationed on the moon, would the Earth appear tp wobble ?

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Re: APOD: Lunation (2012 Feb 05)

Post by neufer » Sun Feb 05, 2012 5:09 pm

noriyosan73 wrote:
This may be an easy question for many, but is the animation the same as viewed from Australia?
Australians are standing on their heads so just stand on your head and it will appear correct.
Wolf kotenberg wrote: If you were stationed on the moon, would the Earth appear tp wobble ?
  • Yes:

    1) The variation in apparent size over a lunation would be identical.

    2) The Earth's libration in longitude would also be identical; however, it would generally be lost in the constant daily movement of 28.5 full earth rotations every 29.5 days. [If an image of the Earth from the Moon were taken regularly every 24.84 hours (= 24*29.5/28.5) then this problem could be compensated for.]

    3) The Earth's libration in latitude would be 3 to 4 times larger due to the large (between 18.29° and 28.58°) inclination between the Earth's axis of rotation and the normal to the plane of the Moon's orbit.
Art Neuendorffer

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Re: APOD: Lunation (2012 Feb 05)

Post by bystander » Sun Feb 05, 2012 6:12 pm

The moon, by her comparative proximity, and the constantly varying appearances produced by her several
phases, has always occupied a considerable share of the attention of the inhabitants of the earth.

  • ~ Jules Verne ~ (From the Earth to the Moon (1865))
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Re: Loon Nation

Post by Chris Peterson » Sun Feb 05, 2012 6:17 pm

neufer wrote:
http://videocafe.crooksandliars.com/david/gingrich-promises-moon-base-could-become-51s wrote:
Gingrich Promises Moon Base That Could Become 51st State
The question is, would it be a red state or a blue state? I guess it depends on whether they end up staffing it with a bunch of military and ex-military people, or with scientists.
Chris

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Re: Loon Nation

Post by rstevenson » Sun Feb 05, 2012 6:49 pm

Gingrich Promises Moon Base That Could Become 51st State
:shock:

The pros and cons of Moon Base Gingrich

Rob

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Re: Loon Nation

Post by luigi » Sun Feb 05, 2012 8:04 pm

Chris Peterson wrote:
neufer wrote:
http://videocafe.crooksandliars.com/david/gingrich-promises-moon-base-could-become-51s wrote:
Gingrich Promises Moon Base That Could Become 51st State
The question is, would it be a red state or a blue state? I guess it depends on whether they end up staffing it with a bunch of military and ex-military people, or with scientists.
The moon is made of cheese so it must be a blue state as there is a blue cheese but not a red one.

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Re: Loon Nation

Post by neufer » Sun Feb 05, 2012 8:04 pm

Chris Peterson wrote:
neufer wrote:
http://videocafe.crooksandliars.com/david/gingrich-promises-moon-base-could-become-51s wrote:
Gingrich Promises Moon Base That Could Become 51st State
The question is, would it be a red state or a blue state?
  • It would be a green cheese state.
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Re: Loon Nation

Post by Chris Peterson » Sun Feb 05, 2012 8:14 pm

luigi wrote:The moon is made of cheese so it must be a blue state as there is a blue cheese but not a red one.
Ha! You've never done much cheese making, have you? You can easily get a red cheese when things go wrong. Blue cheese you eat; red cheese goes in the biohazard bin.
Chris

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Re: APOD: Lunation (2012 Feb 05)

Post by Boomer12k » Sun Feb 05, 2012 8:17 pm

Weeble's wobble, but they don't fall down...

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Re: Loon Nation

Post by Chris Peterson » Sun Feb 05, 2012 8:20 pm

neufer wrote:It would be a green cheese state.
A green state doesn't sound so bad. A green cheese state though... maybe not so different from a few we've already got?
Chris

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Re: Loon Nation

Post by bystander » Sun Feb 05, 2012 8:39 pm

neufer wrote:
http://videocafe.crooksandliars.com/david/gingrich-promises-moon-base-could-become-51s wrote:
Gingrich Promises Moon Base That Could Become 51st State
January 25, 2012 06:05 PMhttp://asterisk.apod.com/viewtopic.php?f=31&t=26845&hilit=russia+lunar
UT: Russia Discussing Moon Base with NASA, ESA
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
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Re: Loon Nation

Post by neufer » Sun Feb 05, 2012 8:46 pm

Image
Chris Peterson wrote:
luigi wrote:
The moon is made of cheese so it must be a blue state as there is a blue cheese but not a red one.
Ha! You've never done much cheese making, have you?
You can easily get a red cheese when things go wrong.
Blue cheese you eat; red cheese goes in the biohazard bin.
MMMMMmmmmm...puttin' on a Ritz :arrow:
Last edited by neufer on Sun Feb 05, 2012 9:20 pm, edited 1 time in total.
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Re: APOD: Lunation (2012 Feb 05)

Post by Beyond » Sun Feb 05, 2012 8:56 pm

QUICK!! Cheese it, the forum cops are coming!!!!
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Re: APOD: Lunation (2012 Feb 05)

Post by noriyosan73 » Sun Feb 05, 2012 10:12 pm

I turned the computer screen upside-down. Still it would be nice to know whether it is the same or not, and if it is not, is it possible for APOD to run a double animation side by side?

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Re: APOD: Lunation (2012 Feb 05)

Post by biddie67 » Mon Feb 06, 2012 2:16 am

I have wondered just how delicately balanced and stable the moon is in its orbit around the Earth.

If we did make a permanent colony up there with a massive influx of heavy equipment for living quarters, life support and then add the weight for mining, processing equipment and large storage/transport bases with minerals being shipped back to Earth, could there be a possibility of causing problems with changing the center of mass and shifting the moon's orbit?

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Re: APOD: Lunation (2012 Feb 05)

Post by orin stepanek » Mon Feb 06, 2012 3:19 am

biddie67 wrote:I have wondered just how delicately balanced and stable the moon is in its orbit around the Earth.

If we did make a permanent colony up there with a massive influx of heavy equipment for living quarters, life support and then add the weight for mining, processing equipment and large storage/transport bases with minerals being shipped back to Earth, could there be a possibility of causing problems with changing the center of mass and shifting the moon's orbit?
No as the Moon is very large indeed! 8-)
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Re: APOD: Lunation (2012 Feb 05)

Post by rstevenson » Mon Feb 06, 2012 3:56 am

biddie67 wrote:I have wondered just how delicately balanced and stable the moon is in its orbit around the Earth.

If we did make a permanent colony up there with a massive influx of heavy equipment for living quarters, life support and then add the weight for mining, processing equipment and large storage/transport bases with minerals being shipped back to Earth, could there be a possibility of causing problems with changing the center of mass and shifting the moon's orbit?
The mass of the Moon is about 7.35 x 1022 kg
The mass of a billion human beans is about 7 x 1010 kg
So even a billion of us is only about 1 x 10-12th the mass of the moon
So even putting a billion humans on one side of the Moon would have no noticeable effect on it.

Thinking ahead a few centuries we can envision large numbers of people living on the Moon, though there's no particular reason for them to concentrate all in one spot. (For safety they'd mostly be living underground, so they'd get their views of Earth from a screen like we do.) If they ever reached the population density that would require hollowing out significant portions of the Moon, say approaching 25% of it (about 5.5 x 109 km3), then they might want to start thinking about keeping things on an even keel. But that sort of scenario can only be dimly imagined for a far distant future.

Rob