Starship Asterisk*

by **petsie** » Thu Mar 22, 2012 9:35 am

bystander wrote:Same video, different music: http://www.youtube.com/watch?v=T6CMvSKsHBo

I found this with Pink Floyd's "The Great Gig In The Sky" at 5min.com but thought I found the wrong one. This can't have too much to do with the formation of the moon (blue planet with oceans, cooled continents, even cities more than 4 gigayears ago

)

Thank you very much!

by **SJoe** » Thu Mar 22, 2012 2:35 am

I wouldn't say a "chunk" was knocked out exactly.

I don't kow how factual the video is, but it shows an decent illustration of how the formation works. I think.

http://www.youtube.com/watch?v=2sr-MriOCzw

I suggest turning the volume down too.

by **Mooner** » Wed Mar 21, 2012 11:43 pm

Thanks Chris for the rational explanation.

One follow-up question, would such a massive ejection of Earth material send one super-chunk-sized Moon material into an Earth-Moon gravitational system in relatively quick fashion (with minor fragments ultimately falling back to Earth), or would there more likely have been multiple larger chunks of material ejected from Earth in addition to many more smaller chunks expelled, which gradually over many years would have formed at various distances from the Earth - themselves eventually lumping together to form a single big moon? I'm just trying to wrap my head around the likely physics behind the actual process, as the video starts from an already-formed starting point. Thanks for any reply.

by **bystander** » Wed Mar 21, 2012 3:48 pm

petsie wrote:is there another place than youtube to view the link behind the words "impacted the earth"? Youtube will not show that in germany due to ownership issues regarding the music
Thanks in advance,
Peter

Same video, different music: http://www.youtube.com/watch?v=T6CMvSKsHBo

The sequence was lifted from a Discovery Channel special, but I've been unable to find the episode.

by **Chris Peterson** » Wed Mar 21, 2012 2:54 pm

Mooner wrote:My first question is; would material 'expelled' from early-history Earth automatically be pulled back into an Earth orbit at a certain distance from the Earth proportionate to it's mass?

Nearly all of the ejected material either fell back to the Earth or collapsed into the Moon. Very little achieved escape velocity from the Earth-Moon system.

And a second question; from where exactly on Earth was this massive chunk of Earth expelled?

No way of knowing, and since the collision pretty much melted the entire surface, after which the Earth kind of reformed, the question itself may not mean much.

by **petsie** » Wed Mar 21, 2012 1:42 pm

is there another place than youtube to view the link behind the words "impacted the earth"? Youtube will not show that in germany due to ownership issues regarding the music

Thanks in advance,
Peter

by **Mooner** » Wed Mar 21, 2012 12:13 am

Interesting vid, but I have two very basic questions I feel embarrassed to ask.

My first question is; would material 'expelled' from early-history Earth automatically be pulled back into an Earth orbit at a certain distance from the Earth proportionate to it's mass?

And a second question; from where exactly on Earth was this massive chunk of Earth expelled?

Thanks in advance.

by **BMAONE23** » Tue Mar 20, 2012 7:37 pm

Rocky planets with moons
Earth - Luna
Believed to have been reformed after a catastrophic impact
Mars - Phobos
------- Deimos
Both are likely captured asteroids
Pluto - Charon (could be similar to Luna)
-------- Nix (unknown)
-------- Hydra (unknown)
-------- P4 (unknown)
Nix, Hydra, & newly discovered P4 could be remnants of a possible impact that created Charon
New Horizons might answer some or none of these questions

The remaining bulk of large Moons orbit Gas Giants or Ice Giants. It is unlikely that an impact of a gas giant would produce a viable stable rocky moon so they might have formed along side their planetary hosts during the accretion process

by **Anthony Barreiro** » Tue Mar 20, 2012 7:09 pm

What a lovely video. I'm going to share it with friends who love looking at the Moon. And the other LRO tour of the Moon video is pretty cool, too.

I enjoyed the music and the sound effects, but I don't have any cats here at work.

In the Random House Dictionary, the first definition of "evolution" is "any process of change or growth; development." Darwinian evolution is the third definition. If I were teaching Darwin's theory of evolution, I would probably start by discussing the general use of the term and clarifying its special meaning in biology. Students learn more when you relate something new to something they already know.

For what it's worth, Mercury, Mars, and Saturn are all retrograde currently, and Venus is approaching retrograde. Given the level of vitriol on Starship Asterisk currently, I'm looking forward to reading some fulminating screeds about astrology! (Is there an emoticon for <poking with a sharp stick>? Tee hee.)

by **Tszabeau** » Tue Mar 20, 2012 4:20 pm

Ever try to teach evolution to a person who has a preconceived incorrect notion of what it is? This flippant use of the word "evolution" contaminates my students' brains, as well as the national discussion of science in general. I stand by my comment.

Treating the word 'evolution' as if it is a religiously sacred concept, that applies ONLY to Darwinism, is what's confusing you and your students. On the contrary, it's a common everyday kind of concept.

by **fafers** » Tue Mar 20, 2012 3:59 pm

Sandstone wrote: My question, up for anyone who wants it: many planets have moons... and, while I'm not well-read on the subject, my impression has been that this theory (huge planet-sized impact ejecting and fragmenting off material to form the moon) has only been advocated for earth's moon. Do we have a reason to think that we have a "special case" scenario here? Or is this thought to be a general process for most moons?

I'm not sure if it's thought to be general for most moons, but it is definitely thought to be one of the processes for their formation. In the Solar System, this process has been advocated for Charon, too.

by **bystander** » Tue Mar 20, 2012 3:12 pm

geckzilla wrote:You sure there's something contaminating your students' brains? It's right there in the dictionary. In fact, the word existed and was used in other ways long before Darwin was born.

Wow, you mean the word evolution evolved to include Darwin's Theory? I thought maybe he created it, kind of an intelligent design.

by **geckzilla** » Tue Mar 20, 2012 2:10 pm

obscurechemist wrote:Ever try to teach evolution to a person who has a preconceived incorrect notion of what it is? This flippant use of the word "evolution" contaminates my students' brains, as well as the national discussion of science in general. I stand by my comment.

You sure there's something contaminating your students' brains? It's right there in the dictionary. In fact, the word existed and was used in other ways long before Darwin was born.

by **Beyond** » Tue Mar 20, 2012 2:04 pm

neufer wrote:
Beyond wrote:
Hmm... kinda looks to me like the moon got hit in the face with a Big pizza pie
That's a Mare.

According to Dean Martin, that's Amore.
"When the moon hits your eye like a big pizza pie, that's amore".
http://www.youtube.com/watch?v=aS6-b7CONDI

by **Chris Peterson** » Tue Mar 20, 2012 1:49 pm

Flase wrote:I believe the main reason the near side of the moon has many fewer impact craters is that it is tidally locked and the Earth makes a great shield. In order to hit this side of the Moon, an asteroid would have to come at the perfect angle past the Earth but not deviate too much.

The Earth provides hardly any physical shielding at all, being only a couple of degrees wide in the lunar sky (perhaps a bit more back then, as the Moon and Earth were closer). Indeed, the Earth may even gravitationally focus meteoroids, slightly increasing the bombardment from that side.

I'm not sure if it's clearly established that the Moon was tidally locked during the early bombardments. I've seen conflicting arguments. Obviously, if it was not yet locked, there wasn't even a lunar nearside to be affected by the Earth one way or the other.

But why did the volcanism stop if it was happening a billion or so years ago?

The Moon cooled down. Internal heat sources became deeper, so tectonic activity was reduced or ceased completely.

by **Chris Peterson** » Tue Mar 20, 2012 1:42 pm

agulesin wrote:If "the Moon we know and love is as dark as coal", then how does it reflect the sun's light so well? I thought it was a sort of greyish colour... Having visited a coalmine I know how (non)reflective coal is...

Our eyes and brain stretch the brightest neutral colored object in our field to white or light gray. The only difference between the color of coal and of snow is intensity, not hue. The brightest parts of the Moon reflect about 15%, the same as freshly laid asphalt (which is bright enough that most people would prefer viewing it with sunglasses under the noonday sun). That's a lot of light against the black nighttime sky- which is why we see it as white and light gray.

by **obscurechemist** » Tue Mar 20, 2012 1:39 pm

Obviously the use of "evolution" was not in a biological sense in this instance. It has a variety of uses and your assertion that it trivializes any of Darwin's work is ludicrous.

Ever try to teach evolution to a person who has a preconceived incorrect notion of what it is? This flippant use of the word "evolution" contaminates my students' brains, as well as the national discussion of science in general. I stand by my comment.

by **neufer** » Tue Mar 20, 2012 1:18 pm

Beyond wrote:
Hmm... kinda looks to me like the moon got hit in the face with a Big pizza pie

That's a Mare.

by **geckzilla** » Tue Mar 20, 2012 12:58 pm

obscurechemist wrote:Hey NASA scientists! Just a note from a retired NIH scientist: "history" is not the same as "evolution." Where is the replication? Where are the replicators? Where is the random variation? What were the selection pressures? Please. give me a break. You are perpetuating the misuse of the word "evolution" in the so-called modern press. It has been used repeatedly incorrectly to describe any form of change, including those, like your history of the Moon story, where evolution is not applicable. Your misuse trivializes the profundity of Darwin's insight. Wake up!

Obviously the use of "evolution" was not in a biological sense in this instance. It has a variety of uses and your assertion that it trivializes any of Darwin's work is ludicrous.

by **obscurechemist** » Tue Mar 20, 2012 12:52 pm

Hey NASA scientists! Just a note from a retired NIH scientist: "history" is not the same as "evolution." Where is the replication? Where are the replicators? Where is the random variation? What were the selection pressures? Please. give me a break. You are perpetuating the misuse of the word "evolution" in the so-called modern press. It has been used repeatedly incorrectly to describe any form of change, including those, like your history of the Moon story, where evolution is not applicable. Your misuse trivializes the profundity of Darwin's insight. Wake up!

by **geckzilla** » Tue Mar 20, 2012 12:38 pm

agulesin wrote:If "the Moon we know and love is as dark as coal", then how does it reflect the sun's light so well? I thought it was a sort of greyish colour... Having visited a coalmine I know how (non)reflective coal is...

As dark as coal (is it really?) but not necessarily with the same properties of coal. This is closer, at least for the maria.

by **alphachapmtl** » Tue Mar 20, 2012 12:01 pm

smitty wrote:Presumably, the Earth was subjected to the same "heavy bombardment" as the moon. Is is generally believed that (with some notable exceptions) evidence of this bombardment has been mostly washed away by our oceans, or what?

Yes, erosion and plate tectonics.
Oceanic crust is constantly being subducted and recycled, while continental crust is being constantly crushed, ripped and eroded.
Look at the Age of the Ocean Floor map.
http://www.ngdc.noaa.gov/mgg/image/imag ... -a0001.pdf
http://www.ngdc.noaa.gov/mgg/fliers/96mgg04.html
http://www.earthbyte.org/Resources/Ageg ... hrons.html

by **orin stepanek** » Tue Mar 20, 2012 11:59 am

Actually the sound is for a dramatic effect! If I didn't want the sound; I could turn it off!

by **alphachapmtl** » Tue Mar 20, 2012 11:52 am

I wish they included the Moon's formation, and also Tycho's impact, which may be the biggest recent (108 My) impact.

by **r937** » Tue Mar 20, 2012 11:07 am

Jeebo wrote:And the people who made this short video particularly should know better.

actually, the people who chose to post this stupid video on our beloved APOD should know better

i mean, come on, sound in space? PUHLEASE...

Starship Asterisk*

APOD: Evolution of the Moon (2012 Mar 20)

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