citizenschallenge.pm - 05 June 2012 07:47 PM

Coldheart Tucker - 05 June 2012 05:47 PM

No, but given that Schmidt is a highly trained geologist, who has experience with the Moon that no other geologist currently has, I’m inclined to at least give him a listen.  Dismissing his theories on the basis of his political views or for his comments on an area outside of his specialization in science is akin to tossing out communication satellites, because their inventor, Arthur C. Clarke, started babbling, near the end of his life, about seeing NASA photos of Martian lifeforms.

Perhaps, but I’m not sure what the brightest geologist could have observed about Moon collision or orbital changes, not sure I buy the “geologists eyes” bit in this particular instance.

There are other clues to the Moon’s origin besides orbital mechanics.  Remember, on one of the later Apollo missions they found orange soil, which nobody expected to be on the Moon.  (Discovered completely by random chance.  One of the astronauts happened to look down after he moved his foot and spotted the stuff.  I’d like to see a rover do that.)  One of the priorities of training the Apollo astronauts was in geology, because by looking at the surface features, they could identify not only the types of rocks likely to be found in an area, but also how the rocks were formed.  All the crews were put through intensive geological training, because the only way to get a clue about the formation of the Moon and the early solar system was to grab the right kind of rocks.  As a trained geologist, Schmidt could pick up on a subconscious level many things that other people would miss.  Perhaps a different geologist on the Moon would come up with a different answer than Schmidt.  We won’t know until that happens.  The Moon is roughly the size of Africa, and a dozen men have poked around an area about the size of Cape Town for a few days, bringing back a couple hundred pounds of rocks.  That’s not really enough to settle the matter.

Other than that, sorry, and you know as a kid of the 60s and into the Space Program he was one of my heroes but no more, given his dishonest discourses on climatology.
Can’t help it, I’m really up to here, listening to these various “great scientists” utterly misrepresent and misdirect, and commit lies of omission and a few of commission when it come to portraying climatology that I could puke. 

As Harry Harrison once said, “Even God is allowed to nod, a little.”  If you haven’t read A Man on the Moon, I urge you to do so, it goes into the Apollo missions in far greater detail than the mini-series based on it did.  Large sections of the book are focused on geology, how important it was to the missions (and how Alan Shepard nearly blew the geologic component of his mission).  Schmidt was the only non-engineer on an Apollo flight.  Not only did he have to keep up with his geological work, while getting into shape to be an astronaut, but he also had to learn how to fly.  He also lobbied for the ballsiest Apollo mission (namely, landing on the far side of the Moon), but was overridden by the brass at NASA who were concerned about something going wrong.

Coldheart Tucker - 05 June 2012 08:16 PM

  If you haven’t read A Man on the Moon, I urge you to do so, it goes into the Apollo missions in far greater detail than the mini-series based on it did.

I’ll take your suggestion on the book.
And I have no argument with the importance of geologic training and all that.

As for Schmidt, I’ll call a truce.
Besides, it would be more fun to pursue this. . .

citizenschallenge.pm - 05 June 2012 07:38 PM

I’ve never heard that Venus is half as young as the other planets, where did that come from?

I’ve never heard any theory that Venus is the product of a collision, where did that come from?

If Earth had been nudged out of a smaller orbit,
wouldn’t that have added a bit of instability into our orbit that astronomers would have known about and wondered about?

citizenschallenge.pm - 05 June 2012 07:38 PM

Ok you guys have made this an interesting discussion, and I’m only marginally familiar with astronomy and astrophysics but a lot of that article didn’t make sense given what I know.

I’ve never heard that Venus is half as young as the other planets, where did that come from?

I’ve never heard any theory that Venus is the product of a collision, where did that come from?

If Earth had been nudged out of a smaller orbit,
wouldn’t that have added a bit of instability into our orbit that astronomers would have known and wondered about?

I hadn’t heard that either. The thing is, there isn’t enough evidence to show that this venus collision theory is definitely wrong, so I guess it’s worth a publication. I am skeptical.

But, I don’t think that such instability from getting nudged would be around after 3 billion years of orbiting. Things do tend to stabilize.

Coldheart Tucker - 05 June 2012 08:16 PM

  As a trained geologist, Schmidt could pick up on a subconscious level many things that other people would miss. 

I sure hope that he isn’t relying on his subconscious for his geological insights. Intuition is notoriously inaccurate in a scientific sense.

TromboneAndrew - 05 June 2012 09:42 PM

citizenschallenge.pm - 05 June 2012 07:38 PM

Ok you guys have made this an interesting discussion, and I’m only marginally familiar with astronomy and astrophysics but a lot of that article didn’t make sense given what I know.

I’ve never heard that Venus is half as young as the other planets, where did that come from?

I’ve never heard any theory that Venus is the product of a collision, where did that come from?

If Earth had been nudged out of a smaller orbit,
wouldn’t that have added a bit of instability into our orbit that astronomers would have known and wondered about?

I hadn’t heard that either. The thing is, there isn’t enough evidence to show that this venus collision theory is definitely wrong, so I guess it’s worth a publication. I am skeptical.

But, I don’t think that such instability from getting nudged would be around after 3 billion years of orbiting. Things do tend to stabilize.

Maybe I misread the article.  I was thinking of the line: “You have a huge time scale range from 1 billion to 10,000 years ago to work with,” Minton said.”

Coldheart Tucker - 05 June 2012 07:55 PM

macgyver - 05 June 2012 06:58 PM

Coldheart Tucker - 05 June 2012 09:43 AM

The possibility you’re overlooking is that the Earth’s rotation was faster than it is now, and this caused material to be flung off the Earth, forming the Moon.  That was the accepted theory before the collision model was developed, as I recall.

There are, no doubt, other theories as well, that just happens to be the one I can recall off the top of my head.

That does not seem to make sense. The physics doesn’t work. For a body to aggregate in space by the coalescence of smaller bodies the net angular momentum would have to be less than that required to pull the body apart.

In other words you cant propose that there was enough gravity to pull a body together but then propose that it wasn’t strong enough to keep it together.

The only way a body can “fling” material into space once it has formed is if the rate of rotation sped up dramatically after the body formed and the only way this can happen in our neck of the woods would be if another body struck the original body in a glancing manner to increase the rotational rate.

It seems that would lead us back to the collision theory of formation.

The standard model is that the Earth was basically already formed (though considerably much larger than it is today) when Theia kranged into it, skipping off somewhere out into space, while hunks of the Earth and Theia globbed together to form the Moon.  The theory I was talking about has the Moon splitting off much earlier in the Earth’s formation, when it hadn’t begun to take its final shape.  Its rate of rotation was different than it is today, and the material that became the Moon was only loosely aggregated with the material of the Earth.  (As a side note, because of their low gravity most asteroids do not have large hunks of ore inside them, the material is instead, randomly distributed about their interiors, so the guys planning to mine asteroids are going to have to sift through a lot of material to get to the stuff they want.)  There’s a few other theories about the formation of the Moon, but I don’t recall any of the details of them to comment about them.

If you want to be technical about it, everything in the solar system (and the universe, for that matter) owes its existence various objects colliding together.

I’m not going to pretend that I fully understand the science between all the various theories, so don’t take anything I say as gospel on the matter.  The formation of the solar system was a fairly chaotic process and we have yet to fully grasp the necessary physics involved.  As we improve our ability to observe things in the universe with telescopes like Hubble and the James Webb, we can expect to see changes in the theories about planetary formation.  (I can remember when I was a kid the standard theory of solar system formation held that the reason the innermost planets of our solar system were rocky, while the outer planets were gas giants was that the pressure from the solar wind blew the gases away from the inner solar system and that no gas giants could form very close to a star.  We now know that to be incorrect.)

The point about objects aggregating together from smaller ones is true. You seem to be missing two concepts here though.

1) My original comment still stands. Objects with enough gravitational attraction to overcome their individual angular momentum so that they can aggregate together can not then spontaneously come apart unless their mutual gravitational attraction diminished ( not likely unless the universal gravitational constant decreased which is an extraordinary claim for which there is no evidence) or their rate of rotation sped up which can really only happen through a glancing collision.

2) While asteroids can certainly exists as loose aggregates, large planets can not. Asteroids can exist in this form because of their extremely low total gravity which allows individual pieces to remain largely intact and only loosely bound to one another. Larger bodies have much larger gravitational forces which crush and melt the material that they are made of to such a degree that loose aggregates are not possible.

On a side note, the question about gas giants forming close to a star may not be answered in the way you think. From what I have read and from talks I have listened to i believe it is still felt that it is not possible for gas giants to form very close to their parent star. While many gas giant exoplanets have been found close to their star most current theories propose that these planets formed further out and gradually moved inward, but our ideas about planetary formation are obviously going through a truly revolutionary period right now.