I know you know this, but it’s worth mentioning. Even if light were “pulled” by gravity along the way, that would only change the *frequency* of the light, not its *velocity*.

A lot of YECist arguments, it appears, rely on using arguments that sound plausible, but don’t actually work in the Universe we inhabit.

If I’ve miscalculated, please let me know.

You haven’t — I was just trying to see if the “1.4 billion year” timeframe made any sense, so I didn’t bother working things out at other times. Over 4.5 billion years, your answer looks right.

Of course, we both assume a constant recession speed. Not only is it variable (in a manner that’s difficult to predict without some fairly heavy-duty math), it’s actually been lower in the past (http://www.talkorigins.org/faqs/moonrec.html). We have measurements based on geologic evidence going back over 2 billion years, so it’s safe to say there’s no realistic physical model that predicts lunar contact 1.4 billion years ago.

Mind you, creationists sometimes do find some goofy equation or other to work with (look up “c-decay” on Google for some fun ones), so I suppose this fellow could have found some plausible but wrong way to come up with 240,000 miles in 1.4 billion years. He never actually says how he got his numbers, so I have no way to comment.

http://en.wikipedia.org/wiki/Spaghettification

All praise His noodly appendage!
Ramen

4.5 X 10^9 years* 1.5 inches per year = 6.75 * 10^9 inches
5.625 X 10^8 feet
106,000 miles in 4.5 billion years.
240,000 miles (approximate current distance) ~ 106,000 miles (4.5 billion years of recession) = ~134,000 miles (original distance)

http://en.wikipedia.org/wiki/Roche_limit

Wikipedia gives the Roche Limit for Earth/Moon as 9496 km/5900 miles (assuming the Moon is a rigid body).

This is, of course, taking the current recession rate as accurate, and unchanging, and allowing for some rounding errors.

If I’ve miscalculated, please let me know.

She said “Why is it mad?”

I said had “M eighty one”
She heard “M-A-D 1″

We got it sorted out.

> I *believe* you’re getting the *WRONG* result…

I *believe* you’re getting the result because you are failing to use Intelligent Math (IM) for your calculation. In order to correctly use IM, you need to start with your conclusion (the Moon is 6000 years old), and then derive your arithmetic from that fact.

The second “problem” is easily dealt with: the Moon’s recession speed isn’t constant. Even if it were, a ~1.4 billion-year old Moon is just as much a problem for “young Earth creationists” as a ~4 billion year old one.

It’s even worse than that. Even though we know (ask Google, if you must) that the recession speed isn’t constant, let’s assume it is. If you use Mr. Lisle’s figure of “the moon moves about an inch and a half away from the earth every year”, then after 1.4 billion years you have:

1.4×10^9 years * 1.5 inches/year = 2.1×10^9 inches
= 1.75×10^8 feet (divide by 12)
= 33,140 miles (divide by 5280)

Oops. That’s only about 13% the Moon’s current distance. The Moon wouldn’t have been touching the Earth 1.4 billion years ago; it wasn’t anywhere close, even with a constant recession speed. An extra 3 billion years or so wouldn’t be a problem.

Depending on the accuracy of his “about an inch and a half” — in particular, if it’s more like an inch and a quarter — he might have gotten 1.4 billion by dropping a zero in his calculation, with an actual result of 14 billion years. This is something physics students the world around can surely relate to. Given this is a creationist, however, I wouldn’t hold my breath waiting for a retraction.

One final comment about the creationist museum from an article I read in New Humanist magazine. Do they really claim T. Rex had sharp teeth so it could eat coconuts?!?

One thing that really did frustrate me quite a bit while I was there today was that I ran into several teachers that actually taught me in high school. Two of them were science teachers at that, which makes me fearful that maybe they’re implanting this garbage into the local youth. There was also a prayer circle outside praying for the souls of darwinists, skeptics and people who believe in the concept of evolution.

On the other hand, I ran into far more people today than on opening day who were obvious skeptics. One T-shirt inparticular: “Creationism is Hilarious!”

To paraphrase Sheriff Brody (from the movie, “Jaws”) “You’re gonna need a bigger book”

It says the spiral structure would become unrecognisable because the inner regions rotate faster than the outer so the spiral becomes tighter.

The same article claims that at the speed the Moon is receding it would have been touching the Earth 1.4 billion years ago.

As is usual for creationists, they pose a problem without bothering to look for the resolution, which in both cases has been known for a long time (and is usually in the top few search results on Google).

The second “problem” is easily dealt with: the Moon’s recession speed isn’t constant. Even if it were, a ~1.4 billion-year old Moon is just as much a problem for “young Earth creationists” as a ~4 billion year old one.

Spiral arms are a little tougher, because the explanation isn’t widely known outside the astronomical community. Our current understanding is that the arms are density waves, regions of enhanced star formation that don’t revolve at the same speed as the stars and star-forming gas themselves. Since these are star-forming regions, we see lots of bright new stars in the arms — but existing stars actually pass through the waves, meaning that over time, the arms consist of entirely different stars. There are several variants on this basic idea, but the end result is the same: the arms’ dynamics are different from the stellar dynamics, and there’s no contradiction. Wikipedia has a good summary (under “spiral galaxy”), and there are plenty of links elsewhere.

[Last time I tried to do links here I got the syntax wrong and my whole comment ended up as a link and I can't edit it!]

It says the spiral structure would become unrecognisable because the inner regions rotate faster than the outer so the spiral becomes tighter.

The same article claims that at the speed the Moon is receding it would have been touching the Earth 1.4 billion years ago.

I can’t do the maths for this, perhaps I should ask on the baut forum!

Carolyn— Not treally directed to you, but since you brought it up… Galaxies’ spiral arms being too tightly wound up would cause them to lose their spiral structure? What are they thinking? I mean, what in the world does that even MEAN? Are we supposed to go, “Oh, that’s right, then” and not realize such a thing makes less sense than an old universe?

CloudFrog – maybe not so off-topic. There’s a link from the Kentucky Museum website to Answers in Genesis which has a pdf “What Does the Bible Say About Astronomy?” which says that spiral galaxies cannot be more than a few thousand years old, because if they were they would have lost their spiral structure due to the arms being too tightly wound up.

I’ve been re-reading Goldsmith, The Astronomers, lately. Last summer’s reading included Overbye, Lonely Hearts of the Cosmos. Along with posts like this one from BA, I swing between being amazed by it all, or overwhelmed.

Rowsdower: I was actually going to add a bit about the background galaxies, but decided not to since it took away from the point I was making. If you go to the links provided in the post, you’ll see some great images of more distant galaxies in the image. There’s a spiral sitting next to an edge-on spiral (or maybe an irregular, hard to tell) and it looks like a lollipop!

Phil -

I know you’re busy unpacking and all, but when you get a chance, could you see if my address has somehow been blacklisted on the blog when coming from a Windows system? That post I just made is the first one that’s gone through in over two weeks. I did that one (and this one) from my Linux system using Firefox.Every other attempt has simply vanished into the ether. There’s no error message, the post just doesn’t show up. If I try to send it a second time, I get the “You already said that” message.

TIA,

- Jack

- Jack