Comments on: Maps, maps, maps

By: The blog of whall » Captains Courageous

The blog of whall » Captains Courageous — Tue, 23 Jun 2009 22:52:22 +0000

[...] on a decent sized property out where the country meets civilzation, and we’re used to lots of creatures coming across [...]

By: Janna

Janna — Thu, 19 Jun 2008 22:16:24 +0000

There's got to be SOME way a good stalker could make use of this... Jannas last blog post..Note to self: Behave Suspiciously

By: Toben

Toben — Wed, 03 Oct 2007 05:51:58 +0000

To go back to your original posting, you commented that you didn’t understand how the google maps photo showed the shadows going north while the MSN Live shadows show “correctly” to the “west.” First, just to be precise, the MSN Live shadows are to the northwest not the west and the google maps shadows are most accurately described as in-between NNE and NE. Second, the explanation as to the difference is simple: the earth’s fixed 23.5 degree tilt which, especially in winter, causes the sun to be south of us in the sky. Thus from sunrise to sunset shadows will extend from extreme WNW to extreme ENE, respectively, never quite reaching due west or east because of the spherical curvature of the earth’s surface. So the MSN Live image was taken, as you stated, in the mid-morning sometime when the shadows would be extending to the NW. The google maps image was taken sometime in the early afternoon when the shadows would have just passed due north and into the NNE direction.

By: Cheldear

Cheldear — Mon, 17 Sep 2007 13:17:10 +0000

I looked at my house when you posted this, but the pic looked really old. It definitely wasn’t recent…

Chelle

By: Ren Maddox

Ren Maddox — Sat, 15 Sep 2007 12:21:07 +0000

Probably not very satisfying, but here you go:

http://hubblesite.org/newscenter/archive/releases/solar%20system/planetary%20moon/1999/14/image/c/

Note that it says that the HST “can resolve features as small as 280 feet across”, which matches up pretty well with the Pluto comparison.

By: whall

whall — Sat, 15 Sep 2007 11:31:37 +0000

Ren, yup, that’s where I went wrong – 745 x 2 is 1.5, didn’t you know that?

So where are all the closeups of the moon? Even something like 400′ across? I wanna see what we can see! I think it’s being hidden from us.

By: Ren

Ren — Sat, 15 Sep 2007 03:14:33 +0000

I said, “So even at maximum distance, the apparent size of Pluto is over 19 times as large as a 20-foot diameter object on the moon.”

Put another way, an object on the moon would need a diameter of about 385 feet to appear the same size from Earth as Pluto does.

By: Ren

Ren — Sat, 15 Sep 2007 03:04:18 +0000

I had to re-read your comment several times before I understood your conclusion. It looks like your mistake was when you said, “Pluto has a mean radius of 745 miles, meaning it should look 1.5 miles across (diameter) if we look right at it.” I don’t know how you went from 745 mile radius to 1.5 mile diameter (instead of 1500 mile diameter).

By: Ren

Ren — Sat, 15 Sep 2007 02:58:07 +0000

Perceived size varies linearly with distance.

Diameter of arbitrary man-made object on the moon: 20 ft.
Average distance from Earth to the moon: 238857 mi.
Diameter of Pluto: 1380 mi. (7,286,400 ft)
Minimum distance from Earth to Pluto: ~ 2,500,000,000 mi.
Maximum distance form Earth to Pluto: ~ 4,500,000,000 mi.

Ratio for arbitrary man-made object: .000084 ft/mi
Ratio for Pluto at minimum distance: .002915 ft/mi
Ratio for Pluto at maximum distance: .001619 ft/mi

So even at maximum distance, the apparent size of Pluto is over 19 times as large as a 20-foot diameter object on the moon.

Does that help?

By: whall

whall — Fri, 14 Sep 2007 21:43:23 +0000

btw, I fully expect that this blog entry and my google searches and the comments have been categorized and scanned by the men in black, and something might coincidentally happen to me on the way home.

Keep the faith.