Date: Fri, 31 May 2013 18:58:58 -0400
From: mark <whitroth at 5-cent.us>
To: undisclosed-recipients:;
Subject: [WSFA] An answer to a lunar mystery: Why is the =?UTF-8?B?bW9vbuKAmXMgZw==? =?UTF-8?B?cmF2aXR5IHNvIHVuZXZlbj8=?=
Reply-To: WSFA members <WSFAlist at KeithLynch.net>

Excerpt:
Ever since the first satellites were sent to the moon to scout landing
sites for Apollo astronauts, scientists have noticed a peculiar
phenomenon: As these probes orbited the moon, passing over certain crater=
s
and impact basins, they periodically veered off course, plummeting toward=

the lunar surface before pulling back up.

As it turns out, the cause of such bumpy orbits was the moon itself: Over=

the years, scientists have observed that its gravity is stronger in some
regions than others, creating a =C3=A2=C2=80=C2=9Clumpy=C3=A2=C2=80=C2=9D=
 gravitational field. In
particular, a handful of impact basins exhibit unexpectedly strong
gravitational pull. Scientists have suspected that the explanation has to=

do with an excess distribution of mass below the lunar surface, and have
dubbed these regions mass concentrations, or "mascons."

Exactly how these mascons came to be has remained a mystery - until now.

Using high-resolution gravity data from NASA's Gravity Recovery and
Interior Laboratory (GRAIL) mission, researchers at MIT and Purdue
University have mapped the structure of several lunar mascons and found
that their gravitational fields resemble a bull's-eye pattern: a center o=
f
strong, or positive, gravity surrounded by alternating rings of negative
and positive gravity.
--- end excerpt ---

<http://web.mit.edu/newsoffice/2013/an-answer-to-why-lunar-gravity-is-so-=
uneven-0530.html>

      mark