Mountain Views News     Logo: MVNews     Saturday, December 12, 2015

MVNews this week:  Page 13



Mountain Views-News Saturday, December 12, 2015 


Dwarf planet Ceres reveals some of its well-kept 
secrets in a study published in the journal Nature, 
thanks to new data from NASA’s Dawn spacecraft. 
They include highly anticipated insights about 
mysterious bright features found all over the 
dwarf planet’s surface and especially in the crater 

 Ceres has more than 130 bright areas, and 
most of them are associated with impact craters. 
Study authors, led by Andreas Nathues at Max 
Planck Institute for Solar System Research, 
Göttingen, Germany, write that the bright 
material is consistent with a type of magnesium 
sulfate called hexahydrite. A different type of 
magnesium sulfate is familiar on Earth as Epsom 

 Nathues and colleagues, using images from 
Dawn’s framing camera, suggest that these 
salt-rich areas were left behind when water-ice 
sublimated in the past. Impacts from asteroids 
would have unearthed the mixture of ice and salt.

 “The global nature of Ceres’ bright spots 
suggests that this world has a subsurface layer that 
contains briny water-ice,” Nathues said.

 The surface of Ceres, whose average diameter is 
584 miles, is generally dark—similar in brightness 
to fresh asphalt. The bright patches that pepper 
the surface represent a large range of brightness, 
with the brightest areas reflecting about 50 
percent of sunlight shining on the area. But there 
has not been unambiguous detection of water ice 
on Ceres; higher-resolution data are needed to 
settle this question.

 The inner portion of the crater called Occator 
contains the brightest material on Ceres. Occator 
itself is 60 miles in diameter, and its central pit, 
covered by this bright material, measures about 
6 miles wide and 0.3 mile deep. Dark streaks, 
possibly fractures, traverse the pit. Remnants of a 
central peak, which was up to 0.3 mile high, can 
also be seen.

 With its sharp rim and walls, and abundant 
terraces and landslide deposits, Occator appears 
to be among the youngest features on Ceres. 
Dawn mission scientists estimate its age to be 
about 78 million years old.

 Study authors write that some views of Occator 
appear to show a diffuse haze near the surface that 
fills the floor of the crater. This may be associated 
with the observations of water vapor at Ceres that 
were reported by the Herschel space observatory 
in 2014. The haze seems to be present in views 
taken at noon local time and absent at dawn 
and dusk. This suggests that the phenomenon 
resembles the activity at the surface of a comet, 
with water vapor lifting tiny particles of dust and 
residual ice. Future data and analysis may test 
this hypothesis and reveal clues about the process 
causing this activity.

 Daytime surface temperatures on Ceres span 
from minus 136 degrees to minus 28 degrees 
Fahrenheit. The maximum temperatures 
were measured in the equatorial region. The 
temperatures at and near the equator are generally 
too high to support ice at the surface for a long 
time, but data from Dawn’s next orbit will reveal 
more details.

 As of this week, Dawn has reached its final 
orbital altitude at Ceres, about 240 miles from the 
surface of the dwarf planet. In mid-December, 
Dawn will begin taking observations from this 
orbit—including images at a resolution of 120 
feet per pixel; infrared, gamma ray and neutron 
spectra; and high-resolution gravity data.


 You can contact Bob Eklund at: b.eklund@




an excerpt from “Extreme Simplicity: Homesteading in the City”

[Nyerges is the author 
of “Extreme Simplicity,” 
“How to Survive 
Anywhere,” “Foraging California,” and other 
books. For information on his classes and books, 
contact him at, or 
Box 41834, Eagle Rock, CA 90041.]

 When we first moved into our home, the front 
yard was ugly – barren and oily. The previous 
residents had used the yard to park their cars, an 
area of about 35 by 15 feet. Just a bit of crabgrass 
grew around the edges. The inner front yard, 
which we called the 
courtyard, was almost as 
barren, though there were 
a few trees there.

 One of our first 
improvements, once we 
had removed bits of old 
metal, wood scraps, logs, 
and and old shack, was 
to very heavily mulch 
the barren yard and the 
neglected courtyard 
areas. Mulch consisted of 
natural materials such as 
wood chips, leaves, grass 
clippings – organic matter 
that can be spread on the 
ground to hold in moisture. 
As the mulch decomposes, 
it helps to increase the soil’s 

 While driving home one 
day, we saw a yard that was 
covered with fall leaves. 
We had our rakes and bags 
with us, so we pulled over 
and knocked on the door.

 “May we rake up your front yard and take the 
leaves with us?” we asked the elderly man who 
came to the door.

 He was silent for a moment, uncertain what we 
had said, or perhaps suspicious of our intentions. 
We repeated the request.

 “We’d like to rake up your yard. We don’t want 
to charge you. We just want the leaves to use for 

 By now, his wife had come to the door and we 
had to repeat the request again. They seemed to 
realize that we were sincere, and agreed. 

 As we raked, they began to laugh at their good 
fortune with sheepish smiles – someone had 
actually knocked on their door requesting to do 
something for free that they usually had to pay 

 “Take all you want!” the man told us, cheerfully 
and loudly.

 We busied ourselves filling up about four large 
trash bags of the yellow leaves, and they watched 
us from their window with large grins. We 
laughed to ourselves too, and wondered if they 
would be telling and re-telling this curious story 
to their friends and grandchildren.

 When we got home, we scattered all those 
leaves around the needy front and courtyard 
areas. We knew that we’d have to add more 
and more organic matter before the soil would 
be fertile enough to grow plants, so we collected 
leaves from other sources as well and spread them 
in our yard.

 Neighbors watched 
our leaf mulch project 

 We contacted an 
acquaintance who runs a 
tree-pruning service. This 
man and his crew prunes 
trees and then chips up 
the prunings, and when 
their truck is full of chips, 
they take it to the local 
landfill and pay to unload 
the chips. In response to 
our invitation, they were 
happy to bring a load to 
our place instead and 
dump it in a huge pile onto 
our front yard.

 The huge pile covered 
most of the front yard, and 
the central peak was nearly 
five feet tall. We knew 
the pile would get smaller 
over time as the chips 
decomposed. In fact, the 
pile had sunk down about 
a foot after the first week, 
and we spread the chips out on each side so we’d 
have a mulch that uniformly covered the entire 

 If you’ve ever been around a big compost 
pile, you know how it generates lots of heat as 
the contents decompose. We noticed our pile 
steaming in about two weeks, and we also watered 
it to help the decomposition process.

 One morning, a neighbor form next door 
yelled, “Your front yard’s on fire!”

 We ran out expecting to see flames somewhere 
but saw only the steaming chip pile. We assured 
our neighbor that everything was fine.

 In two years, after two big truckloads of wood 
chips, we were able to sink our hand down into 
the soil in the front yard, and wild plants had 
begun to grow and thrive. 

get a copy of “Extreme Simplicity: Homesteading in 
the City” wherever quality books are sold.

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