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Meteorites on Ice

Meteorite collection in Antarctica (Image: NASA)

Left: map of Antarctica, where the highlighted area is blown up in a big map showing Transantarctic Mountain range and the ice fields where meteorites have been found. Image: NASA. Right: Sketch showing how meteorites falling on the ice get transported and concentrated next to mountain ranges. Image: NASA.

Although not exactly Moon focused, I hope that this story is of interest to Moon Zoo Forum members as this is the way many lunar meteorites are found here on Earth (see previous Moon Zoo blog ).This past winter (2011-2012) I was lucky enough to join the Antarctic Search for Meteorites (ANSMET) team to hunt for meteorites in Antarctica. The ANSMET programme, funded by NASA and the US National Science Foundation and run between Case Western Reserve University, NASA JSC and the Smithsonian, has been running since 1976 exploring the ice of Antarctica for meteorites. So far about 20,000 meteorites have been collected and made available to the scientific community to study to understand planetary processes. Most of these meteorites originate from the asteroid belt, but some very rare ones have come from Mars and the Moon.Why Antarctica? The team collects meteorites in Antarctica because they are well preserved in the cold dry icy environment. They are also easy to spot as dark rocks on the white ice. Most meteorites are found in icefields close to the Transantarctic Mountain range – you can see a map where all the yellow labels mark places that meteorites have been collected. These localities are really great for concentrating lots meteorites that have travelled from the South Pole ice plateau, and are brought up to the ice sheet surface near mountain ranges

Arriving and life on the ice: Images: Antarctic Search for Meteorites Program / Katie Joy.

Arriving and life on the ice: Images: Antarctic Search for Meteorites Program / Katie Joy.

How do we get to Antarctica and what is life like on the ice? Our team of six guys and two girls flew to Christchurch, New Zealand, and then were flown down to the US McMurdo base in Antarctica. We spent a week or so in McMurdo preparing for our expedition. We packed up our gear and selected food supplies to last us for six weeks camping on the ice. When we were trained and prepared we flewout to the Transantarctic Mountains on a military Hercules plane with skis and then a smaller Twin Otter plane. We set up camp in the Miller Range – a stunning area with mountains and glaciers. Our camp consisted of four tents, where we lived two people to a tent, and a tent with a toilet (a glamorous bucket!) and one that we used to all gather in the evenings (the party tent). Temperatures varied from about -10°C down to -30°C outside, but when the wind was blowing from the South Pole plateau, it felt a lot colder! You have to wrap up in many layers to stay warm – I typically wore four layers on my legs and between five and seven on top, including my big orange down jacket. I also wore a full face mask to protect my face and eyes from the cold and glare from the sun.

Collecting meteorites on the ice (the meteorite are the brown/black rocks we are all gathered around!): Images: Antarctic Search for Meteorites Program / Katie Joy.

Collecting meteorites on the ice (the meteorite are the brown/black rocks we are all gathered around!): Images: Antarctic Search for Meteorites Program / Katie Joy.

How does meteorite hunting work? We had a surprisingly large amount of snow during our field season – which is rather unusual for Antarctica as it is supposed to be a cold dry desert. The snow caused us lots of problems trying to find the meteorites, so we spent a lot of time stuck in our tents rather than looking for meteorites. When the weather was good enough to allow us to look we would get on our snowmobiles (skidoos) and drive out to a new area of ice. We lined up and drove up and down in straight line formation with about ten metres between each team member. When someone spotted a black rock on the ice they would jump off their skidoo, check it was a meteorite, and then wave their arms madly in the air to call the other people over to come and help collect it. We photographed the meteorite, logged its location and carefully put it into a special collection bag ready to send back to NASA. Sometimes we would walk across the ice to search, and other times we would look in rocky areas called moraines to see if we could spot a meteorite. It was a frustrating process when you didn’t find a meteorite, but great fun and satisfying when you did. Our team found 302 stones this year, which considering the bad weather, wasn’t a bad total at all. In fact we were lucky enough to collect the 20,000th sample ANSMET have collected, which was cause for a big celebration.

The samples are all now back at NASA Johnson Space Center ready to be classified and studied by scientists all over the world. Initial identification of the meteorites was recently announced at http://curator.jsc.nasa.gov/antmet/amn/amn.cfm#352 and the meteorites our team collected have been given the name Miller Range 11XXX as they were collected in the 2011 ANSMET season. So far (the curation staff are still working hard to classify all the samples!) it doesn’t look like we found any lunars or martian meteorites this year, but did find a large Howardite and several Diogenite meteorites, which may have originated from the asteroid Vesta.

ANSMET will be taking place this year, the team sets off to the ice at the beginning of December 2012, and you can follow the blog charting the expedition via http://geology.cwru.edu/~ansmet/

More information about the ANSMET programme can be found at http://curator.jsc.nasa.gov/antmet/program.cfm and http://geology.cwru.edu/~ansmet/

This is modified from a blog that first appeared on http://earthandsolarsystem.wordpress.com/2012/07/30/meteorites-on-ice/

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Notched Cavities or INA-like?

User placidstorm posted some Ina-like formations in the Dark Halo Craters thread in December 2011.

I think these look more like “notched cavities” than INA-like formations – see end of posting for references to these features.
These cavities appear to be associated with lava which covers a lava tube or rille, part of which later collapses leaving depressions. I don’t know if that’s what has happened here but this whole region is full of interesting features.

The LPOD Lunar Photo of the Day for 10 August 2007 mentions this area:

Quote from: lpod

A feature, previously unknown to me, is the degraded linear rille segment that extends westward from between Arago Beta and Manners. A similar short but more subtle rille is nearly perpendicular to the Sosigenes Rilles between Beta and Sosigenes A. These two rilles must relate to structures that are now covered by the Tranquillitatis lavas – perhaps whatever is under Lamont. Linear collapse troughs just north of Sosigenes A is evidence for a buried lava tube, another feature from the past of this mare area.


An overview of the features that placidstorm found. This area is in Mare Tranquillitatis north of Sosigenes A crater at approximate coordinates, latitude = 8.1 longitude = 19.0.
Left image: M177508146LE  Right image: M177508146RE


Closeup of one of the “bays”.

The image below gives some context to this feature – the area inside the orange oval is the approximate site of the images above. It shows that there is a rille running underneath the feature and this could help explain how the “notched cavities” were formed. The “feature” crossing the rille is a secondary crater chain.
The Lunar Networks article referenced below the image is well worth a read but does contain a mistake where it refers to “linear rille system in the northeast Mare Tranquillitatis” it should say “southwest”.


Full two kilometer width segment of LROC NAC frame M146858595LE as shown on Lunar Networks 16 Sep 2011
[NASA/GSFC/Arizona State University]

More information about INA features will be found here: TLP Project – INA-like Features and here: INA Images
“Notched Cavities” are discussed here: TLP Project – Notched Cavities in Lava


Strange Whites

Forum member Ewan, otherwise known as Dynamo Duck, found some strange looking craters on the South-East edge of Mare Crisium at Latitude: 12.275° Longitude: 62.1034°. They appear to have unusually high albedo floors and possibly some ejecta of the same high albedo material.

Searching around the area I found some more of these “strange whites.”

Here are two.
And closer…

And then they were everywhere.

At the moment they remain a puzzle. They look like bench/concentric craters but why are the floors so “white”? What is this high albedo material and why are there so many of these craters in this region of Mare Crisium?

While we work out the answers here are some NACs for you to peruse showing the “strange whites” under different illumination.

M137136039RE
M119449091RE
M144212439LE


New Moon Zoo Scientist Position Available

Moon Zoo Science Position Advertised

Dear all

Since it’s launch, Moon Zoo has been an enormous success, with 76,960 people contributing more than 2,858,389 classifications of craters (as of last night!). What we haven’t done, yet, is turn those clicks into results which we can share with the rest of the scientific community. As I noted on my blog from the recent American Astronomical Society conference, that’s the real test of any citizen science project.

An early look at the data looks extremely promising, and I’m pleased to say we’ve just taken two major steps towards that goal. Firstly, thanks to the sterling efforts of Ian Crawford at UCL we’ve obtained funding from The Leverhulme Trust for a three-year postdoctoral position working exclusively on Moon Zoo science. This sort of effort is exactly what we need, and we’ve already got a job ad. out looking for the right person. Having someone working on Moon Zoo full time will also help us investigate some of the weird and wonderful terrains and images uncovered by the Moon Zoo forum.

Secondly, the first paper from Moon Zoo’s sister site, the Milky Way Project, is nearly accepted. As the Milky Way Project uses a modified version of the Moon Zoo interface, the techniques we used there to combine classifications should be easily adapted to the larger Moon Zoo dataset. For example, we have to account for inevitable problems caused by adopting a particular tool – for example, the tendency of classifiers to repeatedly mark craters at the smallest allowed size – but we can do this through careful database manipulation.

We’re tentatively targeting having early results to share by April, and we’ll keep you informed by the blog.

Chris

P.S. Pamela Gay and Stuart Robbins, who had been working with us on Moon Zoo have decided to launch their own, competing, project. Pamela in particular has put a lot of time into the Zooniverse over the last few years, and we’re grateful for her help. Competition in science is usually a good thing, and I hope we’ll see papers from both groups before too long.

The Moonometer (TM) Challenge!

Join in the Moonometer (TM) challenge! We need you to classify 25,000 images between now and Monday to celebrate International Observe the Moon Night. Just go to Moon Zoo and start clicking!

One Year of the Moon in 2.5 minutes

A recent discussion started by our science lead, AstroStu, about photographing the Moon for an entire lunar month, lead me to wonder how this would look as an animation; showing the full cycle of lunar nutation and libration. Also, last month we celebrated our first year of Moon Zoo.

With these two things in mind I found something which I find topical in respect of both lunar cycles and 365 days of the Moon. The following link will take you an animation created by the Goddard Space Flight Center Scientific Visualization Studio. It uses data from the LRO to show ‘One Year of the Moon in 2.5 Minutes’.
As you will read in the accompanying text, the Lunar Orbiter Laser Altimeter (LOLA) has already taken more than 10 times as many elevation measurements as all previous missions combined, thus giving us the global elevation map and the dramatic shadows seen in this animation.

Here is the link to the official NASA page.

I recommend full screen and some moody music for this one.

Enjoy,

Thomas


Thomas J is a volunteer moderator for the Moon Zoo forum

Mapping the Moon – John Russell’s Selenographia

On a recent trip to London I just had time to visit the “Out of this World” Science Fiction Exhibition in the British Library and was surprised to see one of my favourite objects displayed there – the Selenographia by English artist John Russell. It’s a globe of the Moon (and Earth) he produced in 1797, the culmination of 30 years work mapping the lunar surface with a small but powerful refractor given to him as a gift by his grateful portrait sitters.

The Selenographia (excuse the poor quality photo – hand held with no flash on a mobile phone. I saw it and just had to have a photo!)

Here’s one of John Russell’s pastels of the full Moon:

Science Photo Library

More of his beautiful lunar drawings can be found here.

This is what the National Maritime Museum says about John Russell and his Selenographia.

“John Russell’s Selenographia consists of a large lunar sphere and a small terrestrial sphere. It is constructed to reproduce the librations, or motions, of the Moon with respect to the Earth. Only one side is illustrated, the other is blank, since only one side of the Moon is visible from Earth. Russell (1745-1806) spent 30 years perfecting his map of the Moon, producing detailed drawings and inventing the Selenographia. He probably did not make the globes himself and the Selenographia was offered for sale with various stands.

Both the lunar and terrestrial spheres are made of papier mache covered with plaster and twelve full gores that are engraved, hand-coloured and varnished. The lunar sphere is mounted on a heavy brass hemisphere with parts cut away so that the resulting structure consists of one great circle oriented vertically, a concave circular disc centred on the pole and four circular arcs. The terrestrial globe is inclined at 66.5 degrees to the ecliptic and supported by a quarter circle rising from beneath the lunar globe. A number of different mechanisms represent the various relative motions of the Moon and the Earth. The whole is supported by a single-stem pedestal brass stand.

On the lunar sphere, two great circles, the lunar equator, and the lunar prime meridian, are drawn, but these are not graduated. The craters, the seas and the mountains are delicately drawn but no nomenclature is provided. The main craters are marked by a cross. The terrestrial sphere bears a simple outline of the continents and labels five oceans Tasmania is still drawn as a peninsula.”

From the Selenographia to the Lunar Reconnaissance Orbiter. Don’t you just love serendipity?


Jules is a volunteer moderator for the Moon Zoo forum

Let the voting begin…

Last week Moon Zoo moderator Thomas presented us with a superb selection of images from the first year of Moon Zoo. Now it’s time to vote for your favourite. Browse the images below to remind yourself and pick out the one you like the most. Pop over to the forum and cast your vote. You’ll need to create a zooniverse account if you don’t already have one – it’s the work of a moment so go on, do it! Voting ends Tuesday 24 May. The winning picture will be announced soon after and we’ll hunt down the best resolution version we can find so you can have a nice new desktop image!

MAY 2010 INA

JUNE 2010 CARO’S TADPOLE

JULY 2010 GREAT FRESH WHITE

AUGUST 2010 FRACTURES

SEPTEMBER 2010 MOON BRIDGES

OCTOBER 2010 ARISTARCHUS

NOVEMBER 2010 AWESOME CRATER

DECEMBER 2010 DAGUERRE CRATER

JANUARY 2011 SOUTH RAY CRATER

FEBRUARY 2011 STRIPY BOULDERS

MARCH 2011 TYCHO

APRIL 2011 CAVES


Jules is a volunteer moderator for the Moon Zoo forum

The Mystery at Milichius-A Crater

It started off as a normal enough Friday. I checked the Moon Zoo forum and did a little Boulder Wars. Then I received a PM from new forum member Astrospade with a link to a rather interesting picture s/he had found. I went to have a look and as the afternoon quietly slid towards the weekend the Moon Zoo community suddenly sprang into action.

Astrospade had noticed something interesting on a NAC image featured on the NASA mission site. The object in question is on NAC strip M102365048LE just to the right of Milichius A crater and it looked for all the world like a space probe.

This is the site Astrospade looked at with no mention of the “probe” in the main text. A couple of comments below the article are from people who had spotted the same feature but no-one got back to them and the comments feature now appear to be closed. Astrospade had also contacted the coordinator for the Lunar Reconnaissance Orbiter site but got no response.

I was intrigued enough to have a closer look. The blue rectangle on the small reference strip shows the position of the object.

An arrow points to a long thin shadow appearing to come from a tall structure next to a small white topped feature better seen in the enlarged section in the inset. With an incidence angle of 76.02 degrees all the surface features will cast very long shadows anyway but this particular long thin shadow looked different, very antenna-like and the white topped feature didn’t look very much like a rock! Unfortunately there are no further NAC images under different illumination to shed more light on the mystery ( :) ) and my observation request was denied as a similar request had already been submitted.

Milichius A is 10 degrees North and 30.2 West in Oceanus Procellarum region – just west of Kepler Crater.

The only thing we could find that came close was Luna 7 which crashed at 9.8°N 47.8°W. The difference in longitude amounts to around 546km. Was this too far for Luna 7 to scatter, bounce or spread? Could it even have broken up when hurtling towards the lunar surface with bits landing relatively softly away from the main crash site? Could the white object in the NAC image be the remains of the basket-like end of the Luna probe rather than a photographic artefact?

Luna 7
.

Tom 128 took up the story and found this quote from Soviet and Russian Lunar Exploration by Brian Harvey:

” On the third day, two hours before landing and 8,500 km out, the Luna 7 oriented itself for landing. Unlike Luna 5, it was on course for its intended landing area near the crater Kepler in the Ocean of Storms. As it did so, the sensors lost their lock on Earth and, without a confirmed sensor lock, the engine could not fire. This was the second time, after Luna 4, that the astro-navigation system had failed. Ground controllers watched helplessly as Luna 7 crashed at great speed.”

Perhaps we should have heeded those last words “…..crashed at great speed.”

Tom128 also enhanced the image further. He said “My thought is that what we now see is the craft/wreckage with main body upside down and this rod pointing upward.”

.

Members of the Moon Zoo team initially thought it worthy of a closer look but then the Voices of Reason stepped in. Chris Lintott reminded us that our object was at the wrong western longitude to be Luna 7 and Phil Stooke champion of locating spacecraft debris on LRO images advised that although the shadow did look unusual it was likely to be nothing more than the type of linear shadow he had seen many times before of an appropriately placed and shaped rock near the terminator. And he quite rightly stressed that it is known that Luna 7 crashed which means we shoud be looking out for a small crater rather than spacecraft debris.

So were we just seeing what we wanted to see or is there really something there? Another view with overhead illumination would certainly help. But until then the speculation will continue. The full forum thread is here.


Jules is a volunteer moderator for the Moon Zoo Forum.