MV Blog

DISPLAYING POSTS FROM: Mar 2014 (6)

Rings around an asteroid

Author
by Tanya
Publish date
31 March 2014
Comments
Comments (0)

In a surprise discovery, two rings have been found around the asteroid Chariklo, making it the first small Solar System body known to have rings.

Saturn is known for its magnificent rings and the other gas giants - Jupiter, Uranus and Neptune - have ring systems too, though not quite as impressive. Careful searches had not found any other ring systems within the Solar System and many astronomers were beginning to think that rings might only exist around large objects, until now.

Rings from Chariklo An artist's impression of the newly discovered rings around Chariklo.
Source: ESO/L. Calçada/Nick Risinger (skysurvey.org)
 

Chariklo is just 250km across and lies beyond Saturn, at a billion kilometres away. It is much too small and far away for the rings themselves to be seen, but amazing detail is now known about them. The rings are dense but narrow, just three and seven kilometres wide, and are separated by a clear gap of nine kilometres. If you were standing on the surface of Chariklo, the rings would appear as wide as our Full Moon and stretch from horizon to horizon.

The discovery was made possible because last June, Chariklo passed in front of an obscure star (UCAC4 248-108672). Not only did Chariklo block the star's light for 5 seconds, but two tiny dips in the starlight were seen, just before and after Chariklo moved by. This video from the European Southern Observatory (ESO) shows faint dimming caused by the rings, just before and after Chariklo blocks the star completely.

 

This event, known as an occultation, could only be seen from South America and an observing campaign was coordinated across seven observatories, including two telescopes operated by the ESO at La Silla, Chile. Having observations from all seven observatories, ruled out other possible explanations, except for a ring system.

What I really love is the data from the new high-resolution camera on ESO's 1.54m Danish telescope. (Anyone who has been to my Discover the Night Sky series knows that I am particularly fond of beautiful graphs!) This new camera was developed to search for exoplanets and can take up to 40 images per second. It was actually able to see the gap between the two rings – now that's beautiful science!

Chariklo Data The data captured by ESO's 1.54m Danish telescope, showing Chariklo blocking out the light of the star (the main dip). On either side are two small, double dips, as the rings also passed in front of the star.
Image: F. Braga-Ribas et al.
Source: Reprinted by permission from Macmillan Publishers Ltd: Nature (March, 2014)
 

The Planetarium's astronomer, Dr Tanya Hill, was recently appointed the Australian representative of the European Southern Observatory's Science Outreach Network.

Links:

Rehydrating specimens

Author
by Kate C
Publish date
25 March 2014
Comments
Comments (1)

Recent workshops brought together natural sciences collection managers and conservators from far and wide to learn techniques for preserving wet specimens – those preserved in fluids like ethanol and formalin.

Fluid preservation workshops Fluid preservation workshops underway at Melbourne Museum's conservation lab.
Source: Museum Victoria
 

The workshops, hosted at Melbourne Museum, were supported by the Australian Institute for Conservation of Cultural Material (AICCM) and taught by UK natural history conservator Simon Moore. Dani Measday, MV's Natural Sciences Conservator, says "you can’t learn easily natural sciences conservation in Australia, so people are really jumping on the chance to build skills in that area." With participants from Canberra, Sydney, Brisbane and even New Zealand, it was also a rare opportunity to meet others working in the field. “Museum people love to talk shop," says Dani, who toured the visitors around MV's collection stores. "There was definitely a lot of discussion about what people were doing in their museums. It's great to build up a network of people you can call on when you get stuck.”

Over four days, the workshops addressed some of the major problems of wet collections, one of which is dehydration as the preserving fluid evaporates. “The ones that were really dehydrated tended to come out of jars with rubber gaskets in the lids, which can perish quite quickly," says Dani. "Or they can get twisted and end up with a really poor seal.” A highlight of the workshop was seeing dehydrated specimens returned to full size under Simon's guidance.

Workshop participants cleaning Workshop participants cleaning perished rubber gaskets from mammal specimens.
Source: Museum Victoria
 

During the workshop, Dani worked on a juvenile koala specimen affectionately nicknamed Drinky Bill. This koala was originally collected from French Island and came to the museum in 1957 via the Healesville Sanctuary. In the intervening years, poor Bill lost all of his alcohol and was a dry fist-sized husk rattling around an empty jar.

The process of rehydration, explains Dani, begins with placing the specimen in warm water with a surfactant. "It's basically a detergent to break down surface tension to help water penetrate into the specimen." The cells expand as they take in water, and the specimen returns to its original shape and weight over several hours.

 

Next, the specimen is re-fixed in formalin to stop the decay. Then it's back to ethanol in a series of baths of increasing strengths. "You need to move it through several different concentrations of ethanol gradually. If you go straight from water, it's a big change in pressure for the specimen." Dani's koala spent a few hours in each of 10, 30 and 60 per cent before the end point of 70 per cent. To remove any air bubbles and to make sure the koala was submerged, Dani used a vacuum chamber conveniently housed next door in the preparation department. "The preparators use it to remove bubbles when they’re casting in resin."

Koala specimen before (left) and after (right) rehydration treatment. Koala specimen before (left) and after (right) rehydration treatment.
Source: Museum Victoria
 

The resulting transformation is amazing. At the workshop's conclusion, some specimens in very poor condition were returned to near original state. Restoring the animal's natural size is particularly useful, as skins and skeletons can't tell us this information. It leads to some truly amazing applications; Senior Curator of Mammals Kevin Rowe says a researcher recently contacted him to find out the dimensions of a bandicoot. "He was designing radio tracking vests for bandicoots which don’t have necks suitable for collars. The best way to figure out the dimensions of a bandicoot is to look at a fluid specimen." This is because wet specimens "preserve internal soft tissue better than skins and skeletons. They also preserve the anatomical features of sperm, stomach contents, parasites–essentially everything in and on a specimen." 

Gravity waves, cosmic inflation and the multiverse

Author
by Tanya
Publish date
20 March 2014
Comments
Comments (2)

Scientists have been whipping up a frenzy this week, following the announcement of a truly mind-boggling discovery last Monday. Astronomers from the Harvard-Smithsonian Centre for Astrophysics (USA) have captured the signature of gravity waves from the early Universe. Now, just like the Higgs Boson announcement from 2012, this one takes a bit of time to wrap your head around, but the consequences are out of this world.

Gravity waves from after the Big Bang The twisting pattern shown here represents the first direct image of gravity waves from cosmic inflation, in the moments just after the Big Bang.
Source: EPA/Harvard University
 

Firstly, this discovery provides the first evidence for gravity waves, a phenomenon that scientists have been searching for over many decades. Gravity waves are tiny ripples in the fabric of spacetime and they were predicted by Einstein's General Theory of Relativity. This theory has now survived every test that could be thrown at it. Even the bizarre notion of time ticking at different rates, depending on gravity and speed, is put into practical use every time we use a GPS to find where we are.

Finding gravity waves could open up a whole new window on the world around us. We are used to looking at the world using light, which are electromagnetic waves. But gravity waves hold just as great a potential. They could be used to see inside a neutron star, to watch a star collapse within a supernova or to examine two black holes colliding. They could even reveal new physics ideas and make it possible to pick up the vibrations of cosmic strings or determine the number of dimensions of the Universe.

Colliding black holes In this artist's impression, two black holes are entwined in a gravitational tango that will eventually collapse the pair into a single black hole.
Source: NASA
 

Secondly, the discovery provides the best proof of cosmic inflation – the idea that within a fraction of a second after the Big Bang, the Universe went through a period of rapid expansion. Picture a child blowing bubbles, but in this case, the Universe grew from absolutely miniscule to larger than the observable Universe in the blink of an eye.

Only cosmic inflation predicts the rise of gravity waves in the early Universe. And now that the theory has passed this test, other predictions of inflation may well hold true; such as spacetime being infinite and that the multiverse concept is real. We are one step closer to the possibility that there exists an infinite number of Universes, separate to ours, that are continually erupting, just like ours did, out of some sort of ever inflating "sea".

Links:

How the detection was made: First hints of gravitational waves in the Big Bang's afterglow by Krzysztof Bolejko (University of Sydney) and Alan Duffy (University of Melbourne), in The Conversation

Taxidermy conservation workshop

Author
by Kate C
Publish date
18 March 2014
Comments
Comments (2)

It’s clear that the old penguin specimen needs a lot of work. Age or accident has detached the bird’s head from its body, and preparator Steven Sparrey is carefully working PVA glue into the break in the neck. This will consolidate the edge and provide a sound surface for reattachment. Eventually, preened feathers will conceal the join and the penguin will be whole again.

Damaged taxidermied penguin Detail of damaged taxidermied penguin specimen.
Source: Museum Victoria
 

We’re at a workshop for people in the business of preserving natural history specimens – collection managers, preparators and conservators – led by visiting UK expert Simon Moore. The museum’s conservation laboratory is busy with people transforming elderly and damaged collection objects into exhibition-ready specimens, using specialist techniques that are very rarely taught in this country.

Taxidermy workshop Taxidermy conservation workshop in the conservation lab at Melbourne Museum.
Source: Museum Victoria
 

Sometimes the damage occurs from wear and tear, especially where specimens have done time in the museum’s interpretive collection. Other times it’s inadequate preparation at time of taxidermy – overstuffed specimens tend to split as the skin shrinks with age. Simon explains, “many of the specimens are decades old, and materials just become more brittle with time. “A small bump when handling can have drastic results on a fragile specimen, and the head is often the first to go.
We turn back to Steven’s penguin. “The skin on birds in particular is very thin and vulnerable to tearing,” says Simon. “In this case, the neck was overstuffed. As the skin dries out and retracts back onto the underlying material, it starts to split.” 

The penguin also needs a wing reattached, so Steven drills a fine hole for a galvanised steel rod to hold the wing on a natural angle. Next to him, Michael Pennell is finishing work on a mounted Regent Bowerbird, freshly reunited with its tail and perch. “He’s a little bit cleaner than he was this morning and I’ve filled a few little holes and splits.”

Man and bird specimen Preparator Michael Pennell working on a Regent Bowerbird mount.
Source: Museum Victoria
 

Elsewhere in the room, people are creating supporting armature for rabbit ears, cleaning feathers and mending tears in batwings with Japanese tissue. This tissue, says conservator Dani Measday, has unusually long fibres and resists tearing. “It means that it’s really strong and you can do all kinds of things with it. We use it to repair paper and books , but you can use it as fill, to strengthen and replicate fibres , or as a consolidating surface. What we’re doing with it here is making replacement skin. With adhesive, it has a tightness and tautness just like skin.”

repair to bat specimen Careful repairs to a bat specimen using Japanese tissue.
Source: Museum Victoria
 

Karen Roberts and Brendon Taylor are restoring tiny bat specimens. It's painstaking work; they have pinned out the fragile wing membranes and patched the holes with Japanese tissue. The purpose of the specimen dictates the treatment from here. “A scientific collection item can have warts and all, with minimal intervention,” says Simon. “Here we could put a gentle lacquer to hide the tissue, but obviously for display you’ve got to colour them in.” The extent of treatment for exhibition work can be deceptive, as the conservation treatments aim to draw the eye away from repairs so the specimen can be read as a whole.

Two men with penguin specimen L-R: Preparator Dean Smith with Simon Moore, looking at a damaged King Penguin mount.
Source: Museum Victoria
 

Simon’s own knowledge comes from decades of experimentation and consulting with natural history collections around the globe. “I’ve learned lots myself throughout the years and I’m trying to advance the technology, giving credit where it’s due. There aren’t many people doing taxidermy conservation and they keep trade secrets.” The techniques that Simon shares in workshops like this will help keep scientific and display specimens in good nick for study, research and exhibitions in years to come.

Great Melbourne Telescope volunteers

Author
by Kate C
Publish date
13 March 2014
Comments
Comments (1)

Each Wednesday, a dozen or so engineering and astronomy buffs head to a museum workshop to restore one of Marvellous Melbourne's grandest marvels. The Great Melbourne Telescope (GMT), scorched by the Mount Stromlo fires in 2003, is being resurrected thanks to an estimated 10,000 hours of volunteer work (so far). This group recently received a Certificate of Appreciation in the 2013 Arts Portfolio Leadership Awards.

GMT restoration team Mathew Churchward reading out the Arts Portfolio Award commendation to the Wednesday restoration workshop team.
Source: Museum Victoria
 

The workdays have "a bit of a men's shed feel about them," says Senior Curator Matthew Churchward. He coordinates the project alongside Curator of Engineering Matilda Vaughan. The combined knowledge in the room – all members of the Astronomical Society of Victoria, many with experience in engineering, electronics, astronomy and optics – means this piece of 19th-century technology is in expert hands.

Three men with computer L-R: Barry Cleland, John Cavedon, new volunteer Norm and Stephen Bentley working on technical drawings of GMT parts.
Source: Museum Victoria

Building telescopes is a common pastime for amateur astronomers; volunteer Barry Adcock has a home-built a 14-inch diameter telescope for his backyard dome observatory, plus another telescope that allows him to view the stars from inside his house. For many, stargazing is a habit they picked up when very young. Scottish-born Jim Pollock recalls a lunar eclipse in 1949 during which the moon was bright blue after forest fires in Canada. "In the atmosphere, tiny particles of pinene, the oil from the pine trees, scattered red light beautifully and just let the blue light through." Another volunteer, Barry Clelland, remembers looking up as a kid from his backyard in the suburbs and thinking, "that's half the universe there. You could see the Milky Way in Heidelberg back then."

On this day, a sub-group is working on the mirror polishing and grinding machine, a beautiful hulking contraption with a cast iron frame and gears and shafts. The GMT's half-ton speculum metal mirrors tarnished over time, so every few years they were removed and reconditioned with this machine. "We're still trying to work out exactly how it was driven," says Matthew. The mirror sits on a rotating table and as it moves, the polishing head also rotates, "so it doesn't get a flat spot in any part of the mirror. It keeps moving as it's rubbing." Or, like "patting your head and rubbing your tummy," jokes volunteer David Linke. The team hopes to have the polishing machine working within the next year as a hint of what's to come with the telescope itself.

David Linke with the mirror polishing machine. David Linke with the mirror polishing machine.
Source: Musuem Victoria
 

In the workshop, parts of GMT are laid out on pallets and benches. With a grin, David says, "it's a big jigsaw puzzle, isn't it?" Above it all, for equal parts reference and reverence, hangs a large-scale historical picture of the GMT in operation.

Museum workshop A view of the workshop with the GMT’s lattice tube in the foreground. On the back wall hangs the large historical photograph of the GMT at the Melbourne Observatory.
Source: Museum Victoria
 

Most of the large parts of the GMT were recovered after the 2003 Mt Stromlo fires. "Oh golly, it was a dirty job to get everything out of that cube," recounts David. "The aluminium had melted from the dome and filled up the screw holes so you couldn't see where things were undone." Many months of work saw the GMT dismantled and its surviving parts audited. Fortunately, the GMT had an unofficial champion in Barry Clark, who has been involved with the Melbourne Observatory since 1955. At that time, decommissioned equipment went into storage and was at risk of being lost. Says Matthew, "Barry's been instrumental in recovering bits and pieces that were hidden under the floor. He's discovered some key bits of equipment that went right back to the very earliest observatory at Williamstown."

Detail of the dismantled cube of the GMT. Detail of the dismantled cube of the GMT.
Source: Museum Victoria
 

Lengthy reverse-engineering is recreating the missing parts. "We go out there with a ruler and pencil and paper, take measurements and sketch it up roughly," says Campbell Johns. The measurements are made in imperial units to match Irish manufacturer Thomas Grubb's original specifications, before conversion to metric for fabrication. Some of the team with technical drawing expertise convert the workshop sketches into digital CAD files. There's a lot of cross-checking with old photographs, drawings and the extant parts.

"We don't even know if there was ever a full set of working drawings," says Matthew. "It appears they did the basic layout and started building it before they had the detailed design. You can see evidence in the way parts were modified during the construction process, like spots flattened out of a casting to make a seat for another component." A volunteer adds, "Pretty amazing given in those days there were no angle grinders or power drills or oxy welders. It was all done with cold chisels."

Three men with computers L-R: Barry Clark, Barry Adcock and Mal Poulton working on optics design specifications for the GMT.
Source: Museum Victoria

So why are these men devoting their spare time to this project? It's evident from the way they talk about the GMT that they admire its history and innovation. In addition to its astronomical achievements, including the first observations of southern nebulae, the ingenious nature of its design bewitches them. It had two axes and counterweights that allowed just one person to move the beautifully balanced telescope. In its lifetime there were larger scopes, but none so nimble. Matthew's view is that it's an opportunity of a lifetime for amateur enthusiasts to build such a large telescope; few individuals would have the resources to do so alone. Other volunteers nominate restoring an important part of Melbourne's history as their prime incentive – they want to see it back in its old home.

Indeed, the end goal is to return the working telescope to the Melbourne Observatory for public viewings. Its original configuration restored, there may be new electronic additions to allow digital photography or remote operation via the web. As Matthew says "It could be very inspiring for astronomy in Victoria."

Links:

The Great Melbourne Telescope website contains the story of the telescope, and updates about its restoration through the ASV's Phoenix newsletter

Follow the GMT project on twitter: @GMT21stC

Great Melbourne Telescope on Collections Online

One-sixty

Author
by Kate C
Publish date
9 March 2014
Comments
Comments (1)

Harry Telford bought Phar Lap at auction for 160 guineas, back when Big Red was known only as "Good Walker, Great Shoulder, Very Strong Made Colt".

horse auction catalogue The page from the Annual New Zealand Thoroughbred Yearling Sales on 24 Jan 1928, with hand-written notes about Harry Telford's purchase. (HT 8465)
Source: Museum Victoria
 

There were 160 tradesmen working in the Engineering Workshops of the Kodak factory complex in Coburg.

Photo of Kodak workshop Men operating machinery in the Kodak Engineering Workshop, Coburg, circa 1963. (MM 95964)
Source: Museum Victoria
 

Harry Johns drove his famous boxing troupe around in a bright red, customised International AR 160 Series truck.

Harry Johns' boxing truck Harry Johns' boxing troupe truck. (SH 961969)
Source: Museum Victoria
 

This centuries-old English penny in our Numismatics Collection was given the registration number NU 160.

Edward 1 penny Penny, Edward I, England, 1280-1281 (NU 160)
Source: Museum Victoria
 

And today, Museum Victoria is 160 years old! On 9 March 1854, the Assay Office in La Trobe Street opened to the public. Surveyor-General Andrew Clarke arranged for two rooms on the first floor of the Assay Office to be aside for the new Museum of Natural History and its collections.

This letter from the Public Records Office of Victoria records the formal permission granted the newborn museum by Assay Master Dr Edward Davy. (We assume Clarke had taken the liberty of moving a few specimens in before the official word arrived.)

Letter from Assay Master Dr Edward Davy Copy of letter to Surveyor-General Andrew Clark from Assay Master Dr Edward Davy, 1854.
Source: PROV

Transcript:
Government Assay Office
Melbourne 28th Apr 1854
Sir,
In reply to your letter of 22nd inst enquiring what accommodation can be given at the Assay Office for receiving Specimens which may, from time to time, be forwarded to the intended Museum of Natural History, I have the honor to state that there are at present, two rooms on the first floor of the building disposable for the purpose referred to.
I have the honor to be, Sir, Your most Obdt Servant,
E. Davy
Assay Master

 

Now we just need to figure out how to fit 160 candles on a birthday cake... I think we're going to need two cakes.

Boy with two cakes Boy with two cakes on his third birthday, Prahran, 1942. (MM 110629)
Source: Museum Victoria

About this blog

Updates on what's happening at Melbourne Museum, the Immigration Museum, Scienceworks, the Royal Exhibition Building, and beyond.

Categories