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DISPLAYING POSTS FROM: Oct 2011 (15)

Aussie astronomer wins Nobel Prize

Author
by Tanya
Publish date
5 October 2011
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Comments (1)

How exciting it was to wake up to the news this morning that an Aussie astronomer had won the Nobel Prize for physics. Three cheers to Brian Schmidt and Australian science!

Brian Schmidt, professor of physics at the Australian National University, shares the prize with Saul Perlmutter and Adam Riess “for the discovery of the accelerating expansion of the Universe through observations of distant supernovae.”

Winners of the 2011 nobel prize in physics Saul Perlmutter, Brian Schmidt and Adam Riess, winners of the 2011 Nobel Prize in physics.
Source: Nobelprize.org
 

This was, and still is, a mind shattering discovery for astronomy. One that I enjoy sharing with people at the Planetarium's Discover the Night Sky evenings each March and August.

The result was completely unexpected and has led to the concept of dark energy. We don’t know why the expansion of the Universe is accelerating, which is to say that it’s expanding faster now, than it was in the past. But this research puts us on the hunt for an answer and for now dark energy is just what we call it.

The journey to the Nobel Prize for these three astronomers began around 20 years ago. Saul Perlmutter was head of the Supernova Cosmology Project at Lawrence Berkeley National Laboratory, California, while Brian Schmidt headed up the High-z Supernova Search Team from Mt Stromlo Observatory, Canberra. Adam Reiss was an integral part of the High-z Supernova Search Team and based at John Hopkins University, Baltimore.

Oddly enough, the two teams were searching for the exact opposite of what they found. They were trying to measure how much the expansion of the Universe was slowing down not speeding up. The idea went like this. We know the Universe was given a big kick at the start of its life by the Big Bang. So since then everything has been expanding away from everything else. But the Universe is also filled with matter and that means gravity. Gravity works against the expansion, making objects in the Universe tug on each other.

Astronomers had counted up the mass of the Universe and found that there was just enough mass to slow down the expansion but not enough to stop it entirely. The Universe wasn’t going to end in a big crunch, but would likely drift along, forever slowing but never stopping.

That was now, but what about then? The thing about astronomy is that when you look at objects that are far away, it means you are looking into the past. By observing distant supernovae, the two teams were able to look back into the past, to measure how fast the Universe was expanding back then.

So it was assumed that gravity had been slowing things down, or in other words, the expansion of the Universe was decelerating. The HubbleSite, has a fantastic explanation of dark energy, where Adam Reiss, who analysed the data for the High-z Supernova Search Team says:

“I wrote a computer program to tell me, 'so what is the mass of the universe that is causing that much deceleration?', which I was assuming was going on. It reported that the universe had a negative mass. Now the universe can’t have a negative mass but what that really meant is ‘hey dummy you should look at the data!’ It’s not decelerating at all. It’s actually the negative of deceleration, that’s acceleration.”

 

 Video: excerpt from Planetarium show that illustrates the expanding universe.

About 14 billion years ago the Universe began with the Big Bang. This initial expansion was slowed by matter in the Universe. However, around 7.5 billion years ago, when the Universe was half its current age, dark energy kicked in. We don't know the reason why but it makes the expansion of the Universe accelerate.

While the two teams had always had a friendly but competitive rivalry going on, they must have been thrilled to have had each other when this startling discovery first appeared. I've always loved Brian Schmidt's quote at that time which appeared in the New York Times:

"My own reaction is somewhere between amazement and horror. Amazement because I just did not expect this result and horror in knowing that it will likely be disbelieved by a majority of astronomers – who, like myself, are extremely sceptical of the unexpected.”

Each team independently came to the same fantastical conclusion.  This meant that together they could convince the rightly sceptical science world that what they were seeing was correct.

Congratulations to everyone who worked on the two teams and produced this brilliant discovery. It’s your day to enjoy the time when you were amazed by the Universe.

Links:

Brian Schmidt describes the High-z Supernova Search

Resident artist Joceline Lee

Author
by Kate C
Publish date
3 October 2011
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Comments (5)

Artist Joceline Lee has spent her last few Wednesdays in the basement of the Royal Exhibition Building among the palaeontologists, geologists, rocks and fossils. She is working on drawings for her first solo exhibition, Rendered Bones.

Joceline draws skeletons and anatomical forms in pen and ink which makes palaeontological specimens the ideal material for her. When I visited her at work, she was drawing an echidna skeleton that she'd selected from the collection. She was accompanied by her mentor Rob Delves, a sculptor who has worked with Joceline for seven years at Art Day South. This project is run by Arts Access Victoria in Melbourne's south-east to give artists with disabilities opportunities to develop their artwork through workshops, mentorships, collaborations and exhibitions.

  Joceline Lee and Rob Delves Joceline Lee and Rob Delves working on an echidna skeleton in the Museum Victoria Palaeontology Department.
Source: Museum Victoria
 

Rob said that when she first came to Art Day South, her drawings were intricate and very tiny. "Her linework was amazing in these little drawings and they just said 'skeletons'." He started bringing her photographs and models of animal skeletons about three years ago, and Joceline was hooked. "Then we brought in bigger things and it's grown from there." In July this year, MV's Discovery Program visited Art Day South bringing a tortoise shell, a huge model dinosaur leg, fossils and more for the artists to explore.

Joceline works slowly but steadily for hours at a time, with each drawing taking two to three weeks to complete. Rob loves her unique style of drawing. "She goes off in beautiful directions, with all this contrast... dark and fine lines."

Rendered Bones is part of the Melbourne Fringe Festival program from 4 to 9 October in the No Vacancy Project Space in the Federation Square Atrium. Be sure to visit the exhibition if you'd like to see Joceline's distinctive interpretation of fossils, bones and skeletons.

Flyer for Rendered Bones exhibition
Flyer for Rendered Bones exhibition.
Image: Arts Access Victoria
Source: Arts Access Victoria
 

Links:

Melbourne Fringe Festival: Rendered Bones

No Vacancy Gallery: Rendered Bones

Bug of the month

Author
by Melvin
Publish date
1 October 2011
Comments
Comments (6)

This post is by Melvin Patinathan, Assistant Keeper with the Live Exhibits Unit.

The Giant Burrowing Cockroach (Macropanesthia rhinoceros), also known as the Rhinoceros Cockroach, is one of Australia's treasures. It is the world's heaviest cockroach, weighing up to a whopping 30g. Although it is not the longest, it still can get up to 70-80mm in length (the longest is probably the winged Giant Brazilian Cockroach, Blaberus giganteus, growing up to 90mm). This giant critter is wingless and heavily armoured, which helps it withstand predator attacks – if that doesn't work it can emit a hissing noise which can be quite startling.

Giant Burrowing Cockroach Giant Burrowing Cockroach (Macropanesthia rhinoceros).
Image: Alan Henderson
Source: Museum Victoria

I recently took the specimen below to Scienceworks for the Inspiring Scientists weekend, where he was a giant hit with hundreds of young visitors. Although I'm fond of many of the animals we keep at Live Exhibits, Giant Burrowing Cockroaches are one of my favourites.

Giant Burrowing Cockroach in hand The handsome hand shows how big a male Giant Burrowing Cockroach can get.
Image: Adam Elliot
Source: Museum Victoria
 

Giant Burrowing Cockroaches are found in dry eucalyptus scrubland of northern Queensland; Cape York to Rockhampton and the Whitsunday Islands. Male cockroaches have a prominent ridge on their pronotum (an extended first segment of the thorax of the insect that forms a shield over its head) where females do not have a distinct ridge but tend to be larger and heavier than males.

sub-adult Giant Burrowing Cockroaches A few sub-adults collecting dry eucalyptus leaves on the soil surface.
Image: Patrick Honan
Source: Museum Victoria
 

Like their name suggests, they are burrowing creatures and use their shovel-like pronotum and large spiny powerful digging legs to dig burrows as deep as one metre. The cockroaches line their burrows with twigs and dry eucalypt leaves that they gather from the surface. These gentle giants are specialist feeders; they only eat dry, crisp eucalypt leaves.

Giant Burrowing Cockroach emerging from its burrow in a terrarium Giant Burrowing Cockroach emerging from its burrow in a terrarium.
Image: Rodney Start
Source: Museum Victoria
 

Giant Burrowing Cockroaches are nocturnal and spend most of their time hidden in their burrows. They are most active at night when they come to the surface to feed; these giant cockroaches have been mistaken for small turtles when crossing roads.

Giant Burrowing Cockroaches generally do not venture too far away from their burrows except during breeding season when it is warm and humid, especially after rain. The warm humid climate provides ideal mating conditions and mating occurs at night. Once the female is gravid (pregnant) she will prepare her burrow by dragging down leaves to feed her young. This species of burrowing cockroach are oviviparous, which means that the eggs are incubated within the body and are sustained by yolk sacs.

young Giant Burrowing Cockroaches and adult female Juveniles and their mother at the entrance of their burrow.
Image: Patrick Honan
Source: Museum Victoria

Unusual among insects, instead of laying eggs, females of this species give birth to live young. The female giant burrowing cockroach will produce up to 20 live young and she will care for them for up to a year. Juvenile cockroaches reach maturity at about three or four years of age and best of all apart from being the heaviest cockroach in the world, these amazing cockroaches can live up to ten years.

Giant Burrowing Cockroaches are permanently on display under the 'Diversity' exhibit in Bugs Alive!.

Further reading:

Henderson A., Henderson D., & Sinclair J. 2008. Bugs Alive: A guide to keeping Australian invertebrates, Museum Victoria pp. 47

Rentz D.C.F. 1996. Grasshopper country: the abundant orthopteriod insects of Australia, University of New South Wales Press, pp. 225-228

Rugg D. & Rose H. A. 1991. Biology of Macropanesthia rhinoceros Saussure (Dictyoptera: Blaberidae). Annals of the Entomological Society of America, Entomological Society of America, pp. 575-582

Links:

Question of the Week: How to sex a cockroach

Question of the Week: Cockroaches

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

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