Weighing the Earth with a Nobel Laureate

Australian Institute of Physics, Media releases
Weighing the Earth with a Nobel Laureate post image




Launch: Friday 1 March 2013, 9-10.30am

Albert Park College, 83 Danks St, Albert Park, Victoria

Do you weigh more in Melbourne or Canberra?

What does our planet weigh?

Australia’s 2011 physics Nobel Laureate, Professor Brian Schmidt, is today launching the start of a national physics experiment that everyone can participate in.

School students and the public will follow Galileo to measure local gravity. They’ll measure the weight of the Earth, and discover that your weight changes (just a little) as you travel around Australia.

Brian Schmidt will introduce Year 9 students at Albert Park College to the experiment first performed by Galileo, and together they’ll make the first contributions to a new map. Over the year, the Australian Institute of Physics hopes to involve thousands of people around the country.

The experiment is called ‘The BIG little g project’ and is open to people around Australia to participate—all you need is a home-made pendulum, a tape measure and a stop watch. Little g is physics shorthand for the local gravitational field, or how much the Earth pulls (accelerates) objects including people towards it.

“Apart from being fun to do, and contributing to a useful set of results, this experiment is also a great way to expose people to the process of real science,” says Brian. “Because each measurement will not be 100 per cent accurate, it’s important for each participant to take multiple measurements. And the more people who contribute results, the better.”

Brian Schmidt places great value on science education and in 2011 devoted $100,000 of his Nobel Prize award to develop student science and literacy.

While watching a swinging chandelier, Galileo realised that it keeps time very accurately. The same applies to any pendulum. But the time it takes to swing from side to side depends, not on the weight of the pendulum as you might expect, but on the length of its cord and on acceleration due to the Earth’s gravitational field ( ‘little g’) at that spot.

The experiment will show that strength of the Earth’s gravitational field varies from place to place.  Local gravity depends on the ‘weight’ of the earth at that point due to latitude, altitude and local geology. These variations can be used to find underground minerals or water, and to measure shrinking polar ice caps.

Associate Professor Andrew Greentree, Vice-Chancellor’s Senior Fellow at RMIT in Melbourne, is coordinating the project. He will compile the data to build a map of Australia’s gravitational field that in some areas will be more sensitive than current maps. “The most sensitive maps of little g are made with NASA satellites,” says Andrew. “They get down to a resolution of around 100km, but we’d like to measure Earth’s gravitational field to resolutions of around 100m where we can get lots of results coming in. The more citizen scientists we attract, the more accurate the map.

“We want to make this one of the biggest physics experiments ever conducted, in terms of the number of participants. We’re inviting primary and secondary school children and the general public to make a simple pendulum, do the test and submit their results online.

“We are doing this to celebrate the 50th anniversary of the Australian Institute of Physics and the impact of physics on society,” he says.

Physics has helped transform Australia over the past 50 years. Back in 1963 the British nuclear tests at Maralinga were finishing, Australians could for the first time make direct dial international phone calls via an undersea cable, and weather forecasting was more art than science.

Today lasers carry our phone calls, emails, videos zap around the world via optical fibre. Geophysics has helped us exploit our vast mineral and energy wealth. Astronomers have created powerful instruments, discovered the accelerating Universe, and made Wi Fi fast and reliable. Weather forecasts have become surprisingly accurate and computer models are revealing the dangers of a changing climate. Over the anniversary year the AIP we’ll explore how physics might help transform society in the next 50 years.

The Australian Institute of Physics supports professional physicists and promotes all aspects of physics to the wider community.

Media contacts:

Niall Byrne: 0417 131 977, niall@scienceinpublic.com.au

Margie Beilharz: 0415 448 065 margie@scienceinpublic.com.au

For the AIP:

Andrew Greentree: 0425 266 659, andrew.greentree@rmit.edu.au

More information on the BIG little g project at www.aip.org.au/littleg

You can learn more about little g at http://en.wikipedia.org/wiki/Gravity_of_Earth

For interviews contact Margie Beilharz, 0415 448 065, margie@scienceinpublic.com.au

Please go to reception at Albert Park College on arrival.


9-9.30am: Brian Schmidt and Andrew Greentree will introduce and demonstrate the project to the school students

9.30-10am: Brian, Andrew and students will be available for interview, filming and pics while they do their project

10-10.30am: Project results and wrap-up

10.30 ENDS