28 October 2016
  Science by Email  
News: New dinosaur! But how did it get here?    

Scientists have discovered a new Australian dinosaur, and it’s a big one! Several giant bones, some over one metre long, were uncovered near the town of Winton in central Queensland. But what’s got scientists all worked up isn’t what it looks like: it’s where it came from.

Scientists have named the new dinosaur Savannasaurus elliottorum. It was a big, four-legged plant eater, and looked a bit like a brontosaurus. Savannasaurus was as tall as a giraffe, but much heavier.
Fossils from big plant-eating dinosaurs can be found in many places around the world. Some are up to 150 million years old! Several different species are found in Australia, but they only date back to 100 million years ago. Scientists think that these Australian dinos, including Savannasaurus, might be recent arrivals from another continent. Their best guess is that Savannasaurus came from South America.
So how did Savannasaurus get to Australia? They probably walked! During the time of the dinosaurs, the world was a very different place. South America and Australia were both much closer to Antarctica. And that means there may have been dry land linking the three continents.
The world of the dinosaurs was also a lot warmer than today. Antarctica was covered in trees, not ice. Up to around 100 million years ago, it was still pretty cold, but then global warming kicked in. A warmer world might have allowed Savannasaurus to migrate to Australia, along with other large dinosaurs.
We still have plenty to learn from Savannasaurus. We don’t know how far it spread, or how long it lived until it became extinct. Even the story of how it got here is just a best guess. But it’s pretty cool imagining Australia 100 million years ago, filled with giant dinosaurs!

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Picture of two dinosaurs standing beside a lake with a third dinosaur in the water.
Savannasaurus may have looked something like this!
Image: © Australian Age of Dinosaurs, Travis R Tischler
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    Quiz questions    
  1. Where does a geothermal power plant get its energy from?
  2. If you rub a diamond and a piece of glass together, what happens? Does a) the glass scratch the diamond, b) the diamond scratch the glass, or c) each scratch the other?
  3. Which distance is longer: from sea level to the top of the highest mountain, or from sea level to the bottom of the deepest ocean trench?
  4. Where does cotton come from?
  5. Can plants catch viruses?

Try this: Recreating Gondwana
Cutting with scissors around the paper continent marked Africa.
Don't worry about cutting precisely along the coastline.
Cut out continents of South America, Africa, Antarctica, India and Australia, placed aproximately where they are in real life.
Arrange the continents just like in real life.
Cut out continents of South America, Africa, Antarctica, India and Australia, pushed together.
See how closely you can get them to fit.

You will need


What to do

  1. Roughly cut out the different continents. Don’t worry about following the coast exactly.
  2. Arrange them like a world map. Going left to right, first put South America, then Africa, India and finally Australia.
  3. Underneath them all, put the last continent, Antarctica.
  4. We’re going to reverse continental drift. Slowly move each continent down, towards Antarctica. Do you notice any of the coastlines matching up?
  5. Eventually, the continents will join up into one blob. Don’t worry if there are a few gaps here and there – the shape of the continents has changed a bit over the past 100 million years. Congratulations! You’ve recreated the super continent known as Gondwana.

What’s happening?

The ground under your feet might feel pretty stable, but it’s actually moving. The rocks beneath your feet float on a sea of molten magma (lava). When the magma moves, it drags the surface rocks along for the ride. This is known as continental drift.
We haven’t always known about this. Continental drift was a controversial theory for many years. Many scientists could not imagine a force strong enough to shift entire continents. But there was a lot of evidence. For example, the coastlines of South American and Africa match surprisingly well, and similar fossils are found in matching regions on the continents.
Eventually, scientists set up experiments to measure the speed of the continents. One way is to measure the distance from Earth to the Moon, by bouncing lasers off the Moon’s surface. Astronauts set up mirrored reflectors on the Moon just so we could do this!
Current measurements show that Australia is the fastest continent, moving north at about seven centimetres per year. That adds up to 70 kilometres every million years, or a whopping 7000 kilometres since the breakup of Gondwana, 100 million years ago.

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    Quiz answers    
  1. Geothermal energy comes from hot rocks that are deep underground.
  2. b) The diamond will scratch the glass, because diamonds are harder than glass.
  3. The deepest trench is 11 kilometres deep, while the tallest mountain is less than nine kilometres high.
  4. Cotton comes from a plant.
  5. Yes, plants can catch viruses. But plant viruses and human viruses are very different, so you can’t catch a cold from a tree!