Scientists named the creature Mukupirna [meaning Big Bones], having just created a new family of marsupials to accommodate its discovery.

It also belongs to a group of so-called "vombatiform marsupials", which includes wombats and koalas. Mukupirna, though, was more than four times the size of any living wombats today and weighed about 150 kilograms.

Wombats and koalas are the last remaining species in the vombatiform group [with koalas in trouble in NSW and Queensland].

As well as giant marsupials, Australia once had giant reptiles and birds. Why, we wonder, did this megafauna become extinct?

Scientist Tim Flannery and others have theorised that the arrival of early Aboriginal Australians 70,000 years ago, along with hunting and the use of fire may have contributed to the extinction of megafauna.

Mind you, Aboriginals did apparently co-exist with megafauna for thousands of years. Other researchers believe natural climate change [an ice age] was a factor in megafauna extinction.

Anyhow, we recently heard Toby Ord speaking on the podcast, Making Sense with Sam Harris. Toby - an Australian-born philosopher - just released the book, The Precipice: Existential Risk and the Future of Humanity.

The extinction of megafauna does tend to make us wonder if and when humans will become extinct. Toby reckons humans have the potential to live for millions of generations. How's that for optimism!

He states in his book that safeguarding humanity's future is among the most important moral issues of our time. [Sounds a bit like K-Rudd].

The book outlines the major shifts in human history - the agricultural, scientific and industrial revolutions. With each of these upheavals, human power over the natural world rose. Our living standards rose with it.

Then came nuclear weapons and the power to destroy ourselves. We might feel vulnerable now, but life in the 1950s must have been pretty anxious amid the heightened threat of nuclear annihilation.

Toby says humans have neglected existential risk. That is, risks that threaten to destroy humanity's long-term potential. He says the biggest threat to our future is artificial intelligence.

You'll love this part: apparently humanity spends more time on ice cream than protecting its future [but it tastes so good!].

Ord reckons humanity has a 1 in 6 chance of being destroyed by the end of the century. That's 16.7 per cent [he says it's in our hands to dramatically improve those odds].

Those giant wombats would have loved an 83.3 per cent chance of surviving another century.

Daniel Johns sang about acid rain in that famous Silverchair song. But have you heard about plastic rain?

Citing research in the journal Science, Wired.com reported recently that "plastic rain is the new acid rain".

The story spoke of the "hellish scenario" of microplastics falling from the sky in the form of plastic rain.

University of Newcastle researcher Thava Palanisami told us back in 2017 this was "an environmental catastrophe that's under-recognised" and "an emerging global threat to human health".

Topic is calling on Silverchair to reform and create a new version of its Acid Rain track.