Great Moments In Science

We know that the drug called cannabis, or marijuana, increases the appetitecommonly called the 'Marijuana Munchies', and we are finally getting closer to knowing what makes it happen. Half-a-billion years ago a biological system evolved to make sure that hungry animals would eat.

The ancient Romans thought that insects were attracted to bright light, and then there's the well-known phrase, "drawn like a moth to a flame", so it seems like people over many years have spotted insects coming into the lights, at night. But what's the real reason? Host: Dr Karl Kruszelnicki

Some sleepers who act out their dreams are later diagnosed with Parkinson's disease. As Dr Karl explains, it's one of a few slightly odd new diagnostic tools.

The power of smell can't be understated — our noses don't just sniff out tasty treats, they can also alert us to danger.  In this episode of Great Moments in Science, Dr Karl tells the story of a super-sniffer who might've unlocked a powerful diagnostic tool.

Atomic clocks are the most precise time-keepers we have. But that doesn't mean they can escape the timey wimey effects of gravity.  In this episode of Great Moments in Science, Dr Karl explains how this enables super-accurate clocks to not just measure time, but height as well.

Humans have been dunking biscuits for as long as biscuits have existed.  But why do we do it? Why are soggy biscuits so darn good? In this archive episode of Great Moments in Science, Dr Karl submerges himself into the mechanics of this age-old activity.

Thousands of people will descend on the tiny WA town of Exmouth later this month to witness the Moon block out the Sun for a whopping one minute.  But if you're a homebody not all that keen on a road trip, how long might it take to see a total solar eclipse from where you are right now? Dr Karl investigates in this archive episode of Great Moments in Science.

Green potatoes — would you like them here or there? Would you like them anywhere? Well as Dr Karl taught us last week, potatoes contain a potentially deadly chemical, and a green tinge is its greatest tell.  In this archive episode, we explore why green potatoes are best avoided.

Given the right (or wrong) circumstances, the humble potato packs a punch.  It contains a chemical that could kill if ingested in large amounts. The catch-22? That chemical is exactly why potatoes taste so good.  In this archive episode of Great Moments, Dr Karl digs into the science.

What you eat or drink just after you finish pumping iron is crucial to laying down muscle.  Dr Karl weighs up the best way to bulk up, in this archive episode of Great Moments in Science from 2011.

The destructive force of a wall of snow is well known. Major avalanches can not only kill, they can also completely reshape a landscape.   But it's not just mountainsides we need to worry about. There are also avalanches happening under the surface of the ocean — forging canyons and threatening our telecommunications.

There are plenty of reasons why a person might poke their tongue out.  Sometimes it can be a rude or cute gesture. Maori warriors do it as a sign of defiance, and Tibetans do it as a greeting. But many times it's a sign of concentration. So here’s why your tongue helps your brain think. Host: Dr Karl Kruszelnicki

Athletes are not just fit, they also attract a lot of media attention, especially if stories are put around that COVID vaccines are a cause of death in this group. In late 2021 such claims were being made - and they’re plainly not true.

In development is an amazing new technology which may, eventually, turn your thoughts into speech. It's being designed to help people who can’t speak, turn what they're thinking into speech. But it’s still early days.

In 2022 we found that Neanderthal DNA could kill superbugs. Wait, what ... didn't Neanderthals die out?  Yes, but their hidden power could make them important in modern medicine.

Continuing the story about the effects of alcohol we arrive at the “drunchies”—short for the “drunken munchies”. They’re what occur after a bout of too much drinking. You become very hungry and much your way through any fast food within reach. Host: Dr Karl Kruszelnicki

Alcohol in small quantities can make people sociable; but too much of it can mean hangovers and associated consumption of non-nutritional foodstuffs. There's a whole chemical family of 'alcohols', so what's the deal with the one that humans kinda like—ethanol.

For some snapping spaghetti is sacrilege — but for others it’s science.

How do trees face an incoming threat if they can't move, see, or hear?

Trees are solid and dense. However, they're made from air. Wait, what?

About 95 per cent of the mass in the universe seems to be missing — what's going on!?

Our skin is like a personal space suit protecting us from the outside world. Skin is best when you are a child—because of the elastic protein keeping it fresh and supple—but, unfortunately, that freshness doesn’t last. Host: Dr Karl Kruszelnicki Producer: Diane Dean

An interesting demographics exercise is to add up the number of humans who've existed. This is different from how many people are in a population—which in late November 2022, is about 8 billion. But using data going back as far as possible, the number of people who've existed is reckoned at over 100 billion. Host: Dr Karl Kruszelnicki

One might imagine that face masks work because the multiple layers will stop a virus getting through. But no, that's not it—they use a high-tech 'melt-blown' material, developed from a technique first noticed in volcano eruptions. Host: Dr Karl Kruszelnicki Producer: Diane Dean

Nowadays we're pretty familiar with wearing a face mask to reduce infection rates, and that some masks are better than others.But understanding why the N95 mask is a really good mask one came as a surprise. Host: Dr Karl Kruszelnicki Producer: Diane Dean

Nuclear weapons carry enormous destructive power in a very small package. A nuclear weapon weighing about a quarter of a ton can release as much energy as exploding 1.2 million tons of TNT – that’s a multiplication factor of about five million. During the Cold War the combined numbers of US and Soviet nuclear weapons reached about 70,000. There are not so many these days but there are still enough to end civilisation as we know it.

The further adventures of some of the most powerful events in our Universe: Gamma Ray Bursts. The biggest one recorded was in October 2022, in a galaxy far, far away. What would have happened if it had exploded inside our Milky Way galaxy?

First on the list of Most Energetic Events Ever in our universe is The Big Bang. No mean contender for top ranking is the "Gamma Ray Burst" - aka the GRB. GRBs can put out more energy in a few seconds than our Sun produces in its 10-billion-year lifetime.

The invention of the elevator made city-living possible. It made possible a rapid mixing of cultures and concepts, efficient use of energy—and ultimately, increased economic output. And now there's a further improvement called 'destination despatching'.

The first definite proof of a link between humans and dogs is a 15,000-year-old grave holding a dog, a man and a woman. Intensive breeding of dogs began about 200 years ago, which resulted in most of today's 450-or-so breeds. And there's a definite mutual appreciation society between people and canines

In 2013 the academic journal published an article called, “Taste perception: from the tongue to the testis”. It looked at some of the distinct taste sensations that we register in the Gustatory Cortex - the taste centre of our brain which are picked up by taste buds on the tongue. However, there's a difference between taste buds and taste receptors ... which is where the testis enters the story.

Earth's defence against the existential threat of extraterrestrial rocks has been bolstered.  But is it really all that important for humanity to have a plan of attack for an asteroid ambush?

It wasn't the first, second or even third issue to come up in the wake of this year's huge undersea volcanic eruption in Tonga.  But the eruption, and the ensuing tsunamis, did have a far-reaching impact on the kingdom's neighbours and beyond — including on Australia's coastline.

For a long time our home solar system was all we knew. But since we’ve gotten a better look at other systems near and far, it has become apparent... our solar system is weird.

Dr Karl explains how artificial intelligence detects and distinguishes between look-alikes.

The term 'doppelgänger' goes back centuries, but in recent years the internet has made it much easier to find your look-alike

There's a precise science behind the impact of small, falling objects. Some can be deadly. Others don't pack much of a punch.

The final installment of why the Earth is suddenly speeding up—after more than a billion years of slowing down.  How do we measure the rate of the Earth’s revolution, and what happens when the time on our clocks doesn’t quite match up?

Part 2 of the explanation about the accelerating spin of the Earth - which is against the trend of the last one-and-a-half billion years.

Part 1 about how the Earth is unexpectedly speeding up, and has recorded its shortest day ever – 1.59 milliseconds shorter than the standard 86,400 seconds

Electricity supply is shifting to renewables, so batteries are important. It might even be cheaper to power your house with the battery from your electric car, rather than batteries specifically designed for houses.

Nose-picking is something that people find disgusting—yet we still do it.  And how about the gunk that’s in your nose—is it ok to eat that?

We tend to think of computers as being a fairly recent invention. But the world’s oldest known computer is actually a few thousand years old. It’s called the Antikythera Mechanism

The highest standard for measuring body temperature is via a heart sensor—after that, it's from inside a body cavity; and you can do it from inside the mouth or the ear, but that's not as accurate, and even less so when measured on the skin. Measuring brain temperature is different again—and be astonished that the temperature of the human brain differs from the rest of the body.

Have you ever been winded? You suddenly lose the ability to do something you've done 15 times each minute of your life. It's one part anatomy, one part physiology, and one part don't panic.

Dogs tend to hang around humans but do they really love us—and what’s with the head tilt? Their affability might be due to two genes known to influence sociability in mammals. Gradually genetics turned dogs and humans into best friends.

Measles is a nasty infection that you don't want to get. It can cause death and, what's more, it can also erase your immune system's memory. Only relatively recently scientists have measured this directly - by concentrating on antibodies – which can be generated by natural infection, and by vaccines.

Anticipation is a strange experience. It can take you all the way from hope and trust, to anxiety and fear. But there’s a happy balancing point where anticipation can enrich your life.

Who’d’ve thought that one of the most sober animals is the humble hamster. They love alcohol but it doesn’t affect them. And who’d’ve thought that there’s a way to measure inebriation levels in animals - it’s called the Wobbling Scale – but hamsters NEVER wobble.

The average recommendation is to wash your bed sheets at least every two weeks. This is because every day you shed a mix of dead skin cells, sweat, germs, and body oils.. Sometimes you can delay bed sheet washing, it all depends on what kind of things you get up to in bed.

Very long and very widebut only a few kilometres thick, atmospheric rivers carry water from the tropics towards the poles – and they shift huge amounts of heat as well. A few decades ago, atmospheric rivers hit West Antarctica and collapsed two massive ice shelves.

A discovery in weather in the 1990s was the Atmospheric River. They've been around for pretty much ever though - one of them bankrupted California in 1862, and another dumped lots and lots of water onto Brisbane, in February 2022.

Whales are the giants of the marine realm, and here's why they get that way. This episode was originally published in May 2018

The star Earendel came into existence a long time ago, and is now famous as the most distant single star that astronomers have been able to obtain an image of.

The Koran, the Bible, the Sanskrit Mahabharata, and the Greek Illiad all mention plagues of locusts, and they're seen as carvings in ancient Egyptian tombs. Large numbers of locust could have come about because, in certain circumstances, grasshoppers metamorphose—into locusts.

The drug ivermectin is really good for treating worms; unfortunately it was falsely promoted as a COVID cure due to data errors, drug trial anomalies, or insufficient publication review.

There are many cases of drugs being repurposed once a new aspect of them is discovered—their new use is often very beneficial. One such drug is ivermectin. It works well against various parasitic infections. It does not work against COVID.

Ball games were happening 3,500 years ago, and ever since then we’ve bounced and batted in all sorts of fun ways. We're especially interested in the mechanics of a ball curving as it travels through the air—which happens in swing bowling.

At Australia's Antarctic base they do lots of cool science stuff, and aim to create as little waste as possible—including the toilets. There's actually a toilet known as the 'Fire Breathing Dragon'—so more exciting than its official name of Electric Incinerating Toilet.

Wood has a loads of potential—from it we can make semi-conductors, batteries, steel, concrete, even plastics. It does need a lot of processing but we already do that with materials like steel, glass and concrete.

We're now quite familiar with terms like 'herd immunity' and 'epidemic', and that when separate groups of people—with separate germs—meet for the very first time, things can turn out badly. If you have never been exposed to a specific germ you won't be primed for protection against it.

When digging the compost pile into the garden, Dr Karl noticed a ball of entangled shape-shifting worms. You might think 'yuck'—but there's a 'wow' factor because some animal groupings can generate intelligence, giving the group an advantage over solitary individuals.

The final piece about why the 100 million or so black holes in our Milky Way galaxy are missing.

More on the almost-emptiness that is black holes. Because they're invisible, they're difficult to find—but sometimes get discovered because they give off X-rays.

Even though it sounds totally crazy, astronomers are very confident that black holes exist. Our galazy is really old, it should carry at least 100 million black holes but we’ve found only a couple of dozen of them.

There's really no 'genteel' way to say it, this week we're... passing wind. But even though it's totally natural, it can be embarrassing.

It used to be thought that a pathogen (or germ) and its host develop in a 'mutually benign relationship'—this was called the 'Law of Declining Virulence'. If the common cold killed us there would be less hosts and the virus would decrease. So the common cold virus mutated to become less lethal, and more common. The Law of Declining Virulence was debunked in the 1980s, and the pathogen/host relationship is actually pretty complicated.

Power steering on a car involves various rods of steel moving relative to one another. How the rods connect is why mechanics are dealing with an unexpected problem.

Thanks to some fuzzy-looking photos, bat echolocation just got more amazing. This program was originally published on 3 September 2019

During World War II a curious aircraft was built by the German air force. Its purpose was to combat Allied bombers, but not everything went to plan. What sounded like a ‘good idea at the time’ became, probably, the Worst Plane of World War II.

Why would the fossil fuel company BP promote the idea of reducing our individual 'carbon footprint'?

Climate change has begun displacing species, but just how many are on the move?

What was the mysterious Carrington Event of 1859? And why did it affect telegraph systems?

Is it true that our bodies would prefer the 'Paleo diet'?

What twisted trickery causes ribbons to curl?

What's the maximum number of hot dogs someone could eat in 10 minutes?

Where does the world's dust come from? And how does it constantly fill up our homes!?

Are discussions about your individual 'carbon footprint' really a distraction, shifting blame onto everyday citizens?

Would you eat a hamburger patty that was grown in a lab? What about fake meat that looks and tastes just like the real thing?

A cuppa tea can be a life-saver - sometimes, literally!

Understanding thyself, and taking the middle path, can lead to a much faster and calmer parking experience

Could we really rid the world of Hepatitis C?

Hepatitis C is one sneaky little disease, caused by an equally sneaky virus.

What is it with red food and stains? So many things!

Regrowing your tail is one thing - but what if you lose more than your tail in the first place?

Copper is like kryptonite to COVID-19.

They can be superemassive, but black holes still have no size.

Why you should always read back copies of the Journal of Fluid Mechanics.

That's not a dinosaur - it's a flying catapult!

Why are scientists exercising fish ... with a coffee plunger?

This creature has the only known case of an 'on-demand anus'

The anus is highlight of animal evolution - but it's still full of surprises.

They've got brains smaller than a pinhead, but spiders can count!

Arachnophobes beware - flying B-grade horror spiders ahoy!

The short story: he passed the test. Again.

There are very few places weird enough to test out Einstein's General Theory of Relativity.

At last - the real secret to the perfect espresso!

A lot of players had a role in our horrific 2019/2020 bushfire season. Luckily, El Nino was not one of them.