IF you are in line at the signing of Dr Karl Kruszelnicki's new book 50 Shades of Grey Matter, try not to get behind someone with a question about the big bang.
The only thing the multi-disciplinary scientist loves more than answering questions is pondering those he can't.
"I was advised to write the book in sections to match the length of a middle-aged man's bowel movement, which is why there is a website that provides more information. I had to go into more depth," he says.
Despite the beloved broadcaster's tendrilled approach to science and conversation, his new book is a perfectly pruned 41 punchy chapters of 'sexy groundbreaking' science, covering everything from ovulating lap dancers to radioactive cigarettes.
Left no choice but to read the popular erotic tale from which his book's title borrows, Dr Karl's scientific mind found a hole in the 50 Shades equation.
"I'm offended. Here we have a 28-year-old man who is a connoisseur of everything - of food, of drink, of the arts, of sciences - but he feeds his girlfriend a teabag of the orange pekoe variety. Now everybody knows that the prince of teas comes in leaf form and is Darjeeling. At that stage the book lost all credibility," Dr Karl says.
"I mean, this guy can make a woman fall into a state of orgasmic unconsciousness in 20 seconds just by touching her toe, which is just unfair for most men. In my experience it takes at least 30 seconds.
"But the good thing about the book is that it encourages people to have sex. You can't have too much sex or vegetables," advises the Doctor.
Dr Karl also can't get enough of Northern NSW, having lived in Dorrigo, and Promised Land near Coffs Harbour as well as frequently staying with friends on the North Coast hinterland.
However, his attraction to the place can't be explained by magnetism, or ley-lines or biochemistry.
"Science is a good tool but not for explaining why you love somewhere. It's like the hammer is the wrong tool when you're cooking. You might use it occasionally but it's not what you'd like to use," he says.
Australia loves Dr Karl. He is a regular on the Most Trusted Australian list and this year he was named an Australian National Treasure. But it's a trust that goes both ways.
"There is no such thing as a silly question. Many academics are stuck asking the academic questions but not the deep questions. I love the questions from listeners. It's not so much the answer but the questions which hold the insight and wisdom.
"It is lay people's questions that produce Nobel Prize answers. Take this conundrum: If the reaction from a human's bite is nastier than a dog's, why don't bleeding gums cause us massive infection?
"The answer is that your tongue makes special antibiotics. This finding has resulted in a whole new line of antibiotics coming onto the market. And this is good because we are running out of antibiotics," he says.
Woven among pop-science oddities - like 'How do marshmallows predict your future?' the book does some kick-ass myth busting, felling science's dark forces.
In one chapter he slays the myth that hybrid cars produce more carbon than petrol ones.
"People will always tell lies and will continue to do so. They are telling lies about solar cells that cost more energy than they give back. There are those who denied that the permafrost was melting. These are the same people that told us that tobacco was safe.
"It's terrible the lies they come out with,"
The 'they' Dr Karl refers to is the George C Marshall Institute, a small but well-funded subset of the science community which has a lot of political sway.
Given Dr Karl has spent his career persuing the truth and disseminating it widely with humour and goodwill, does he despair that we have largely ignored the science that matters?
"I find it hard because it is going to affect our children and grandchildren. Back in 1988, we knew about global warming, climate change and greenhouse effect, we knew that it was real, we knew it was going to be bad but we wasted the intervening 24 years doing nothing so that it will only make it so much more expensive and nastier when it happens."
But until the science speaks to us with Armageddon-like certainty, life goes on.
In the lead up to Christmas Dr Karl will be spruiking his book, spreading the truth about cigarettes, breast milk and tyre dust one bowel movement at a time.