"The short answer," said Brian Greene, theoretical physicist, professor at Columbia University, founder of the World Science Festival, best-selling author and one of the most prominent scientists alive today, "is no."

This made for a slightly awkward moment, given that the question had been considerably longer than the reply.

It concerned Greene's specialist area, the brain-meltingly complex field known as superstring theory, the combination of calculation and cosmic observation that attempts to reconcile the fundamental differences between quantum theory and classical physics.

Briefly, it works (and it has to work, otherwise Albert Einstein, or Isaac Newton, or both, were wrong) by positing the existence of several extra dimensions in addition to the four we're used to: all tiny, all curled up and vibrating like subatomic strings. It is superstring theory that gives rise (not just logically, but inevitably) to the well-worn sci-fi tropes of infinite universes, parallel and multiple.

The mathematics that underpin string theory are thoroughly tested and robust. The empirical evidence, however, given the size of the cosmos and the limitations of human engineering, is a bit thin on the ground.

My question had concerned whether anything discovered in the past 12 months had provided an indication that Greene's work was on the right track.

Maths the key to the cosmos

Greene, thankfully, is not just a skilled theorist, he is also a master communicator and well used to chatting to the media. He was not about to leave a reporter hanging on a monosyllable.

"There's been some progress in physics with the first detection of gravitational waves [predicted by string theory], which obviously gives us yet more confidence that mathematics does shine this wonderful light into the dark corners of reality," he said.

"If you follow the math, sometimes it really takes you to true things about the world. Obviously, that's what we do as string theorists, but just because it's worked in this one case doesn't mean it will work in others, so the bottom line is string theory is still beyond the direct reach of the machines we have at the moment."

These machines, by the way, are not the kind of kit you can pick up at Bunnings. They range from the Hubble Space Telescope to the Large Hadron Collider. Big as they are, they are still not big enough.

"It would take a minor miracle, a confluence of every possible way in to assessing the theory, to really get some good data in the next few years," he added.

And Greene, of course, being a physicist, isn't in the miracle business – which is probably why Donald Trump didn't pick him as his new science supremo.

Scientist with showbiz in the genes

Like the President, however, he is very much at home on the small screen. Handsome at 53, he is in constant demand on United States television and radio, where his easy manner and ready humour make him one of the high profile go-to guys when it comes to science stories, alongside cosmologist Neil deGrasse Tyson and popular presenter Bill Nye.

Despite this, he is still heavily involved in the number-crunching grunt work of coal-face theoretical physics. His most recent academic paper – due for publication soon – is called Numerical Evaluation of Accelerated-Assisted Entanglement Harvesting. Non-string theorists will likely be lost before the end of the first sentence of the abstract, as soon as they hit the phrase, "two accelerating Unruh detectors coupled to a scalar field".

But academic papers are not intended for a general audience. Greene's books – among them The Fabric of the Cosmos (2004) and The Hidden Reality (2011) – and his stage shows are. And it is in this field that he feels keenly the benefits of his New York upbringing.

His father was a vaudeville showman – a link he shares, coincidentally enough, with his close friend and collaborator Alan Alda. (This reporter once asked the great actor if the pair ever discussed paternal similarities. Alda brushed the idea aside, stating that whenever he was with Greene he had far too many questions to ask about science to worry about father stuff.)

"I grew up in a family where performance was central to our day to day activities," he said.

"My father was a vaudevillian, a comedian, a singer, a bass fiddle player – so that notion of reaching out to the world and communicating with a wider public was certainly with me since I was quite young.

"Obviously I went in a very different direction, but at least in some of the things I do I feel like it's coming a little bit full circle."

Universally intriguing mysteries of time

These things include guest appearances on sitcom The Big Bang Theory and the 2000 sci-fi flick Frequency, starring Dennis Quaid. His 2008 children's book, Icarus at the Edge of Time, was adapted to film, with minimalist composer Philip Glass (he of Einstein on the Beach and Songs from Liquid Days fame). At last year's World Science Festival he teamed up with Alda for Dear Albert, a piece written by Alda and based on letters to Einstein.

The festival, by the way, began in New York in 2008, founded by Greene and his wife, science journalist Tracy Day. In 2015, it took up secondary residence in Brisbane – and will take place there again this year starting on March 22.

Thereafter, at the end of the month, he will visit Melbourne and Sydney to present his latest show, A Time Traveller's Tale, a multi-media collaboration with Melbourne-based rapper and spoken word artist Hugo the Poet.

"Among all the things that happen in science, I find the nature of time is the one subject that grabs people deeply," said Greene.

"It certainly grabs me. What's the one thing you want to know about before you die? I would say I want to know what time is. I want to know where it comes from. I want to know if it's fundamental or if it's something that we humans invent to let us order our lives. It's one of the most mysterious concepts we've ever encountered."

With string theory concentrating much of its focus on the instant after the Big Bang, at which space and time first came into being, there is probably no one more qualified to turn the subject into an entertaining romp.

The Trump era: 'perhaps there's a silver lining'

It will, of course, be an exercise in explaining something that is almost – but not quite – inexplicable. It's a skill that Greene thinks has suddenly become much more important, now that, to use a term coined by Richard Dawkins, the anti-Enlightenment movement is in charge.

"The change in the administration in the United States is a very loud and urgent wake-up call to all scientists who have become accustomed to a world in which science is respected and funded," he said.

"It's going to require a vigilance now, it's going to require an attention to the day-to-day happenings in Washington DC to avoid things going in what could well be a dangerous and very unfortunate direction for all that science has achieved in the last 500 years.

"I certainly feel that I'm more attentive and more engaged to what's happening right now than I ordinarily would be, so perhaps there's a silver lining to all this, where scientists will take a greater stake in what's happening in the world of politics."

In these early days of the Trump White House, Greene's analysis seems to be playing true, with "rogue" Twitter accounts springing up from muzzled science agencies, and the formation of an organisation called 314 Action, which comprises more than 400 scientists pledging to stand for public office. (The name is derived from the first three digits of Pi, in case you were wondering.)

"At the end of the day, a rational perspective that evaluates truth based on observation and data and fact," said Greene, "does not solve government's problems, but it does at least set the ground for rational decision-making. And that's what we have to ensure happens."

Dangerous appeal of 'alternative facts'

One of the issues identified by several observers in recent weeks is that scientists are often people who talk in complex terms about complex matters, and thus confuse the hell out of lay-people. Popularists and conspiracy theorists offer easy to understand pseudo-alternatives, and therein lies their terrible and seductive lure.

What are needed, more than ever, said Greene, are scientists and science communicators who can cross the divide between academia and the mob.

"We need to have a general public that's not cut off from science, that doesn't feel that science is another universe," he said. "Because if you have a public like that and a government comes along and starts to spout things that are absolutely untrue, the public won't necessarily feel that they are in a position to assess that."

With climate change off America's agenda, the baseless vaccination-autism link revived by Trump's inner circle, and blue-sky research into the origins of the universe derided from on high as a waste of money, these are dark days indeed for science.

Greene, though, remains optimistic. He probably has to, the alternative being despair.

"There is still hope, except now the hope has to be generated by we the people," he said. "We need to take the lead in crafting and ensuring that hope."

Brian Greene: A Time Traveller's Tale, Sydney, March 30 and Melbourne, March 31. For more information: thinkinc.org.au  He will also appear at the World Science Festival in Brisbane, March 22-26.