26 Jan 2020

Dr Neil deGrasse Tyson: Letters from an Astrophysicist

From Sunday Morning, 10:05 am on 26 January 2020

Astrophysicist and host of National Geographic's StarTalk, Dr Neil deGrasse Tyson's has attracted one of the world's largest online followings with his fascinating, widely accessible insights into science and our universe.

He joined Jim Mora to discuss his new book, Letters from an Astrophysicist and why people need to get over the fact that Pluto was downgraded to dwarf planet status 14 years ago.

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Photo: Supplied

A couple of the letters in the book are from people vexed about the status of Pluto after it was downgraded to a dwarf planet 14 years ago. In one, Dr Tyson is called a ‘big poo poo head’ for his stance on the issue.

“Get over it! I wish I could be kinder and maybe more sensitive to your emotions about this, but Pluto never should have been ranked as a planet from the beginning.”

He says it was only out of ignorance that Pluto was given the status of planet in the first place and each decade since scientists have discovered it’s smaller than previously thought.

“It’s made of mostly ice. If it came near the sun, it would grow a tail like comets do. There are other objects of commensurate size orbiting with it in the outer solar system. So, while we lost a planet, we gained a swarm of icy bodies in the outer solar system called the Kyper Belt of objects. I think Pluto’s happier there, because it’s with brethren.”

One of the aspects of astronomy that makes it such a vibrant scientific field is the amount of mystery still out there in the universe.

“I kid about the fact that we don’t know what dark matter is. We can measure that it’s there, but we don’t know what’s causing it. It’s really dark gravity, if you want to be specific, we measure its gravity but we don’t see anything causing it.

“Dark energy is some mysterious pressure in the vacuum of space forcing the universe to accelerate in its expansion. We don’t know what’s causing that either. I joke because we shouldn’t even be giving it a name at all, because that could bias you.”

For instance, he says dark matter may not be matter and dark energy may not be energy.

“We have no clue. We may as well just call it Fred and Wilmar.”

Not all the letters in the book relate to matters of the universe. Some are deeply personal and, in his answers, Dr Tyson reveals a side of himself he normally keeps hidden.

“For my replies, I make sure I fulfill an unstated contract with the person. I could just give an encyclopaedic answer, but then I wouldn’t be walking in their shoes. I wouldn’t have a sensitivity to what mattered to them. So, when I communicate, I try to make sure that what I say is maximally sensitive to where they are coming from where they want to go.”

Dr Tyson is a self-proclaimed atheist and has said in the past that, seeing all the ways the universe wants to kill us, he can’t believe in a benevolent God. A commonly held thread among atheists is that science will eventually explain everything with no room for God. Instead, as scientific progresses, the room for God remains.

“There’s no end of gods whose dominion over the natural world has been entirely usurped by the tools and methods and discoveries of science. Not only that, we no longer live in a world where religious heads control world politics.”

He says the main thing that puts him off the main three monotheistic religions – Islam, Judaism and Christianity – is that, if God is all powerful and all good, why is there suffering in the world.

“If you’re best answer is ‘God moves in mysterious ways’ then that’s really the end of the conversation.”