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Home » Transcript: The Brutal Truth About Astrology! – Neil deGrasse Tyson on DOAC Podcast

Transcript: The Brutal Truth About Astrology! – Neil deGrasse Tyson on DOAC Podcast

Read the full transcript of world-renowned astrophysicist Dr Neil deGrasse Tyson’s interview on The Diary Of A CEO with host Steven Bartlett, October 13, 2025.

Existential Curiosity and Mortality

STEVEN BARTLETT: I’ve been watching a lot of videos of yours, I think, because I’ve reached the stage in my life where I’ve become really existentially curious.

DR NEIL DEGRASSE TYSON: I think we all do at some point, and especially the more you’ve lived, the more it all sort of… You ask, what does it all mean? How does it all come together? What will it mean in five years, 10 years?

I don’t know if you’re old enough to think about your mortality, but that’s a thing when you have fewer years left than the years you’ve lived. And I think the way they say it is, you can have a good expectation to live as long as your parents did. I lost both of them in the last five years, so that’s my horizon.

And the fact that we die has a capacity to bring focus into the remaining time you’re alive. Because think about it: if knowing you’re going to die brings focus and purpose and resolve and action, then if you live forever, what’s your hurry?

For me, knowing I’m going to die gives meaning to my remaining life, whereas if I’m never going to die, then mathematically that would mean I’d lead a life of no meaning at all, because there’s no way to focus an infinite amount of time into anything and have it be meaningful.

So I’m taking mortality as a very serious force operating on happiness, productivity. Can you do something for the world? And on my tombstone, what I want it to say is a quote from Horace Mann: “Be ashamed to die until you have won some victory for humanity.”

I want to have made a difference in the world. I want the world to have been better off because I lived in it. Is that too much to ask of any of us, really? We’re all capable of good deeds. So if the world is better off, I played my part as a citizen of planet Earth.

The New Book: Just Visiting This Planet

STEVEN BARTLETT: And this all sort of dovetails into this new book that you’ve written. I call it a new book, but it’s really a revision of a very successful book that I think the first copy was published in 1998, called “Just Visiting This Planet: Merlin Answers More Questions About Everything Under the Sun, Moon, and Stars.”

DR NEIL DEGRASSE TYSON: Yeah.

STEVEN BARTLETT: When I think about these bigger questions about the universe, meaning, purpose, death, why am I here, religion, all these things, so often I think about them through the context and information that I find in your work.

Because when I think of the world being so big as you talk about in this book, and so infinite and all these stars, I feel meaningless. And in a nice way, sometimes I feel like the things that I worry about no longer matter. But then when you talk about…

DR NEIL DEGRASSE TYSON: You feel meaningless in a happy way.

STEVEN BARTLETT: Yeah. I feel like the things that cause me suffering don’t matter as much as I thought they did. And then you talked about shortening time by realizing that you’re going to live for 90 years or 80 years, creating great amounts of meaning. And it feels somewhat like a… I don’t know.

The Scale of the Universe

DR NEIL DEGRASSE TYSON: Yes, the universe is huge in size, in age, in contents. There’s nothing we can put on the table that can rival those measurements that we make of the universe, however.

STEVEN BARTLETT: How big?

DR NEIL DEGRASSE TYSON: Well, the light from the most distant galaxies has been traveling for nearly 14 billion years, 10 billion years more than Earth has even existed, if you want to get a sense of that.

But think about it a whole other way: if you look at the ingredients of life, not just human life, but life on Earth, and you can rank the elements. What’s the number one element in life? We mentioned the human body. Number one element is hydrogen. That’s contained in the H₂O of the water content of your body, which, depending on how chubby you are, anywhere from a half to three quarters of your body weight is water.

And all right, what’s the next most abundant element in your body? It’s oxygen attached to the water. H₂O. And both the H and the O appear in many, many other molecules in our body, in the DNA and then your muscle tissue, all of this, and in the blood.

What’s third? Carbon, which you would have thought had to be somewhere in the list because you know we’re carbon-based life. Fourth is nitrogen. Fifth, I’ll put them all together and just say “other.”

So that’s the sequence of elements. And now you say what are the sequence of elements in the universe? The number one is hydrogen, the number two is helium, but that’s chemically inert. You might remember from high school chemistry, you can’t do anything with it anyway. Helium. Next in the universe: oxygen. Next: carbon. Next: nitrogen. Next: other.

So we are one for one, matched to the ingredients of the universe. And one of the gifts of 20th century astrophysics, gifts to civilization, is where those ingredients came from. We trace those ingredients, the hydrogen, to the Big Bang itself and all these heavier elements to stars that manufactured those elements in their core, in the crucible that is their core.

They lived out their lives, they exploded, scattered that enrichment into gas clouds so that the next generation of stars would have planets, and at least one of them have life as we know it, life on Earth.

We Are Stardust

So we can think of us not just figuratively, but literally composed of stardust.