JLF 2018: Harvard astrophysicist says only 5% of universe is made of atoms that we understand
Speaking at the Jaipur Literature Festival 2018, Harvard astrophysicist Lisa Randall explains how dark matter and dinosaurs made human beings possible.
In an unusual first session of a literature festival, this year’s Jaipur Literature Festival’s Charbagh venue opened with Prof. Lisa Randall, a theoretical physicist at Harvard, speaking about her book Dark Matter and the Dinosaurs: The Astounding Interconnectedness of the Universe invoking everything from the Barringer Crater in Arizona to the problems of having a human-centric worldview. As Angela Saini, author of Inferior: How Science Got Women Wrong, introduced the speaker, a well-timed joke about how dinosaurs may have become extinct from earth, but we still have them in academia seemed perfectly in place.
Dark matter, Randall insists is a misnomer. This is matter that does not interact with light in the way that all matter and atoms we know does. And since we’re not exactly sure what it is, we call it “dark”. It’s a concept that’s a bit hard to grasp. Only 5% of the universe is made up of ‘ordinary’ atoms, and all of the rest is either dark matter or dark energy. That we, humans, are not the stuff of the universe; that everything we know and recognise and are capable of studying is only 5% of everything out there is a sobering thought.
Perhaps this dark matter has a light of its own, suggests Randall. Perhaps we think it is ‘dark’ simply because we don’t know how to understand or ‘see’ its interactions.
“But what does all this have to do with dinosaurs?” asks someone in the audience to their neighbour. As though on cue, Randall explains how this mysterious stuff of the universe may have been the reason a comet was nudged into its orbit and then crashed into the earth at an insane speed some 66 million years ago.
That was what caused the dinosaurs to go extinct. A crash like that could have triggered earthquakes, tsunamis and forest fires causing the mighty dinosaurs to go extinct: “Land dwelling ones,” Randall explains, “because there is evidence that birds may have descended from the others.”
And if these massive reptiles hadn’t become extinct, mammals would never have taken over the world. And humanity would never have come into being. The interconnectedness of the universe, indeed.
As the audience began asking questions about the possibility of other dimensions of space, and whether climate change could be a result of cosmic phenomenon, one worried gentleman asked how likely another collision was and if the Jaipur Literature Festival would have to be shut down because humanity would be extinct! In response, Randall explained how another collision could certainly happen, “but it’s only been about 2 million years since we last passed through the dark matter disc”. A collision was only likely in about 30 million years. So, we aren’t in danger of extinction by asteroid. Randall conceded, though, that she wasn’t ruling out any other causes.
Another gentleman wondered if the “ancient Hindu” idea of “the soul and an unconscious energy” could have been referring to dark matter and if perhaps, “dark matter was an invisible god?” Randall’s response: “Since it seems like a ‘yes’ or ‘no’ question, ‘no’.”
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