Mapping the Heavens
About This Project
Mapping Dark Matter
Priyamvada Natarajan: When you’re looking out into the night sky, you’re looking back in time, so we’re seeing light from galaxies that left billions of years ago. I find that still so intriguing even after all these years of being a professional astrophysicist I find that so incredible.
Heather McElhatton: That’s Priyamvada Natarajan, she’s an astrophysicist, and a professor in the Department of Astronomy at Yale. She says her love of the heavens started early, when she was 14 in New Delhi, and she saw Haley’s Comet through a telescope. She says she was hooked.
Natarajan: I
had a commodore 64 and I learned how to program it, and I was itching to do something with my skill of programming. So, I went to the Nehru Planetarium, which had this new director, and she said “Well, why don’t you make a map of the sky for Delhi, so you can tell us every month which planets you can see – sort of a star map.”
McElhatton: It was a hard problem, Priya says it took her 6 weeks to crack the code and create a starmap.
Natarajan: She couldn’t really believe I’d done it. Then she said, “But what if you moved to Boston or Brisbane, wouldn’t you want to know what the night sky looks like?” So I said “Oh, I’ve already done it. You just have to put the latitude and longitude of any place on earth and I can fire up the map for you.”
McElhatton: Today her specialty is mapping one of the most elusive substances in the universe: DARK MATTER.
Natarajan: Dark Matter is some kind of exotic particle that is likely produced in the early universe, that doesn’t emit, absorb or reflect light. It merely deflects light. And this is stuff that’s not in the periodic table. This is not the stuff we are made of, this is something entirely different.
McElhatton: Priya says the entire universe is replete with dark matter, it’s everywhere, but it’s not spread out evenly.
Natarajan: So it’s lightly smeared in some places, and kind of lumped in some places. And if you think of space as some sort of stretchable fabric, the presence of matter will cause a pothole where the matter is.
McElhatton: These potholes in space allow priya to locate and map dark matter.
Natarajan: And because the universe is this sheet, there’s nothing above or below, light travels along this sheet. So light from a distant galaxy when it arrives at us at a telescope on earth, has actually traversed all these potholes and all these bumps.
McElhatton: Priya is able to create highly detailed dark matter maps using exquisite data gathered form the Hubble Space Telescope.
Natarajan: My contribution has been to map the dark matter in its full granularity, so to pick out all the little lumps and bumps, and the reason for that is the nature of dark matter is illusive. We dont actually know what it is, but the way in which dark matter lumps may hold a clue to what it might be made of.
McElhatton: Priya’s book,”Mapping the Heavens” explores her work with dark matter and some of the more radical ideas that reveal the cosmos. It discusses black holes, the expansion of the universe, the big bang, the discovery of exoplanets, and the possibility of other universes. Priya also discusses why the acceptance of new ideas about the universe and our place in it has never been linear and always contested even within the scientific community.
Natarajan: So one of my interests is really the arc of acceptance of radical scientific ideas. Particularly in cosmology if you look at the last 100 years we’ve had dramatic shifts in our understanding of the cosmos.
McElhatton: This is handy, as the very topic of dark matter is controversial. Some scientists don’t even believe it exists. Priya affirms that shifting and incomplete as science always must be, it still offers the best path we have toward making sense of our wondrous, mysterious universe.
Natarajan: A beautiful world is a world in which we are aware of the preciousness of our planet, and the resources, and the sheer luck and serendipity that we’re born now, when we have all the advantages that science and technology have offered us.
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