Without Dark Matter, It's Unlikely That Any of Us Would Exist at All
Never have so many owed so much to — something so invisible.
Lisa Randall studies theoretical particle physics and cosmology at Harvard University. Her research connects theoretical insights to puzzles in our current understanding of the properties and interactions of matter. She has developed and studied a wide variety of models to address these questions, the most prominent involving extra dimensions of space. Her work has involved improving our under-standing of the Standard Model of particle physics, supersymmetry, baryogenesis, cosmological inflation, and dark matter. Randall’s research also explores ways to experimentally test and verify ideas and her current research focuses in large part on the Large Hadron Collider and dark matter searches and models.
Randall has also had a public presence through her writing, lectures, and radio and TV appearances. Randall’s books, Warped Passages: Unraveling the Mysteries of the Universe’s Hidden Dimensions and Knocking on Heaven’s Door: How Physics and Scientific Thinking Illuminate the Universe and the Modern World were both on the New York Times’ list of 100 Notable Books of the Year. Higgs Discovery: The Power of Empty Space was released as a Kindle Single in the summer of 2012 as an update with recent particle physics developments.
Randall’s studies have made her among the most cited and influential theoretical physicists and she has received numerous awards and honors for her scientific endeavors. She is a member of the National Academy of Sciences, the American Philosophical Society, the American Academy of Arts and Sciences, was a fellow of the American Physical Society, and is a past winner of an Alfred P. Sloan Foundation Research Fellowship, a National Science Foundation Young Investigator Award, a DOE Outstanding Junior Investigator Award, and the Westinghouse Science Talent Search. Randall is an Honorary Member of the Royal Irish Academy and an Honorary Fellow of the British Institute of Physics. In 2003, she received the Premio Caterina Tomassoni e Felice Pietro Chisesi Award, from the University of Rome, La Sapienza. In 2006, she received the Klopsteg Award from the American Society of Physics Teachers (AAPT) for her lectures and in 2007 she received the Julius Lilienfeld Prize from the American Physical Society for her work on elementary particle physics and cosmology and for communicating this work to the public.
Randall has also pursued art-science connections, writing a libretto for Hypermusic: A Projective Opera in Seven Planes that premiered in the Pompidou Center in Paris and co-curating an art exhibit for the Los Angeles Arts Association, Measure for Measure, which was presented in Gallery 825 in Los Angeles, at the Guggenheim Gallery at Chapman University, and at Harvard’s Carpenter Center. In 2012, she was the recipient of the Andrew Gemant Award from the American Institute of Physics, which is given annually for significant contributions to the cultural, artistic, or humanistic dimension of physics.
Professor Randall was on the list of Time Magazine's "100 Most Influential People" of 2007 and was one of 40 people featured in The Rolling Stone 40th Anniversary issue that year. Prof. Randall was featured in Newsweek's "Who's Next in 2006" as "one of the most promising theoretical physicists of her generation" and in Seed Magazine's "2005 Year in Science Icons". In 2008, Prof. Randall was among Esquire Magazine's “75 Most Influential People.”
Professor Randall earned her PhD from Harvard University and held professorships at MIT and Princeton University before returning to Harvard in 2001. She is also the recipient of honorary degrees from Brown University, Duke University, Bard College, and the University of Antwerp.
Lisa Randall: Dark matter is just a form of matter, which is to say it acts like matter when it comes to gravity. So it clumps together like the matter we know about. It’s found in galaxies, for example, because of gravitational force. What distinguishes dark matter from ordinary matter is that it has no interaction as far as we know with light. So we see ordinary matter. It’s made up of atoms. Atoms are made up of charged particles. But so far as we know, dark matter is just an entirely new form of matter not made up of atoms, not made up of the stuff we’re familiar with. And the question we eventually have is what is it made up of exactly?
But as far as the physics of the universe goes, it’s just a form of matter. The reason we’re aware of dark matter is because of the gravitational effects. In fact, if you look at just the energy stored there’s five times as much dark matter as there is ordinary matter. So you observe this gravitational effects in galaxies for example. I mean one of the ways we first knew about dark matter was by looking at the motion of stars. The motion of stars responds to the gravitational force of all the matter around. It doesn’t care whether or not it interacts with light. The stars of course are bright because they interact with light. But they’re responding to the gravity of the matter including the dark matter. So that was evidence for dark matter. And now there’s lots of other evidence for dark matter too having to do with the way light bends or what galaxy clusters look like when they merge. So there’s really a lot of physical evidence that tells us dark matter is out there in the universe. Then the question for theoretical physicists like myself becomes: What is this stuff and what do we mean by that? Well, is it an elementary particle? Is it more than one elementary particle? If it is a particle, what is the mass of that particle? Does it have any interactions at all?
So far we haven’t seen any interactions with the light with which we’re familiar, but maybe there’s a small interaction that we just haven’t seen yet or maybe it attracts in an entirely different way. The only thing we know for sure is that there is this matter and it interacts via gravity. Dark matter was actually essential to the formation of structures we see in the lifetime of the universe. Now it’s important to say structures we see in the lifetime of the universe. Even without dark matter, structure would have formed. But the actual size of the galaxies that we see is only possible because dark matter was present. Ordinary matter interacts with radiation. Radiation would have washed away small objects like galaxies. Now I realize galaxies don’t seem small to you, but on the scale of what radiation could wash away they’re actually small. So dark matter was essential to forming objects of that size. It also was important because it meant that matter came to dominate over radiation sooner in the evolution of the universe because there was a lot more matter. And again matter domination is important for the formation of structure because radiation won’t form structure. I mean just think about it. Light’s not clumping into little balls the same way matter would. So both because of its abundance and because it doesn’t interact with light, dark matter was actually essential to the formation of the structure that we see.
Here's what we know about dark matter:
1. It's there.
2. Its gravity affects things around it.
3. Aside from those two, we don't really know much.
That doesn't mean there aren't plenty of people who would like to help out...
Physicist Lisa Randall steps up to the Big Think camera this week to share her thoughts on dark matter and space in general. She's just recently published a book about dark matter, called Dark Matter and the Dinosaurs: The Astounding Interconnectedness of the Universe.
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