Post by pim on Nov 17, 2016 15:09:17 GMT 10
... than are dreamt of in anyone's philosophy - with apologies to the Bard!
Dark matter, other dimensions, "mysterious matter that's not made of the stuff we're made up of ..." I understand this lady's a very public atheist, but I doubt she'd disagree with the Bard in that Hamlet quote ...
Did dark matter kill the dinosaurs? Dr Lisa Randall answers your questions
mobile.abc.net.au/news/2016-11-16/dr-lisa-randall-answers-questions-did-dark-matter-kill-dinosaurs/8030592?section=science
Dr Lisa Randall is known for her radical theory of dark matter wiping out dinosaurs and planet Earth.
Dr Lisa Randall has been dubbed America's "superstar scientist". She is known for her radical theory of dark matter wiping out dinosaurs, and for her research on extra dimensions. Lateline received many viewer questions for Professor Randall, including from prominent scientists. Here are her responses to some of the best.
Your book Dark Matter and the Dinosaurs poses a very interesting hypothesis — how is it possible that one may have killed the other?
"Sixty-six million years ago a giant meteorite, 10-15 kilometres in size, came to Earth and basically wiped out three quarters of the species on the planet including the dinosaurs… Now it is possible it was random, but it could be that every time the solar system bobs up and down through the Milky Way, there's this extra gravitational tidal force from this dense disc of dark matter, mysterious matter that's not made of the stuff we're made up of… and it's possible that that matter triggered very weakly-bound objects at the edge of the solar system, something called the Oort Cloud. So maybe one of these giant objects was triggered so that it would leave the solar system or come hurtling towards Earth."
ABC science journalist Robyn Williams asks, how may have dark matter changed the shape of the universe?
"Dark matter is responsible in many ways for the shape of our universe. And galaxies basically are what's responsible for everything we know about the star formation, everything that allowed for complex things to happen because stuff got denser. And the reason dark matter was essential is actually twofold ..."
Dr Lisa Randall is a theoretical physicist and an expert on particle physics and cosmology
"One is that there is more energy carried by dark than ordinary matter… there's about five times as much matter as stuff that we don't know what it is. But because there was that much more matter, stuff could start to clump sooner. Light doesn't clump, only matter clumps, so because there was more matter for structure to begin to form sooner, it could turn into the kind of structures we see today. And the other reason is that dark matter doesn't interact with light the way ordinary matter does and light would wash out structure on, say, a galactic scale. So because dark matter could clump, ordinary matter could kind of come along for the ride and hitchhike, and so therefore it could all get formed into galaxies."
How are scientists planning to use the Large Hadron Collider to prove the existence of extra dimensions?
"To put this in context, I wrote a book about 10 years ago or so called Warped Passages… We had this idea that maybe gravity is so weak because gravity is concentrated in another dimension. Now everyone is rolling their eyes, what do we mean by another dimension? Well the fact is, I can't see this other dimension either, but we can actually figure out mathematically what would happen if this other dimension existed. "And so it's a very natural explanation for a very major problem we have in particle physics. Now why do we care about it? Well, if it does solve this problem, then it does have testable consequences at this machine you mentioned, the Large Hadron Collider where protons get accelerated and collide together. Because it could be that if the energy is high enough, and that's a big 'if' … it could produce particles that travel in the other dimension, that have momentum associated with the other dimension."
Astrophysicist Dr Alan Duffy asks, as a theoretical astrophysicist undertaking exciting research to worldwide acclaim, are you worried about the push from governments and funding bodies to ever more short term and practical focused outcomes?
"I'm very worried about that as a theoretical physicist, as a scientist, but even throughout society. Governments these days really focus on short-term thinking and it doesn't work in the long run. The classic examples that we give in theoretical physics are general relativity is used for GPS, or even, the internet and all the electronics revolution actually came out of semiconductors, which came out of quantum mechanics, and nothing could seem more theoretical than that. And people were not thinking about these things — if you asked what would this be good for, no-one knew. Even in other scientific fields, I always like to say, Watson and Crick were not trying to solve cancer, they were trying to find out the structure of DNA, but now the genetics revolution is changing the way people are thinking about biology, medicine and science. So it's just a mistake to focus so exclusively on that because really by trying to address problems, theoretical problems, we've made so much progress."
Dark matter, other dimensions, "mysterious matter that's not made of the stuff we're made up of ..." I understand this lady's a very public atheist, but I doubt she'd disagree with the Bard in that Hamlet quote ...
Did dark matter kill the dinosaurs? Dr Lisa Randall answers your questions
mobile.abc.net.au/news/2016-11-16/dr-lisa-randall-answers-questions-did-dark-matter-kill-dinosaurs/8030592?section=science
Dr Lisa Randall is known for her radical theory of dark matter wiping out dinosaurs and planet Earth.
Dr Lisa Randall has been dubbed America's "superstar scientist". She is known for her radical theory of dark matter wiping out dinosaurs, and for her research on extra dimensions. Lateline received many viewer questions for Professor Randall, including from prominent scientists. Here are her responses to some of the best.
Your book Dark Matter and the Dinosaurs poses a very interesting hypothesis — how is it possible that one may have killed the other?
"Sixty-six million years ago a giant meteorite, 10-15 kilometres in size, came to Earth and basically wiped out three quarters of the species on the planet including the dinosaurs… Now it is possible it was random, but it could be that every time the solar system bobs up and down through the Milky Way, there's this extra gravitational tidal force from this dense disc of dark matter, mysterious matter that's not made of the stuff we're made up of… and it's possible that that matter triggered very weakly-bound objects at the edge of the solar system, something called the Oort Cloud. So maybe one of these giant objects was triggered so that it would leave the solar system or come hurtling towards Earth."
ABC science journalist Robyn Williams asks, how may have dark matter changed the shape of the universe?
"Dark matter is responsible in many ways for the shape of our universe. And galaxies basically are what's responsible for everything we know about the star formation, everything that allowed for complex things to happen because stuff got denser. And the reason dark matter was essential is actually twofold ..."
Dr Lisa Randall is a theoretical physicist and an expert on particle physics and cosmology
"One is that there is more energy carried by dark than ordinary matter… there's about five times as much matter as stuff that we don't know what it is. But because there was that much more matter, stuff could start to clump sooner. Light doesn't clump, only matter clumps, so because there was more matter for structure to begin to form sooner, it could turn into the kind of structures we see today. And the other reason is that dark matter doesn't interact with light the way ordinary matter does and light would wash out structure on, say, a galactic scale. So because dark matter could clump, ordinary matter could kind of come along for the ride and hitchhike, and so therefore it could all get formed into galaxies."
How are scientists planning to use the Large Hadron Collider to prove the existence of extra dimensions?
"To put this in context, I wrote a book about 10 years ago or so called Warped Passages… We had this idea that maybe gravity is so weak because gravity is concentrated in another dimension. Now everyone is rolling their eyes, what do we mean by another dimension? Well the fact is, I can't see this other dimension either, but we can actually figure out mathematically what would happen if this other dimension existed. "And so it's a very natural explanation for a very major problem we have in particle physics. Now why do we care about it? Well, if it does solve this problem, then it does have testable consequences at this machine you mentioned, the Large Hadron Collider where protons get accelerated and collide together. Because it could be that if the energy is high enough, and that's a big 'if' … it could produce particles that travel in the other dimension, that have momentum associated with the other dimension."
Astrophysicist Dr Alan Duffy asks, as a theoretical astrophysicist undertaking exciting research to worldwide acclaim, are you worried about the push from governments and funding bodies to ever more short term and practical focused outcomes?
"I'm very worried about that as a theoretical physicist, as a scientist, but even throughout society. Governments these days really focus on short-term thinking and it doesn't work in the long run. The classic examples that we give in theoretical physics are general relativity is used for GPS, or even, the internet and all the electronics revolution actually came out of semiconductors, which came out of quantum mechanics, and nothing could seem more theoretical than that. And people were not thinking about these things — if you asked what would this be good for, no-one knew. Even in other scientific fields, I always like to say, Watson and Crick were not trying to solve cancer, they were trying to find out the structure of DNA, but now the genetics revolution is changing the way people are thinking about biology, medicine and science. So it's just a mistake to focus so exclusively on that because really by trying to address problems, theoretical problems, we've made so much progress."
