This is the 2009 lecture from Lawrence Krauss, given at the invitation of Richard Dawkins, covering the big questions of cosmology. In about an hour he covers the origins of the universe and how we know about it.
We’ve posted clips of this lecture, but I don’t think we’ve posted the entire lecture before. It’s an hour long, but it’s both fascinating and funny.
Via Open Culture
I love this lecture, but I’m a bit confused when he says that all the matter we can see and perceive is less than %1 of the mass of the universe, when Richard Panek published a book saying that what we can perceive is %4. Can anyone shed any light on this?
BTW, Lawrence Krauss should stick to seminars, and avoid the debates >.>
Well it depends on what you mean by “matter we can see and perceive.” About 4% of the universe is baryonic matter (matter made mostly of protons and neutrons), but about 90% of that (so 3.6% of the universe) is diffuse intergalactic plasma. Only 0.4% of the mass of the universe is bright matter in galaxies.
Oh wait, I didn’t see Panek’s reply below. So yeah, what he said.
I’m the author of the book that Nzo mentions, The Four Percent Universe: Dark Matter, Dark Energy, and the Race to Discover the Rest of Reality. Perhaps I can shed some light (no pun intended–honest!) on the question. The 4 % (actually, 4.6 %) refers to baryonic matter–matter made up of neutrons and protons. The difference between that 4% and the 1% that Krauss mentions could refer to baryonic matter that we know is there but haven’t been able to see. These two sites might help. The first explains the 4.6 number. The second gives some insight into the kind of matter that is “missing,” loosely speaking. And thanks for citing my book!
http://map.gsfc.nasa.gov/universe/uni_matter.html
http://sanantonioskywatch.com/2010/05/16/much-of-the-missing-baryonic-matter-found/
Thanks for the reply Richard, and sorry for the late response!
Those links cleared it up, as did your explanation, and Michael’s above.
I’m really happy that you posted, I’ve been wanting to grab your book for a while, but (insert generic ‘busy’ ‘lazy’ ‘haven’treadanactualbookinforever’ comment.) I’ll have to buy it now, regardless. It’s not every day a published and established author on a subject you’re interested in answers your question!
What’s the best way to go about getting an signed copy?
Thanks, Nzo. Glad these explanations helps. By now you’ve probably heard that the discovery of evidence for dark energy has won the Nobel in Physics. Very exciting! As for a signed copy of my book, please e-mail me and I’ll give you my address. Thanks again.
The Nobel, eh? It hadn’t trickled down the grapevine to me, but that’s really awesome, I’ll have to read up on it!
Any srvr munkehs able to get Richard’s email to me? Thanks in advance!
Oh, I thought you’d just be able to see it somehow. Try richard.panek@goddard.edu
Excellent talk! Wow.
Silly Atheists! The answer to the question of “Dark Matter” is simple: JESUS! JESUS is 95.4% of the matter in the Universe!
There! Problem Solved! I await my Nobel Prize in Physics!
(/sarcasm tag/lol)
Pingback: ‘A Universe From Nothing’ by Lawrence Krauss, AAI 2009 | Unsettled Christianity
Pardon my question, I have not watched the video yet, but the subject caught my attention. What does dr. Krauss define as “nothing”? Is he referring to the “vacuum” or an actual nothingness (no space, energy, or time)?
Vacuum is not nothing.
I know that the vacuum is not nothing, but I’ve heard some scientists from various disciples call it such. I was just wondering if Krauss did the same thing. Its a rather frustrating trend amongst PBS specials on the universe and its beginning!
No> he doesn’t equate his definition of “nothing- ness” to what you or I may very well connotate. He postulates that in empty space there is still mass, and when magnified (using quantum physics) it can be shown that the “nothing” that is found within this space, can be mechanized to originate the entirtey of the universe. In fact, mathematically, he demonstrates that this “nothing- ness” is precisley the reason matter, energy and all rest of evolution occurs in the first place.
I, for one, am more informed for having spent an hour watching the lecture. Thanks, UF!
I’m not a physicist, but I am a scientist, and my general training includes the notion that the vacuum is not nothing (although that’s a pretty good approximation of what a vacuum is for most ordinary purposes). Instead, at the very finest levels, the quantum vacuum is a seething cauldron of particles popping in and out of existence whose energies average to zero.
I have never studied the math behind it, and beyond the above conceptualization I get lost, if I am not lost already. Would a real physicist care to enlighten us?
Thats a great explanation. And yes more enlightening please!
We have to be careful about this idea of nothing that we are attached to. If we use common language nothing mean absolutely nothing, no space, no time, no matter, no energy. If we believe in the supernatural nothing probably would also mean no spirit or soul of any kind. But this nothing then becomes impossible by definition. If doesn’t contain anything, if it is not made of anything, if it is the opposite of anything that may exist then is not even possible, it is the opposite of existence. But this why physicists say “Shut up and calculate !”. Words and metaphysical word games are not a good way of describing reality. We didn’t do much progress by playing word games. Anything achieved by science and physics in particular has been achieved by finding relationships between measurable quantities, performing experiments, building mathematical models to reduce reality to simple relations that can be calculated, estimated and measured. It works, this why we can fly airplanes and watch TV. Even subtle and strange phenomena as time dilation and quantum tunneling are used in practical applications as GPS and tunneling microscopes. There is no better way to show you really start to understand how nature works than using this understanding to make something work on a practical level. So let’s leave alone the metaphysical concept of nothing as our grammatical intuition tells us should be. Let’s ask instead if there is something in science that can represent the closest to our intuitive concept of nothing. The quantum vacuum is such a concept. And as discussed in previous posts this quantum vacuum (both theoretically and experimentally) is full of energy and matter that happen to cancel each other out.
As always nature is clever than us. This how you can have a nothing by cancelling all the possible things by the simultaneous coexistence of mutually cancelling opposites. One can use a lot of analogies from science. For example the concept of a static object. Perfect stillness can be obtained by the presence of a multitude of forces that cancel each other. A book on the table doesn’t move not because there are no forces applied to it but because the force of gravity and the normal force of the table cancel each other. Two beam of light cancel perfectly each other, creating perfect darkness, if the beams are out of phase by 90 degrees. One can have a room full of sound and you could create perfect silence by introducing sounds with equal magnitude but also out of phase by 90 degrees. But such perfect balances are also unstable, in particular in quantum mechanical situations. So creation from this perfect balanced nothingness is the most natural thing to happen. In the end the main point is that science tells us again that nature seems to work from simple to complex, that yes indeed a universe from something as close to nothing, that is the simplest thing we could imagine, is possible. And the complexity we see in the Universe came from a process of evolution from something simple, as life did. No god needed.
There are other hints that we live in a universe that was generated from empty space. In fact, we don’t need quantum mechanics to see that hint. It is all around us.
I’m referring to the ordinary, everyday laws of classical mechanics. When we throw a ball against a wall and it bounces back and comes back to us we experience conservation of momentum, when we ride a bike and it is conservation of angular momentum in the wheels that keeps us balanced, when an mix hot water with cold we notice that a middle temperature is reached as a consequence of energy conservation (plus entropy increase).
One could rewrite all the laws of classical physics in terms of conservation laws. One of the most beautiful achievements in Physics is Noether’s theorem. Noether was able to show that the conservation laws are manifestations of symmetries in the physical laws. These symmetries can be understood as geometrical properties of space and time in which the laws operate. If you have conservation of a physical law then there is some symmetry somewhere. If you understand the symmetry of a space you can determine a lot about the properties of the space. So given conservation of momentum, angular momentum, energy (and atomic physics adds many more conservation-symmetries to the laws of physics) what is the type of space that would have so many symmetries? Of course the most symmetrical space of all: empty space, uniform, featureless empty space. So whenever you see a ball bouncing remember is what you would expect from living in a perfectly empty universe.