Return Home

Master of the Universe

Back to Episode

As faster and faster technology schools us with its super speed, we’re left looking for something, anything, we can beat. Enter Lene Vestergaard Hau, who has found a way to harness the one thing we all thought -- by its very nature -- was unbeatable.


Lene Vestergaard Hau

Comments [21]

JPT from FL, USA

Great comments.

I wonder how this contributes to distances in our universe.

How about our perceived slowing expansion? Where is it coldest?

Thank you RadioLab : )

May. 17 2014 02:47 PM
charles from Buenos Aires, Argentina

Fantastic episode. Daniel Barkolow, I was interested in the answer you provided (with the puppy metaphor). So just to clarify-the light is not, in fact, stopped (or even slowed), its movement is just restricted to the cloud of cold atoms? Is this sort of like if light was somehow en-capsuled inside of a perfectly spherical mirror? Because I thought (though I know essentially nothing about physics) that the speed of light was a fundamental universal constant and as such could not be modified.

Apr. 25 2014 11:16 AM
taojones from long island

lenas results in stoping a photon dead in its tracks seems to me to lend support to string theory! by seemingly storing the photon in a 2 dimensional space as an "impression" of the string and then getting it to vibrate again in 3 dimensional space how else would a particle be stored as an impression?

Feb. 22 2014 01:58 PM
JohnZ from Milwaukee, WI

When I first heard this story I wanted to tell the radio hosts and every listener to read the short story "Light of Other Days" by Bob Shaw. Unfortunately it took me a few months to get around to making this comment so no one may read this comment but I did want to offer it anyway. The story was originally published in Analog magazine and is available as a free download on a few web sites.

Sep. 07 2013 06:30 PM
Gustavo Paredes from Mexico City, Mexico

Hi, I've tried to get in touch with your guest, I'm an engineer in profesion and I'm interested on doing research of this topic. I've also tried to contact her by phone, but it seems her phone line is not available anymore. Would you please be kind to tell me by email how I can get in touch to her ??? Thanks in advance.

Jun. 27 2013 04:32 PM
grendl from New Orleans, LA

If true and interpreted correctly. does this phenomenon have any relation to a "black hole"?

May. 06 2013 09:34 PM
troland from TN USA

thought 1: Ok, so Einstein basically says that c is a constant. I know that mediums of different densities slow light down, but this medium is essentially a very diffuse matter any diffraction should be minimal, correct?
If so, doesn't that imply that within the cloud time has slowed drastically and if the 'properties' can be 'tweaked' to stop light doesn't that imply that time has stopped for those photons? It didn't seem that they were talking about some sort of internal refraction but that the light actually stopped.
thought 2: could this mean that theoretically the surface (if that term can be used) of an old, very cold neutron star (which would necessarily be near 0K because of gravitational forces restricting motion) acts as a recorder of all the light that hits it and could be used as an information bank for astronomy?
thought 3: Since photons either are absorbed, reflected, or don't interact at all with normal matter and these photons are doing none of those things doesn't that imply some other unknown force of interaction between matter and energy?

Apr. 30 2013 11:01 AM
SBS from MN

So what does it look like? Does a frozen ray of light glow? I would assume not, since that would mean it's still moving. Then what? If I looked at this something with the appropriately powerful microscope, what would I see?

Another way to approach this might be thus: If light is both particle and wave and the wave's movement is stopped, is there a thing that is captured? Something with mass, as the word "particle" suggests to a non-scientist like myself? (This quickly gets to the subject of Radiolab's wonderful "Solid as a Rock" segment.)

Apr. 18 2013 10:16 AM
physics student

All waves move. When you see a standing wave on a string it is because the waves traveling back and forth match in frequency and amplitude. They constructively and destructively interfere to form what you see as a stationary wave.
Light can be expressed as changes in the electromagnetic field. Space-time and the electromagnetic field can be thought of as like a tight membrane. When one part of the field is disturbed, the parts around it move as a result. This process propagates outwards and form what we call light. If you have ever plucked a long string, you can observe this effect. Since every part of the string is connected to adjacent portions, when you disturb one part, the disturbance spreads out and you see a moving wave.

Mar. 27 2013 12:12 AM


Because light is also a particle.

Mar. 23 2013 08:57 PM

OK could we back up here a second (or at least a light-second :-) Could someone explain why light moves at all. For example a vibrating string has a frequency and a wave length but it just sits there and does its thing. Why cant light (or electromagnetic radiation of any frequency) do this. Why does it HAVE to move through space? I have a rough understanding of special relativity and I have read about how the speed of light is the same for every observer (unlike sound) but that still begs the question: WHY DOES IT MOVE IN THE FIRST PLACE?

Mar. 22 2013 10:38 PM

Paul- The choral piece used a couple of times is Lux Aurumque by Eric Whitacre. The rhythmic mallet piece during the credits is Music for 18 Musicians by Steve Reich. Not sure about the others.

Mar. 11 2013 12:55 PM
John from Indiana

@Jeff from Berkeley
Your thoughts are (almost) right on target. The uncertainty principle, more accurately stated, is that you can't know both position and velocity to high precision at the same time ("exact" is not involved here since no real measurement is ever exact- there's always a margin of error or level of uncertainty in our knowledge of a physical quantity). At very low temps, velocity is very low, so it's high precision since there's a bottom limit of 0, so it's limited between "very low" and 0. So the position must be uncertain, so the atoms essentially blend together and act like one big atom (Lene said the cloud was contained within 0.1mm, but that's not at all "precise" on an atomic scale.) This is the Bose-Einstein condensate that the other commentor Daniel Barkalow mentioned.

Mar. 05 2013 12:28 PM
Daniel Barkalow

The light doesn't actually go slowly in a instantenous-velocity way. It goes slowly in that it doesn't make any progress through the trap. Light is like a very fast, very distractable puppy: it's always running at a very high speed, but it doesn't run straight ahead if there's stuff around. In a vacuum, it gets a light-second each second; in air, it doesn't manage to cover that much distance in the same time, because it's bouncing off of stuff a little bit. In a Bose-Einstein condensate, it can still be in the same place second after second, even though it has a velocity of 186000 miles per second. To be a little more precise, light is actually like a pack of puppies; when some puppies veer left, others veer right, and they all stay pretty close together, so the pack goes straight overall despite individuals not going straight, which is why a beam of light going through glass will exit later than it would in vacuum even if it goes out straight. (The pack is an uncollapsed wavefunction, and it's all eigenstates of a single photon; but it moves like a group moves rather than like you'd expect an individual to move, because quantum is weird like that.)

Feb. 19 2013 01:29 AM
GQ Lewis from Atlanta, GA

This was wicked cool. I am telling everyone I know about this, including my very close friend Mary K. Jones. :) I love fascinating science. If Lene doesn't win a Noble prize for this, the selection committee should all resign.

Feb. 17 2013 11:50 PM
Paul from Brooklyn, NY

Who did the music used in this segment?

Feb. 16 2013 03:42 PM

Radiolab never ceases to amaze me. That was riveting.

But the whole time she was explaining the experiment, I really wanted know... Can you see this beam of light travelling at 15 miles per hour? Could you witness a beam slow down like that? I assumed not, because that would require the light to travel fast enough, and in a different direction of the experiment itself, to hit your eyes. Thoughts anyone?

Feb. 15 2013 11:14 PM
Jeff from Berkeley

Does what Lene did nullify any principles of quantum physics?

If I remember my college physics correctly, the Heisenberg Uncertainty Principle states that you can't know a particles position and velocity at the same time. But if you 'trap' light, you know exactly where the photons are and their velocity is zero.

I'm sure I'm missing or confusing something. Can anyone shed some more light on this? (I couldn't help myself!)

Feb. 13 2013 11:48 PM
Ben from Grass Valley CA

Is it just me or did the last guy reading the credits (Bill from South Bend, Indiana) sound exactly like Kermit the Frog?! Is Kermit in the witness protection program or something? I'm onto you "Bill"!

Feb. 11 2013 04:51 PM
Matthew from British Columbia, Canada

This is the stuff of science fiction literature and imagination that is absolutely amazing. I could not believe my ears as I listened to this. Really, really fascinating.

Feb. 07 2013 10:15 PM
eville from Ellenville, NY USA

I can't remember the last time I was so totally immersed, mesmerized, simply sitting still, listening closely to a riveting piece of science unfolding right before my ears. You've gotten my attention as a new hooked-on-Radiolab listener.

Feb. 06 2013 01:47 PM

Leave a Comment

Email addresses are required but never displayed.