January 24, 2020 • 34 mins
What are tractor beams? How do photons normally react with matter? How are scientists using beams of light to pull microscopic objects? Listen in as Jonathan and Lauren explore the tech behind tractor beams.
Learn more about your ad-choices at https://www.iheartpodcastnetwork.com
See omnystudio.com/listener for privacy information.
Mark as Played
Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Speaker 1 (00:04):
Welcome to tech Stuff, a production of I Heart Radios
How Stuff Works. Hey there, and welcome to tech Stuff.
I'm your host, Jonathan Strickland. I'm an executive producer with
I Heart Radio and I love all things tech and
today is a Friday, so it is time for another
tech Stuff classic episode. This episode originally published on February
(00:29):
two thousand thirteen. It is titled tech Stuff is Caught
in a Tractor Beam. Lauren Vogelbaum and I sat down
to talk about the technology of tractor beams. Is it
realistic in what ways? Is it realistic versus unrealistic? How
might it actually work? And would it be remarkably different
from the way it's depicted in science fiction films. I
(00:49):
hope you guys enjoy it, So let's sit back and
listen to this classic episode tractor Beam, tractor beams. Yes, Yeah,
this is This was something that Lauren had suggested because
she saw an item in the news, and at the time,
I would imagine Lauren had no idea how incredibly complex
a topic this would turn out to be. Ye, As
it turns out, particle physics is not simple necessarily, but
(01:12):
we're gonna tackle it anyway. We are We are indeed,
because you know what, we've watched a lot of star
Trek between the two of us. We have faith in ourselves.
So let's let's talk about what a tractor beam is,
especially in that realm of science fiction, because I think
that's where most people have encountered the original idea, right sure,
and especially since tractor beams do not exist as such
in three dimensions in the real world yet, not on
(01:33):
the macro level anyway, right, not not nothing that you
could see with your own two eyeballs. Right. So essentially
it's a intergalactic tow truck kind of thing. Yes, a
beam of light that can be used to pull objects
towards the source of that light. Yeah, which is that's
pretty phenomenal because, as we understand in physics, light does
(01:54):
in fact exert a pressure time push stuff. Kepler said
that Yep, exactly, yep, yep Kepler. Kepler observed this, and
in fact it serves as the basis for uh futuristic
technologies such as sun sales. Similar sales. These would be
enormous sales, literally sales that you would extend from a
(02:15):
spacecraft and allow sunlight to press against the sale and
thus propelled the StarCraft because you're talking about being in
an environment where there's no there's no gravity that's affecting
you apart from well, I mean, they're gonna have gravity
within the Solar System, but you're not working like trying
to escape gravity. At that point. You're actually already out
in space, so you're not having to worry as much
(02:39):
about things like friction and gravity. So smaller forces, for example,
photons can so so to have a kind of light
that would be able to trap an object and even
pull it in is sort of counterintuitive based upon the
knowledge that photons can push stuff away. So we've seen
(03:00):
tractor beams used in lots of different science fiction you.
Star Trek, of course, is one of the big examples. Yeah.
The first reference was actually in The Skylark of Space,
which was a drama by Et Smith, originally serialized in
n and published as a novel in nine. Wow, I
did not know that. I do know that it's used
in Star Trek quite a bit. There are two things
(03:21):
that you have to remember about Star Trek tractor beams.
They can pull just about anything anywhere, and if you
reverse the polarity, you can turn it into a weapon. Well,
reversing the polarity, as we all know, is how you
do things in Star Trek. Yeah, I was explaining earlier.
It is the have you tried turning it off and
on again approach in Star Trek. If if it's something's
not working, reverse the polarity and then it works. Uh.
(03:43):
And then, of course in Star Wars it was used.
The Death Star catches the Millennium Falcon in a tractor
beam and a series of tractor beans, a whole connexus
of tractor being right, and pulls it back into the
Death Star so that the Millenium Falcon cannot make its
daring escape. This, of course allows dar Vader to face
off against Obi one Kenobi, and I could go on,
but that's not what this episode is about. Also, I
(04:06):
suspect that a few of our listeners have seen Star Wars,
maybe maybe one or two. Episode four is amazing. If
you have not seen it, you need to go check
it out. But anyway, yeah, so, so science fiction is
one of those things that is a really useful tool
for storytellers. Uh. If they have a story about a
ship encountering some sort of wreck or other kind of
(04:28):
of body out in space, it needs to be pulled away.
And the nice thing is is that we've got scientists
here on Earth who are saying, hey, how can we
do this science fiction thing for reels right? Knowing how
light behaves and uh, and maybe finding new ways to
make light behave in perhaps an unexpected fashion. Well, I
suspect that, in fact, Star Trek used some actual research
(04:52):
that was going on in the nineteen sixties as a
basis for their tractor beam, because according according to the
Star Trek universe, the way that their tractor beam works
is it's actually WILLI a graviton force beam and I
just made little quote marks in the air for the
benefit of nobody really, so that was weird. Gravitons are
hypothetical particles that that essentially mediate the force of gravity. Uh.
(05:13):
They're hypothetical because we have not observed an actual graviton.
We don't know how we would We don't we know
that in order for our quantum model of the universe
to make sense, we need something like a graviton to
exist to explain the force of gravity. There are four
fundamental forces in the universe. There's strong, nuclear, weak, nuclear,
(05:35):
electro magnetic, and gravity. Out of those, gravity is the weakest,
but it's also the one that we cannot easily incorporate
into the quantum model of the physics. Right, It's sort
of assumed by Einstein's general theory of relativity that gravitational
waves are a thing that exists, that ripples in the
spacetime continuum, caused by very large moving objects, particularly, but
(05:59):
nobody has detected these. So so really the way we
observe this is through the force of gravity. I mean,
that's that's that's we can see the outcome just exactly so.
And to explain to you guys how weak gravity is
in comparison to the other forces, here's a very simple,
uh experiment anyone can do anyone who has access to
(06:20):
a comb and a balloon. So let's say you've got,
you know, get a balloon. You just inflate the balloon
with oxygen. Don't do helium because that will negate the
results of this test. Check. So oxygen inflated balloon, you
sat down on a table. Gravity is pulling the balloon downward.
I am oversimplifying here, so physicists please don't don't write
(06:41):
in and complain. But the balloon is held to the
table in part due to friction, but also in part
due to gravity. If you were to take your comb
and rub it against say a sweater, and get build
up some stack electricity on the comb, and then touch
the comb to the balloon and lift, you would see
that the stag electricity that was generated while you were
rubbing the comb against your your sweater would be enough
(07:04):
to attract the balloon and lifted off the table. That
means that the any amount of electromatic force, the static
is stronger than the gravity. And the gravity, yeah, You've
got an entire planet beneath you that is got this
very strong gravitational pull, strong in comparison to other things
that we directly observe throughout the day, and yet it
(07:26):
is dwarfed by strong enough Yeah, strong enough to pull
a bowling ball from the top of tower. Right but
right so, and and gravity just so. To complete the
whole picture here, it depends on two things. It depends
on really you have to have two different bodies, but
it depends on the body's mass and their distance from
one another. But they do exert gravity, a gravitational pull
(07:49):
against each other. So, for instance, I have a cup
of tea in front of me, I am exerting a
very tiny gravitational pull on the cup of tea, and
it is exerting a very tiny gravitational poll on me.
Now this is dwarfed by the fact that I'm also
on the planet Earth and that the Earth is exerting
gravitational force on both of you. Right, So I you know,
(08:10):
I can't observe this. I don't really, I'm not aware
of it in any way. But that's that's yeah. So
keeping that in mind, one easy, relatively easy way of
having a tractor beam like effect, even though you wouldn't
be beaming anything, is to use the gravity of one
object to influence the movement of another object. Now, this
(08:34):
is something that we've talked about before on tech stuff,
when we were chatting about could an asteroid destroy the
Earth if if, if some space agency. I was gonna
say NASA because that's the one that I'm most familiar with.
But if NASA were too identified that an asteroid twenty
years away has the the uh the chance potential to yeah,
(08:58):
that would be a bad thing. Yes, because we all
learned in the documentary arm Again, Yes, that wonderful documentary
that taught me that Steve bu Simmy is a better
singer than Ben affleck Uh, which I had no way
of knowing until I saw that anyway that one way
of potentially deflecting the asteroid would be to send a
spacecraft up so that you move the spacecraft so it's
(09:21):
close enough to the asteroid so that they are are
pulling one another with a gravitational pull, and then you
use thrusters with the spacecraft to just very slowly push
just not really really it's pull. You're yeah, you're pulling
the asteroid because as you move the spacecraft away, the
gravitational pull makes the asteroid move with it, and all
(09:41):
you have to do is move it. The further out
you go from Earth, the less you need to move
the asteroids so that it has it misses the Earth right,
because you're talking about angles, So a couple of degrees
of difference way the way way the heck out in
space make enough difference to not kill everything on it, right,
it'll miss the planet in hirely, So that's the idea.
So that's kind of like a tractor beam in the
(10:03):
sense that you're using an object to tow another object,
in this case objects that are in space, but you're
not actually shooting a beam of anything. Right. However, Yeah,
it's not it's not made of light. It doesn't do
that cool visual effect that you have a sound effect,
which obviously that would not not anything in space anyway. Sure,
but hey, why why should we start criticizing Now that's
(10:25):
a that's a whole different episode. Um. And So, in
the nineteen sixties, people were really excited about detecting gravitational waves,
and a few people in fact, suggested that we might
make a gravity laser. A couple of people, Helper and Laurent,
proposed that this could be called a gazer, which I
think is a terrific word. Yeah, and I think means
(10:46):
something entirely different. These are modern times, I think, Yeah,
I think I agree with you. I think at this
point the scientific community would say, can we ya? Um.
They proposed that we could vibrate some types of electric
crystals and create a whole thing. And but that's it's
never really come to fruition because the above re we
(11:06):
have never discovered gravitons, We have never measured gravitational waves.
Right for us to be able to create an object
that would use gravitons to to make a tractor being
we first sort of need to prove that gravitons in
fact exist, because again they're hypothetical right now. It's sort
of like the Higgs boson, right The Higgs boson was
a theoretical particle that physicists said, for our understanding of
(11:30):
the universe to make sense, we need this thing to
exist to explain why matter has mass, same sort of thing.
In order for our understanding of gravity to make sense,
within the within the framework that we have of our
knowledge of the universe, knowing that we are by our
very nature limited in our understanding, a graviton needs to
(11:53):
exist for that model to really make sense. So we're
talking about mathematically, yes, these things to exist, but in reality,
we just haven't tracked it down yet. So if we
ever do, maybe we can make some sort of technology
that can take advantage of that. But until then, until then,
maybe no gravitational lasers. Yeah, I personally hope that we
(12:15):
do crack that nut, because that would be I mean,
it would be an incredibly useful tool, and not just
in the context of space exploration. That's the one that
we all think about because again in science fiction, that
tends to be where tractor beams come into play. But
as it turns out, tractor beams can have a really
useful uh well in implementation here on Earth in space
(12:38):
on the planet, and I mean moving things is hard,
they're heavy, or even if they're or they're really small.
And so yeah, we'll talk a bit in a second
all about how some scientists are making micro versions of
tractor beams here on Earth and what those could be
(12:59):
used for. But first let's take a moment to thank
our sponsor for this episode, and now back to the show.
All right, so we've talked about using gravity to create
a tractor beam like effect, or possibly even using gravitons,
(13:20):
assuming we ever understand them. But that's not the only
way scientists are looking into creating a tractor beam like device.
There's actually been quite a bit of news over the
last decade about scientists using various ways of manipulating light
to pull an object as opposed to push it away. Right,
(13:41):
Starting way back in six people started playing with what's
called optical tweezers, which are lasers that are capable of
manipulating molecules and moving them with precision. And now this
is not pulling a particle towards the light source, so
it's not technically a tractor beam, right, but it is.
It is a method of manipulating microscopic particles very precisely.
(14:04):
So if you're thinking about a plane like an X
and Y axis, you could move particles within the X
and y axis, but you're not moving them along the
Z axis. That would be you know, from the source
of light to wherever the particle is. So in relation
to the source of light, the particle would not get
closer further away, but you could trap it and move
(14:25):
it within that X Y plane. That's that's my understanding. Yeah, yeah,
and these are well I I that's my understanding as well.
These these laser beams that are being used for this
have a Gaussian intensity profiles, which means that they're brighter
in the center than they are at the edges. Right.
A Gaussian distribution is a normal distribution, and it can
be for anything from lasers to really you can even
(14:47):
see this in social sciences where you do a survey
and you have a Bell curve that shows a normal
distribution that's essentially a Gaussian distribution. So, Okay, light has momentum, right, right,
and so when it hits an object, the object bends
the light which changes its momentum, and thus the object
is pushed back equally and oppositely by the light. Okay,
(15:08):
I see, so the lights momentum has changed. The object's
momentum is also changed correct according to the conservation of momentum,
which you can see in normal, non microscopic classic physics. Right.
And so the Gaussian beam is important because if the
sample gets off center in the beam, the weaker light
at the edges is bending around the object and pushing
it out, but the stronger lighted center is bending around
(15:29):
it and pushing it back in, and the stronger force wins.
I see. Okay, Yeah, that makes way more sense than
everything else I read, because everything I read was a
lot of this. This research that we did for this
Pathicunar podcast is in is from scientific journals and uh.
And this is a good point for us to make.
Lauren and I we're advocates of science education. Absolutely, we
(15:51):
both love science. That being said, neither of us are scientists,
and we certainly are not particle physicists. And so when
you get onto the quantum level, there's a certain level
of understanding that we are able to achieve. And beyond that,
this stuff is it is like magic to us. So
we're going to explain things as best we can, but
(16:11):
please understand there are subtleties to this that we cannot
easily explain because we haven't dedicated our lives to understanding
them exact and by so if we get anything wrong,
please do right us in Um, we love getting that
kind of feedback, right, Yeah, No, we definitely want to
to communicate the correct information as best we can. But uh,
(16:32):
you know this, this is exciting stuff. So in this case,
what Laurence talking about is using light to to uh
to isolate and then manipulate microscopic particles. But at this
point the stage what we're talking about does not include
pulling those particles towards the light source. However, we have discovered,
(16:54):
or rather I should say we predibly smart people have
discovered ways of using light to act pull things towards
the source in a bunch of different ways. Actually, um,
there's one of those is called an optical vortex. Um
sounds kind of kind of freaky people. The main research
that I've read from this was from Australian National University
(17:16):
around so pretty recently, and the the idea of this
one is that they use a hollow laser beam to
trap light absorbing particles, and um, they get trapped in
the center of this laser beam because the heated air
molecules around them are pushing in on them goutches, so
they cannot they can't escape the laser beam. They're stuck
(17:37):
in that little hollow center, in the hollow center in
the in the the doughnut shaped laguer Gaussian laser beam. Yes,
that right there, that thing exactly that you just said. Yeah,
I have the note. I'm so glad that you did
more research on this because when I read that, my
eyes kind of glazed over. Yeah. Apparently they were able
(17:58):
to move particles about one and a half meters in
the air. Yeah, it's it's really exciting. By they found
out that by using too concentric hollow lasers, they can
adjust the brightness of the two of them there by
heating and cooling the air around the molecules and and
then therefore have the molecules move up and down as
they will through this hollow tube of light. Wow. So
(18:21):
so you're using two different lasers in order to make
that maintain this kind of movement. That makes sense, I
understand now. Yeah, I was wondering how that worked beforehand.
But yeah, that that totally makes sense. And yeah, and
these are nanofoam particles that they were using to the
got transported over a meter and and all of this
is on the scale again of a very microscopic things. Right.
That's something that's important and we'll talk a little bit
(18:42):
more about that when we finish with all the different
laser methods. But yeah, the methods we're talking about are
very exciting. Don't get us wrong. They are incredibly exciting,
particularly in certain very specific implementations like in the medical field.
Oh yeah, this is all going to be extremely exciting
for for example, removing bacteria from samples, sorting cells, municially
(19:04):
manipulating DNA strands is something the optical tweezers have been
used extensively for, right, so that there there are real
uses for this. But these are not the same technologies
that will let us move spacecraft like toe spacecraft away.
And we'll talk about why that is when we get
a little further in, because there are a couple of
other laser methods that we need to talk about, right right, Um,
back back on the kind of sale, the sort of
(19:26):
solar sale theme that we were discussing earlier. Optical lift
is another version of of light that can be used
to do stuff. It's it's actually just a really simple
analog of aerodynamic lift, which of course is when um
you create uh uh, how is it? It's higher pressure
(19:47):
underwing than over awing and therefore letting a plane lift
off the ground in the game. Before we get any
further physicists, that's also an oversimplification, and we acknowledge that, yes,
there's more than geology, there's more than just that when
it comes to get an airplane off the ground. Also,
we know all about the other forward momentum and everything else,
but but that that is the concept of lift. Thank you,
(20:11):
And so to get slightly fewer angry emails, it's only
because Chris and I received all those emails already, but
but deservedly so right, oh no, absolutely, yes we love
negative feedback. But so I nearly spit tea all over
my laptop. Please don't take that as a as a
Please don't take Lawrence Lauren's statement as a means to
(20:33):
send us the most negative feedback ever, because my feelings
do get hurt, and I apparent you just made a
complete liar out of me. That you almost snorfing your
tea completely made me crack up. Sorry about that, excellent,
But anyway back to optical lift. It's uh. The scientists
have discovered that that you can take an object with
(20:55):
a differently shaped top and bottom surface and it will
experience a lift force when please standing uniform stream of
light that's fast. This is all blowing my mind because
before we did this research, I never knew about these
different properties of light and and it just it really
stresses to me one amazing universe. This is, you know,
to to know that things behave on such a different
(21:17):
level than my previous understanding, and also illustrates quite effectively
how ignorant I am. But I love to learn, so
that's okay. Yeah we get we get paid to learn
this stuff and pass it on to you, which is
basically the most exciting thing. Um. One of the other
categories that I ran across were optical conveyors, which are
really fun. Those are those are the ones that are
(21:39):
using Bessel beams, and I think I think Jonathan has
a whole section about this one. Yeah, not a whole section,
but I can at least tell you what a Bessel
beam is. Because when I encountered that term, I thought, huh, what,
what exactly do they mean by Bessel beam. It's a
specific type of radiation, and that sort of radiation can
be a laser, it can be electroma, metic, it can
(22:00):
be acoustic, it could be gravitational. It doesn't really matter
what the type of radiation is, it's the form it takes.
And that form is a radiation where the amplitude is
described by a Bessel function of the first kind. Does
that mean essentially, it means that as this radiation moves forward,
it does not diffract in any way. It doesn't diffuse,
(22:23):
it does not spread out. In other words, it remains concentrated.
So what we think of that like a laser beam.
When you shine a laser beam, it doesn't spread out
like a flashlight does. But this is a very specific
format of that. And in fact, because actually those those
laser beams that were that you point at something are
Gaussian laser beams. That's we discussed there, and so this
(22:43):
is different is different. This is different. It is it
is focused, It does not diffract in any way, it
does not spread out at all. And in fact, one
a a a feature of a true bessel beam would
be that if you were to just interrupt part of
vessel beam. Let's let's imagine that the vessel beam is
as big around as a pencil, Okay, just for the
(23:05):
purposes of illustration, and then imagine that you had, uh
use a sheet of paper and cut a little slit
in that pencil, and you make the sheet of paper
interrupt the vessel beam. Right, So you've got the sheet
of paper that's interrupting half the vessel beam. The other
half is going beyond the edge of the paper. A
true vessel beam will heal itself beyond the point of interruption.
(23:29):
So if I were to interrupt that beam further down
the beam, it would become whole again. So it would
be the same diameter as it was um at the
before a point where you had that interruption. So that's
an awesome thing about a vessel beam. Now here's the
here's the caveat. A true vessel beam would require essentially
(23:49):
unlimited power. Uh. So Dr Doom would want to make one, uh, certainly,
but none of us would be capable of doing it.
It's a true vessel beam is effectively impossible for us
to make. We can make things that approach vessel beams
and that UH emulate many of its features, but a
(24:09):
true one is beyond our capability. That is the short
and sweet definition of vessel beam. And do keep in
mind we're not just talking lasers. Like I said, it
could even be acoustic. So you could create a vessel
beam of acoustic energy and make a noise that could
be heard perfectly at the destination, no matter how far
away it was. That that is fascinating, pretty awesome, that's terrific.
(24:31):
It's Jonathan from again here to once again break up
the episodes that we can take a quick break. So
researchers are using these. Specifically, some people at New York University,
building on research by a Chinese team at the a
Star Data Storage Institute, I believe in around two thousand eleven,
(24:54):
two twelve people have been working on using a lens
to bend and overlap two of these vessel beams um
thereby creating what I can crudely, crudely describe as kind
of a Strobe effect that will, Okay, it'll hit the
front of a particle, and because of that, because it
can reform around an object, it will reform behind the particle.
(25:17):
With enough energy that it actually pushes the particle back
towards the light source. All right, so what's happening is
the photon is is hitting the particle in such a
way as to give it a little kick back toward
the actual source of the photons correct, which is kind
of crazy. It's awesome. Like there was one point where
I was reading one of these descriptions and I was thinking,
(25:38):
the only way I could describe this is if you
were thinking about having a smaller particles being pushed forward,
because larger particles are sinking down, so instead of being
pushed down, they're actually going up. And then the more
I read about the more I'm like, this is a
complete misunderstanding of this, and I cannot go with this analogy.
(25:58):
And that's what I thought. I hope Lauren has got discovered,
and luckily she did. Yes. I like the physics, but
physics were always the interesting part to me. I was
always terrible at algebra, but really good at geometry. I
love classical physics. Quantum physics makes my head hurt. I
just that's the fun headache. I like the I like
the quantum physics headache. If better you than me, what's
(26:21):
that terrific quote. Off. If you're not kind of upset
by quantum physics, you haven't understood it properly. I think
all of us haven't understood it properly. I think the
people who haven't understood it probably the most have the
biggest headaches. Those are quantum physicists anyway. But then I
say that as as I you know, every quantum physicist
interview I've said I've watched tends to include a question
(26:42):
that's all similar to, but do you really understand what
it is you're talking about? And the quantum physicist almost
always says, you know, there's a certain level where I
don't like. There's certain things that you just say, all right,
this is how it is, because that's how it is.
But to be able to answer, I can't. And so it's,
(27:02):
you know, one of those things you just have to accept.
And my brain starts to melt out of your ears. Yeah,
there's a lot of screaming and waving of fists inside
the craneyde the brain. Yeah. But so the special beaming
optical conveyor technology might be an interesting practical use for
it could be to test the tensile strength of cells.
For example, if if a cell has been infected with malaria.
(27:25):
It's more rigid than a normal blood cell, and so
it could be super useful in tiny microscopic medical purposes.
Similar to another breakthrough that was very recent as of
the recording of this podcast, we're recording this in early February,
and there were some publications that we're talking about an
(27:46):
experiment that had been performed by scientists from Scotland and
the Czech Republic about using a beam of light with
a specific geometry to pull particles of polystyrene. And these
particles are very very small, in fact, beyond microscopic, we're
talking about nanometers for fos, about four hundred ten nanometers specifically.
(28:09):
Think most of the particles we've been talking about have
been on on that scale. Yeah, pretty pretty tiny stuff,
but fomes and one thousand nanometer particles essentially think about
tiny spheres of polystyrene that are only a few hundred
nimeters in diameter. That's essentially what we're talking about here.
(28:30):
And they found that by uh polarizing the light in
a particular way, they can manipulate these particles, and in fact,
not only could they manipulate the particles, but depending upon
the way they polarized the light, they could selectively manipulate
particles of a certain size while not affecting particles of
(28:51):
another size. Yeah, there's a there's a little video of this,
by the way, in a press release. We'll link it
somewhere on our on our tech staff media. Yeah, yeah,
you'll have to take a look at this. It's pretty
amazing because you think about that, that means that you
will be able to selectively uh, grip, sort and move
right particles, so that way you could you could keep
some undisturbed while you're the ones you're interested in, those
(29:14):
are the ones you can manipulate and uh and that
is a huge breakthrough you're talking about just by by
again changing the nature of the light itself, being able
to affect very specific sizes of particles and it doesn't
really matter what the particle is made out of. They
were using polystyrene in a liquid solution. So again, this
(29:36):
was another breakthrough was that this was something that could
work within a liquid, making it very useful for medical purposes.
So if you wanted to take a blood cell and
you needed to move certain particles in that blood cell
out or off to a side so that you could
either examine them more closely, or perhaps get them out
(29:57):
of the way so you can examine something else in
the blood cell more closely. It would be a very
useful tool. One description that I saw of this said that,
and and this one in particular. There are a lot
of very intelligent people have said very ierdite things about
all of the rest of these forms of tractor beam manipulation,
and I read them and have said them back to you.
(30:20):
This one is so new that not that many people
who are smarter than us have really said that many
things about it, and so therefore my understanding is tenuous.
But one explanation that I saw said that they used
a mirror to bounce the laser beam back across itself,
interfering with the head on photons and thereby pushing right.
And the the interesting thing to me was that it
(30:42):
was through that interference that creates this pulling. It was not, however,
because you hear mirror and you think, oh, well, all
they're doing is shooting the photons, bouncing it off the mirror,
and then the photons hit the particle and then push
the particle. But that's not what's happened. That's not what's happening.
It's the it's the interaction of the the oncoming beam
(31:03):
and the reflected beam that create this pulling motion. And
that to me is phenomenal because at first I thought, oh, well,
what they're really doing is just yeah, they're just they're
just pushing, they're not pulling. But that's not the case.
That actually is pulling actually the light source they're The
really fascinating thing about this is that apparently, under certain conditions,
the objects held by the beam rearranged themselves into a
(31:25):
structure that made the pull stronger. That's pretty awesome. I
mean this, this is so mind blowing to me that this,
this world on the nanoscale is every time I read
anything about it, it amazes me. It's like, you know,
the two areas I find the most interesting when it
(31:45):
comes to exploration are outer space and nanospace because there
are a lot of parallels, I mean weird parallels between
outer space and nanospace fractals. Fractals say that that's a
that is a known quantity. That just make me think
of the Jonathan Coulton song Mandel brought Set, which is awesome.
Have you heard that? I do not believe I had.
(32:06):
I guess what we're doing. After the podcast is over,
you get to hear a song. Alright, trip, so uh
we we We alluded to the fact that this is
stuff that works on a microscopic scale and would not
translate to macroscopic Yes, and here's the reason why. Yeah,
the reason why is that all of all of this
work with lasers. Lasers, of course, um can burn stuff.
(32:26):
And if you had a big enough laser to move
you know, the one of the physicists I think mentioned
a football. I assume that they were meaning a soccer
ball because they were from Scotland, and that was Thomas Sissmar.
There you go, um, and it would fry a long
time before you would move that soccer ball. Yeah. In
(32:47):
other words, the laser would have to be of such
an intensity and size as to destroy whatever it was
you were trying to move. So it might move, but
only because someone didn't want it to burn down everything else, Right,
it would be moved by some one else who's saying,
why do you have this flaming soccer ball in the
middle of the field. Yeah, that's the that's a problem, obviously,
I mean, it's it's a it's a non trivial problem
(33:09):
and I mean, I know it's a non trivial problem
and it sounds like I'm being silly, but no, it's
non trivial, and that as far as we are able
to determine, there's no way to get around that using
this particular implementation of the tractor beam idea. So this
would strictly be on the nano and micro scale and
never get beyond that. That does not mean that we
(33:31):
won't find some other way of creating a tractor beam.
We very well made, but it's not going to be
using these particular methods because obviously we would end up
destroying whatever it was we were trying to manipulate. So
we hope, we hope that we will see some of
that in the future. I hope you guys enjoyed that
classic episode of tech Stuff. If you have suggestions for
(33:52):
future episodes, send me an email. The addresses tech stuff
at how stuff works dot com, or you can draw
me a line on Facebook or Twitter. The handle it
both of those is tech Stuff hs W. Don't forget.
You can pop on over to our website that's tech
stuff podcast dot com. There you're going to find an
archive of every episode we've ever recorded. It's entirely searchable,
(34:14):
so you can check and see if I've covered your
favorite tech topic, and if not, well get in touch
with me. I mentioned how you could already. You also
find on that website a link to our online store,
so if you've ever wanted any sort of tech Stuff merchandise,
whether it's a sticker or a mug or a mouse
pad or t shirt, go check that out. Every purchase
(34:34):
you make goes to help the show, and we greatly
appreciate it, and I'll talk to you again really soon.
Tex Stuff is a production of I Heart Radio's How
Stuff Works. For more podcasts from my heart Radio, visit
the I heart Radio app, Apple Podcasts, or wherever you
listen to your favorite shows.
Welcome to tech Stuff, a production of I Heart Radios
How Stuff Works. Hey there, and welcome to tech Stuff.
I'm your host, Jonathan Strickland. I'm an executive producer with
I Heart Radio and I love all things tech and
today is a Friday, so it is time for another
tech Stuff classic episode. This episode originally published on February
(00:29):
two thousand thirteen. It is titled tech Stuff is Caught
in a Tractor Beam. Lauren Vogelbaum and I sat down
to talk about the technology of tractor beams. Is it
realistic in what ways? Is it realistic versus unrealistic? How
might it actually work? And would it be remarkably different
from the way it's depicted in science fiction films. I
(00:49):
hope you guys enjoy it, So let's sit back and
listen to this classic episode tractor Beam, tractor beams. Yes, Yeah,
this is This was something that Lauren had suggested because
she saw an item in the news, and at the time,
I would imagine Lauren had no idea how incredibly complex
a topic this would turn out to be. Ye, As
it turns out, particle physics is not simple necessarily, but
(01:12):
we're gonna tackle it anyway. We are We are indeed,
because you know what, we've watched a lot of star
Trek between the two of us. We have faith in ourselves.
So let's let's talk about what a tractor beam is,
especially in that realm of science fiction, because I think
that's where most people have encountered the original idea, right sure,
and especially since tractor beams do not exist as such
in three dimensions in the real world yet, not on
(01:33):
the macro level anyway, right, not not nothing that you
could see with your own two eyeballs. Right. So essentially
it's a intergalactic tow truck kind of thing. Yes, a
beam of light that can be used to pull objects
towards the source of that light. Yeah, which is that's
pretty phenomenal because, as we understand in physics, light does
(01:54):
in fact exert a pressure time push stuff. Kepler said
that Yep, exactly, yep, yep Kepler. Kepler observed this, and
in fact it serves as the basis for uh futuristic
technologies such as sun sales. Similar sales. These would be
enormous sales, literally sales that you would extend from a
(02:15):
spacecraft and allow sunlight to press against the sale and
thus propelled the StarCraft because you're talking about being in
an environment where there's no there's no gravity that's affecting
you apart from well, I mean, they're gonna have gravity
within the Solar System, but you're not working like trying
to escape gravity. At that point. You're actually already out
in space, so you're not having to worry as much
(02:39):
about things like friction and gravity. So smaller forces, for example,
photons can so so to have a kind of light
that would be able to trap an object and even
pull it in is sort of counterintuitive based upon the
knowledge that photons can push stuff away. So we've seen
(03:00):
tractor beams used in lots of different science fiction you.
Star Trek, of course, is one of the big examples. Yeah.
The first reference was actually in The Skylark of Space,
which was a drama by Et Smith, originally serialized in
n and published as a novel in nine. Wow, I
did not know that. I do know that it's used
in Star Trek quite a bit. There are two things
(03:21):
that you have to remember about Star Trek tractor beams.
They can pull just about anything anywhere, and if you
reverse the polarity, you can turn it into a weapon. Well,
reversing the polarity, as we all know, is how you
do things in Star Trek. Yeah, I was explaining earlier.
It is the have you tried turning it off and
on again approach in Star Trek. If if it's something's
not working, reverse the polarity and then it works. Uh.
(03:43):
And then, of course in Star Wars it was used.
The Death Star catches the Millennium Falcon in a tractor
beam and a series of tractor beans, a whole connexus
of tractor being right, and pulls it back into the
Death Star so that the Millenium Falcon cannot make its
daring escape. This, of course allows dar Vader to face
off against Obi one Kenobi, and I could go on,
but that's not what this episode is about. Also, I
(04:06):
suspect that a few of our listeners have seen Star Wars,
maybe maybe one or two. Episode four is amazing. If
you have not seen it, you need to go check
it out. But anyway, yeah, so, so science fiction is
one of those things that is a really useful tool
for storytellers. Uh. If they have a story about a
ship encountering some sort of wreck or other kind of
(04:28):
of body out in space, it needs to be pulled away.
And the nice thing is is that we've got scientists
here on Earth who are saying, hey, how can we
do this science fiction thing for reels right? Knowing how
light behaves and uh, and maybe finding new ways to
make light behave in perhaps an unexpected fashion. Well, I
suspect that, in fact, Star Trek used some actual research
(04:52):
that was going on in the nineteen sixties as a
basis for their tractor beam, because according according to the
Star Trek universe, the way that their tractor beam works
is it's actually WILLI a graviton force beam and I
just made little quote marks in the air for the
benefit of nobody really, so that was weird. Gravitons are
hypothetical particles that that essentially mediate the force of gravity. Uh.
(05:13):
They're hypothetical because we have not observed an actual graviton.
We don't know how we would We don't we know
that in order for our quantum model of the universe
to make sense, we need something like a graviton to
exist to explain the force of gravity. There are four
fundamental forces in the universe. There's strong, nuclear, weak, nuclear,
(05:35):
electro magnetic, and gravity. Out of those, gravity is the weakest,
but it's also the one that we cannot easily incorporate
into the quantum model of the physics. Right, It's sort
of assumed by Einstein's general theory of relativity that gravitational
waves are a thing that exists, that ripples in the
spacetime continuum, caused by very large moving objects, particularly, but
(05:59):
nobody has detected these. So so really the way we
observe this is through the force of gravity. I mean,
that's that's that's we can see the outcome just exactly so.
And to explain to you guys how weak gravity is
in comparison to the other forces, here's a very simple,
uh experiment anyone can do anyone who has access to
(06:20):
a comb and a balloon. So let's say you've got,
you know, get a balloon. You just inflate the balloon
with oxygen. Don't do helium because that will negate the
results of this test. Check. So oxygen inflated balloon, you
sat down on a table. Gravity is pulling the balloon downward.
I am oversimplifying here, so physicists please don't don't write
(06:41):
in and complain. But the balloon is held to the
table in part due to friction, but also in part
due to gravity. If you were to take your comb
and rub it against say a sweater, and get build
up some stack electricity on the comb, and then touch
the comb to the balloon and lift, you would see
that the stag electricity that was generated while you were
rubbing the comb against your your sweater would be enough
(07:04):
to attract the balloon and lifted off the table. That
means that the any amount of electromatic force, the static
is stronger than the gravity. And the gravity, yeah, You've
got an entire planet beneath you that is got this
very strong gravitational pull, strong in comparison to other things
that we directly observe throughout the day, and yet it
(07:26):
is dwarfed by strong enough Yeah, strong enough to pull
a bowling ball from the top of tower. Right but
right so, and and gravity just so. To complete the
whole picture here, it depends on two things. It depends
on really you have to have two different bodies, but
it depends on the body's mass and their distance from
one another. But they do exert gravity, a gravitational pull
(07:49):
against each other. So, for instance, I have a cup
of tea in front of me, I am exerting a
very tiny gravitational pull on the cup of tea, and
it is exerting a very tiny gravitational poll on me.
Now this is dwarfed by the fact that I'm also
on the planet Earth and that the Earth is exerting
gravitational force on both of you. Right, So I you know,
(08:10):
I can't observe this. I don't really, I'm not aware
of it in any way. But that's that's yeah. So
keeping that in mind, one easy, relatively easy way of
having a tractor beam like effect, even though you wouldn't
be beaming anything, is to use the gravity of one
object to influence the movement of another object. Now, this
(08:34):
is something that we've talked about before on tech stuff,
when we were chatting about could an asteroid destroy the
Earth if if, if some space agency. I was gonna
say NASA because that's the one that I'm most familiar with.
But if NASA were too identified that an asteroid twenty
years away has the the uh the chance potential to yeah,
(08:58):
that would be a bad thing. Yes, because we all
learned in the documentary arm Again, Yes, that wonderful documentary
that taught me that Steve bu Simmy is a better
singer than Ben affleck Uh, which I had no way
of knowing until I saw that anyway that one way
of potentially deflecting the asteroid would be to send a
spacecraft up so that you move the spacecraft so it's
(09:21):
close enough to the asteroid so that they are are
pulling one another with a gravitational pull, and then you
use thrusters with the spacecraft to just very slowly push
just not really really it's pull. You're yeah, you're pulling
the asteroid because as you move the spacecraft away, the
gravitational pull makes the asteroid move with it, and all
(09:41):
you have to do is move it. The further out
you go from Earth, the less you need to move
the asteroids so that it has it misses the Earth right,
because you're talking about angles, So a couple of degrees
of difference way the way way the heck out in
space make enough difference to not kill everything on it, right,
it'll miss the planet in hirely, So that's the idea.
So that's kind of like a tractor beam in the
(10:03):
sense that you're using an object to tow another object,
in this case objects that are in space, but you're
not actually shooting a beam of anything. Right. However, Yeah,
it's not it's not made of light. It doesn't do
that cool visual effect that you have a sound effect,
which obviously that would not not anything in space anyway. Sure,
but hey, why why should we start criticizing Now that's
(10:25):
a that's a whole different episode. Um. And So, in
the nineteen sixties, people were really excited about detecting gravitational waves,
and a few people in fact, suggested that we might
make a gravity laser. A couple of people, Helper and Laurent,
proposed that this could be called a gazer, which I
think is a terrific word. Yeah, and I think means
(10:46):
something entirely different. These are modern times, I think, Yeah,
I think I agree with you. I think at this
point the scientific community would say, can we ya? Um.
They proposed that we could vibrate some types of electric
crystals and create a whole thing. And but that's it's
never really come to fruition because the above re we
(11:06):
have never discovered gravitons, We have never measured gravitational waves.
Right for us to be able to create an object
that would use gravitons to to make a tractor being
we first sort of need to prove that gravitons in
fact exist, because again they're hypothetical right now. It's sort
of like the Higgs boson, right The Higgs boson was
a theoretical particle that physicists said, for our understanding of
(11:30):
the universe to make sense, we need this thing to
exist to explain why matter has mass, same sort of thing.
In order for our understanding of gravity to make sense,
within the within the framework that we have of our
knowledge of the universe, knowing that we are by our
very nature limited in our understanding, a graviton needs to
(11:53):
exist for that model to really make sense. So we're
talking about mathematically, yes, these things to exist, but in reality,
we just haven't tracked it down yet. So if we
ever do, maybe we can make some sort of technology
that can take advantage of that. But until then, until then,
maybe no gravitational lasers. Yeah, I personally hope that we
(12:15):
do crack that nut, because that would be I mean,
it would be an incredibly useful tool, and not just
in the context of space exploration. That's the one that
we all think about because again in science fiction, that
tends to be where tractor beams come into play. But
as it turns out, tractor beams can have a really
useful uh well in implementation here on Earth in space
(12:38):
on the planet, and I mean moving things is hard,
they're heavy, or even if they're or they're really small.
And so yeah, we'll talk a bit in a second
all about how some scientists are making micro versions of
tractor beams here on Earth and what those could be
(12:59):
used for. But first let's take a moment to thank
our sponsor for this episode, and now back to the show.
All right, so we've talked about using gravity to create
a tractor beam like effect, or possibly even using gravitons,
(13:20):
assuming we ever understand them. But that's not the only
way scientists are looking into creating a tractor beam like device.
There's actually been quite a bit of news over the
last decade about scientists using various ways of manipulating light
to pull an object as opposed to push it away. Right,
(13:41):
Starting way back in six people started playing with what's
called optical tweezers, which are lasers that are capable of
manipulating molecules and moving them with precision. And now this
is not pulling a particle towards the light source, so
it's not technically a tractor beam, right, but it is.
It is a method of manipulating microscopic particles very precisely.
(14:04):
So if you're thinking about a plane like an X
and Y axis, you could move particles within the X
and y axis, but you're not moving them along the
Z axis. That would be you know, from the source
of light to wherever the particle is. So in relation
to the source of light, the particle would not get
closer further away, but you could trap it and move
(14:25):
it within that X Y plane. That's that's my understanding. Yeah, yeah,
and these are well I I that's my understanding as well.
These these laser beams that are being used for this
have a Gaussian intensity profiles, which means that they're brighter
in the center than they are at the edges. Right.
A Gaussian distribution is a normal distribution, and it can
be for anything from lasers to really you can even
(14:47):
see this in social sciences where you do a survey
and you have a Bell curve that shows a normal
distribution that's essentially a Gaussian distribution. So, Okay, light has momentum, right, right,
and so when it hits an object, the object bends
the light which changes its momentum, and thus the object
is pushed back equally and oppositely by the light. Okay,
(15:08):
I see, so the lights momentum has changed. The object's
momentum is also changed correct according to the conservation of momentum,
which you can see in normal, non microscopic classic physics. Right.
And so the Gaussian beam is important because if the
sample gets off center in the beam, the weaker light
at the edges is bending around the object and pushing
it out, but the stronger lighted center is bending around
(15:29):
it and pushing it back in, and the stronger force wins.
I see. Okay, Yeah, that makes way more sense than
everything else I read, because everything I read was a
lot of this. This research that we did for this
Pathicunar podcast is in is from scientific journals and uh.
And this is a good point for us to make.
Lauren and I we're advocates of science education. Absolutely, we
(15:51):
both love science. That being said, neither of us are scientists,
and we certainly are not particle physicists. And so when
you get onto the quantum level, there's a certain level
of understanding that we are able to achieve. And beyond that,
this stuff is it is like magic to us. So
we're going to explain things as best we can, but
(16:11):
please understand there are subtleties to this that we cannot
easily explain because we haven't dedicated our lives to understanding
them exact and by so if we get anything wrong,
please do right us in Um, we love getting that
kind of feedback, right, Yeah, No, we definitely want to
to communicate the correct information as best we can. But uh,
(16:32):
you know this, this is exciting stuff. So in this case,
what Laurence talking about is using light to to uh
to isolate and then manipulate microscopic particles. But at this
point the stage what we're talking about does not include
pulling those particles towards the light source. However, we have discovered,
(16:54):
or rather I should say we predibly smart people have
discovered ways of using light to act pull things towards
the source in a bunch of different ways. Actually, um,
there's one of those is called an optical vortex. Um
sounds kind of kind of freaky people. The main research
that I've read from this was from Australian National University
(17:16):
around so pretty recently, and the the idea of this
one is that they use a hollow laser beam to
trap light absorbing particles, and um, they get trapped in
the center of this laser beam because the heated air
molecules around them are pushing in on them goutches, so
they cannot they can't escape the laser beam. They're stuck
(17:37):
in that little hollow center, in the hollow center in
the in the the doughnut shaped laguer Gaussian laser beam. Yes,
that right there, that thing exactly that you just said. Yeah,
I have the note. I'm so glad that you did
more research on this because when I read that, my
eyes kind of glazed over. Yeah. Apparently they were able
(17:58):
to move particles about one and a half meters in
the air. Yeah, it's it's really exciting. By they found
out that by using too concentric hollow lasers, they can
adjust the brightness of the two of them there by
heating and cooling the air around the molecules and and
then therefore have the molecules move up and down as
they will through this hollow tube of light. Wow. So
(18:21):
so you're using two different lasers in order to make
that maintain this kind of movement. That makes sense, I
understand now. Yeah, I was wondering how that worked beforehand.
But yeah, that that totally makes sense. And yeah, and
these are nanofoam particles that they were using to the
got transported over a meter and and all of this
is on the scale again of a very microscopic things. Right.
That's something that's important and we'll talk a little bit
(18:42):
more about that when we finish with all the different
laser methods. But yeah, the methods we're talking about are
very exciting. Don't get us wrong. They are incredibly exciting,
particularly in certain very specific implementations like in the medical field.
Oh yeah, this is all going to be extremely exciting
for for example, removing bacteria from samples, sorting cells, municially
(19:04):
manipulating DNA strands is something the optical tweezers have been
used extensively for, right, so that there there are real
uses for this. But these are not the same technologies
that will let us move spacecraft like toe spacecraft away.
And we'll talk about why that is when we get
a little further in, because there are a couple of
other laser methods that we need to talk about, right right, Um,
back back on the kind of sale, the sort of
(19:26):
solar sale theme that we were discussing earlier. Optical lift
is another version of of light that can be used
to do stuff. It's it's actually just a really simple
analog of aerodynamic lift, which of course is when um
you create uh uh, how is it? It's higher pressure
(19:47):
underwing than over awing and therefore letting a plane lift
off the ground in the game. Before we get any
further physicists, that's also an oversimplification, and we acknowledge that, yes,
there's more than geology, there's more than just that when
it comes to get an airplane off the ground. Also,
we know all about the other forward momentum and everything else,
but but that that is the concept of lift. Thank you,
(20:11):
And so to get slightly fewer angry emails, it's only
because Chris and I received all those emails already, but
but deservedly so right, oh no, absolutely, yes we love
negative feedback. But so I nearly spit tea all over
my laptop. Please don't take that as a as a
Please don't take Lawrence Lauren's statement as a means to
(20:33):
send us the most negative feedback ever, because my feelings
do get hurt, and I apparent you just made a
complete liar out of me. That you almost snorfing your
tea completely made me crack up. Sorry about that, excellent,
But anyway back to optical lift. It's uh. The scientists
have discovered that that you can take an object with
(20:55):
a differently shaped top and bottom surface and it will
experience a lift force when please standing uniform stream of
light that's fast. This is all blowing my mind because
before we did this research, I never knew about these
different properties of light and and it just it really
stresses to me one amazing universe. This is, you know,
to to know that things behave on such a different
(21:17):
level than my previous understanding, and also illustrates quite effectively
how ignorant I am. But I love to learn, so
that's okay. Yeah we get we get paid to learn
this stuff and pass it on to you, which is
basically the most exciting thing. Um. One of the other
categories that I ran across were optical conveyors, which are
really fun. Those are those are the ones that are
(21:39):
using Bessel beams, and I think I think Jonathan has
a whole section about this one. Yeah, not a whole section,
but I can at least tell you what a Bessel
beam is. Because when I encountered that term, I thought, huh, what,
what exactly do they mean by Bessel beam. It's a
specific type of radiation, and that sort of radiation can
be a laser, it can be electroma, metic, it can
(22:00):
be acoustic, it could be gravitational. It doesn't really matter
what the type of radiation is, it's the form it takes.
And that form is a radiation where the amplitude is
described by a Bessel function of the first kind. Does
that mean essentially, it means that as this radiation moves forward,
it does not diffract in any way. It doesn't diffuse,
(22:23):
it does not spread out. In other words, it remains concentrated.
So what we think of that like a laser beam.
When you shine a laser beam, it doesn't spread out
like a flashlight does. But this is a very specific
format of that. And in fact, because actually those those
laser beams that were that you point at something are
Gaussian laser beams. That's we discussed there, and so this
(22:43):
is different is different. This is different. It is it
is focused, It does not diffract in any way, it
does not spread out at all. And in fact, one
a a a feature of a true bessel beam would
be that if you were to just interrupt part of
vessel beam. Let's let's imagine that the vessel beam is
as big around as a pencil, Okay, just for the
(23:05):
purposes of illustration, and then imagine that you had, uh
use a sheet of paper and cut a little slit
in that pencil, and you make the sheet of paper
interrupt the vessel beam. Right, So you've got the sheet
of paper that's interrupting half the vessel beam. The other
half is going beyond the edge of the paper. A
true vessel beam will heal itself beyond the point of interruption.
(23:29):
So if I were to interrupt that beam further down
the beam, it would become whole again. So it would
be the same diameter as it was um at the
before a point where you had that interruption. So that's
an awesome thing about a vessel beam. Now here's the
here's the caveat. A true vessel beam would require essentially
(23:49):
unlimited power. Uh. So Dr Doom would want to make one, uh, certainly,
but none of us would be capable of doing it.
It's a true vessel beam is effectively impossible for us
to make. We can make things that approach vessel beams
and that UH emulate many of its features, but a
(24:09):
true one is beyond our capability. That is the short
and sweet definition of vessel beam. And do keep in
mind we're not just talking lasers. Like I said, it
could even be acoustic. So you could create a vessel
beam of acoustic energy and make a noise that could
be heard perfectly at the destination, no matter how far
away it was. That that is fascinating, pretty awesome, that's terrific.
(24:31):
It's Jonathan from again here to once again break up
the episodes that we can take a quick break. So
researchers are using these. Specifically, some people at New York University,
building on research by a Chinese team at the a
Star Data Storage Institute, I believe in around two thousand eleven,
(24:54):
two twelve people have been working on using a lens
to bend and overlap two of these vessel beams um
thereby creating what I can crudely, crudely describe as kind
of a Strobe effect that will, Okay, it'll hit the
front of a particle, and because of that, because it
can reform around an object, it will reform behind the particle.
(25:17):
With enough energy that it actually pushes the particle back
towards the light source. All right, so what's happening is
the photon is is hitting the particle in such a
way as to give it a little kick back toward
the actual source of the photons correct, which is kind
of crazy. It's awesome. Like there was one point where
I was reading one of these descriptions and I was thinking,
(25:38):
the only way I could describe this is if you
were thinking about having a smaller particles being pushed forward,
because larger particles are sinking down, so instead of being
pushed down, they're actually going up. And then the more
I read about the more I'm like, this is a
complete misunderstanding of this, and I cannot go with this analogy.
(25:58):
And that's what I thought. I hope Lauren has got discovered,
and luckily she did. Yes. I like the physics, but
physics were always the interesting part to me. I was
always terrible at algebra, but really good at geometry. I
love classical physics. Quantum physics makes my head hurt. I
just that's the fun headache. I like the I like
the quantum physics headache. If better you than me, what's
(26:21):
that terrific quote. Off. If you're not kind of upset
by quantum physics, you haven't understood it properly. I think
all of us haven't understood it properly. I think the
people who haven't understood it probably the most have the
biggest headaches. Those are quantum physicists anyway. But then I
say that as as I you know, every quantum physicist
interview I've said I've watched tends to include a question
(26:42):
that's all similar to, but do you really understand what
it is you're talking about? And the quantum physicist almost
always says, you know, there's a certain level where I
don't like. There's certain things that you just say, all right,
this is how it is, because that's how it is.
But to be able to answer, I can't. And so it's,
(27:02):
you know, one of those things you just have to accept.
And my brain starts to melt out of your ears. Yeah,
there's a lot of screaming and waving of fists inside
the craneyde the brain. Yeah. But so the special beaming
optical conveyor technology might be an interesting practical use for
it could be to test the tensile strength of cells.
For example, if if a cell has been infected with malaria.
(27:25):
It's more rigid than a normal blood cell, and so
it could be super useful in tiny microscopic medical purposes.
Similar to another breakthrough that was very recent as of
the recording of this podcast, we're recording this in early February,
and there were some publications that we're talking about an
(27:46):
experiment that had been performed by scientists from Scotland and
the Czech Republic about using a beam of light with
a specific geometry to pull particles of polystyrene. And these
particles are very very small, in fact, beyond microscopic, we're
talking about nanometers for fos, about four hundred ten nanometers specifically.
(28:09):
Think most of the particles we've been talking about have
been on on that scale. Yeah, pretty pretty tiny stuff,
but fomes and one thousand nanometer particles essentially think about
tiny spheres of polystyrene that are only a few hundred
nimeters in diameter. That's essentially what we're talking about here.
(28:30):
And they found that by uh polarizing the light in
a particular way, they can manipulate these particles, and in fact,
not only could they manipulate the particles, but depending upon
the way they polarized the light, they could selectively manipulate
particles of a certain size while not affecting particles of
(28:51):
another size. Yeah, there's a there's a little video of this,
by the way, in a press release. We'll link it
somewhere on our on our tech staff media. Yeah, yeah,
you'll have to take a look at this. It's pretty
amazing because you think about that, that means that you
will be able to selectively uh, grip, sort and move
right particles, so that way you could you could keep
some undisturbed while you're the ones you're interested in, those
(29:14):
are the ones you can manipulate and uh and that
is a huge breakthrough you're talking about just by by
again changing the nature of the light itself, being able
to affect very specific sizes of particles and it doesn't
really matter what the particle is made out of. They
were using polystyrene in a liquid solution. So again, this
(29:36):
was another breakthrough was that this was something that could
work within a liquid, making it very useful for medical purposes.
So if you wanted to take a blood cell and
you needed to move certain particles in that blood cell
out or off to a side so that you could
either examine them more closely, or perhaps get them out
(29:57):
of the way so you can examine something else in
the blood cell more closely. It would be a very
useful tool. One description that I saw of this said that,
and and this one in particular. There are a lot
of very intelligent people have said very ierdite things about
all of the rest of these forms of tractor beam manipulation,
and I read them and have said them back to you.
(30:20):
This one is so new that not that many people
who are smarter than us have really said that many
things about it, and so therefore my understanding is tenuous.
But one explanation that I saw said that they used
a mirror to bounce the laser beam back across itself,
interfering with the head on photons and thereby pushing right.
And the the interesting thing to me was that it
(30:42):
was through that interference that creates this pulling. It was not, however,
because you hear mirror and you think, oh, well, all
they're doing is shooting the photons, bouncing it off the mirror,
and then the photons hit the particle and then push
the particle. But that's not what's happened. That's not what's happening.
It's the it's the interaction of the the oncoming beam
(31:03):
and the reflected beam that create this pulling motion. And
that to me is phenomenal because at first I thought, oh, well,
what they're really doing is just yeah, they're just they're
just pushing, they're not pulling. But that's not the case.
That actually is pulling actually the light source they're The
really fascinating thing about this is that apparently, under certain conditions,
the objects held by the beam rearranged themselves into a
(31:25):
structure that made the pull stronger. That's pretty awesome. I
mean this, this is so mind blowing to me that this,
this world on the nanoscale is every time I read
anything about it, it amazes me. It's like, you know,
the two areas I find the most interesting when it
(31:45):
comes to exploration are outer space and nanospace because there
are a lot of parallels, I mean weird parallels between
outer space and nanospace fractals. Fractals say that that's a
that is a known quantity. That just make me think
of the Jonathan Coulton song Mandel brought Set, which is awesome.
Have you heard that? I do not believe I had.
(32:06):
I guess what we're doing. After the podcast is over,
you get to hear a song. Alright, trip, so uh
we we We alluded to the fact that this is
stuff that works on a microscopic scale and would not
translate to macroscopic Yes, and here's the reason why. Yeah,
the reason why is that all of all of this
work with lasers. Lasers, of course, um can burn stuff.
(32:26):
And if you had a big enough laser to move
you know, the one of the physicists I think mentioned
a football. I assume that they were meaning a soccer
ball because they were from Scotland, and that was Thomas Sissmar.
There you go, um, and it would fry a long
time before you would move that soccer ball. Yeah. In
(32:47):
other words, the laser would have to be of such
an intensity and size as to destroy whatever it was
you were trying to move. So it might move, but
only because someone didn't want it to burn down everything else, Right,
it would be moved by some one else who's saying,
why do you have this flaming soccer ball in the
middle of the field. Yeah, that's the that's a problem, obviously,
I mean, it's it's a it's a non trivial problem
(33:09):
and I mean, I know it's a non trivial problem
and it sounds like I'm being silly, but no, it's
non trivial, and that as far as we are able
to determine, there's no way to get around that using
this particular implementation of the tractor beam idea. So this
would strictly be on the nano and micro scale and
never get beyond that. That does not mean that we
(33:31):
won't find some other way of creating a tractor beam.
We very well made, but it's not going to be
using these particular methods because obviously we would end up
destroying whatever it was we were trying to manipulate. So
we hope, we hope that we will see some of
that in the future. I hope you guys enjoyed that
classic episode of tech Stuff. If you have suggestions for
(33:52):
future episodes, send me an email. The addresses tech stuff
at how stuff works dot com, or you can draw
me a line on Facebook or Twitter. The handle it
both of those is tech Stuff hs W. Don't forget.
You can pop on over to our website that's tech
stuff podcast dot com. There you're going to find an
archive of every episode we've ever recorded. It's entirely searchable,
(34:14):
so you can check and see if I've covered your
favorite tech topic, and if not, well get in touch
with me. I mentioned how you could already. You also
find on that website a link to our online store,
so if you've ever wanted any sort of tech Stuff merchandise,
whether it's a sticker or a mug or a mouse
pad or t shirt, go check that out. Every purchase
(34:34):
you make goes to help the show, and we greatly
appreciate it, and I'll talk to you again really soon.
Tex Stuff is a production of I Heart Radio's How
Stuff Works. For more podcasts from my heart Radio, visit
the I heart Radio app, Apple Podcasts, or wherever you
listen to your favorite shows.
TechStuff News
Hosts And Creators
Oz Woloshyn
Karah Preiss
Popular Podcasts
Stuff You Should Know
If you've ever wanted to know about champagne, satanism, the Stonewall Uprising, chaos theory, LSD, El Nino, true crime and Rosa Parks, then look no further. Josh and Chuck have you covered.
24/7 News: The Latest
The latest news in 4 minutes updated every hour, every day.
Crime Junkie
Does hearing about a true crime case always leave you scouring the internet for the truth behind the story? Dive into your next mystery with Crime Junkie. Every Monday, join your host Ashley Flowers as she unravels all the details of infamous and underreported true crime cases with her best friend Brit Prawat. From cold cases to missing persons and heroes in our community who seek justice, Crime Junkie is your destination for theories and stories you won’t hear anywhere else. Whether you're a seasoned true crime enthusiast or new to the genre, you'll find yourself on the edge of your seat awaiting a new episode every Monday. If you can never get enough true crime... Congratulations, you’ve found your people. Follow to join a community of Crime Junkies! Crime Junkie is presented by audiochuck Media Company.