Interview Interlude Playlist, Part 10: Dr. Jeff Hoffman

Let's talk about life beyond Earth's magnetosphere. Here's our 2018 chat with astronaut Dr. Jeff Hoffman.

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Episode Transcript

Speaker 1 (00:03):
Welcome to Stuff to Blow Your Mind from how Stuff
Works dot Com. Hey, welcome to Stuff to Blow your Mind.
My name is Robert Lamb and I'm Joe McCormick. And
today we've got a very special episode for you all
out there. We are doing a partnership with National Geographic YEA.

(00:25):
So they've got a new show coming out called One
Strange Rock and it is produced by Darren Aronofsky of
Mini Movie Fame and all about it's all about the
science of planet Earth and the sort of intricate interconnected
processes both geological and biological to keep the Earth stable

(00:45):
as a sanctuary for life as we know it. And
in that sense, it has a kind of uh, ecological
Alexander von Humboldt kind of vibe that I really like.
I like it when you can see the large scale
and small scale interconnectedness of all things to to make
the world how it is. Yes, And speaking of Steve,
this is a visual spectacle. Yeah, it's got a lot

(01:06):
of really beautiful photography and it's hosted by Will Smith.
I don't know if he ever says Welcome to Earth,
and it kind of hope so, uh, And it it
tells stories through the experiences of a large cast of
real life astronauts who are the only humans ever to
venture beyond the shield that protects us from the universe
at large. And so because of our partnership with National

(01:27):
Geographic for this episode, we got an opportunity to talk
to one of the astronauts on the show, Dr Jeff Hoffman,
who flew five Space Shuttle missions, including a Hubble Space
telescope repair mission. And this is a great interview. We're
just delighted to share it with everybody. Yeah. Dr Hoffman
is very knowledgeable from multiple vantage points about the thing
that we're gonna be focusing on today, which is the

(01:48):
radiation risk from space and how Earth protects us. And
he's knowledgeable in a couple of different domains because he's
done high energy astrophysics and knows all about the radiation
environment of our Solar system in the universe at large.
But he also has a direct experience of what it's
like to be an astronaut out in space to sort
of go beyond our protective barriers. And that kind of

(02:11):
perspective is kind of hard to come by because I
would say, one thing, it's really easy to lose sight
of in your day to day life, when you're reading
about politics or playing with your dog or making some dinner.
Is that your body is made of molecules, and in
order for molecules in your body to do what they do,
they have to remain what they are. And most of

(02:31):
the time, the internal chemistry of our bodies is pretty stable, right,
But we have to recognize that the chemical stability of
our bodies is an enormous and unique privilege provided to
us by virtue of the fact that we live on
planet Earth. Yea. And this we get into a truth
that we touch on quite a bit on the show,
and that is that Earth is just the right planet

(02:53):
for life as we know it. Kind of unsurprising, of course,
being creatures that evolved on planet Earth, that planet Earth
is just the right planet for us. But despite realizing
the kind of anthropic obviousness of that fact, it is
still a kind of strange and comforting feeling. Well, wait
a minute, is it comforting or is it discomforting? The
fact that most of the universe is going to be

(03:15):
so hostile to us, so unbelievably hostile, so incredibly violent,
that it's just impossible to even consider. And I'm not
even talking about the vaporizing heat of stars or the cold,
airless void of deep space. I'm talking about the fact
that the universe is an acid bath of killer radiation,
including ionizing radiation, which often takes the form of these

(03:36):
high energy charged particles that blast through animal bodies, damaging
and changing the molecules within them as they go along,
and even changing the DNA of ourselves, altering the blueprints
for cell replication and bringing about tissue damage, sterility, and cancer.
And so that body integrity and chemical stability we so
take for granted to keep living is only possible because

(03:59):
of the planet, the inhabit which shields us from being
blasted by the Sun nearby and by the galaxy at large. Yeah,
it's it's interesting to think about this that we we
are creatures of the shallows. So life as we know
it essentially thrives in a tide pool, protected from the
full onslaught of wind and wave. You know, if you've

(04:20):
ever been to a to a number of beach environments,
you've seen those areas right where um, where that the
waves are crashing but there, but but there's this pool,
this uh, this area of calm water that is protected
from all of that, and that's where a lot of
life can thrive that otherwise would not be able to
bear the hostilities beyond the rocks. And it actually reminds

(04:43):
me of this quote by John Steinbeck Uh and and uh,
he's not directly talking about what we're talking about here,
but the comparison is just beautiful. He he wrote, the
knowledge that all things are one thing, and then one
thing is all things plankton, a shimmering phosphorescence on the sea,
and the spinning planets and an expanding universe, all bound

(05:06):
together by the elastic string of time. It is advisable
to look from the tide pool to the stars and
then back to the tide pool again. Yeah, our earth
is protected not from wind and waves, but from the
full blast of solar and cosmic radiation. Instead of rocky
sea walls were protected by a robust atmosphere and most importantly,
the magnetosphere. Yeah. The interesting other side to the fact

(05:28):
that we've got this kind of connected consciousness that we're
aware of, Like there is no real division between the
Earth and the heavens. They're just different places. The only
real division is distance, And so all the universe really
is connected and does have a common origin in the
Big Bang. But at the same time that connectedness, we
use the word connected in such a happy way. It's

(05:50):
like nice to be connected to things. But you can
also think about that is extreme vulnerability, like you are
right next door to everything in the universe that would
Russian annihilate you. And what we've got standing in the
way of those those crushing annihilating forces beyond our power
to control, is essentially a big magnetic field and a

(06:10):
thin layer of gas around the rocky surface of the planet.
That's right. So basically what we have going on here
is the Earth solid intercore and liquid outer core. They
play a crucial role in protecting life as we know
it from deadly deadly radiation. Differences in temperature and composition
in the two core regions drive a powerful dynamo emitting

(06:33):
Earth project protective electro magnetic field. And remember this is
one of the key factors we have to consider improposed
interplanetary space travel and establishing stations in other worlds. The
only planets in our Solar System with some form of
magnetosphere in place our Mercury, Earth, Jupiter, Saturn, Uranus, and Neptune. Right,
so then, of course you've also on the surface of

(06:53):
the Earth got the atmosphere to count on, because that
means that there's more stuff that radiation has to get
through to it to you, and so the atmosphere will
block some kinds of incoming radiation. But the other big
protector is the magnetosphere that keeps these particles directed away
from the Earth. Some of course still get through, right,
And also the magnetosphere serves to protect the atmosphere as well, Yes,

(07:15):
because if you don't have a magnetosphere, your atmosphere over
time can be stripped away, which is one of the
things that they think probably happen to Mars long ago. Right.
So it's our protective barrier against the elements. It's our battlements.
And the only humans who have walked these battlements are
astronauts such as Dr Jeff Hoffman. Now, most astronauts never
even go beyond the shield that protects us, right, we

(07:38):
know that astronauts in space are exposed to extra levels
of radiation, and that's one reason you want to limit
your time and space. You're like, you can't go live
in the I S S forever. They want to bring
you back eventually because the more time you spend up there,
the more you're exposed to this dangerous radiation that could
harm you in the long run. But even up in
the I s s you're still you're still benefiting from

(07:59):
a large part of the Earth's protective shield. Right. Yes,
it gets a lot worse if you want to go
to the Moon, right to Mars, or colonize another planet. Yeah,
because then you're going beyond Earth's protection. So I guess
we want to go now to our conversation with Dr
Jeff Hoffman UH to talk about the radiation risks posed
by the universe and what astronauts have done and can

(08:20):
do to protect themselves. But first I guess we should
give you just a little bit of background on Dr Hoffman. Yeah,
So his original research interest were in high energy astrophysics,
specifically cosmic gamma radiation and X ray astronomy, and then
his doctoral work at Harvard entailed balloon born low energy
gamma ray telescopes and the design and then the testing

(08:41):
of this technology. From nineteen seventy to nineteen seventy five.
During post doctoral work at Leicester University, he worked on
several X ray astronomy rocket payloads, and then he worked
in the Center for Space Research at the Massachusetts Institute
of Technology from nineteen seventy five to nineteen seventy eight
as projects scientist in charge of the orbiting h e
A oh one A four hard X ray and gamma

(09:03):
ray experiment, which launched in August ninety seven. But then
in seventy eight he was selected to become an astronaut
and he went on a total of five different Shuttle flights.
So in eighty five he went up on a Discovery,
nineteen ninety on Columbia, two on Atlantis, ninety three on Endeavor,
and then in nine on Columbia. All told, one thousand,

(09:26):
two hundred and eleven hours in space twenty one point
five million miles. That's a lot of miles. Frequent flyer, Yeah,
so he he is a not only a pedigreed scientist,
of a pedigreed astronaut. Five Shuttle flights, that's impressive. That's
five more than the vast majority of human beings. All right,
we're gonna take a quick break and when we come back,

(09:47):
we will be heading straight into our interview with Dr
Jeff Hoffman. Thank hey, Dr Hoffman, welcome to the show.
We're really glad to have you well, nice to be here,
looking forward to it. I was wondering if you'd would
start off by telling us a little bit about your
research from before you became an astronaut. What what made
you interested in high energy astrophysics and um, what were

(10:11):
your pursuits in that field. Well, I grew up with
an interest in space. I lived in or near New
York City. My dad used to take me to the
planetarium to see the new show every month. UM. I
saw the birth of the space age. You know, I
was alive whence but Nick was first launched when You're

(10:32):
a Gagaran and John Glenn flew and so. I was
also interested in human spaceflight, although it was apparent to
me that all the early astronauts were military test pilots
and that was not a career for me. But space
in general I was fascinated with and went on to
become an astronomer. I got a doctorate in an astrophysics

(10:56):
at Harvard UM, and I was attracted by UH, what
we call high energy astrophysics. It was a totally new
field at the time UM the discovery of X rays
from celestial objects and gamma rays. UM. It was a
new branch of astronomy opening up just like radio astronomy

(11:20):
opened up back in the nineteen thirties. And UM that
struck me as being UH an area where we were
almost bound to make new discoveries because we had never
looked at this type of radiation before. So my professional

(11:41):
career as an astronomer consisted in designing X ray telescopes
and then putting them into space. First with I was
using high altitude balloons when I did my pH d thesis,
and then UM I spent three and a half years
at Leicester University in England, UH and we had both

(12:04):
sounding rocket experiments where we would put our telescopes up
above the atmosphere. You have to go above the atmosphere
because X rays and gamma rays are absorbed in the atmosphere,
which is a good thing for us here on the ground,
but it makes life difficult for astronomers because you have
to go above the atmosphere to see this radiation. And
and that was kind of cool as well, because I
was always interested in space and rockets and and so

(12:28):
I was combining the technological interest with what I thought
was a very exciting scientific field. And then I came
back to M I t and we we had actually
our own X ray satellite, and the most exciting research
that I was doing we discovered these things called X
ray bursts. You look at an X ray object giving

(12:49):
out relatively low level of radiation fairly constantly, you know,
and then all of a sudden, you know, bam, it
increases by hundreds and hundreds of times and then gradually
fades away over the course of anywhere from a few
seconds to a few minutes. And we we discovered lots
of these, and this was a completely new phenomena, and

(13:12):
that was probably the most exciting thing that I did scientifically,
was uh, finally figure out what was what was causing these.
It was actually neutron stars um orbiting around regular stars,
and the gravitation of the neutron star was such that

(13:32):
it would suck hydrogen off the regular star, and the
hydrogen would accumulate in a layer on the surface of
the neutron star, and then eventually the whole thing would
detonate in a in a huge thermonuclear explosion. So what
we were looking at were hydrogen bombs, you know, ten
miles in diameter. Uh, you know, it's pretty spectacular stuff.

(13:55):
So that was really exciting, and I was all set
for a uh you know, career as an astronomer. And
but that was now in the mid to late seventies
when NASA was getting ready to fly what was then
the brand new Space Shuttle. And neat thing about the
Stay Shuttle from my point of view, was that it

(14:17):
had a crew of seven, but they only needed two pilots.
The pilots were still going to be military test pilots,
but it really opened things up for engineers, scientists, and
medical doctors. And when NASA put out a call for
for astronauts for the Space Shuttle and and indicated that yes,
they really did want scientists and engineers and doctors, um,

(14:41):
I thought, well, I'll apply and I was lucky enough
to get selected the first time around. So that basically
was the end of my career and astronomy research. I
had a I'd say it was quite successful, and had
I not been selected, I I hope I would have
had a good career as a research aster physicist. But

(15:05):
getting selected by Nazis and astroall certainly changed my life. Interesting,
before we ask you about a little bit of your
spaceflight experience, I just wonder does research into high energy astrophysics, Like,
if you're looking at neutron stars and bursts of X
rays and gamma rays and stuff in the universe, does
that change the way you feel about the sky when

(15:26):
you look up at it and most people look up
and see twinkling stars and it feels kind of nice
and cool and calm. Do you do you envision the
universe emotionally as one full of radiation and danger and
high energy? Oh? Absolutely? I mean, you know, when you
look up, just a simple look up at the stars,

(15:48):
everything looks pretty constant and unvarying. And when you realize
that there's things exploding and going off all over the
place that trem in this areas of high gravitation, high
magnetic fields, charge particles. Uh, yeah, the universe is a
pretty violent place. Um and uh, you don't see it

(16:12):
with your naked eye, but modern astronomy has has opened
this up to us. Dr Hoffman, can you tell us
about some of your your space flight experience? So what
was the Hubble service mission? Like, well, let me let
me start a little bit further back with my first
base flight, because that, of course, for any astronaut, is

(16:34):
is an exciting moment when you get the call from
management and they say, oh, you've been You've got an
assignment to your first space flight. Um. We were supposed
to take up two satellites and put them into orbit
and theres pop them out of the cargo bay of
the shovel, which was what the shovel was doing in
the early days, and then come home. It was going

(16:55):
to be a short, relatively short mission four days or so. UM.
And as it turned out, the second of the two
satellites that we popped out of the Shuttle didn't turn on. UM.
You know, I had nothing to do with us. All
we were supposed to do was was get it out
of the Shuttle into orbit. But when when we reported

(17:17):
that it did not seem to have activated, NASA went
into a big study mode and they figured out the
there was only one single point failure that we could
possibly do something about. There's a little switch on the
outside of the satellite that maybe had gotten stuck. And
so they scheduled, for the first time in NASA history,

(17:40):
an unplanned spacewalk where my partner and I went out.
See I had been trained to use space suits, but
we weren't planning to do a space walk on my
first flight, but they sent us out to fix it,
and um, so that was a totally unexpected, uh, incredible experience,

(18:02):
you know, getting to go out and do a spacewalk,
which you know all astronauts would like to go out.
It's the most intimate experience that you can have of
being in space, is actually putting on a space suit
and going out of the airlock and and it's you know,
kind of you face to face with the rest of
the universe. It's it's an incredible experience. And we did

(18:24):
a good job. And and so um I got identified
as as somebody who was good at space walking, and
I worked on a lot of advanced spacesuit development and
various things. And then when it came time to select
a crew to go up and try to repair the
Hubble telescope. And of course, nowadays, people who weren't alive

(18:47):
at the time when Hubble was put in orbit don't
don't really appreciate what a disaster it was for NASA.
I mean, this billion and a half dollar telescope which
had been launched with great expectations about how was going
to revolutionize our view of the universe, and then to
find out that it couldn't focus properly. I mean, how
could NASA make a huge mistake like that? Was what

(19:09):
everybody was was asking and it was absolutely critical. I mean,
as I say, people don't remember what a disaster it was.
But NASA and Hubble were the joke of late night comedians.
Pubble was denounced in the halls of the U. S.
Congress as a techno turkey. NASA was trying to get
Congress to approve funding for the International Space Station at

(19:32):
the time, and as you can imagine, NASA wasn't very
popular with Congress, so UM, basically they were told, you know,
go to something about Hubble and then come back and
talk to us about the space Station. In any case,
NASA wanted to do everything possible to reduce the risk
of failure in this rescue mission, and one of the
things that they decided was that only people who had

(19:53):
previously done spacewalks would be eligible to do the spacewalks
for the Hubble rescue. And and because of this unplanned
space walk that I did way back on my first flight, UM,
and I had had two subsequent flights since then, so
Hubble for me was my fourth flight, and I had
my spacewalkers Union cards. So I was fortunate enough to

(20:17):
be on the crew and that was suddenly, of all
the things I did as an astronaut, the one with
the most lasting impact was obviously rescuing Hubble and turning
it from basically nassas worst disaster um scientifically to its
most successful and productive scientific mission ever. So it was

(20:37):
a and and of course as a former astronomer, as
well as being an astronaut, being able to put my
two hands on the Hubble telescope up in orbit was
I mean, it was the thrill of a lifetime and
we fixed it and a great thing you did well.
I I know that many of my former astronomy colleagues

(20:59):
after the mission would come I can't tell you how
many people would come up to me and say, oh, Jeff,
thank you so much for thinking novel, because you know,
my my professional career was depending on this, And all
I could say was, well, it was a pleasure, you know,
thank you. It was pleasure, It really was. So you
mentioned that when you were out on spacewalks in in

(21:21):
the e v A, that you had this kind of
intimate experience with the universe. It was like putting you
face to face with the outer universe, and I wonder
about something. So there was a sci fi novel I
read a couple of years ago where a character is
born and lives her whole life in simulated environments inside
a generation starship, and she finally at one point comes

(21:41):
back to Earth late in life, and she's outside and
discussing the idea of getting sun burned. And she's so
unfamiliar with the concept of Earth and the Sun that
she calls this. She's horrified, and she calls this getting
burned by radiation from a star. I wonder, is there
a moment in space, you know, outside vehicle activity, where

(22:03):
you begin to think of the Sun not as the
sun but as a star and other kinds of alienation effects? Now, absolutely,
I mean this is something when I give public talks,
I I often show a picture of the sun in space,
and then I asked the audience, there's something very strange
about this picture. Can you figure out what it is?

(22:26):
And most people don't quite get it. But what you're
seeing is the sun in a black sky. And think
about it. You've never seen the sun in the black
sky because every time the weather is clear, you go
out and of course, our atmosphere scatters the blue light preferentially,
and so the sky is blue, and so every human

(22:47):
being throughout human history until the space age, has only
seen the Sun in the blue sky. We see the
stars in the black sky because there's not enough really
from the stars to be scattered and make the sky
look blue, but not the Sun. But in space, you

(23:07):
really see the Sun as a star in a black sky.
Of course, it's it's bigger and brighter than any of
the other stars because it's close to us. But yeah,
you really do appreciate the Sun as a star and
that that that was something I didn't have to go
out and it just looking out the window of the shuttle.
You you get that appreciation, but it's a totally different perspective,

(23:30):
as are so many other things that you see. I mean,
that's one of the things about being off the surface
of the Earth is that you look with a totally
new perspective. Just like most people don't remember the first
time they ever flew in an aeroplane, But if you
if you pay attention and look out the window, you
also get a totally new perspective on the on the Earth.

(23:51):
Although most people don't bother to look out the window
these days, but from space, we spent a lot of
time looking out the windows and I never got fired
of it. It was a completely um different perspective, not
only on the Earth, but on on the heavens. It
was great flying during the nighttime. You know, we'd start,

(24:13):
we'd enter darkness in the northern hemisphere and you could
look up and see all the familiar northern constellations, the Signus,
the Swan, which is the Northern Cross. And then fifteen
minutes later you'd be in the southern hemisphere and see
Alpha Centauri and the Southern Cross. And that's something else
that you never do when you're on the surface of
the Earth, is to see the northern and the southern

(24:34):
skies at the you know, within a half hour of
one another. Would you describe this as as being a
kin to the the overview effect? Well, the overview effect
um maybe some of the listeners don't aren't familiar with that,
but it was coined by Frank White. He's an author
who thought a lot about I guess he had this

(24:57):
kind of inspiration during an air airplane flight when he
was looking at the ground and and feeling a little
bit removed from the Earth. But then he started thinking about,
you know, what what must it be like for the astronauts.
So he came down to Houston and I was one
of the first astronauts that he interviewed. And you know,
the idea is it It really does change your perception

(25:20):
of planet Earth to to look at it, uh and
and actually see the Earth as a planet um to
see from an airplane, you can look out the window
and see entire cities spread out below you. But from
an orbiting spacecraft you you can see entire countries or continents.
Really the Earth is very beautiful, and so you you

(25:44):
do get this relationship that develops between you and the planet.
At the same time, you can see examples of environmental
degradation caused by humanity, which is you know, now visible
from a cosmic perspective, and that's pretty scary, you know,
the deforestation of the Amazon, the silting up of harbors

(26:08):
and rivers and uh, just all sorts of things. And
you realize that you definitely get a feeling of the
finiteness of planet Earth and this sense of what it
is to be removed from the Earth and how that

(26:28):
changes your feelings for Planet Earth. Is what Frank called
the overview effect, and many astronauts have reported this. There's
now actually a movie that that you can find on
on YouTube or vimeo u the about the overview effect,
made by a cinematographer in in the UK interviews with

(26:53):
a lot of different astronauts, myself included. So yeah, it's
um it so totally different perspective you get when you're
hundreds of miles above the surface of the Earth. So uh,
going back to the idea of radiation risk beyond the
surface of the Earth. On the missions you flew in
the eighties and nineties, what did you and the other

(27:16):
crew members understand about radiation risk in space and what
what kind of measures were in place to protect you
other than just limiting the duration of missions. Shuttle flies
like the International Space Station and what we call low
Earth orbits. So we are basically below the Van Allen
radiation belts, were inside the Earth's magnetic fields, which shields

(27:40):
us from most h cosmic radiation. So um, it's it's
a much more benign environment than when you actually left
the Earth to head out to the Moon and you're
outside the Earth's magnetic shield and then you're exposed to
the direct um impact of galactic cosmic rays and U

(28:05):
and charge particles coming from the sun. UM you ultra
violet light, of course, is not deflected by the magnetic field,
and we have to have protection against ultra violet light
otherwise it would destroy our eyes, which is why the
space helmet spacesuit helmets have those those gold visors which

(28:28):
protect you. And there's ultra violet protection on all of
the windows of the Space Shuttle and the International Space
Station windows. So UM, you know, electromagnetic radiation, cosmic the
the ultra violet rays we have to protect ourselves against.
And then of course there's the infrared radiation from the sun.

(28:51):
The heat when you're in the direct sunlight, temperatures of
things exposed to direct sunlight and space can go up
above the boiling point of water. And so when you're
out in your space suit, you need good cooling and
we do that by sublimating ice and that cools off

(29:13):
the water, which we then circulate in in UH liquid
cooling garment with lots of tubes where you can run
the cold water right over your body and take away heat.
UH and you can adjust that because when you go
into the dark side, it gets very very cold, and
there you don't want this extra cooling so um. From

(29:36):
the electromagnetic point of view, we've got to protect ourselves
against ultra violet radiation, and we've got to have good
thermal control for heat for the charge particle radiation. As
I say, we're in a relatively benign place. When we
did our Hubble mission. Hubble was put as high up
as the Shuttle could go, about four hundred miles six uh,

(30:00):
and we were kind of scraping the bottom of the
van Ellen intervan Ellen radiation belts. So it was calculated
that we were going to get about ten times the
normal exposure for shuttle flight, which which still was nothing
to be concerned about from a cancer point of view.
But but they had us where radiation monitors the whole time,

(30:24):
and particularly when we went outside, and they tried to
schedule the spacewalks so that we would not be outside
when we went through what is known as the South
Atlantic anomaly, which was a part of the orbit where
the radiation is much higher than the rest of it.
That's about all you can do, obviously, if there were
ever a huge solar eruption. UH. We always had the

(30:49):
option of coming home and and uh, you know, getting
underneath the atmosphere for the extra protection, but we never
had to do that. What about extended future missions, how
did the change and what sort of solutions are being
developed to protect future astronauts. The radiation risk is recognized
as being one of the most serious if you're going
to be outside the Earth's magnetic field for a long time,

(31:12):
either on the surface of the Moon or on an
extended trip to Mars. On the surface of the Moon.
Actually getting to the Moon is is not such a
big deal because you can get there in three days
and so your exposure time is limited. But if you're
gonna spend any significant amount of time on the surface
of the Moon, obviously the Moon blocks about half of

(31:33):
the galactic cosmic rays, but but you're still exposed to
all the rest of them. And it may be that
you know, will they're they're talking about possibly having underground
habitats in waba tubes, which we know exists on the Moon.
You're gonna have to do something to shield yourself from
the radiation because being exposed to it for a long

(31:56):
time is going to be dangerous. That's something that very
difficult to do. If you're on a trip to Mars,
because you can't carry that much mass with you to
protect yourself and UM, so NASSE is interested in other ways.
There are some I think very interesting research going on

(32:19):
about UM pharmacological protection against radiation. If there were some
way that we could enhance the body's ability to repair
d NA UM, that would make the impact of radiation
much less serious. We know that there's bacterias which can

(32:42):
withstand hundreds of times the amount of radiation that a
human can. They've developed the ability to repair much more
significant damage to DNA than we're able to do. UM.
There may be genetic clues about how to protect against radiation,

(33:03):
so the point being that we've got to look for
other ways besides just shielding, and of course developing better,
more powerful propulsion systems so that we could get the
Mars quicker would be a big help as well, not
just from a radiation point of view, but logistically, you've
got to carry everything you need UH. You can't get

(33:26):
resupplied once you're on your way to Mars, so all
the food, the medical equipment, the UH spare parts and everything.
They quicker you can get there, the better, So there's
a lot of ways that that we're looking at that
will make long duration spaceflight outside the Earth's magnetic field safer.

(33:49):
But most of these things are still works in progress
right now. We we don't have those solutions available now,
and and correct me if I'm wrong, But once you
get to Mars on a Mars mission on the surface,
you're not a whole lot better off than you are
in space right as far as radiation because first of all, Mars,

(34:11):
just like when you're on the surface of the Moon,
Mars is blocking half of the radiation just by its mass.
And then Mars does have a bit of an atmosphere
which gives you a little bit of protection. But you're right,
there's still the radiation environment on the surface of the
Mars of Mars is more severe than being in lower orbit,

(34:32):
and so radiation protection on the surface of Mars will
continue to be an issue, just like it will be
on the Moon. You'll have to have a certain amount
of protection in your habitats. But again, the other the
other thing, um, you know, there's two aspects of the
dangers of radiation. One of them is that in the

(34:54):
long term it will lead to an increased incident of
cancers like leukemia. Well, one of the things that we're
realizing is that our ability for early detection and treatment
in cancer is continually improving, and so maybe, you know,
twenty thirty years from now, that's just not going to
be as much of a problem. The other UH potential

(35:17):
problem from radiation are acute impacts. There. There have been
some experiments that have shown a potential loss of cognitive
capability for rats when they're exposed to radiation. Um, you
certainly would not like to get to Mars and find

(35:37):
out that your i Q is decreased by twenty points. UM.
There are potential effects of acute effects of radiation on
the circulatory system, on the nervous system, and that's an
area of very active research now it's relatively new. Traditionally,

(35:59):
we were just concerned with the long term impact of
radiation that is ultimately causing cancer, unless, of course, you
had a huge solar flare. You know, if you get
enough radiation all at one time, you're going to die
or have serious UH illnesses, and and um, you know,

(36:20):
we we would like not to be in space when
they have a huge solar flare. But you know, statistically
those don't happen very often and so far we've been lucky.
So we've discussed the ambient radiation risks in space. Obviously,
within our solar system, you you've got solar radiation to
worry about, and you've got charged particles from the from

(36:40):
the galaxy of the universe to worry about. But also UM,
apart from these ambient radiation risks, does it make sense
to also, uh, for space farers to worry about anomalous
radiation risks UM? I know, for example, like X ray
bursts and gam rey bursts are extremely rare in the universe.
Are they so rare that uh that we just don't

(37:02):
have to think about that? Or will the future of
space exploration needs don't really think about it? I mean
if if, uh, if there were a huge black hole
merger like I was observed with the gravitational radiation, you know,
billions of light years away, if something like that happened
right near us in the galaxy, it would be bad news.

(37:24):
But there's absolutely nothing we can do about it, and
so it's just not something that that we even bother
to think about. And what about solar anomalies, I know
you mentioned like a solar event solar I mean solar
flairs are recognized. I mean, there was a big solar
flare in nineteen seventy two in August, which just happened

(37:46):
to occur between Apollo sixteen and Apollo seventeen. Had it
occurred when astronauts were on the lunar surface, there's been
a lot of discussion of whether we've would have been
fatal or whether it would have just been very bad
for them. But it would have been a very serious effect.
But that solar flare in nineteen seventy two was not

(38:07):
nearly the strongest solar flare that's ever existed. I mean,
there was the Carryington event back in the mid nineteenth century,
which was so powerful. Of course, that was we didn't
have satellites, we didn't have electronics going, but they did
have telegraph lines, and that solar flare collapsed the Earth's
magnetic field to the extent that the moving magnetic field

(38:28):
induced voltages in the telegraph lines, which caused fires in
telegraph offices. I mean, if if a flare like that
hit us today, it would cost Lloyds of London did
an estimate of that. I mean, it would be like
a trillion dollars worth of damage. All of our satellites
would be destroyed, Electronic systems all over the world, electrical

(38:50):
power grids would go down, and there's nothing we can
do about it except that statistically something like that happens
maybe once every five hudred years or so. UM. So
far we've been lucky. Not too much more you can
say about it. Uh, we are. People are still doing

(39:10):
research to try to be able to predict solar flares,
so far without many positive results. But I just read
recently some new researches indicating that, you know, maybe they've
made a breakthrough. UM. Being able to predict solar flares
in advance would be a big help, so that at

(39:31):
least you could get ready for it, and if you
had astronauts on the Moon, at least they could try
to get inside their shielding. But other than that, UM,
it's statistics, and so far we've been lucky, all right,
Dr Hoffman. In other interviews, you have stated that shimp
cocktail was your favorite food in space. Can you explain
for our listeners why you selected? Sure? You know, when

(39:54):
when when you take away gravity, there's an upward migration
of it from your lower body to your upper body,
and so you get a lot of extra fluid in
your head. It's a little bit like having sinus congestion,
and it it decreases your sense of smell, so that, um,
you you, the food becomes very bland. They provide extra

(40:18):
Tabasco sauce that we can sort of spice up our food.
The nice thing about the shrimp cocktailers dehydrated, so the
shrimp themselves, uh, you know, there's nothing to write home
about you. You put a little bit of water on
them and they don't have that much taste, but they
pack it in a really really hot horse radish sauce.
So I found if I would eat a shrimp cocktail

(40:42):
before dinner every night, that horse radish would kind of
open up my nasal passages so that I could smell
and taste the rest of the food a little bit more. So.
That's why it was my favorite food, not because it
intrinsically taste good. I mean, as a shrimp cocktail, it
was you know, if they served it to you in
a restaurant, you'd send it back, But it really opened

(41:05):
up the nasal passages so that I can enjoy the
rest of my meal. Well, I guess it's those little
pleasures that make life forth living. There you go. Well,
thank you so much. It's been such a privilege to
talk to you, Dr Hoffman. We really appreciate your sharing
your time with us. Been a pleasure, and I hope
it's given maybe a new perspective to some of the
listeners who haven't heard some of this stuff. So um,

(41:29):
thanks for your interest and it's been fun. Yeah, thank
you so much. Thank you. You have a great day, sir.
All Right, well, thanks once more to Dr Jeff Hoffman
and to National Geographic for enabling us to have this
wonderful chat. We're gonna take a quick break and we
come back. Joe and I will discuss the interview a
little bit before we close out the episode. All right,

(41:53):
we're back, So Robert. Dr Hoffman mentioned a few things
in that interview that I thought were really interesting and
we might want to follow up and talk about a
little bit. One of the things you mentioned when we
were talking about solar anomalies was the idea of the
Carrington event or the solar storm of eighteen fifty nine,
And this just stuck in my mind because this is
one of the most fascinating and I think maybe lesser

(42:16):
known crazy astronomical events in history. Yeah, and indeed it
may have been the largest solar energetic particle event in
the past several hundred years. So why do we call
it the Carrington event? Well, it's a name for amateur
astronomer Richard Carrington, who observed quote two patches of intensely
bright and white light erupting from a cluster of dark

(42:36):
sun spots. They vanished within five minutes, but then within
a matter of hours, the effects of this event were
felt on Earth. So what do those effects look like? Well,
as a Dr Hoffman uh alluded to, telegraph communication around
the world began to fail. Sparks were flying from telegraph machine.
Telegraph operators were in some cases shocked, and then also

(42:57):
colorful auras in the sky were causing the birds to
chirp at night. Yeah. So the solar flaring question had
the power of an estimated ten billion atomic bombs, and
ice core samples reveal that the Carrington event was twice
as big as any other solar storm within the last
five hundred years. This is the kind of thing where

(43:19):
if it were to hit today, the estimates are just
in trillions of dollars worth of damage, it would just
be a massive blow. And Dr Hoffman alluded to this
as well, the idea that it would have. It would
impact our satellites, it would impact technology on a scale
that just simply did not exist in eighteen fifty nine.
But of course it would also greatly affect any exposed

(43:40):
astronauts or space farers that you know, we're colonists, or
wherever outside of the protection of our shield that didn't
didn't even fully protect us from this event. Yeah, yeah,
you know. I I actually interviewed a heliophysicist Dr c
Alex Young several years ago about solar storms, and he
pointed out that that our mom are an electrical grid

(44:00):
in particular, is just highly vulnerable to this sort of thing.
He told me, quote, the power grids that we have
in the US and actually all over the world are
interconnected in very fragile If the currents large enough, it
can short out the largest of the transformers, which can
knock out the power grid over the scale of a country,
of a continent, or even across the whole globe. Yeah,

(44:21):
and uh, for just a minor example of the sort
of thing, in Canada's hydro Quebec power grid experienced a
similar shock in nine from a particularly powerful sunstorm, and
this caused the grid to go down for over nine hours,
resulting in revenue losses estimated in the hundreds of millions
of dollars. And that was just the small potatoes compared

(44:42):
to something like the Carrington event. Yeah, with our earthbound minds,
it's impossible for us to grasp the real power and
magnitude of solar events. Like if you've never seen one
of those pictures of the Earth superimposed to scale against
a solar prominence, it's it's amazing solar prominence. Are these
events where this monstrous loop of plasma erupts out of

(45:04):
the photosphere, which is the apparent surface of the Sun,
and then it curves through the Sun's corona guided by
solar magnetic fields. And this is not even really the
core of the Sun itself, is just an event. It's
like weather, it's a it's an event on the surface
of the Sun. But this event itself is tens of
times bigger than the entire planet Earth. And you see

(45:24):
one of these pictures. When you look at the vulnerability
and tininess of human scale projects becomes absurdly apparent. The
comparison that comes to My mind is if you ever
been out in nature, as as I know you, you
like to venture out in the nature on hikes and
and so forth, you ever observe a bird's nest or
a wasp nest, some sort of animal structure or nest,

(45:48):
and you think about yourself, well, that's a horrible place
to put that, don't you know, tiny bird that eventually
the wind is gonna blow. Uh, don't you know that
when it rains, that's that's just not a very protected place.
Don't you know that's my front porch. And I'm probably
gonna knock you down eventually, just because you're inconvenient to me.
And then when you think about everything that that that

(46:08):
is life on earth, and then everything that humans have built,
and you think of the vulnerability that is intrinsic in
all of that. Uh, we're really no different from from
any wasp that decides to build its nest on the
bottom of a porch. Swing on a geologic or cosmic
time scale, our projects are so hilariously short sighted. But

(46:30):
then again that that's just how we're built, right. I Mean,
it's very difficult for us to seriously focus on a
project that we think will take place over say a
hundred thousand years or even a million years. Yeah, totally.
We're just we we are short sighted as a species.
That's what we've evolved to be. Now. On the subject
of long time scales and and the cosmic scale of events,

(46:53):
I asked Dr Hoffman about whether a space faring species
should really worry about things like murray bursts or X
ray bursts, which I think is kind of a weird
question because on one hand, it's something that would pose
a very serious threat, but these things are also incredibly
rare in the universe, and they're incredibly rare in the galaxy,

(47:15):
So it's hard to factor into one's idea about something
like space exploration how much you should worry about something
that is almost never going to happen anywhere near you,
but if it did, it would be catastrophic. Yeah, it's
coming to It kind of reminds one of of, of course,
the the seafaring explorers of old and to say, well,

(47:36):
if you go out in that boat, you you might
very well drown, you might run into a hurricane, etcetera.
And the hurricanes are pretty common. Yeah, those are pretty common,
and like if it was you would have to say, oh, yeah, well,
I we've we may very well drown, we may very
well die die on some distant island, but in the
chances here are are less. But it's ultimately the same scenario,

(47:58):
like it's it's of course it's safer to go out
and explore is certainly in the short term. But are
we the type of species that is going to do that?
Of course, then again, if there were a nearby gamma
ray burst, as unlikely as that is, that would be
bad even if we were on Earth. Yeah, yeah, so
these in particular, like so the gamma ray bursts um
are omitted by powerful supernova that are dubbed hypernova and

(48:21):
you can think of these is it's just like the
energy shrapnel from a Titanic exploding star. And uh, you know,
even though they are rare, the radiation killing zone for
an exploding hyperstar has been estimated to be around six
thousand light years across compared to a normal star's thirty
light year kill zone, and even smaller gamma ray doses

(48:42):
can have a serious neurological impact on an individual. Oh yeah,
you don't want gamma rays no matter what. There was
a Cold Spring Harbor Laboratory study on mice that found
that gamma radiation targeted a particular type of stem cell
and the hippocampus, the an area of the brain you
know believe to be important for learning and mood control,
and normal doses of space radiation also pose a serious risk.

(49:04):
In a separate experiment, the NASA Space Radiation Laboratory dosed
mice with radiation equal to the amount and astronaut might
receive on a three year voyage to Mars, and scientists
discovered significant damage to hympocampus stem cells responsible for repopulating
the brain with new cells. So, without proper radiation shielding,
lengthy space exploration might be a recipe for the kind

(49:26):
of like cognitive and emotional breakdown that Dr Hoffman alluded to,
the idea that you would have your astronauts arrived at
their destination with reduced cognitive abilities, and that this is
exactly the time when presumably all the hard work is
right in front of them. They're gonna have to land
on the planet and the planetary explorers, but have to

(49:48):
do so with the reduced with reduced brain power, it's
a daunting problem. Now. Of course, in all of this discussion,
we don't want to give the impression of discouraging space
exploration or anything like. No, no, no, uh, just because
of all these risks. But in talking about them, it's
just that we have to recognize how hard this project
is and how dangerous it is, and how much investment

(50:09):
of research and technology it's going to take to make
this something that humans can safely and reasonably do. Yeah. Well,
we did an episode last year we talked about proposed
ways of genetically altering UH astronauts of the future so
that they might be less susceptible to the damages of radiation.
So there there are multiple fronts on which science, current

(50:32):
science and future science may be able to to tweak
all of this in our favor. But it is still,
as you said, it's a dangerous universe and UH and
we're ultimately a very fragile species. It is evolved to
thrive within a very slim portion of our own UH
atmosphere and within a slim portion of our own terrestrial environment.

(50:53):
Even a large portion of the Earth will kill you,
It's true. Yeah, if you were to teleport up to
the top of Mount Everest, you would not be able
to breathe, or if you were to suddenly appear at
the bottom of the ocean and find yourself of surrounded
by what three thousand atmosphere is worth of pressure, or
the north or South pole, or in the middle of
a desert. There's just a lot of bad places to be.

(51:16):
But I don't mean to trash the Earth, of course.
I mean this takes us back to the idea of
the overview effect that we mentioned a little bit with
Mr Hoffman, that having a cosmic perspective on the Earth,
realizing the ultimate kind of emptiness and violence and hostility
of the universe at large, and the the incredible uniqueness
and privilege of this one little rock floating in space,

(51:40):
it really should give us a perspective of thankfulness and transcendence. Uh,
something that makes the petty human squabbles kind of fade
away into non importance. All right, today you have it.
I hope everyone enjoyed our chat with Dr Hoffman. We
certainly enjoyed chatting with him. Absolutely. It was a pleasure
and I don't know, he gave me a lot of
stuff to think about. Yeah, this is the first time

(52:01):
we've had an actual space traveler on the show. Uh,
and it did it did not disappoint Maybe it won't
be the last time. Yeah, who knows. Now, if there's
anything in our discussion with Dr Hoffman that really leapt
out at you and you would like to hear a
whole episode of Stuff to Blow Your Mind on, let
us know about that, because because he covered a lot
of ground in the interview totally. Don't be shy to

(52:22):
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(52:45):
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(53:13):
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