0:03

This is NASA's Curious Universe. Our

0:06

universe is a wild and wonderful place.

0:09

I'm your host, Patty Boyd. And I'm

0:11

Jacob Penner. In this podcast, NASA

0:13

is your tour guide. We're

0:15

shining a light on the sun with

0:18

a mini-series all about our neighborhood star.

0:21

This is episode number five. Today's

0:24

story starts with an astrophysicist named

0:26

Nor Rawafi. First of

0:28

all, when you tell people I do

0:30

space physics and astrophysics, they say, yeah,

0:33

you guys are the smartest people on

0:35

Earth. Nor is the

0:37

project scientist for NASA's Parker Solar Probe.

0:40

He's based at the Johns Hopkins Applied Physics

0:42

Laboratory. Well, you know what? Probably

0:44

we are not. Everybody is smart in their

0:46

own way, but probably what we have is

0:48

passion and curiosity that we want to know

0:50

of things out there. Nor's

0:54

passion for space started when he was a kid.

0:57

He was born in Tunisia in the

0:59

countryside, and he remembers summer nights when

1:01

he would lay on his back and

1:03

look up into clear, starry skies. I

1:08

asked my father one day, why the sun is so

1:10

hot? And he

1:12

told me, well, it's a ball of fire. But

1:15

I asked another question, and I asked it multiple

1:17

times, but nobody could answer it to me.

1:20

And the question was, how comes

1:22

this fire never goes out? And

1:25

now that you're a real-life astrophysicist, do

1:27

you know the answer? Well,

1:30

I know more about the sun. But

1:33

if you ask me honestly, what keeps me interested

1:36

in it is the things we don't know, and

1:38

there is so much about it. The

1:41

good news is, we do know a lot about the sun.

1:44

After all, we've studied it more than any other

1:46

star in the universe. But there

1:48

are still huge mysteries to solve. NASA

1:51

investigates those mysteries in many ways, including

1:54

using a fleet of spacecraft, which give us

1:57

all kinds of different views of the sun.

2:00

Now we're getting our closest look yet with

2:02

Parker Solar Probe, a mission that

2:04

flies through the sun's atmosphere for the first

2:06

time ever. The probe

2:08

has already touched the sun. Later

2:11

in 2024, it makes its closest

2:13

approach yet, and Nora and other

2:16

scientists will be piecing together information to

2:18

try to solve some of our biggest

2:20

burning questions. To

2:23

understand those science questions, let's start with what

2:25

we do know. For one,

2:27

the sun isn't literally made of fire. It's

2:30

a huge ball of hydrogen and helium. The

2:33

sun is not really a solid body. It's

2:35

a ball of ionized gas, which is what

2:37

we call it plasma. So there is no

2:40

solid surface to land on, but

2:42

its atmosphere is pretty extended. The

2:45

center of the sun is unimaginably hot,

2:47

27 million

2:50

degrees Fahrenheit. This is

2:52

where the sun generates light and heat through nuclear

2:54

fusion. As you move away

2:56

from the core, things get less intense.

2:59

By the time you make it to the layer we see with our

3:01

eyes, which is called the photosphere, the

3:04

temperature is down to 10,000 degrees Fahrenheit. Now

3:07

that's still hot enough to boil diamonds,

3:10

but at least it's not in the millions. As

3:14

you keep going and make it to the sun's

3:16

outer layer, which is called the corona, things

3:19

get weird. The temperature of

3:21

the gas will skyrocket to more than

3:23

a million degrees Celsius. That is over

3:25

two million degrees Fahrenheit. That

3:27

is so puzzling because from

3:29

everyday experience, if you

3:31

step away from a fire, from a

3:34

heat source, it gets cooler. That's

3:36

not how the solar corona works. This

3:39

is one of the biggest mysteries, not just

3:41

about the sun, but of

3:43

all our questions about space. Why

3:45

is the sun's corona so hot? Parker

3:48

Solar Probe goes right to the source. In

3:51

2021, it became the first spacecraft

3:53

ever to fly through the corona.

3:56

And it's still getting even closer to the

3:59

sun's surface. The second

4:01

big question for Parker Solar Probe also

4:03

starts in the corona, but it doesn't end

4:05

there. The corona is

4:07

so hot that it essentially

4:10

boils off a stream of charged

4:12

particles. Scientists call this

4:14

solar wind. Although

4:17

it can measure solar wind, and Parker

4:19

Solar Probe can even hear it by

4:21

translating magnetic field data into

4:23

sound, we don't totally understand

4:26

where it comes from. It

4:28

starts at low speeds, early close to the

4:30

sun, but over a short

4:33

distance, the particles like electrons, protons

4:35

and heavy ions start

4:37

flowing at speeds of

4:39

about 2 million miles per

4:43

hour. Meaning they are

4:46

getting so much energy from somewhere, but

4:49

we don't know what is that energy source. And

4:52

that is so extremely complex

4:54

and puzzling for us. Top

4:57

number three for Parker Solar Probe

4:59

is gathering information about solar flares

5:01

and coronal mass ejections, outbursts

5:04

of energy and plasma from the sun. We've

5:07

gone into detail about those in other episodes

5:09

of this series. Suffice it

5:11

to say, they can have serious effects here

5:13

on Earth. A close-up look

5:15

from Parker Solar Probe can help us understand

5:18

them better. But let me say this.

5:20

Parker Solar Probe is way, way more than

5:22

these three phenomena. Parker Solar Probe

5:25

is venturing into a region of space that

5:27

we never visited before. And

5:30

any measurements we make is a potential

5:32

discovery. Touching

5:34

the Sun has been on NASA's wish list from

5:36

the very beginning. As far back

5:38

as the 1950s, scientists have brainstormed

5:41

a mission like this. But

5:43

it took decades of refining the plan and

5:45

solving engineering challenges to get it off the

5:47

ground. On

5:50

one level, flying toward the Sun

5:52

seems pretty straightforward. Our

5:55

star has enough gravity to keep entire

5:57

planets in orbit. spacecraft

6:00

would get sucked right in. Believe

6:02

it or not, it's extremely hard to

6:05

get any object close to

6:07

the sun. And the reason is pretty simple.

6:10

Because Earth is orbiting the sun at

6:13

very high speed. And

6:15

if you launch a spacecraft from Earth,

6:17

it will inherit that speed. Instead

6:20

of shooting the probe directly toward the sun,

6:23

it takes a complicated series of

6:25

maneuvers using other planets' gravity to

6:27

regulate speed. A

6:30

few years ago, early versions of this mission

6:32

actually proposed shooting the probe away from the

6:34

sun. By circling

6:36

Jupiter and using its gravity like a

6:38

slingshot, the probe would fly past

6:40

the sun once, screaming by

6:42

a tremendous speed. Eventually,

6:45

we found a different way. Instead

6:48

of Jupiter, the probe relies on Venus'

6:50

gravity. But Venus isn't

6:52

a slingshot, it's a way to tap the

6:54

brakes. Every time we

6:56

fly by Venus, we slow the spacecraft a

6:58

tiny bit. And when you

7:00

slow it, it will dive closer to the sun. By

7:03

doing it multiple times, we

7:05

gradually decrease the closest approach to

7:08

the sun. In

7:10

all, Parker's Solar Probe will orbit the

7:12

sun two dozen times. On

7:15

December 24, 2024,

7:17

it makes its closest approach yet, about

7:19

4 million miles from the sun. If

7:23

that still sounds far, think of it this way.

7:26

If you built the scale model of the solar

7:28

system with the sun and Earth ten feet apart,

7:31

Parker's Solar Probe would fly less than

7:33

five inches from the sun. During

7:37

that close approach, it will also set

7:39

a new spacecraft's speed record, 430,000 miles

7:43

an hour, fast enough to get from

7:45

New York to Tokyo in one minute. Besides

7:48

speed, the engineering team faced plenty of

7:51

other challenges. Here's

7:53

one key problem they had to crack. The

8:00

solar probe will be exposed at almost

8:02

500 times that heat. It's

8:05

extremely hot. So you have

8:07

to come up with a material that

8:09

is so efficient in dissipating heat

8:12

and basically act like an umbrella in front

8:14

of the spacecraft. When

8:16

Parker Solar Probe is closest to the sun,

8:19

its outer layer will be 2,500 degrees Fahrenheit.

8:25

Engineers came up with a material that

8:27

could not only survive. It

8:29

could protect the delicate scientific instruments

8:31

on board. It's really a

8:33

piece of carbon foam. That's

8:36

what it is. We cannot say how it

8:38

was fabricated because that's a secret. That

8:41

carbon foam always faces the sun

8:44

and the probe's instruments sit a few feet behind

8:46

it. While the heat

8:48

shield endures temperatures in the thousands of

8:50

degrees, the instruments will stay at a

8:52

cozy 85 degrees Fahrenheit, just

8:54

above room temperature. With

8:57

all of that solar energy, maybe

8:59

it's not a surprise that the spacecraft gets power

9:01

from solar panels. It's

9:03

just a problem solving to make those survive too.

9:06

We know from the get-go that these

9:08

solar panels will get extremely hot. So

9:11

we need to cool them down. And

9:13

to cool them down, for the

9:15

first time, we used liquid. Can

9:17

you guess what that liquid is? Something

9:22

called liquid nitrogen. It

9:24

is just water. Oh, it's

9:26

a gallon of water. That's all we needed

9:29

before. Which is amazing. It's

9:31

a first, by the way, in space. Solving

9:35

these technical problems made it possible for

9:37

Parker Solar Probe to reach a part

9:39

of space where humans have never explored.

9:43

Like any mission of discovery, this

9:45

probe is looking for answers. But

9:47

it could also show us that we need to ask

9:49

different questions. My biggest

9:51

hope is that we discover new things

9:54

that we didn't know before, because that's what

9:56

we are looking for. Scientists,

9:58

in a way, are weird creatures. People

10:00

usually look for the easy life. Scientists,

10:03

they are always looking for problems. And

10:06

we love them. Nor,

10:08

and the whole team behind this probe, are

10:11

standing on the shoulders of many other

10:13

scientists who were also obsessed with problems.

10:18

Back in the 1950s, not

10:20

long before the very first iteration of

10:22

the solar probe was taking shape, a

10:24

young physicist was trying to solve his own

10:27

mysteries. His name

10:29

was Eugene Parker. I

10:32

got hold of these old Harvard books on astronomy,

10:34

which at the time weren't so old. And

10:36

I read every volume in the series

10:39

of something like seven or eight volumes,

10:41

and I found it very

10:43

interesting. This is Parker speaking

10:45

in a TV interview from 1993. It's

10:48

a lot of new physics, a lot of things that happen

10:50

out there that don't happen in the laboratory. Then

10:53

it was just fun, problems that

10:55

you could actually solve. In

10:58

the late 50s, Parker tried to answer questions about

11:00

the sun's corona. Physicists

11:02

at the time had already established that

11:04

the corona was much hotter than they

11:06

expected. They were debating how

11:08

far the corona extended. At

11:11

this point, Parker was 31, and he

11:13

had been a professor for only a few years. But

11:16

as he made his way through a series of

11:18

physics equations, he realized he had

11:20

discovered something. He came up

11:22

with a theory saying that the

11:24

boiling gas, the multi-million degree gas

11:27

in the solar corona, cannot be

11:29

static. It has

11:31

to create a stream that

11:33

flows away from the sun, and he calls

11:35

it the solar beam. And

11:37

he was ridiculed for that idea. Years

11:42

later, Parker recalled just how

11:45

badly other scientists responded. One

11:48

wrote, I would suggest that Parker

11:50

go to the library and read up on the

11:52

subject, because this is

11:55

utter nonsense. Now, Parker's

11:57

new idea was based on working through

11:59

equations. not direct observation. So

12:02

how could he prove this theory? August

12:05

26th. The Mariner 2

12:07

countdown begins. Events move

12:10

on a strict timetable. Five,

12:14

four, three, two,

12:17

one. At

12:22

the dawn of the space age, NASA was taking

12:24

its first steps to explore the rest of the

12:26

solar system. In 1962, a

12:29

spacecraft called Mariner 2 blasted out

12:31

of Earth's orbit, headed for Venus.

12:35

Mariner 2 has successfully traversed 180 million

12:37

miles of space. February

12:41

26, 1963. The preliminary results. At

12:47

the encounter altitude, Venus has... Mariner

12:49

2 flew by Venus and made a

12:51

series of scans. The first time

12:54

humans had successfully sent a probe to

12:56

another planet ever. For

12:58

astronomers, it was a treasure trove. Years

13:01

will be required to digest and

13:04

finally interpret the 65 million bits

13:06

of data that Mariner radioed back

13:08

to Earth. And for

13:10

Eugene Parker, it was a chance to turn the

13:13

tables. As

13:15

it was sailing through space, Mariner

13:17

2 detected particles whizzing by at

13:20

hundreds of miles per second. It

13:22

was the solar wind, just as

13:24

Parker had proposed. This

13:26

discovery cemented solar wind as

13:29

a scientific fact. And

13:31

it was a milestone in the long,

13:34

legendary career of Eugene Parker. I

13:37

knew him for over 20 years,

13:39

so he's an amazing human being.

13:41

But, Jean Parker's contribution went

13:43

well beyond just theorizing the existence of

13:46

the solar wind. He

13:48

has interest in the galaxy, he

13:50

has interest in magnetosphere, he has

13:52

interest in planets. You see

13:54

him through his career jumping from one research

13:56

topic to the next to the next. That

14:00

thing about Parker proposing

14:02

solar winds, being ridiculed,

14:05

being vindicated a few years later, it just

14:07

seems so interesting. And did you ever get

14:09

a chance to talk to him about what

14:12

that was like personally or do you know

14:14

how he felt about that period

14:16

in his life or anything like that? This

14:19

is a nice thing about him. He did

14:21

not really make a big deal out of it. People

14:23

disagree with me. We are fine. Let's move

14:26

on to the next thing. I

14:32

wrote my speech down here. For

14:35

most of its development, Parker Solar Probe had

14:37

a different name. It

14:39

was originally called Solar Probe Plus. But

14:42

in 2017, NASA announced the

14:45

mission was being renamed in honor of

14:47

Eugene Parker. This

14:50

was a historic announcement. NASA

14:53

had never named a mission after a

14:55

researcher during their lifetime. A

14:58

few days before his 90th birthday, Parker

15:00

took the stage at the University of

15:02

Chicago. I'm certainly

15:04

greatly honored to be associated

15:07

with such a heroic scientific

15:09

space mission. By

15:12

heroic, of course, I'm referring to

15:14

the temperature, the thermal radiation from

15:17

the Sun, and the

15:19

extreme measures developed to survive

15:21

that radiation and collect scientific

15:23

data should be fully appreciated.

15:27

As a theoretician, I greatly admire

15:29

the scientists and engineers whose patient

15:31

efforts together converted the Solar Probe

15:34

concept into a

15:36

functioning reality ready to do battle

15:38

with the solar elements as it

15:40

divulges the secrets of the expanding

15:42

corona. So hooray for

15:45

Solar Probe. Thank you. Status

15:47

check. Go Delta. Go PSP.

15:50

In 2018, Eugene Parker logged another first. For

15:58

the first time in NASA history. the

16:01

person who gave their name to a mission watched

16:03

it lift off. One, two, three, four,

16:06

five. Yes! There

16:11

we go. Wow.

16:14

There we go. Go, baby, go! Whoo!

16:19

Whoo! Yeah!

16:27

All I can say is, wow, here we

16:29

go. We're in for some learning

16:31

over the next several years. Once

16:35

the probe became operational, NASA showed Eugene

16:38

Parker some of its very first science

16:40

results. In

16:42

2022, Parker died at the age of 94.

16:46

His contributions to science will last far

16:49

into the future, and

16:51

so will the legacy of the probe bearing his name.

16:54

He's one of a kind. His contribution was so,

16:56

so high up there. And

16:59

more than that, it just makes sense

17:01

that he's the only person after whom

17:03

it is adequate to name this extremely

17:05

important mission. Just

17:14

as Parker's Solar Probe builds on the

17:16

work of Eugene Parker and other pioneering

17:18

scientists, it also relies on

17:20

what NASA has learned from previous solar

17:23

missions. Parker's Solar Probe

17:25

is going closer to the sun than ever.

17:28

But before it and alongside it came a

17:30

long line of spacecraft showing us the

17:32

sun in ways our eyes never could.

17:35

I think we take it

17:37

for granted. I mean, we get really

17:39

beautiful sunrises and sunsets sometimes. When

17:42

you look at it from space, when

17:44

you put telescopes above the atmosphere, there's

17:46

all kinds of wavelengths of light that

17:49

we don't see with our eyes that

17:51

we don't get here on the ground.

17:55

Alex Young is a solar astrophysicist.

17:58

He's been studying the sun at NASA for a long time. For more

18:00

than 20 years, NASA's observatories

18:02

give us crucial clues about activity

18:04

on the surface of the Sun,

18:06

the processes going on inside the

18:08

Sun, and even its influence to

18:10

the far reaches of the solar system. Now,

18:13

you already know that the Sun produces a

18:15

lot of light, but our eyes

18:18

only give us part of the story. The

18:20

Sun produces all kinds of electromagnetic

18:23

radiation, from radio waves to the

18:25

ultraviolet light that gives you sunburns,

18:28

x-rays, and gamma rays. In

18:30

his first job out of grad school, Alex

18:33

worked on a spacecraft that can see some

18:35

of those wavelengths. It's

18:37

called Solar and Heliospheric Observatory,

18:40

or SOHO. Once

18:43

I started seeing the Sun from

18:46

extreme ultraviolet, which actually was with the

18:49

SOHO spacecraft for the first time, it

18:51

just blew my mind. In

18:54

orbit more than 1,800,000 kilometers from Earth, SOHO's position means

18:56

its 12 instruments can

19:01

observe the Sun without the interaction

19:03

of the Moon and the Earth

19:05

passing through into Earth. SOHO launched in

19:07

1995 as a

19:09

joint mission between NASA and the European

19:11

Space Agency. It's still

19:13

operating today, even though its

19:16

original mission was scheduled to last just three

19:18

years. Some of

19:20

those instruments show us aspects of the Sun

19:22

that no other telescope can. You

19:25

can find out what's happening inside

19:27

the Sun. We see rivers of

19:29

superheated gas called plasma flowing

19:32

inside the Sun. We

19:34

can see down into

19:36

where sunspots are forming before we can

19:38

see them on the visible surface. SOHO

19:41

was not the first mission to

19:43

do it, but SOHO provided such

19:46

amazing data over such

19:49

a long period of time that it's

19:51

given us a completely new perspective. But

19:54

SOHO almost didn't make it. A

19:56

few years before Alex joined the team, SOHO

19:59

was on the of being lost

20:01

in space forever. We

20:03

have a euphemism for that called the

20:05

vacation. Soho took vacation

20:08

for six months. Basically

20:11

we lost contact and assets. Everything was

20:13

powered off. This

20:15

is Harold Benfield. He was

20:17

Soho's missions operations leader at NASA. The

20:20

trouble started in 1998, less

20:23

than three years after the mission launched. The

20:25

spacecraft was in the middle of a routine maneuver.

20:28

And then it went to Earth. We

20:31

weren't sure exactly what happened. We were able to piece

20:33

together a story based on the last thing we saw.

20:36

Soho started spinning out of control. The

20:39

team didn't know if they could rein it in. Normally

20:42

Soho's power came from solar panels that were

20:44

supposed to face the sun all the time.

20:47

The spin swung them out of line. Not

20:50

facing the sun meant no power for the

20:52

spacecraft. That would make it

20:54

impossible to communicate. And Soho could be

20:56

a goner. But you

20:58

know that saying a broken clock is right

21:00

twice a day? Well even

21:03

a spinning spacecraft faces the right direction

21:05

every once in a while. The

21:07

team kept sending messages in the hopes that

21:09

Soho would hear. We were

21:11

sending commands in the blind. Obviously we didn't

21:13

know when those periods were. So we sent

21:15

the sequence repeatedly. And we were able

21:18

to at one point get the transmitter turned on and

21:20

get a brief burst of telemetry. Re-establishing

21:22

contact was great news. It

21:25

gave the team hope that they could use Soho's

21:27

thrusters to get it back in position. But

21:30

there was bad news too. In

21:32

the cold void of space, Soho's

21:34

fuel would freeze without heaters keeping

21:36

it warm. No solar

21:39

power meant no heaters. Soho's

21:41

fuel was frozen solid. So

21:44

you're thinking about a 200 pound block of ice that

21:46

you get a fall with a 40 watt light bulb.

21:49

So you know it's not something that happens right

21:51

away. It takes some time. Over

21:54

the course of a couple weeks, the team

21:56

gingerly used Soho's batteries to bring the fuel

21:58

back to a usable state. state. I

22:01

mean, so we were able to do that and then

22:03

we were able to fire the thrusters and stop the spoon. Analysis

22:07

showed that while SOHO was in communicado,

22:09

its instruments had been exposed to wild

22:12

temperature swings from more than 200 degrees

22:14

Fahrenheit to almost minus

22:16

200 degrees Fahrenheit. It

22:19

was dicey, but SOHO was back. One

22:23

of the particular instruments did

22:26

not survive and another instrument

22:28

was partially damaged. So

22:31

we did have a toll on the spacecraft,

22:33

but all in all, it

22:35

came out for the most part

22:37

relatively unscathed. SOHO's

22:39

vacation happened more than 25 years ago. During

22:43

its long life, SOHO has observed an

22:45

entire 11-year solar cycle and the beginning

22:47

of another one. It's

22:49

also taken on an unexpected side job

22:52

discovering comets, which you can hear more

22:54

about elsewhere in our Sun series. Alex

22:57

says SOHO can teach us a valuable

22:59

lesson about exploring space. Absolutely

23:02

part of the way we learn

23:04

is by mistakes. If you don't

23:06

make mistakes, you don't,

23:08

I mean, we don't really learn

23:10

unless we make mistakes. SOHO's

23:13

perseverance has allowed it to team up

23:15

with other spacecraft in NASA's fleet, like

23:18

STEREO, which used twin spacecraft to give

23:20

us a unique view of the Sun's

23:22

activity, Solar Dynamics

23:24

Observatory, which investigates the Sun's magnetic

23:26

changes, and coming soon, Hermes,

23:30

which will orbit the Moon and measure

23:32

solar radiation as Artemis astronauts head back

23:34

to the lunar surface. I

23:37

still kind of think of the time

23:39

of SOHO as sort of the golden

23:41

age of solar physics

23:43

because it was such

23:45

a comprehensive look at

23:47

the Sun, you know, from inside,

23:50

outwards, and then all the

23:52

things that are coming off the Sun. It's

23:54

an amazing feat of engineering that

23:57

has lasted so long and produced

23:59

such amazing imagery still to

24:01

this day. NASA's

24:03

fleet works together, giving us different views of

24:06

the Sun that we can piece together like

24:08

a mosaic. And by

24:10

touching the Sun, Parker's solar probe gives

24:12

us close-ups of things we normally see

24:14

from a distance, like flares and coronal

24:17

mass ejections. We

24:19

designed Parker's solar probe to fly through these

24:22

big coronal mass ejections. Because

24:25

that's a science we were, part of the science we were to

24:27

do. But still, until

24:29

you experience it, you don't

24:31

really know how to space-clog the Earth. Scientists

24:35

call these coronal mass ejections CMEs

24:37

for short. We've observed

24:39

them from a distance, like with SOHO. Flying

24:43

through one and point-blank distance from the

24:45

Sun is a totally different

24:47

proposition. We need a

24:49

lot of simulations before launch. And

24:52

we imagine the strongest CMEs,

24:56

and see how much torque those

24:58

structures will transfer to the spacecraft.

25:01

In September 2022, ready

25:04

or not, Parker's solar probe put

25:06

those simulations to the test. The

25:09

Sun released a huge CME. We

25:12

don't know exactly how big, but probably

25:14

on par with the biggest one ever

25:16

recorded to hit Earth. Fortunately,

25:18

the Sun released this outburst to its

25:21

far side. So we were

25:23

all safe, but Parker's solar probe was

25:25

directly in its path. What

25:32

you're hearing is the spacecraft's collision

25:34

with that CME. This

25:36

is magnetic field data converted to audio.

25:40

At the time, Parker's solar probe was less than

25:42

6 million miles from the Sun,

25:45

or about one-sixth the average distance

25:47

to Mercury. And

25:49

since it was on the far side of the Sun, it

25:52

couldn't communicate with Earth in real-time. It

25:55

was all on its own. We

25:57

think, okay, we have a clear idea about

25:59

the Sun. the other aspects of the

26:01

CMEs. But

26:03

what Bacchus or a probe gave us the first images? It

26:07

was so complex. It's

26:09

like we never seen CMEs before. Data

26:13

from the spacecraft show that the CME

26:15

vacuumed up dust floating in space. Scientists

26:18

had theorized that this was possible, but

26:20

nobody had seen it before. This

26:23

deeper understanding of solar activity could

26:26

improve our space weather forecasts, and

26:28

that could keep us safe if Earth does end

26:30

up in the crosshairs. The

26:33

data from Parker Solar Probe also showed

26:35

that its autonomy system worked perfectly. After

26:38

the impact, it corrected course right away.

26:42

This is probably the highest risk mission

26:44

NASA ever built. But

26:46

still, it is working so, so beautifully,

26:48

and knock and word, it will help for you

26:50

to continue that way. With

26:54

Parker Solar Probe running smoothly, Nor

26:56

says it sets a powerful example for the

26:59

future. Not every risky

27:01

mission goes off without a hitch. Having

27:03

a mission that

27:06

is extremely high risk mission with the

27:08

level of success that Parker Solar Probe

27:10

has achieved is driving

27:12

the community to boldness. If

27:16

you go back, let's say, a decade ago, there

27:18

are certain ideas and certain missions. We thought,

27:20

yeah, just forget about them. They are not

27:22

feasible in our time. But now

27:24

the community is going after these missions,

27:27

and that's thanks in particular to Parker Solar

27:29

Probe. And with Parker

27:31

Solar Probe, the best is yet to come.

27:36

In November of this year, the probe will make

27:38

its final pass of Venus. And

27:41

on December 24, it makes its

27:43

closest approach to the sun, and

27:45

then returns twice next year. Now

27:47

that we are going to embrace a star

27:49

for the first time ever, it's

27:52

going to drive the new generations, the young

27:54

kids, to say, you know what? I'm

27:57

going to get even closer to a star. I

27:59

want to go back. elsewhere in the universe. The

28:03

science data will take time to unravel. Nor

28:06

is definitely excited to see how that turns

28:08

out. Scientists

28:10

will have a lot of work to do,

28:12

and probably some friendly debates about what exactly

28:14

the data show. But

28:16

for me, I want to stress one thing. The

28:20

achievement that we are going to do

28:22

in the eve of Christmas of this

28:24

year is so

28:27

humongous. Let

28:29

me go back to Gene Parker when he

28:31

was ridiculed about his theory, and

28:33

I want to tell every child out there, if

28:37

you got ridiculed about something, the

28:39

best way to think of it is

28:42

that that thought or idea is

28:44

so original that nobody

28:46

can get it, except you. Before

29:02

we go, we have another installment of our

29:04

new segment, What Are You Still Curious About?

29:10

We ask that question to every single person we

29:12

interview for the show, and we want

29:14

to know what you're curious about too. So

29:17

it's time to take a question from a curious listener

29:19

and track down the answer. Today's

29:21

question comes from Charles Bergquist. He's a

29:23

senior producer with the show Science Friday.

29:25

Charles, how's it going? Hey Jacob. You're

29:31

a science journalist, so I imagine you're curious about

29:33

all kinds of things, but when it comes to

29:35

space, what are you still curious about? Yeah,

29:38

so recently on Science Friday, guest

29:40

Umer Irfan Avak was talking with

29:42

our host Ira Flato about

29:44

a White House request for NASA

29:47

to create a lunar time zone. And

29:49

it really got me thinking about here

29:52

on Earth we've got our hours and our

29:54

days that are based on

29:56

how our planet rotates, right? But what

29:58

happens when humans need to tell time

30:00

somewhere that doesn't have that same set

30:03

of physical references. Like, if

30:05

you're on the space station, you get a sunrise, what, every 90 minutes

30:08

or so. So I started thinking

30:10

about what their clocks are set to

30:12

and if there are other space time

30:14

zones. Yeah,

30:17

so let's start with the astronauts who

30:19

are in space now, the International Space

30:21

Station. Those astronauts use Greenwich Mean Time.

30:23

It's the time zone where the Prime

30:25

Meridian is in the UK and

30:28

it's also the basis for a time

30:30

zone called Coordinated Universal Time which is

30:32

kind of like the measuring stick for timekeeping

30:34

around the world. So the International Space

30:36

Station is really measuring time based on

30:38

Earth time zones. For

30:40

now, there is no official moon

30:42

time but like you mentioned, NASA

30:44

proposes creating a new system called

30:46

Coordinated Lunar Time. And the reason

30:49

for this is that if you know your theory of relativity,

30:51

you know that time can tick at different

30:53

rates in two different places in the universe

30:55

depending on location and velocity. This is one

30:57

of those things that you see in sci-fi

31:00

movies like when one character goes off on

31:02

a space adventure and they age at a

31:04

different rate from somebody who stays on Earth.

31:07

Time on the moon ticks by at

31:09

a slightly different rate from Earth. And

31:11

as we send astronauts back to the

31:14

moon and as we establish a long-term

31:16

presence there, this will become really important.

31:18

When you're dealing with space travel, you

31:20

need accuracy down to a fraction of

31:22

a second. So this Coordinated Lunar Time

31:25

Zone will be traceable to Coordinated Universal

31:27

Time so we can convert back and

31:29

forth between moon time and Earth time

31:31

and it will make sure that our clocks are super

31:33

accurate. So if

31:36

NASA does establish this Coordinated Lunar Time

31:38

that you're telling me about, would they

31:40

need to sort of subdivide the

31:42

moon even further into lunar time

31:44

zones set on that clock? We

31:47

don't expect to have time zones on

31:49

the moon. So the new Coordinated Lunar

31:52

Time Scale, it applies to all

31:54

of the moon. You know, the main thing

31:56

is just those differences caused by relativity. eventually

32:01

going even beyond the moon

32:03

to Mars. Are

32:05

there similar effects with the relativity? Do

32:07

we need different time zones for

32:09

every place in the solar system we end

32:12

up? So this is something that

32:14

NASA is still studying and will keep studying

32:16

as we get ready for crewed missions to

32:18

Mars. It is possible that Mars will get

32:20

divided into time zones like Earth. Although

32:22

when you think about that, one thing to keep in

32:24

mind is that Mars is only about half the size

32:26

of Earth. Just to put it into perspective, like if

32:29

you picture Earth as the size of a nickel, Mars

32:31

is about as big as a raspberry. And

32:35

then when the time comes to keep time on

32:37

Mars, a couple of other things to keep in

32:39

mind are that a Martian day is about the

32:41

same length as an Earth day. It's 24.6 hours

32:43

but a year is

32:46

much longer. It's 687 Earth

32:48

days. And one thing that

32:50

I find really interesting is that on Earth, we

32:52

have these four seasons and they're spread evenly throughout

32:55

the year. So each season is three months. But

32:57

Mars has an orbit that is egg-shaped

32:59

and so it gives the seasons different

33:01

lengths. So if you live in the

33:04

northern hemisphere of Mars, spring is the

33:06

longest season, autumn is the shortest,

33:08

and then summer and winter are in between.

33:10

And that might not

33:12

affect how NASA measures time necessarily, but if

33:14

I move to Mars, I think it would

33:16

definitely affect how I perceive time. Definitely.

33:21

Charles, thanks so much for sharing your questions with us.

33:23

Thanks for having me, Jacob. That's Charles

33:26

Bergquist. He's a senior producer with the

33:28

show Science Friday. Thanks

33:34

for listening to our Sun series here on

33:36

Curious Universe. We'll be

33:38

back with a bonus episode featuring dispatches

33:40

from the total solar eclipse. If

33:44

you have questions about the eclipse or

33:46

the Sun or anything else you want

33:48

to ask NASA astronauts, scientists, and engineers,

33:50

drop us a line. You

33:52

can email us at

33:54

nasa-curiousuniverse at mail.nasa.gov and

33:57

we may answer your question in a future episode. Also,

34:00

you can find so much more

34:02

about the sun at science.nasa.gov. Slash

34:05

then. This

34:10

is NASA's Curious Universe. This

34:12

episode was written and produced by me, Jacob Penner.

34:15

Our executive producer is Katie Conans. The

34:18

Curious Universe team includes Christian Elliott,

34:20

Maddie Olsen, and Michaela Sosby. Christopher

34:23

Kim is our show artist. Our

34:25

theme song was composed by Matt Russo and

34:27

Andrew Santaguida of System Sales. Huge

34:30

thanks to Michael Chesness and the NASA Enterprise

34:33

Library for research help with the archival tape

34:35

you heard in this episode. Clips

34:38

from the 1993 television interview with Eugene

34:40

Parker are used courtesy of the New

34:42

Mexico Public Media Collection and the American

34:44

Archive of Public Broadcasting. Some

34:47

archival clips about SOHO were produced by the

34:49

European Space Agency. Special

34:51

thanks to the Niels Bohr Library and Archives

34:53

at the American Institute of Physics and

34:55

an extra special thanks to NASA's Heliophysics team

34:58

for their help throughout this entire series. If

35:01

you enjoyed this episode of NASA's Curious Universe,

35:04

please let us know by leaving us a review and

35:06

sharing the show with a friend. And

35:09

remember, you can follow NASA's Curious Universe in

35:11

your favorite podcast app to get a

35:13

notification each time we post a new

35:15

episode. Curiosity

35:26

in some quarters is now considered a dirty

35:28

word, but I don't think so. I think

35:30

as humans, we naturally would like to know

35:32

what's going on. And

35:35

that's the ultimate game. Three,

35:38

two, one. This

35:41

is an official NASA podcast.