July 16, 2022 • 25 mins
This 2016 episode delves into the search for a planet lurking in the gap between Mars and Jupiter, resulting in the finding of Ceres. This object's story is one of scientific cattiness and our ever-evolving understanding of space.
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Speaker 1 (00:02):
Happy Saturday. Today is the birthday of Giuseppe Piazzi, who
was born on July sixty six. So Today's Saturday Classic
is our episode on his discovery of series and the
ensuing debate about exactly what that was. This episode originally
came out on June. We hope you enjoy Welcome to
(00:26):
Stuff You Missed in History Class, a production of I
Heart Radio. Hello, and Welcome to the podcast. I'm Holly
Fry and I'm Tracvie Wilson, and I have to confess
up front that um and I might offend people by
saying this a little bit. The impetus for this episode
(00:50):
is because I can get a little cranky and fussy
about people who are still campaigning to get Pluto back
as a planet. Yeah, doesn't have feelings. I don't think
what people do personally hurt by having been no longer well,
and some of it for me, it's just that like
(01:12):
there are there are rules and reasons. There's still a
debate that can certainly happen, but there are rules and reasons,
and it it's explained why it was made a dwarf planet,
and people will come back and say it shouldn't matter
that it's small, it's still a planet, and it's like, hey,
that doesn't have anything to do with it. So but
we're not talking about Pluto. We've done that before. But
(01:33):
instead we're going to talk about some other heavenly bodies
that had a similar kind of uh discovery misclassification shift.
It's kind of you know, I wanted to talk about
how like our our knowledge and our what we believe
to be true, and how we lay out our knowledge
of the universe, and the Solar System specifically changes all
(01:56):
the time based on new information. So there were only
seven known planets in the Solar System, and at that
point it was Mercury, Venus, Earth, Mars, Jupiter, Saturn, and Uranus.
Wondering if there might be a planet in between Mars
and Jupiter had really taken up headspace for a lot
of astronomers up to that point. Once Uranus was discovered
(02:17):
in one by Sir William Herschel, it validated a theory
that indicated that there should be sort of regular spacing
between the orbital ellipses of planets, and this gave astronomers
even stronger conviction that there must be a planet there
in that swath of space between Mars's orbit and Jupiter's orbit,
but no one had identified a planet there. Uh. Johannes
(02:40):
Kepler even theorized about a planet in that gap between
those two planets in fiftet six in his work Mysterium Cosmographicum,
and he actually hinted that there would be more than
one they're writing quote. Yet the interposition of a single
planet was not sufficient for the huge gap between Jupiter
and Mars. Plenty of astronomers dedicated huge chunks of their
(03:02):
careers to try to find this elusive planet that they
felt absolutely must be lurking in that empty swath of space,
but to no avail. But eventually an Italian astronomer who
was really a mathematician found something. And today we're going
to talk about the celestial object Series, the man who
spotted in, what it is, what it's been in terms
(03:24):
of nomenclature, and how science shifts, it shifts it's thinking
as new information is uncovered. To talk about series, we're
going to talk a little bit about Giuseppe Piazzi. He
was born on July sixteenth, seventeen forty six, so we
are coming up on his birthday. He was one of
ten sons and His parents, who lived in Ponty in
(03:45):
Baltalina in the north of Italy, were really well off financially.
Because many of his siblings had died when they were
still very young. Giuseppe was baptized in a very quick
home ceremony, with the official record quote because of impending
danger of death and though his parents had been fearful
of his health. Jesseppe grew to adulthood and at the
(04:08):
age of nineteen, as was often customary for wealthy sons,
he took holy orders to become a priest, and he
pursued a number of academic studies and eventually, starting in
seventeen seventy, at the request of the church, he began
teaching philosophy and mathematics as a touring lecturer throughout Italy.
In seventeen eighty one, he became the chair of mathematics
(04:30):
at a new educational institution that would eventually become the
University of Palermo. Six years later, he was named chair
of astronomy at the school. This is an interesting move
because he hadn't really been a studying astronomy for that
all that long, but he was a really devoted scholar
and astronomy would eventually become the thing that he was
(04:52):
known for. In early seventeen eighty seven, the same year
that he was named chair of Astronomy, Piazza began an
intensive three year study trip so that he could really
become as familiar with astronomy as he could. And during
that time he spent time in Paris and London, and
he became the colleague and friend of astronomers in both
of those cities. It was because of these connections and
(05:15):
the study that he was able to secure a five
foot circular scale altessimus telescope that would become a crucial
component of the observatory that he had been tasked with
building at the university. That telescope was made in London
by mathematician and astronomical instrument specialist Jesse Ramsden. When Piazzi
returned to Palermo at the end of seventeen eighty nine,
(05:37):
he focused entirely on the construction of the observatory, and
it was only a matter of months before it was completed.
It was built on top of a tower at the
Royal Palace. With his new observatory completed and this impressive
telescope telescope installed, Gesseppe set to work making observations, focusing
primarily on accurately mapping the positions of stars, and this
(06:02):
mapping effort was truly painstaking. Each star had to be
observed for a minimum of four nights, and this had
to be done for each observable star. This work would
eventually culminate in the publication of a star catalog in
eighteen o three, which one Piazzi an array of accolades.
But while he was mapping all those stars, he stumbled
across something else entirely. So it's a little early normally
(06:26):
for a break for a sponsor, but we want to
keep this next section altogether, so we're gonna pause here
and have a little sponsor break, and then we will
come back and talk about what it was that Piazzy
stumbled upon. On New Year's Day eighteen o one, Piazzy
(06:49):
noticed a tiny dot in the heavens, specifically in the
shoulder of the Taurus constellation. As was his method, he
observed it again the file bowing night, and it had
moved after two more nights of observation. He thought he
might have identified something new which might perhaps be a comment,
(07:10):
so we contacted the press. Yeah, that was customary. It
wasn't like he was a glory hound. It was just
something you did. You reported that you had maybe found something.
So I'm imagining that as he was doing this, he
was he was measuring all the stars at like the
same time every night, because they moved anyway. Yeah, he
was mapping them throughout the course of the night. Okay,
(07:34):
So that's why they would each get four nights observation.
And as this story hit the papers and the news spread,
other astronomers, of course started taking notice. But for his part,
Piazzi was a little reluctant to put a label on
his observation. He still was not confident about exactly what
it was. In late January, he wrote a letter to
(07:55):
his best friend in Milan about the discovery, and he
voiced his uncertainty and excitement all at once. Just here's
what he said. I've announced this star as a comet,
but since it shows no nebulosity, and moreover, since it
had a slow and rather uniform motion, I surmised that
it could be something better than a comet. However, I
(08:16):
would not, by any means advance publicly this conjecture. As
soon as I shall have a larger number of observations,
I will try to compute its elements. And in fact,
a second letter that he wrote the very same time,
but to another colleague, also in Milan, is a little different.
He indicated in that letter, with more certain language, that
(08:38):
he felt that his observed object was a comet, and
this inconsistency as to whether it might be a planet
or whether it certainly was a comet was noted by
the two recipients, who knew each other well. They basically
gossiped about their comment letter well, and in the writings
about it, the one that he wrote to and said
(08:59):
it was a it seemed almost peeved that he hadn't
shared the possibility that it could be a planet like
he seemed kind of offended at how he had been
left out of the loop. So, to further complicate matters,
Piazzi became ill after his first forty one days of observation,
and his study of this new object had to be halted.
Then the son's halo made it impossible to see for
(09:22):
a while. Piast's colleagues had to use the data he
had collected up to that point to try to calculate
where the planet would appear again once it would become
observable again, and eventually it was the young German UH,
Carl Friedrich Gauss, who was only twenty four at the time,
who devised a calculation method that correctly located piazz has
(09:43):
lost planet or comment. As the public interest group people
started asking astronomers about Piazzi's discovery. This actually led to
some interesting cattiness regarding what to name it. When Johann
elert Bode spoke to the Prussian Academy then the press
at Easter just a few months after Piazza had made
(10:03):
his first observation, he declared the discovery of a new planet,
this really being Piazzi's discovery, not his own, which he
called Juno. Astronomer of Baron Franz Zavit von Zach, who
will talk about more in just a moment, called it Harra.
And Piazza had actually named his discovery series Ferdinandea, after
(10:25):
the Roman goddess of agriculture. That's the series portion when
the patron goddess of Sicily as well series was UH
and King Ferdinand of Bourbon, and he was not too
pleased about the other names being spouted by other astronomers,
and in a letter to a colleague. In August of
eighteen o one, he said, quote, if the Germans think
they have the right to name somebody else's discoveries, they
(10:46):
can call my new star the way they like. As
for me, I will always keep it the name of Serer,
and I will be very obliged if you and your
colleagues will do the same. It was like the Bone Wars.
We already have that in the archive from past hosts
if you want to hear about it. Yeah. The name
Series was eventually acknowledged throughout the astronomical community, although the
(11:11):
Ferdinandia was dropped largely because it made the name terribly long.
And as for the nature of Series, by mid eight
o two, after another astronomer had observed it and its
orbit had been tracked, was fairly settled to most that
it was indeed a planet and not a comet. It
wasn't entirely settled. There were some people who doubted it entirely,
(11:31):
and when Piazzy rewrote his observations in a new edition
with different data, it caused quite a stir. Von Zac wrote, quote,
what is going on with Series Fernandia? Nothing has been
found as yet, either in France or Germany. People's are
starting to doubt already, skeptics are making jokes about it.
(11:52):
What is devil Piazzi doing? I love finding out? How
caddy this whole, this whole group of scientists was. They're
so often so catty. Uh. Piazzi's full findings with all
of the updated data, were published in September of eighteen
o two, and while Series was obviously much smaller than
(12:14):
any planet identified up to that point, astronomers were still
categorizing it as a new planet, and finding a new
planet was a really important event at this juncture in history. Uh.
And in the wake of the publishing there was this
flurry of activity as other astronomers analyzed the data and
calculated the orbit of Series and hashed out any and
all details, and they were ever debating the merit of
(12:37):
Piazzi's work, and Piazzi himself was busy working on other
responsible abilities at the university. However, he also maddened the
astronomical community by continually and casually referring to Series as
a star or a comet sometimes rather than a planet.
There's actually a funny bit of coincidence around Piazzy discovering Series, because,
(12:58):
as we mentioned, earlier, there were other astronomers who were
really focused on looking for this planet they thought must
be in the region of space him then by the
orbits of Jupiter and Mars. One of them, a German
Hungarian astronomer named Baron Franz Zabra von Zach, who we
mentioned earlier, had determined what was that what was needed
(13:19):
was a collective effort, so von Zak invited most of
the prominent astronomers of the day to be part of
this project, and this group became known as the Celestial Police.
They each patrolled for to keep with the policing metaphor,
a designated section of the heavens in search of the
missing planet, and eventually Piazzy was invited to be part
(13:41):
of the team, but it appears that the invitation, which
was relayed through a letter written to another colleague, was
actually dated after Giuseppe Piazzy had found series already, and moreover,
Piazzy never received that invitation. So there is some speculation,
given the evidence of how Caddie all of these dudes
could be, that they were trying to kind of like
(14:06):
loop him into their crowd so that they could all
share some of the glory of having found it after
the fact, No, we totally. We invited him to be
part of our group. You got, guys, it sounds like
middle school really does. When a new element was found
in three was named sirium and a tribute to Series.
(14:28):
This was definitely a time of Series fever, and the
practice of naming elements after recently discovered planets has happened
several times. Uranium, neptunium, and plutonium are all named for
planets as well. Because Series was so small in comparison
to any of the other known planets, it eventually was
(14:48):
sort of classified as a minor planet, and the search
for another planet between Mars and Jupiter that might perhaps
have greater mass uh continued. It was spurred on, in fact,
by zis Fined. So not long after the Series discovery
and over a period of six years, three other planets
were discovered in that same band of space. So that's right.
(15:10):
There's a time that was believed that we had four
entire planets between Mars and Jupiter, and the first of
these was initially observed on March eighteen o two, so
that was even before Piazzi had published his final data
on Series, and that was identified by Wilhelm Olbers, and
(15:30):
he saw something in the wing of the Virgo constellation
that he had not observed prior, and after two days
of observation of this object, he was convinced it was
a planet, and he named it Palace. Other astronomers were
also pretty quickly convinced, and it made them even more
certain that there might be yet other planets in that
Mars Jupiter gap. On September one, st eight, you know,
(15:51):
for Carl Ludwick Harding spotted the next planet at the
intersection of the orbits of Series and Palace, and this
one was called Juno. Bill Holm Ober's once again had
the honor of discovering the fourth new planet of the
nineteenth century, Vesta, on March seven. Palace, Juno, Investa were
(16:12):
all smaller than Series, so they too were considered minor planets.
But of course, if you crack open any current textbook
that features our Solar system, none of these objects are
listed as planets at all, So you may be wondering
what happened, And we're going to talk about how Series
and its siblings ceased to be classified as planets, whether
minor or not. Right after we pause once again for
(16:34):
a quick word from one of our sponsors to get
back to what happened the Series. Slowly the realization was
made the Series and its neighbors where maybe not actually
planets after all. When a fifth body named Austraia was
(16:58):
discovered in eighteen forty five by Ale Hanky, it was
classified as an asteroid. The term asteroid had actually been
used by William Herschel as a proposed classifier when Palace
was first found. But the discovery of the asteroid Australia
really started a shift in thinking about the four previous
discoveries that had happened in that belt. And soon more
(17:20):
and more asteroids were identified in that same area where
all of these objects were existing together. Soon more and
more asteroids were identified in that same area where all
of these objects existed, and eventually it dawned on people
that what was actually there was an asteroid belt. So
(17:41):
to talk about how Series and all these other asteroids
came from, we have to go way way way back
four point six billion years. At that point, a disc
shaped dust and gas cloud was around our still forming Sun.
So that's the solar nebula, slowly leading to the formation
(18:02):
of planets within that cloud. Yes, so as some particles
would bump into each other, they would stick to one another,
and then they would collide with more particles and form
progressively larger and larger clumps, eventually growing large enough that
these clumps would develop gravitational pull and then attract more
mass to them. But not all gravity bearing clumps are
(18:25):
created equal, some grow larger than others. Once Jupiter developed,
it's highly likely that it's gravity was so great that
it just dominated the material attraction game in that part
of the Solar nebula. So Jupiter, with its massive size,
rob Series and other objects of the chance to grow
into full sized planets. That asteroid belt that Series is
(18:49):
part of is sometimes just sometimes described as that missing
planet between Mars and Jupiter that just couldn't pull itself
together into one cohesive body because of Upiter's incredible gravitational pull.
That's selfish Jupiter. No, I'm don't write me hate mail
because you love Jupiter. I love it too, But it
(19:10):
did uh cost the opportunity of Series and other objects
uh from forming into bigger objects. So the diameter of
Series and its equator it's about six hundred and five
miles or nine kilometers, and its surface area is equivalent
to about thirty eight percent in the United States. So
if you could unwrap the surface of Series and lay
(19:32):
it out on a map of the US, that's how
you would get that percentage number. As to why this
is not a planet, the requirements for a heavenly body
to be classified as a planet, as formally determined by
the International Astronomical Union in two thousand and six, are
as follows. A planet's a celestial body that is in
(19:53):
orbit around the Sun, has sufficient mass for its self
gravity to overcome rigid body forces so that it assumes
a hydrostatic equilibrium, which means nearly round shape, and it
has cleared the neighborhood around its orbit. And these are
the same requirements you may recall that Pluto was not
(20:13):
able to meet and so got demoted to dwarf planet.
Series does not clear the neighborhood around its orbit. So
while it's particularly unusual in comparison to other asteroids in
one case because it is so round compared to others,
still no dice on planethood. We should mention, though, that
when the argument about Pluto's stand status as a planet
(20:34):
or not was still in play, it briefly brought up
the possibility of reclassifying Series as a planet once again.
But even though it's not a planet but a dwarf planet,
serious is still the dominant feature of the asteroid belt.
It's a lot larger than anything else in the belt
by a significant margin. Series contains approximately thirty of the
(20:56):
total mass found in the asteroid belt. That a lot
if you think about all of that stuff floating in
the asteroid belt, of it is all concentrated in Series.
On September two thousand seven, NASA's Dawn mission, which was
read led by the Jet Propulsion Lab at California, launched
a spacecraft from Cape Canaveral Air Force Station, Florida and
(21:19):
its destinations that's destination's plural VESTA and Series. After spending
some time with VESTA in terms of a year and
a few months, Dawn arrived at Series in early March.
That made it the first spacecraft to orbit two extraterrestrial
targets as well as the first to orbit an asteroid. Yeah,
(21:40):
that's sort of one of the cool things in all
of this and one of the things that I love
particularly about spaces that we're watching history be made all
the time, which is really cool. Uh, and you may
be wondering why it would be so important to study series.
As we mentioned earlier, it was likely on its way
to becoming a planet before Jupiter mucked that whole thing up,
(22:00):
so it's considered a proto planet, and by studying proto
planets we have the potential to discover all kinds of
things about planetary development and as a consequence, our own
planet Earth. It's like traveling back in time and looking
at history sort of in an arrested state. This is
like the space version of the Island of Curtsey that
we talked about in our Hamy episode that like it's
(22:23):
been protected since it was farmed, so scientists can study
like how islands get plants and animals living on them,
like that boot space and without plants and animals living
on it that we know of. As we mentioned earlier,
Series is the Roman goddess of harvests, so the naming
(22:45):
convention for the features of series discovered by the Dawn
Mission follows that theme, with gods and goddesses, vegetation and
festivals related to agriculture serving uh as the well of
the options for naming things on it, and thanks to
the Dawn Project, we now know a lot more about
Series than we did just a few years ago. It's
(23:06):
covered with shallow craters, which we didn't know. It appears
to have water ice on its surface. There are numerous
bright spots on the dwarf planet surface, likely a substance
such as ice or salt that's reflecting light. Dawn has
now photographed of the surface with a resolution of a
hundred and twenty feet or thirty five ms per pixel. Yeah,
(23:26):
and I didn't put the exact number. That far exceed
exceeds the projected goal for Series. I think the goal
was to photograph approximately eight percent of the planet's surface.
So the Dawn mission has really exceeded all expectations. It's
been quite amazing. Uh. And kind of in line with that.
The Dawn spacecraft was originally intended to remain a satellite
(23:49):
of Series indefinitely once the mission had ended. In the
time since it arrived at Series, it's performed more than
one thousand orbits and it is extremely stable there. But
quite recently in April of this year, so a new
proposal was submitted to extend Dawn's mission. A team from
University of California at Los Angeles headed by Chris Russell
(24:10):
would like for series to visit yet another object rather
than just be parked in orbit. As of this recording,
I could not find any news on a decision one
way or another. But there could be a whole another
phase of life for this really cool mission, which is
exploring this really cool dwarf planet that we once thought
was a planet and now is not. And thankfully enough
(24:31):
time has passed that the sour grapes that may have
existed over that demotion are completely died down and I
can't wait for that to be the case with Pluto
as well. Pay so much for joining us on this Saturday.
(24:51):
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or something similar over the course of the show, that
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Podcast at I heart radio dot com. Our old how
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(25:13):
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Apple podcasts, or wherever you listen to your favorite shows.
Happy Saturday. Today is the birthday of Giuseppe Piazzi, who
was born on July sixty six. So Today's Saturday Classic
is our episode on his discovery of series and the
ensuing debate about exactly what that was. This episode originally
came out on June. We hope you enjoy Welcome to
(00:26):
Stuff You Missed in History Class, a production of I
Heart Radio. Hello, and Welcome to the podcast. I'm Holly
Fry and I'm Tracvie Wilson, and I have to confess
up front that um and I might offend people by
saying this a little bit. The impetus for this episode
(00:50):
is because I can get a little cranky and fussy
about people who are still campaigning to get Pluto back
as a planet. Yeah, doesn't have feelings. I don't think
what people do personally hurt by having been no longer well,
and some of it for me, it's just that like
(01:12):
there are there are rules and reasons. There's still a
debate that can certainly happen, but there are rules and reasons,
and it it's explained why it was made a dwarf planet,
and people will come back and say it shouldn't matter
that it's small, it's still a planet, and it's like, hey,
that doesn't have anything to do with it. So but
we're not talking about Pluto. We've done that before. But
(01:33):
instead we're going to talk about some other heavenly bodies
that had a similar kind of uh discovery misclassification shift.
It's kind of you know, I wanted to talk about
how like our our knowledge and our what we believe
to be true, and how we lay out our knowledge
of the universe, and the Solar System specifically changes all
(01:56):
the time based on new information. So there were only
seven known planets in the Solar System, and at that
point it was Mercury, Venus, Earth, Mars, Jupiter, Saturn, and Uranus.
Wondering if there might be a planet in between Mars
and Jupiter had really taken up headspace for a lot
of astronomers up to that point. Once Uranus was discovered
(02:17):
in one by Sir William Herschel, it validated a theory
that indicated that there should be sort of regular spacing
between the orbital ellipses of planets, and this gave astronomers
even stronger conviction that there must be a planet there
in that swath of space between Mars's orbit and Jupiter's orbit,
but no one had identified a planet there. Uh. Johannes
(02:40):
Kepler even theorized about a planet in that gap between
those two planets in fiftet six in his work Mysterium Cosmographicum,
and he actually hinted that there would be more than
one they're writing quote. Yet the interposition of a single
planet was not sufficient for the huge gap between Jupiter
and Mars. Plenty of astronomers dedicated huge chunks of their
(03:02):
careers to try to find this elusive planet that they
felt absolutely must be lurking in that empty swath of space,
but to no avail. But eventually an Italian astronomer who
was really a mathematician found something. And today we're going
to talk about the celestial object Series, the man who
spotted in, what it is, what it's been in terms
(03:24):
of nomenclature, and how science shifts, it shifts it's thinking
as new information is uncovered. To talk about series, we're
going to talk a little bit about Giuseppe Piazzi. He
was born on July sixteenth, seventeen forty six, so we
are coming up on his birthday. He was one of
ten sons and His parents, who lived in Ponty in
(03:45):
Baltalina in the north of Italy, were really well off financially.
Because many of his siblings had died when they were
still very young. Giuseppe was baptized in a very quick
home ceremony, with the official record quote because of impending
danger of death and though his parents had been fearful
of his health. Jesseppe grew to adulthood and at the
(04:08):
age of nineteen, as was often customary for wealthy sons,
he took holy orders to become a priest, and he
pursued a number of academic studies and eventually, starting in
seventeen seventy, at the request of the church, he began
teaching philosophy and mathematics as a touring lecturer throughout Italy.
In seventeen eighty one, he became the chair of mathematics
(04:30):
at a new educational institution that would eventually become the
University of Palermo. Six years later, he was named chair
of astronomy at the school. This is an interesting move
because he hadn't really been a studying astronomy for that
all that long, but he was a really devoted scholar
and astronomy would eventually become the thing that he was
(04:52):
known for. In early seventeen eighty seven, the same year
that he was named chair of Astronomy, Piazza began an
intensive three year study trip so that he could really
become as familiar with astronomy as he could. And during
that time he spent time in Paris and London, and
he became the colleague and friend of astronomers in both
of those cities. It was because of these connections and
(05:15):
the study that he was able to secure a five
foot circular scale altessimus telescope that would become a crucial
component of the observatory that he had been tasked with
building at the university. That telescope was made in London
by mathematician and astronomical instrument specialist Jesse Ramsden. When Piazzi
returned to Palermo at the end of seventeen eighty nine,
(05:37):
he focused entirely on the construction of the observatory, and
it was only a matter of months before it was completed.
It was built on top of a tower at the
Royal Palace. With his new observatory completed and this impressive
telescope telescope installed, Gesseppe set to work making observations, focusing
primarily on accurately mapping the positions of stars, and this
(06:02):
mapping effort was truly painstaking. Each star had to be
observed for a minimum of four nights, and this had
to be done for each observable star. This work would
eventually culminate in the publication of a star catalog in
eighteen o three, which one Piazzi an array of accolades.
But while he was mapping all those stars, he stumbled
across something else entirely. So it's a little early normally
(06:26):
for a break for a sponsor, but we want to
keep this next section altogether, so we're gonna pause here
and have a little sponsor break, and then we will
come back and talk about what it was that Piazzy
stumbled upon. On New Year's Day eighteen o one, Piazzy
(06:49):
noticed a tiny dot in the heavens, specifically in the
shoulder of the Taurus constellation. As was his method, he
observed it again the file bowing night, and it had
moved after two more nights of observation. He thought he
might have identified something new which might perhaps be a comment,
(07:10):
so we contacted the press. Yeah, that was customary. It
wasn't like he was a glory hound. It was just
something you did. You reported that you had maybe found something.
So I'm imagining that as he was doing this, he
was he was measuring all the stars at like the
same time every night, because they moved anyway. Yeah, he
was mapping them throughout the course of the night. Okay,
(07:34):
So that's why they would each get four nights observation.
And as this story hit the papers and the news spread,
other astronomers, of course started taking notice. But for his part,
Piazzi was a little reluctant to put a label on
his observation. He still was not confident about exactly what
it was. In late January, he wrote a letter to
(07:55):
his best friend in Milan about the discovery, and he
voiced his uncertainty and excitement all at once. Just here's
what he said. I've announced this star as a comet,
but since it shows no nebulosity, and moreover, since it
had a slow and rather uniform motion, I surmised that
it could be something better than a comet. However, I
(08:16):
would not, by any means advance publicly this conjecture. As
soon as I shall have a larger number of observations,
I will try to compute its elements. And in fact,
a second letter that he wrote the very same time,
but to another colleague, also in Milan, is a little different.
He indicated in that letter, with more certain language, that
(08:38):
he felt that his observed object was a comet, and
this inconsistency as to whether it might be a planet
or whether it certainly was a comet was noted by
the two recipients, who knew each other well. They basically
gossiped about their comment letter well, and in the writings
about it, the one that he wrote to and said
(08:59):
it was a it seemed almost peeved that he hadn't
shared the possibility that it could be a planet like
he seemed kind of offended at how he had been
left out of the loop. So, to further complicate matters,
Piazzi became ill after his first forty one days of observation,
and his study of this new object had to be halted.
Then the son's halo made it impossible to see for
(09:22):
a while. Piast's colleagues had to use the data he
had collected up to that point to try to calculate
where the planet would appear again once it would become
observable again, and eventually it was the young German UH,
Carl Friedrich Gauss, who was only twenty four at the time,
who devised a calculation method that correctly located piazz has
(09:43):
lost planet or comment. As the public interest group people
started asking astronomers about Piazzi's discovery. This actually led to
some interesting cattiness regarding what to name it. When Johann
elert Bode spoke to the Prussian Academy then the press
at Easter just a few months after Piazza had made
(10:03):
his first observation, he declared the discovery of a new planet,
this really being Piazzi's discovery, not his own, which he
called Juno. Astronomer of Baron Franz Zavit von Zach, who
will talk about more in just a moment, called it Harra.
And Piazza had actually named his discovery series Ferdinandea, after
(10:25):
the Roman goddess of agriculture. That's the series portion when
the patron goddess of Sicily as well series was UH
and King Ferdinand of Bourbon, and he was not too
pleased about the other names being spouted by other astronomers,
and in a letter to a colleague. In August of
eighteen o one, he said, quote, if the Germans think
they have the right to name somebody else's discoveries, they
(10:46):
can call my new star the way they like. As
for me, I will always keep it the name of Serer,
and I will be very obliged if you and your
colleagues will do the same. It was like the Bone Wars.
We already have that in the archive from past hosts
if you want to hear about it. Yeah. The name
Series was eventually acknowledged throughout the astronomical community, although the
(11:11):
Ferdinandia was dropped largely because it made the name terribly long.
And as for the nature of Series, by mid eight
o two, after another astronomer had observed it and its
orbit had been tracked, was fairly settled to most that
it was indeed a planet and not a comet. It
wasn't entirely settled. There were some people who doubted it entirely,
(11:31):
and when Piazzy rewrote his observations in a new edition
with different data, it caused quite a stir. Von Zac wrote, quote,
what is going on with Series Fernandia? Nothing has been
found as yet, either in France or Germany. People's are
starting to doubt already, skeptics are making jokes about it.
(11:52):
What is devil Piazzi doing? I love finding out? How
caddy this whole, this whole group of scientists was. They're
so often so catty. Uh. Piazzi's full findings with all
of the updated data, were published in September of eighteen
o two, and while Series was obviously much smaller than
(12:14):
any planet identified up to that point, astronomers were still
categorizing it as a new planet, and finding a new
planet was a really important event at this juncture in history. Uh.
And in the wake of the publishing there was this
flurry of activity as other astronomers analyzed the data and
calculated the orbit of Series and hashed out any and
all details, and they were ever debating the merit of
(12:37):
Piazzi's work, and Piazzi himself was busy working on other
responsible abilities at the university. However, he also maddened the
astronomical community by continually and casually referring to Series as
a star or a comet sometimes rather than a planet.
There's actually a funny bit of coincidence around Piazzy discovering Series, because,
(12:58):
as we mentioned, earlier, there were other astronomers who were
really focused on looking for this planet they thought must
be in the region of space him then by the
orbits of Jupiter and Mars. One of them, a German
Hungarian astronomer named Baron Franz Zabra von Zach, who we
mentioned earlier, had determined what was that what was needed
(13:19):
was a collective effort, so von Zak invited most of
the prominent astronomers of the day to be part of
this project, and this group became known as the Celestial Police.
They each patrolled for to keep with the policing metaphor,
a designated section of the heavens in search of the
missing planet, and eventually Piazzy was invited to be part
(13:41):
of the team, but it appears that the invitation, which
was relayed through a letter written to another colleague, was
actually dated after Giuseppe Piazzy had found series already, and moreover,
Piazzy never received that invitation. So there is some speculation,
given the evidence of how Caddie all of these dudes
could be, that they were trying to kind of like
(14:06):
loop him into their crowd so that they could all
share some of the glory of having found it after
the fact, No, we totally. We invited him to be
part of our group. You got, guys, it sounds like
middle school really does. When a new element was found
in three was named sirium and a tribute to Series.
(14:28):
This was definitely a time of Series fever, and the
practice of naming elements after recently discovered planets has happened
several times. Uranium, neptunium, and plutonium are all named for
planets as well. Because Series was so small in comparison
to any of the other known planets, it eventually was
(14:48):
sort of classified as a minor planet, and the search
for another planet between Mars and Jupiter that might perhaps
have greater mass uh continued. It was spurred on, in fact,
by zis Fined. So not long after the Series discovery
and over a period of six years, three other planets
were discovered in that same band of space. So that's right.
(15:10):
There's a time that was believed that we had four
entire planets between Mars and Jupiter, and the first of
these was initially observed on March eighteen o two, so
that was even before Piazzi had published his final data
on Series, and that was identified by Wilhelm Olbers, and
(15:30):
he saw something in the wing of the Virgo constellation
that he had not observed prior, and after two days
of observation of this object, he was convinced it was
a planet, and he named it Palace. Other astronomers were
also pretty quickly convinced, and it made them even more
certain that there might be yet other planets in that
Mars Jupiter gap. On September one, st eight, you know,
(15:51):
for Carl Ludwick Harding spotted the next planet at the
intersection of the orbits of Series and Palace, and this
one was called Juno. Bill Holm Ober's once again had
the honor of discovering the fourth new planet of the
nineteenth century, Vesta, on March seven. Palace, Juno, Investa were
(16:12):
all smaller than Series, so they too were considered minor planets.
But of course, if you crack open any current textbook
that features our Solar system, none of these objects are
listed as planets at all, So you may be wondering
what happened, And we're going to talk about how Series
and its siblings ceased to be classified as planets, whether
minor or not. Right after we pause once again for
(16:34):
a quick word from one of our sponsors to get
back to what happened the Series. Slowly the realization was
made the Series and its neighbors where maybe not actually
planets after all. When a fifth body named Austraia was
(16:58):
discovered in eighteen forty five by Ale Hanky, it was
classified as an asteroid. The term asteroid had actually been
used by William Herschel as a proposed classifier when Palace
was first found. But the discovery of the asteroid Australia
really started a shift in thinking about the four previous
discoveries that had happened in that belt. And soon more
(17:20):
and more asteroids were identified in that same area where
all of these objects were existing together. Soon more and
more asteroids were identified in that same area where all
of these objects existed, and eventually it dawned on people
that what was actually there was an asteroid belt. So
(17:41):
to talk about how Series and all these other asteroids
came from, we have to go way way way back
four point six billion years. At that point, a disc
shaped dust and gas cloud was around our still forming Sun.
So that's the solar nebula, slowly leading to the formation
(18:02):
of planets within that cloud. Yes, so as some particles
would bump into each other, they would stick to one another,
and then they would collide with more particles and form
progressively larger and larger clumps, eventually growing large enough that
these clumps would develop gravitational pull and then attract more
mass to them. But not all gravity bearing clumps are
(18:25):
created equal, some grow larger than others. Once Jupiter developed,
it's highly likely that it's gravity was so great that
it just dominated the material attraction game in that part
of the Solar nebula. So Jupiter, with its massive size,
rob Series and other objects of the chance to grow
into full sized planets. That asteroid belt that Series is
(18:49):
part of is sometimes just sometimes described as that missing
planet between Mars and Jupiter that just couldn't pull itself
together into one cohesive body because of Upiter's incredible gravitational pull.
That's selfish Jupiter. No, I'm don't write me hate mail
because you love Jupiter. I love it too, But it
(19:10):
did uh cost the opportunity of Series and other objects
uh from forming into bigger objects. So the diameter of
Series and its equator it's about six hundred and five
miles or nine kilometers, and its surface area is equivalent
to about thirty eight percent in the United States. So
if you could unwrap the surface of Series and lay
(19:32):
it out on a map of the US, that's how
you would get that percentage number. As to why this
is not a planet, the requirements for a heavenly body
to be classified as a planet, as formally determined by
the International Astronomical Union in two thousand and six, are
as follows. A planet's a celestial body that is in
(19:53):
orbit around the Sun, has sufficient mass for its self
gravity to overcome rigid body forces so that it assumes
a hydrostatic equilibrium, which means nearly round shape, and it
has cleared the neighborhood around its orbit. And these are
the same requirements you may recall that Pluto was not
(20:13):
able to meet and so got demoted to dwarf planet.
Series does not clear the neighborhood around its orbit. So
while it's particularly unusual in comparison to other asteroids in
one case because it is so round compared to others,
still no dice on planethood. We should mention, though, that
when the argument about Pluto's stand status as a planet
(20:34):
or not was still in play, it briefly brought up
the possibility of reclassifying Series as a planet once again.
But even though it's not a planet but a dwarf planet,
serious is still the dominant feature of the asteroid belt.
It's a lot larger than anything else in the belt
by a significant margin. Series contains approximately thirty of the
(20:56):
total mass found in the asteroid belt. That a lot
if you think about all of that stuff floating in
the asteroid belt, of it is all concentrated in Series.
On September two thousand seven, NASA's Dawn mission, which was
read led by the Jet Propulsion Lab at California, launched
a spacecraft from Cape Canaveral Air Force Station, Florida and
(21:19):
its destinations that's destination's plural VESTA and Series. After spending
some time with VESTA in terms of a year and
a few months, Dawn arrived at Series in early March.
That made it the first spacecraft to orbit two extraterrestrial
targets as well as the first to orbit an asteroid. Yeah,
(21:40):
that's sort of one of the cool things in all
of this and one of the things that I love
particularly about spaces that we're watching history be made all
the time, which is really cool. Uh, and you may
be wondering why it would be so important to study series.
As we mentioned earlier, it was likely on its way
to becoming a planet before Jupiter mucked that whole thing up,
(22:00):
so it's considered a proto planet, and by studying proto
planets we have the potential to discover all kinds of
things about planetary development and as a consequence, our own
planet Earth. It's like traveling back in time and looking
at history sort of in an arrested state. This is
like the space version of the Island of Curtsey that
we talked about in our Hamy episode that like it's
(22:23):
been protected since it was farmed, so scientists can study
like how islands get plants and animals living on them,
like that boot space and without plants and animals living
on it that we know of. As we mentioned earlier,
Series is the Roman goddess of harvests, so the naming
(22:45):
convention for the features of series discovered by the Dawn
Mission follows that theme, with gods and goddesses, vegetation and
festivals related to agriculture serving uh as the well of
the options for naming things on it, and thanks to
the Dawn Project, we now know a lot more about
Series than we did just a few years ago. It's
(23:06):
covered with shallow craters, which we didn't know. It appears
to have water ice on its surface. There are numerous
bright spots on the dwarf planet surface, likely a substance
such as ice or salt that's reflecting light. Dawn has
now photographed of the surface with a resolution of a
hundred and twenty feet or thirty five ms per pixel. Yeah,
(23:26):
and I didn't put the exact number. That far exceed
exceeds the projected goal for Series. I think the goal
was to photograph approximately eight percent of the planet's surface.
So the Dawn mission has really exceeded all expectations. It's
been quite amazing. Uh. And kind of in line with that.
The Dawn spacecraft was originally intended to remain a satellite
(23:49):
of Series indefinitely once the mission had ended. In the
time since it arrived at Series, it's performed more than
one thousand orbits and it is extremely stable there. But
quite recently in April of this year, so a new
proposal was submitted to extend Dawn's mission. A team from
University of California at Los Angeles headed by Chris Russell
(24:10):
would like for series to visit yet another object rather
than just be parked in orbit. As of this recording,
I could not find any news on a decision one
way or another. But there could be a whole another
phase of life for this really cool mission, which is
exploring this really cool dwarf planet that we once thought
was a planet and now is not. And thankfully enough
(24:31):
time has passed that the sour grapes that may have
existed over that demotion are completely died down and I
can't wait for that to be the case with Pluto
as well. Pay so much for joining us on this Saturday.
(24:51):
Since this episode is out of the archive, if you
heard an email address or a Facebook U r L
or something similar over the course of the show, that
could be obsolete now. Our current email address is History
Podcast at I heart radio dot com. Our old how
stuff Works email address no longer works, and you can
find us all over social media at missed in History
(25:13):
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