Earth's Inner Core Mysteries, China's Lunar Quest, and Hot Jupiter Insights: S28E21

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This is Space Time Series 28
Episode 21 for broadcast on the

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17th of February 2025. Coming up
on Space Time, new research

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suggests the Earth's inner core
could be far less solid than

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previously thought. China's new
Lunar South Pole mission

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designed to search for water ice
and the hot Jupiter exoplanet

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that could provide new insights
into how these bodies form. All

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that and more coming up on Space
Time.

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Welcome. To Space Time with
Stuart Gary.

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A new study has found that the
Earth's inner core is undergoing

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structural transformation and
may in fact be far less solid

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than previously thought. Planet
Earth's core consists of a

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molten metallic outer layer
surrounding what was thought to

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be a spherical solid mostly
iron-nickel alloy in a core with

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a radius of about 1,220 km,
making it about 20% of the

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entire planet, and with a
temperature of around 5,430 °C.

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The characteristics of the core
have been deduced mostly from

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measurements of seismic waves in
the Earth's magnetic field.

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But now a report in the journal
Nature Geoscience suggests that

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the surface of the inner core
may be changing. The study's

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lead author, John Vidal from
Dornsif College, says changes to

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the inner core have long been
the topic of debate among

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scientists. However, most of the
research has been focused on

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assessing the core's rotation.

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What Vidal and colleagues ended
up discovering is evidence that

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the near surface of the inner
core undergoes structural

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change. The findings shed new
light on the role that

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topographical activity plays in
the rotational changes in the

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inner core, changes that have
minutely altered the length of a

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day and may relate to the
ongoing slowing of the inner

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course rotation.

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The original aim of the research
was to further chart that

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slowing of the inner course
rotation. But as they analysed

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multiple decades of
seismographs, one dataset of

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seismic waves curiously stood
out from the rest.

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Vidal says he realized he was
staring at evidence that the

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inner core wasn't solid. The
study utilized seismic waveform

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data, including 121 repeating
earthquakes from 42 locations

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near Antarctica's South Sandwich
Islands, which occurred between

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1991 and 2024, providing a
glimpse of what takes place in

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the inner core.

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As the authors analyzed the
waveforms from receiver array

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stations located near Fairbanks
in Alaska and Yellowknife in

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Canada, one set of seismic waves
from the latter station included

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uncharacteristic properties
which the team had never seen

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before.

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At first, the dataset confounded
Vidal, but once his research

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team were able to improve the
resolution of the data, it

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became clear that these seismic
waveforms represented additional

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physical activity in the inner
core.

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And this physical activity can
best be explained as temporal

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changes in the shape of the
inner core. The new study

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suggests that the knee surface
of the inner core may be

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undergoing viscous deformation,
in other words, changing its

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shape and shifting at the inner
core's shallow boundary.

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Now, the clearest cause of this
structural change would be

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interaction between the inner
and outer cores. The molten

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outer core is widely known to be
highly turbulent, but this

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turbulence hasn't been known to
disrupt the inner core, at least

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not on human timescales, until
now.

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Vidal says what we're observing
in this study for the first time

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is likely the outer core
disturbing the inner core. This

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discovery is opening a new door,
revealing previously hidden

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dynamics deep within the Earth's
core, and it will lead to a

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better understanding of the
Earth's thermal and magnetic

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field.

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This is Space Time. Still to
come, China's new Lunar South

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Pole mission Chang'E 7, which
will do a surface search for

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water ice, and the hot Jupiter
exoplanet that could provide new

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insights into how these bodies
form. All that and more still to

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come on Space Time.

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Beijing has issued a new press
release, saying it's on track to

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launch its Chang'E 7 mission
next year to search for water

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ice deposits at the Lunar South
Pole. And once they're

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identified, mission managers
will trial new technologies

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designed to help Taikonauts
extend manned operations on the

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lunar surface.

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Chang'E 7 will include a new
type of molecular analyzer,

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specifically designed to verify
the presence and extent of water

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ice in South Pole craters whose
floors are in permanent shadow,

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never receiving sunlight. While
Beijing's earlier Chang'E 3 and

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5 missions landed on the lunar
nearside, Chang's 4 and 6 both

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touched down on the lunar far
side.

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Chang'E 7 will build on that
success, uncovering usable lunar

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water ice, which can then be
broken down and used to make

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rocket fuel, water for drinking
and air for breathing. This

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would dramatically lower costs,
reducing the logistics needed to

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establish a permanent base on
the lunar surface and support

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future manned missions to the
Moon, Mars and beyond.

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Beijing says China plans to land
Taikonauts on the lunar surface

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before 2030. And shortly
afterwards commence construction

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with the Russians of a joint
base. Next year's Chang'E 7

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mission will consist of an
orbiter, a lander, a rover and a

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mobile hopper designed to jump
from sunlit areas to shadowed

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craters using a new type of
active suspension system.

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As well as gathering data about
its surroundings, the mission

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will also use a landmark image
navigation system in order to

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determine its location,
something NASA's been doing for

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a while but which will be new
for China. This is Space Time.

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Still to come, the hot Jupiter
exoplanet that could provide new

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insights into how these bodies
form.

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And later in the science report,
the World Meteorological

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Organization has now confirmed
that 2024 was the first year

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where average global
temperatures were greater than

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the 1.5 degrees above
pre-industrial levels specified

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by the Paris Agreements. All
that and more still to come on

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Space Time.

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When you study astronomy at
university, you quickly become

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proficient in classical
mechanics and Keplerian orbits.

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They allow you to accurately
predict the motions of two

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bodies, say planets or a planet
and a star, based on their

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masses, velocities and
distances.

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Trouble is, astronomy is not
always that simple. In the real

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world, other bodies and their
added gravitational influences

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add additional complexity to
these problems. And this is the

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basis of the three-body problem.

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Once you add a third variable in
physics, you need to take into

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account the initial positions
and velocities, that is,

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momenta, of all three point
masses that orbit each other in

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space, and then calculate their
subsequent trajectories using

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Newton's law of motion and
universal gravitation.

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But unlike the two-body problem,
which uses a very simple

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equation, the three-body problem
has no general closed-form

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solution. You see, when three
bodies orbit each other, the

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resulting dynamical system is
chaotic for most initial

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conditions.

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Now, astronomers have found an
unexpected three-body problem in

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the discovery of a hot Jupiter's
eccentric orbit. The authors

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were analysing data from a newly
discovered massive planet on an

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extreme orbit in order to
understand how hot Jupiter

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planets form.

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The discovery of this strangely
acting exoplanet 1,100

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light-years away has helped
astronomers better understand

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the formation of a class of
planets known as hot Jupiters.

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These are gas giants orbiting
close to their host stars. The

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new discovery, known as TIC
241249530B, is a gas giant about

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five times the size of Jupiter.

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It was discovered by NASA's
TESS, that's the Transiting

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Exoplanet Survey Satellite, a
space telescope gathering

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information about exoplanets,
that is, planets orbiting stars

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other than the Sun.

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So far, over 5,000 exoplanets
have been found, and many others

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are suspected, but not yet
confirmed. That's part of what

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TESS is doing. Macquarie
University astronomers Dr Jamie

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Alvarado Montes and Associate
Professor Christian Schwab were

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among a team of 60 researchers
from 8 countries and more than

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35 institutions studying this
fascinating system.

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Their findings, reported in the
journal Nature, showed that the

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exoplanet's strange orbit
indicates that it's under the

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influence of a second star,
indicating a binary system. Now,

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binary systems aren't that
uncommon.

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In fact, most stellar systems in
the Milky Way are multiple star

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systems. Even our nearest
stellar neighbour, Alpha

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Centauri, is actually a triple
star system.

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Schwab designed the optics for
NASA's Extreme Precision Radio

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Velocity Spectrograph, a crucial
part of the ground-based

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equipment used to home in on the
target planet, after tests first

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spotted an indication that a
planet could be orbiting the

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star TIC 241249530. The
spectrometer was fitted to the

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3.5 metre wind telescope, making
over 50 high-precision

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observations spanning some two
and a half years.

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Schwab says the observations
measured the planet's mass and

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revealed its extreme orbit.
Based on this work, he was able

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to determine that TIC 241249530B
experiences radical temperature

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changes during the six months it
takes to orbit its main host

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star.

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When closest to the star, the
planet's atmosphere would expand

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and partially evaporate from the
intense heat and radiation, and

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the side of the planet facing
the star would be hot enough to

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melt rock or vaporize metals.

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But as the planet orbits away
from the star, it would cool

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dramatically, as the constant
heating and cooling cycles

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create powerful storm systems
far more extreme than anything

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seen on Jupiter and certainly
heaps more than anything seen on

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the Earth.

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Once the orbital parameters were
precisely known, Alvarado Montes

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got to work on computer
modelling, simulating how the

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planet's orbit would change over
time. The models suggest that

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this planet did initially form
as a cold Jupiter far from its

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host star, but the influence of
gravity from that star and from

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the star's binary partner caused
it to gradually migrate inwards

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and eventually become a hot
Jupiter.

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Alvarado Montes says that
several billion years ago, the

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planet formed as a cold Jupiter,
far from its star in a region

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cold enough to condense and take
shape.

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Then gravitational forces from
the second binary star in the

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system caused the planet's orbit
to gradually stretch and grow

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more eccentric, and it began to
swing ever closer to the primary

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star. The authors have dubbed
this newly discovered planet a

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hot Jupiter progenitor.

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And have modelled the exoplanet
's slow evolution to its current

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highly eccentric 166 Earth-Day
orbit. From very close to its

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host star, 10 times closer than
Mercury is to the Sun, the

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planet moves in an egg-shaped
orbit, swinging further out to

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about as far as Earth is from
the Sun.

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Few exoplanets have orbits this
extreme. In fact, it's more

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eccentric than any other known
transiting exoplanet. Hot

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Jupiter is fascinating because
they challenge our understanding

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of planetary formation and
evolution. In fact, the very

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first exoplanet ever discovered,
51 Pegasi, was a hot Jupiter.

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Alvarado Montes says that in our
own solar system, Mercury is a

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tiny rocky marble orbiting the
Sun every 88 Earth days, while

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the gas giant Jupiter, the king
of planets in our solar system,

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takes around 12 Earth years to
complete each orbit.

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Now, by contrast, hot Jupiters
are gas planets like Jupiter or

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even bigger, but so close to
their host stars, their orbits

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can take less than 10 Earth
days, sometimes just a matter of

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hours. Now, theoretically, these
planets should only be able to

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form at very far distances from
the star.

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That's because the gas making up
more than 90% of their mass

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shouldn't be able to accumulate
or survive close to the star's

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intense heat and radiation.
Typically, as planets form close

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to young stars and grow from
tiny clouds of dust and gas, a

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star's heat causes gas particles
to evaporate or condense so that

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only rocks and metal remain.

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NASA's Galileo probe, which
gathered data about Jupiter back

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in 1995, transmitted for an hour
and reached a depth of about 160

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kilometers below the cloud tops
before the planet's mounting

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atmospheric pressure crushed it
out of existence.

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Although Jupiter could fit a
thousand Earths within its

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atmosphere, it only has a tiny
core about the size of the Earth

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's core, and that's buried under
some 70,000 kilometers of gas.

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That results in pressures
millions of times greater than

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what we see here on Earth's
surface. This newly discovered

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exoplanet sheds light on the
formation of hot Jupiters, and

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provides a real-world example of
the mathematical puzzle of the

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three-body problem.

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The authors have modelled the
history and likely progression

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of this planet, and they predict
a happy ending. Alvarado Montes

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00:13:16,182 --> 00:13:19,345
says that over the next million
years or so, the planet's likely

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00:13:19,365 --> 00:13:22,507
to settle into a more stable
close orbit around its primary

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00:13:22,587 --> 00:13:25,390
star and fully transform into a
hot Jupiter.

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00:13:25,670 --> 00:13:29,733
The first data that we work on
to confirm this planet was taken

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00:13:29,793 --> 00:13:35,918
in 2020. So the initial data was
data taken by the S satellite.

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00:13:35,998 --> 00:13:39,421
It's a mission from NASA to
observe exoplanets. Before that

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00:13:39,441 --> 00:13:42,283
we have Kepler that only
observed very far stars, but now

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00:13:42,303 --> 00:13:45,185
we have S which is observing.
Kind of like the nearby

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00:13:45,425 --> 00:13:47,966
universe. What it does is just
measure the change in the

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00:13:47,986 --> 00:13:48,946
brightness of the stars.

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All right.

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00:13:49,486 --> 00:13:52,867
And detecting, yeah, the
transit, using, well, the

241
00:13:52,887 --> 00:13:56,248
transit method. And then based
on that, depending on what you

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00:13:56,288 --> 00:13:59,749
observe, then you do follow-up
observations with ground-based

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00:13:59,829 --> 00:14:02,790
instruments or telescopes. So it
's a planet that has a very

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00:14:02,850 --> 00:14:05,571
large orbit. So it's a planet
that has an orbit of... Then

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00:14:05,611 --> 00:14:08,632
observing with TESS continuously
is not possible.

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00:14:08,652 --> 00:14:12,813
It's very hard because TESS only
observes one sector. So the

247
00:14:12,873 --> 00:14:16,394
way... It observes its observing
sectors of the sky, and each

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00:14:16,494 --> 00:14:20,436
sector it observes only for 27
days. So that means that in the

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00:14:20,456 --> 00:14:23,377
case of this planet, observing
it with tests is very

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00:14:23,437 --> 00:14:26,458
complicated because to get to
the same sector, it will take

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00:14:26,819 --> 00:14:29,840
almost a year or two years to
get back to the same sector. So

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00:14:30,600 --> 00:14:32,101
we need to do follow-up
observations.

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00:14:32,121 --> 00:14:35,502
So the first observations were
done with tests, but then after

254
00:14:35,562 --> 00:14:38,743
a transit was detected, like a
transit signal was detected,

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00:14:38,763 --> 00:14:42,705
then the goal was to observe
more transit. So the initial...

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00:14:43,125 --> 00:14:48,128
Data that we have, well, the
ephemeris of this planet were a

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00:14:48,148 --> 00:14:50,549
bit complicated. They weren't
very well constrained.

258
00:14:50,649 --> 00:14:54,351
So that means that some of the
attempts that we did with

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00:14:54,491 --> 00:14:57,453
ground-based telescopes were
unsuccessful because we were

260
00:14:57,473 --> 00:15:00,535
observing supposedly the
transit, but not transit was

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00:15:00,655 --> 00:15:03,376
coming up in the observation.
Just because we didn't have

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00:15:03,416 --> 00:15:06,238
enough information to know with
very good precision at what time

263
00:15:06,338 --> 00:15:09,219
the observations were, like the
transit was going to happen. So

264
00:15:09,259 --> 00:15:12,401
it took a couple of attempts
until we refined the...

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00:15:12,541 --> 00:15:15,423
The ephemeris of the planet and
then once the ephemeris of the

266
00:15:15,443 --> 00:15:18,566
planet were refined then we were
able to do more transit

267
00:15:18,606 --> 00:15:21,768
observations and also we did
ground-based observations with

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00:15:21,928 --> 00:15:24,810
instruments that are called
spectrographs and that's where

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00:15:25,131 --> 00:15:30,274
Chris comes into play. Chris is
the main investigator and one of

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00:15:30,254 --> 00:15:33,436
the people who designed and
built the Nui spectrograph.

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00:15:33,576 --> 00:15:36,759
So the Nui spectrograph is an
instrument that is located in

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00:15:36,739 --> 00:15:39,741
the state. Like a big bunch of
the observations, like a lot of

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00:15:39,721 --> 00:15:43,283
the data that was collected to
do follow-up observations were

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00:15:43,303 --> 00:15:47,046
taken with this instrument, with
Nui. What we did was observing

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00:15:47,266 --> 00:15:51,109
now not just transit, but we
also did observe the radial

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00:15:51,129 --> 00:15:53,830
velocities, the wobbling of the
planet.

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00:15:53,991 --> 00:15:57,376
So All of these combined,
combining photometric

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00:15:57,416 --> 00:16:01,778
observations, then we were able
to constrain the size of the

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00:16:01,798 --> 00:16:05,519
planet, not just constrain the
radius of the planet, but also

280
00:16:06,100 --> 00:16:09,441
the mass of the planet. And
there is something that you can

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00:16:09,621 --> 00:16:11,862
get. There is a piece of
information that is actually

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00:16:11,962 --> 00:16:16,364
quite, quite valuable. And that
is only possible to obtain once

283
00:16:16,564 --> 00:16:20,245
you observe transits and radial
velocities at the same time.

284
00:16:20,325 --> 00:16:24,871
So that's what we did with NUIS
and with other telescopes. So by

285
00:16:24,911 --> 00:16:28,273
observing the transits and the
radial velocities, the wobbling,

286
00:16:28,433 --> 00:16:31,774
at the same time, you're able to
recover something that is called

287
00:16:31,974 --> 00:16:35,636
the projected obliquity of the
orbit of the planet. So this is

288
00:16:35,976 --> 00:16:40,918
how inclined the orbit is with
the equator of the star.

289
00:16:41,238 --> 00:16:44,520
So this is an important piece of
information because it can tell

290
00:16:44,560 --> 00:16:47,881
you a lot about the history of
the planet, like how the planet

291
00:16:47,941 --> 00:16:51,723
was formed. So by doing all of
these observations and the name

292
00:16:52,043 --> 00:16:55,984
of... This method, the name of
this combination of photometric

293
00:16:56,044 --> 00:17:00,485
data and spectroscopic data.
That combination is called the

294
00:17:00,545 --> 00:17:03,046
Rossi-Therma-Claude effect, and
that's something that we did

295
00:17:03,106 --> 00:17:05,567
with NUID, with the instrument
that Chris built.

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00:17:05,667 --> 00:17:08,868
How do you know where the
equator of the star is? Are you

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00:17:08,908 --> 00:17:12,129
looking at the star as it's
rotating? Is that what's letting

298
00:17:12,129 --> 00:17:14,649
you see the different areas of
the star?

299
00:17:14,789 --> 00:17:19,351
Yeah, basically. Yeah, very
good, very good. Yeah, it has to

300
00:17:19,371 --> 00:17:20,991
do with how the star rotates.

301
00:17:22,204 --> 00:17:26,666
So if the stars are rotating, so
the equator is defined by the

302
00:17:26,766 --> 00:17:29,988
axis of the rotation. And
basically, because these are

303
00:17:30,088 --> 00:17:33,730
very, very big bodies, then what
you observe is that when the

304
00:17:33,910 --> 00:17:37,312
star is rotating, one side of
the star is coming towards you

305
00:17:37,472 --> 00:17:41,334
and the other side is going away
from you. And so the side that

306
00:17:41,334 --> 00:17:44,616
is coming towards you that is
getting closer, that's called,

307
00:17:44,916 --> 00:17:47,437
that's a blue strip and the
other side is a red strip.

308
00:17:47,597 --> 00:17:51,580
So if you are able to measure
this tip. This is called the

309
00:17:51,600 --> 00:17:54,962
Doppler effect, so that's kind
of like an optical Doppler

310
00:17:54,982 --> 00:17:57,224
effect. So you're able to
observe that optical Doppler

311
00:17:57,284 --> 00:18:01,607
effect while the planet is
moving in front of the star.

312
00:18:01,787 --> 00:18:06,630
Then you are able to tell how
the planet is orbiting around

313
00:18:06,630 --> 00:18:10,853
the star. If it's doing it in an
aligned orbit or an orbit with

314
00:18:11,033 --> 00:18:13,375
20 degrees or with 40 or with
50.

315
00:18:13,655 --> 00:18:17,257
So that's what we call the
projected obliquity. It's like

316
00:18:17,458 --> 00:18:20,379
with respect to the star in the
background. The planet passing

317
00:18:20,379 --> 00:18:24,501
in front of the star and you
observing from Earth, how is the

318
00:18:24,541 --> 00:18:28,083
planet passing in front? Is it
passing through a horizontal

319
00:18:28,143 --> 00:18:31,184
line, completely flat, or is it
moving a little bit with an

320
00:18:31,204 --> 00:18:34,585
inclination? So that's what we
observe with this effect.

321
00:18:34,705 --> 00:18:38,067
If it's moving horizontally with
the rotation of the star, that

322
00:18:38,107 --> 00:18:40,828
would tell you that it was
formed in a planetary nebula

323
00:18:40,968 --> 00:18:41,968
when the star was moving.

324
00:18:41,968 --> 00:18:42,108
Exactly.

325
00:18:42,509 --> 00:18:43,449
Very good, very good.

326
00:18:43,469 --> 00:18:44,970
At an angle, what does that tell
you?

327
00:18:45,070 --> 00:18:48,431
So if it's moving at an angle,
then there's different reasons.

328
00:18:48,531 --> 00:18:52,873
For it, but one of the best
theories we have is called

329
00:18:53,714 --> 00:18:57,356
isentricity tidal migration. So
basically, when you find that

330
00:18:57,456 --> 00:19:00,518
planets are, like you said,
aligned with the orbit, these

331
00:19:00,518 --> 00:19:03,819
are planets that probably
migrated with the disk. So this

332
00:19:03,839 --> 00:19:06,501
is called disk migration, which
you described before with the

333
00:19:06,501 --> 00:19:07,782
planetary nebula or the disk.

334
00:19:07,962 --> 00:19:11,303
But when you find that there is
an obliquity, then you have a

335
00:19:11,323 --> 00:19:14,745
planet that didn't migrate
through disk migration, but a

336
00:19:14,765 --> 00:19:18,647
planet that instead was excited
by the presence of other bodies

337
00:19:18,667 --> 00:19:22,530
in the system. And that is one
of the reasons why this planet

338
00:19:22,570 --> 00:19:27,272
is so important, because so far
we only have one planet that was

339
00:19:27,632 --> 00:19:33,816
kind of like a potential member
of the sample, that is HbA0606b.

340
00:19:34,116 --> 00:19:39,059
So this planet has a very high
eccentricity, like 0.93, has a

341
00:19:39,079 --> 00:19:42,421
very high mass, and was the only
one. We didn't have any other

342
00:19:42,521 --> 00:19:45,642
planet in this sample. So now
with this planet, we have added

343
00:19:45,743 --> 00:19:49,624
an extra point in the sample
showing that there is a trend

344
00:19:49,904 --> 00:19:53,425
between the mass of the planet
and the eccentricity of the

345
00:19:53,445 --> 00:19:53,805
planet.

346
00:19:53,865 --> 00:19:57,946
So what we have found before is
that low mass planets tend to be

347
00:19:58,446 --> 00:20:02,807
in like roughly circular orbits
or orbits with very small

348
00:20:02,867 --> 00:20:08,489
eccentricity, while massive
planets like HD 8, 06, 06b or

349
00:20:08,469 --> 00:20:11,550
the one that we just found that
are high eccentricity planets,

350
00:20:11,730 --> 00:20:15,523
they're also very massive
planets. And what happens is

351
00:20:15,584 --> 00:20:19,166
that this also proves another
thing, or it can help us study

352
00:20:19,347 --> 00:20:21,448
another effect of why this is
happening.

353
00:20:22,369 --> 00:20:26,733
Why is this birth of planets
with low orbits, with a small

354
00:20:26,833 --> 00:20:30,376
orbit, but that are not
migrating or becoming hot

355
00:20:30,436 --> 00:20:32,717
Jupiters? Because at the end of
the day, that was the whole

356
00:20:32,758 --> 00:20:35,680
point of this investigation, of
this research, right? That these

357
00:20:35,740 --> 00:20:39,343
planets that are undergoing this
high eccentricity tidal

358
00:20:39,383 --> 00:20:42,886
migration will eventually become
hot Jupiters. Why?

359
00:20:43,286 --> 00:20:46,989
Because they are in such a
centric orbit that when they

360
00:20:47,069 --> 00:20:50,272
pass through the periastron,
which is the closest point in

361
00:20:50,252 --> 00:20:52,855
the orbit of a planet to the
star, when they pass through the

362
00:20:52,855 --> 00:20:56,958
periastron, a lot of energy is
lost. This orbital energy is

363
00:20:57,038 --> 00:21:00,321
stolen by the star. So what
happens is that with time, then

364
00:21:00,541 --> 00:21:04,445
the planet will start precessing
and the orbit or the semi-major

365
00:21:04,545 --> 00:21:05,846
axis of the planet will shrink.

366
00:21:06,026 --> 00:21:10,610
So reaching final orbits of only
10 days or less than that. Which

367
00:21:10,630 --> 00:21:13,351
is the definition for hot
Jupiter. So that's why the title

368
00:21:13,371 --> 00:21:16,493
of this paper is called like a
progenitor, a hot Jupiter

369
00:21:16,533 --> 00:21:20,315
progenitor, because it's a
planet that will become a hot

370
00:21:20,375 --> 00:21:24,157
Jupiter eventually. Now we know
about hot Jupiters and we have a

371
00:21:24,177 --> 00:21:25,477
lot of information about them.

372
00:21:25,517 --> 00:21:28,459
Well, Pegasi 51 is the best
example, isn't it?

373
00:21:28,459 --> 00:21:32,841
Yeah, yeah. But the problem, the
problem is that so far we didn't

374
00:21:32,881 --> 00:21:36,462
have a lot of evidence for this
mechanism. For the mechanism

375
00:21:36,462 --> 00:21:39,123
that I just described, the high
eccentricity tidal migration.

376
00:21:39,143 --> 00:21:41,824
We didn't have enough evidence
because the evidence for this

377
00:21:41,885 --> 00:21:45,486
mechanism is precisely that you
need very massive planets with

378
00:21:45,586 --> 00:21:49,067
very high eccentricities and
then observing these planets

379
00:21:49,428 --> 00:21:51,849
well enough and long enough so
you can constrain their

380
00:21:51,969 --> 00:21:54,750
ephemeris and then eventually
knowing what's going to happen

381
00:21:54,770 --> 00:21:55,370
with this planet.

382
00:21:55,490 --> 00:21:58,731
So the prediction that we have
with this planet is that this is

383
00:21:58,711 --> 00:22:03,253
a planet that started in a very,
very eccentric orbit, also with

384
00:22:03,373 --> 00:22:07,732
a larger semi-major axis. So
very far from the star. And

385
00:22:07,912 --> 00:22:12,135
eventually, because the star of
the planet is orbiting at a

386
00:22:12,535 --> 00:22:15,217
binary companion, so there is
another star in the system.

387
00:22:15,377 --> 00:22:18,559
So that's another requirement of
this mechanism, of the high

388
00:22:18,579 --> 00:22:21,641
eccentricity tidal migration
mechanism, is that you have a

389
00:22:21,701 --> 00:22:25,264
star, you have a planet, and
there has to be another body

390
00:22:25,664 --> 00:22:29,887
perturbing the orbit of the
planet. In some cases, that

391
00:22:30,267 --> 00:22:32,569
extra companion could be a
planet.

392
00:22:32,889 --> 00:22:35,510
But in this case, it's a star.
Star. It's the binary star of

393
00:22:35,490 --> 00:22:38,831
the system. So what happens is
that you have the star, this

394
00:22:38,911 --> 00:22:43,233
planet started very far, roughly
10 astronomical units, and

395
00:22:43,413 --> 00:22:48,454
eventually the orbit of the
planet undergoes a coupling with

396
00:22:48,534 --> 00:22:49,854
the binary companion.

397
00:22:49,954 --> 00:22:53,255
So that's what happened to this
planet. So the binary companion

398
00:22:53,295 --> 00:22:56,296
is starting preserving the orbit
of the planet. So the planet

399
00:22:56,456 --> 00:22:59,717
starts becoming very eccentric.
The orbit of the planet becomes

400
00:22:59,797 --> 00:23:00,857
highly, highly eccentric.

401
00:23:00,957 --> 00:23:03,938
And when it becomes highly
eccentric, there is a quantity

402
00:23:04,198 --> 00:23:06,780
that decreases, the orbital
angular momentum of the planet

403
00:23:06,960 --> 00:23:09,781
decreases. That's what we say
that the binary companion is

404
00:23:09,801 --> 00:23:13,142
extracting this angular momentum
from the planet.

405
00:23:13,322 --> 00:23:16,984
And the consequence of that is
that when the orbit starts

406
00:23:17,024 --> 00:23:20,505
becoming super eccentric, then
you have these closed passages

407
00:23:20,845 --> 00:23:23,546
of the planet through the
periastrum. So before you didn't

408
00:23:23,566 --> 00:23:26,728
have that, but once the orbit
becomes super eccentric, then

409
00:23:27,048 --> 00:23:30,569
you have a planet that is
passing really, really close to

410
00:23:30,549 --> 00:23:32,230
the star. So the star...

411
00:23:32,650 --> 00:23:36,532
Eventually start extracting
orbital energy. And with each

412
00:23:36,632 --> 00:23:40,273
cycle, with each path of the
planet through the periastral,

413
00:23:40,373 --> 00:23:44,275
more energy is extracted, and
more, and more, and more. And

414
00:23:44,295 --> 00:23:47,496
eventually, the orbit of the
planet shrinks, and you end up

415
00:23:47,856 --> 00:23:48,857
with a hot Jupiter.

416
00:23:48,877 --> 00:23:52,438
That's Dr. Jamie Alvarado Montes
from Macquarie University.

417
00:23:52,978 --> 00:23:55,859
Schwab says this shows that
patterns in predictability do

418
00:23:55,959 --> 00:23:59,121
emerge when we view the progress
of celestial bodies over

419
00:23:59,261 --> 00:24:00,941
astronomical timescales.

420
00:24:01,081 --> 00:24:05,924
It's looking. For change of the
brightness in the star. And it

421
00:24:05,944 --> 00:24:09,466
finds planets by looking at
stars and checks, you know, if a

422
00:24:09,486 --> 00:24:12,287
planet goes in front of the
star, it will cast a shadow, and

423
00:24:12,287 --> 00:24:14,969
so the star goes dimmer for a
short amount of time. And this

424
00:24:14,969 --> 00:24:18,771
is exactly what we saw for the
particular star that the planet

425
00:24:18,771 --> 00:24:20,212
that we're talking about is
orbiting.

426
00:24:20,292 --> 00:24:23,213
But in the initial discovery
data, we only saw that once. So

427
00:24:23,193 --> 00:24:25,715
it's just, okay, star got
dimmer, star got brighter. We

428
00:24:25,775 --> 00:24:28,136
followed this up with a
ground-based telescope with a

429
00:24:28,156 --> 00:24:31,218
spectrometer. I had built that
spectrometer, it's called NUID.

430
00:24:31,478 --> 00:24:34,559
Mounted on the wind telescope in
Arizona, a very precise

431
00:24:34,619 --> 00:24:39,310
instrument, and that then looked
at data that revealed, oh, there

432
00:24:39,310 --> 00:24:41,683
's indeed a planet orbiting that
star.

433
00:24:43,063 --> 00:24:46,205
Once we were sure that, it's
probably a planet, we put more

434
00:24:46,225 --> 00:24:49,466
observing time behind it and
started observing it regularly,

435
00:24:49,866 --> 00:24:53,948
really get to the parameters
that the planet is having. And

436
00:24:54,168 --> 00:24:57,029
once we did this, we realized
that the planet is in a very

437
00:24:57,170 --> 00:25:00,130
unusual orbit. Normally planets
in our solar system, as you

438
00:25:00,150 --> 00:25:02,755
know, they all go around the Sun
basically in a circle, a little

439
00:25:02,795 --> 00:25:03,737
bit of an ellipse.

440
00:25:04,879 --> 00:25:07,624
In the plane that we call the
ecliptic, all in the same plane,

441
00:25:07,684 --> 00:25:11,590
they're all nice and they orbit
all nice and round. Now what we

442
00:25:11,671 --> 00:25:16,054
saw when we got more data in on
this planet, we saw that it's

443
00:25:16,234 --> 00:25:19,237
orbiting its star on a very,
very elliptical orbit. So it

444
00:25:19,257 --> 00:25:22,960
comes very close, very fast, and
it goes out, slows down, and

445
00:25:22,980 --> 00:25:26,343
comes back, goes very fast
around the star, very close by,

446
00:25:26,463 --> 00:25:28,425
goes back out very far again.

447
00:25:28,625 --> 00:25:31,527
The objects in our solar system
that do this are comets. And

448
00:25:31,587 --> 00:25:34,290
comets have this thing where
they get very close to the Sun

449
00:25:34,330 --> 00:25:37,312
on a very elliptical orbit, and
then they leave again. And we

450
00:25:37,352 --> 00:25:40,034
don't know planets in our solar
system that do this. And so

451
00:25:40,154 --> 00:25:43,576
finding one that is on an orbit
that's elliptical, that's the

452
00:25:43,656 --> 00:25:46,318
one that we are looking at, that
comes so close to the Sun and

453
00:25:46,338 --> 00:25:48,499
goes so far away again, it's
very rare.

454
00:25:48,860 --> 00:25:51,641
And when it gets very close, it
gets very hot, which is why we

455
00:25:51,661 --> 00:25:53,783
call this the hot Jupiter. And
we call it the hot Jupiter

456
00:25:53,943 --> 00:25:56,825
because the size of the planet
is about five times the size of

457
00:25:57,005 --> 00:26:00,227
Jupiter, the largest planet in
our own solar system. And it's

458
00:26:00,227 --> 00:26:03,749
an intriguing discovery that
only two planets of that mass in

459
00:26:03,769 --> 00:26:06,350
such an orbit ever discovered
this system. The second one.

460
00:26:06,350 --> 00:26:09,132
In our own solar system, we've
seen something similar with

461
00:26:09,192 --> 00:26:12,775
Pluto as it orbits the Sun at a
highly elliptical and tilted

462
00:26:12,835 --> 00:26:16,538
angle, and that's being caused
by Neptune. So that must have

463
00:26:16,538 --> 00:26:20,620
given you an idea that this was
a binary star system, and the

464
00:26:20,660 --> 00:26:24,423
second star or some other object
was affecting the orbit of the

465
00:26:24,723 --> 00:26:25,244
hot Jupiter.

466
00:26:25,244 --> 00:26:28,366
Yeah, so we would call it the
hierarchical triplet system.

467
00:26:28,546 --> 00:26:31,688
Indeed, the host star has a
companion star, and the

468
00:26:31,708 --> 00:26:34,950
companion star with its
gravitational forces... Tidal

469
00:26:35,050 --> 00:26:37,972
forces is disrupting the orbit
of that planet. You mentioned

470
00:26:37,992 --> 00:26:41,035
Pluto. Pluto, these similar
things from the gravitational

471
00:26:41,055 --> 00:26:45,318
influence of the planets further
in, Neptune and Uranus, but the

472
00:26:45,358 --> 00:26:48,280
effect on this hot Jupiter here
is way more extreme.

473
00:26:48,500 --> 00:26:51,922
Pluto is on a, for a solar
system point of view, elliptical

474
00:26:52,003 --> 00:26:54,865
orbit. But if you look at this,
if you look at from a map, it

475
00:26:54,885 --> 00:26:59,008
looks a bit like an egg and not
very, very elongated. But this

476
00:26:59,128 --> 00:27:02,250
one here is indeed very
elongated. So the effect is much

477
00:27:02,370 --> 00:27:06,013
more extreme. Hence the comet
allergy. Yeah, and it comes in

478
00:27:06,033 --> 00:27:08,875
very close to the star as well
and gets very hot which Pluto of

479
00:27:08,895 --> 00:27:09,515
course doesn't do.

480
00:27:09,795 --> 00:27:12,537
But yeah, we think, or
astronomers in general think

481
00:27:12,597 --> 00:27:15,860
that those elliptical orbits are
caused by gravitational forces

482
00:27:15,980 --> 00:27:19,362
of the other heavier bodies in
the system. In this case, a

483
00:27:19,402 --> 00:27:23,385
second smaller star that also
orbits the main star and that

484
00:27:23,706 --> 00:27:26,808
these gravitational forces,
these tidal forces throw the

485
00:27:26,848 --> 00:27:28,389
planet to such an extreme orbit.

486
00:27:28,449 --> 00:27:31,331
I like the headline. The
three-body problem. When I

487
00:27:31,371 --> 00:27:34,452
studied astronomy, the
three-body problem terrified me,

488
00:27:34,713 --> 00:27:39,935
as it does, I think, most
post-grads. This was a good test

489
00:27:39,975 --> 00:27:42,817
of that three-body problem
because you had these three

490
00:27:42,877 --> 00:27:45,458
primary masses. One of them was
being influenced by the other

491
00:27:45,498 --> 00:27:46,039
two. Yeah.

492
00:27:46,339 --> 00:27:49,521
I mean, the gravitational
interplay between those in this

493
00:27:49,821 --> 00:27:53,523
really complex, weird orbit
scenario is a complicated thing,

494
00:27:53,543 --> 00:27:58,005
and that is indeed the expertise
of Hyman, who just graduated. He

495
00:27:57,985 --> 00:28:00,706
was my student. He worked on
this. So his expertise is

496
00:28:00,766 --> 00:28:04,528
looking at how orbits develop
over time due to the

497
00:28:04,728 --> 00:28:07,289
gravitational pull of the bodies
on each other.

498
00:28:07,389 --> 00:28:09,830
My expertise is actually
building the instruments that we

499
00:28:10,090 --> 00:28:13,432
cover these with. But Heimer has
looked at the orbit and the

500
00:28:13,492 --> 00:28:16,253
orbital evolution. So we don't
think that this particular

501
00:28:16,293 --> 00:28:18,394
planet will stay in this orbit
for very long.

502
00:28:18,494 --> 00:28:22,776
We think that the orbit we see
and the fact that, you know, the

503
00:28:22,796 --> 00:28:25,877
gravitation from that second
star in the system put the

504
00:28:25,897 --> 00:28:28,538
planet on an orbit that brings
it very close to its star is...

505
00:28:28,598 --> 00:28:31,540
It's one of the mechanisms, and
this is scientifically the

506
00:28:31,560 --> 00:28:34,701
exciting part of the paper. We
think this is the smoking gun

507
00:28:34,841 --> 00:28:38,723
for the mechanism that brings
large planets close to the star.

508
00:28:38,944 --> 00:28:39,984
We have found these.

509
00:28:40,044 --> 00:28:43,886
In fact, the very first planet
orbiting a main-sequence

510
00:28:43,886 --> 00:28:47,668
solar-type star is hot Jupiter.
It's a Jupiter-like planet, a

511
00:28:47,708 --> 00:28:51,090
heavy planet with a gas
atmosphere that orbits its star

512
00:28:51,330 --> 00:28:53,732
in a very close orbit. Now,
again, we don't see this in the

513
00:28:53,752 --> 00:28:56,553
solar system, and for a while we
didn't understand how can you

514
00:28:56,573 --> 00:28:58,054
form these so close to the star.

515
00:28:58,254 --> 00:29:01,096
We actually don't think you can
make these planets very close to

516
00:29:01,116 --> 00:29:04,277
their star. It's just too hot.
It will evaporate. The material

517
00:29:04,337 --> 00:29:07,959
of the planet can form a planet
that big. And so current

518
00:29:08,019 --> 00:29:11,161
thinking is those planets form
far away from their star, and

519
00:29:11,161 --> 00:29:13,962
then something must happen that
brings them closer, called that

520
00:29:14,043 --> 00:29:14,943
orbital migration.

521
00:29:15,083 --> 00:29:19,626
And we think that we see here
the mechanism that forces this,

522
00:29:19,746 --> 00:29:22,767
that the second star in the, or
a mechanism that forces this,

523
00:29:22,807 --> 00:29:25,509
the second star in the system
puts that planet on a weird

524
00:29:25,609 --> 00:29:29,091
orbit that brings it close to
its host star. And tidal forces

525
00:29:29,131 --> 00:29:31,953
will make that orbit less and
less and less eccentric over

526
00:29:32,013 --> 00:29:33,634
time, more and more and more
around.

527
00:29:33,914 --> 00:29:38,338
And then we'll eventually end up
in a close, tight orbit around

528
00:29:38,438 --> 00:29:41,400
the primary star of the system,
being a hot Jupiter in a

529
00:29:41,600 --> 00:29:44,242
normal-looking orbit. And we see
this while it's happening. And

530
00:29:44,262 --> 00:29:48,285
so this is exciting from a
scientific standpoint because

531
00:29:48,325 --> 00:29:51,047
here we can see, okay, how does
the orbit actually look like

532
00:29:51,087 --> 00:29:51,928
while this is happening?

533
00:29:52,088 --> 00:29:55,350
And does it make sense from how
we calculate this? Three-body

534
00:29:55,410 --> 00:29:58,452
problems and how we calculate
the gravitational interaction

535
00:29:58,512 --> 00:30:01,334
between the bodies does that fit
with what we think what's

536
00:30:01,394 --> 00:30:05,236
happening when those hot
cupiders are in a way being made

537
00:30:05,456 --> 00:30:08,118
that's associate professor
Christian Schwab from Macquarie

538
00:30:08,178 --> 00:30:11,420
University and this is Space
Time.

539
00:30:27,243 --> 00:30:29,164
And time now to take a brief
look at some of the other

540
00:30:29,204 --> 00:30:32,246
stories making use in science
this week with a science report.

541
00:30:33,086 --> 00:30:36,988
Scientists have confirmed that
2024 was the world's first year

542
00:30:37,149 --> 00:30:40,270
with an average global
temperature greater than 1.5

543
00:30:40,270 --> 00:30:43,112
degrees Celsius above
pre-industrial levels.

544
00:30:43,704 --> 00:30:46,406
The findings, reported in the
journal Nature Climate Change,

545
00:30:46,446 --> 00:30:49,808
are based on two independent
studies. The authors looked at

546
00:30:49,888 --> 00:30:52,950
averages over a 20 to 30 year
period in order to allow for

547
00:30:52,990 --> 00:30:56,693
exceptionally high years. They
found that the climate data

548
00:30:56,753 --> 00:30:59,955
confirmed temperature averages
have now passed long-term

549
00:31:00,015 --> 00:31:01,276
historical thresholds.

550
00:31:01,996 --> 00:31:04,318
In the first study, the authors
found that it was likely that

551
00:31:04,318 --> 00:31:06,500
the planet is currently
somewhere in the middle of its

552
00:31:06,560 --> 00:31:11,123
first 20 years of 1.5 degree
Celsius warming. The second

553
00:31:11,163 --> 00:31:14,989
study looked at month-to-month
data. They say models show 12

554
00:31:15,009 --> 00:31:18,171
consecutive months above climate
thresholds indicate the

555
00:31:18,211 --> 00:31:20,092
threshold had already been
reached.

556
00:31:20,673 --> 00:31:24,055
Keeping planetary temperatures
below 1.5 degrees above

557
00:31:24,135 --> 00:31:27,537
pre-industrial levels was also
the primary target of the Paris

558
00:31:27,637 --> 00:31:30,799
Climate Change Agreement.
However, only two of the more

559
00:31:30,819 --> 00:31:33,701
than 100 nations which signed
that agreement have actually

560
00:31:33,781 --> 00:31:37,704
provided a progress report, and
Australia was not one of them.

561
00:31:39,348 --> 00:31:42,130
Meanwhile, Australia's Bureau Of
Meteorology has released its

562
00:31:42,210 --> 00:31:45,133
annual climate statement
summarising weather and climate

563
00:31:45,213 --> 00:31:49,436
in 2024. The report found that
last year was Australia's second

564
00:31:49,477 --> 00:31:52,919
hottest on land since records
began back in 1910 and the

565
00:31:52,959 --> 00:31:54,621
hottest year on record globally.

566
00:31:55,401 --> 00:31:58,144
Sea surface temperatures in the
Australian region as well as

567
00:31:58,184 --> 00:32:02,247
globally were also the warmest
on record. Interestingly, it was

568
00:32:02,367 --> 00:32:05,630
also Australia's eighth wettest
year on record, with overall

569
00:32:05,710 --> 00:32:07,932
rainfall 28% above the average.

570
00:32:08,524 --> 00:32:11,765
However, while rainfall was high
in the north, partly due to

571
00:32:11,785 --> 00:32:14,606
tropical cyclones early in the
year, it was much drier than

572
00:32:14,707 --> 00:32:17,948
usual in Victoria, parts of
South Australia and some parts

573
00:32:17,948 --> 00:32:21,349
of the west, leading to reduced
water storage levels in parts of

574
00:32:21,369 --> 00:32:21,949
the south.

575
00:32:22,610 --> 00:32:25,371
The report also found that
Australia's total water storage

576
00:32:25,451 --> 00:32:30,553
volume was just under 73% at the
end of 2024. That's similar to

577
00:32:30,533 --> 00:32:33,454
the previous year. And the
report also showed that

578
00:32:33,494 --> 00:32:36,455
Australia was affected by
low-intensity to severe heat

579
00:32:36,495 --> 00:32:40,837
waves during both early and
late. 2024.

580
00:32:41,057 --> 00:32:43,938
Scientists have found that the
best way to get your dog to pay

581
00:32:43,998 --> 00:32:47,299
attention to something is to
both point and stare at it at

582
00:32:47,319 --> 00:32:51,480
the same time. The authors
tracked the gaze of 20 pet dogs

583
00:32:51,520 --> 00:32:53,981
wearing eye-tracking goggles,
while their owners tried to get

584
00:32:54,001 --> 00:32:56,882
them to pay attention to a
hidden food reward using five

585
00:32:56,922 --> 00:32:57,802
different methods.

586
00:32:58,402 --> 00:33:01,543
There was pointing, pointing
plus gazing, gazing, fake

587
00:33:01,563 --> 00:33:04,996
throwing, and no action at all.
A report in the Journal Of The

588
00:33:04,996 --> 00:33:08,517
Proceedings Of The Royal Society
B found gestures shifted dogs'

589
00:33:08,537 --> 00:33:11,558
gazes towards the owner's hand,
but when combined with a

590
00:33:11,578 --> 00:33:14,779
directed gaze, their attention
then shifted towards the treat.

591
00:33:15,239 --> 00:33:17,440
The results show that a
combination of pointing and

592
00:33:17,480 --> 00:33:20,641
staring was the most effective
way to alert dogs to a hidden

593
00:33:20,721 --> 00:33:23,962
treat. Of course, accidentally
dropping something, anything

594
00:33:24,042 --> 00:33:26,222
really onto the kitchen floor,
works even better.

595
00:33:27,903 --> 00:33:31,104
Warnings about soothsayers and
witches go back thousands of

596
00:33:31,144 --> 00:33:35,278
years to biblical times. The
idea of witches as evil servants

597
00:33:35,278 --> 00:33:39,260
of Satan was ingrained in
Judeo-Christian belief. The

598
00:33:39,300 --> 00:33:42,403
Malleus Maleficarum, usually
translated as the Hammer of

599
00:33:42,443 --> 00:33:45,525
Witches, is the best-known
treatise about witchcraft, and

600
00:33:45,525 --> 00:33:48,567
often described as the ultimate
compendium of literature on

601
00:33:48,627 --> 00:33:50,608
demonology in the 15th century.

602
00:33:51,249 --> 00:33:54,031
It was written by the German
Catholic clergyman Heinrich

603
00:33:54,091 --> 00:33:58,574
Kramer in 1486. Years later, the
Puritans took their biblical

604
00:33:58,654 --> 00:34:01,616
views to colonial America and
the village of Salem.

605
00:34:02,244 --> 00:34:05,006
The Salem witch trials were the
most famous flashpoint,

606
00:34:05,126 --> 00:34:08,988
culmination of religious
extremism, xenophobia, social

607
00:34:09,048 --> 00:34:13,410
divides and rivalries between
settlers. But as Tim Mendham

608
00:34:13,490 --> 00:34:16,572
from Australian Skeptics points
out, ties to witchcraft and the

609
00:34:16,632 --> 00:34:19,093
supernatural are common
throughout the world.

610
00:34:19,393 --> 00:34:24,716
Obviously, the big witchcraft,
witch trials in the 1700s or

611
00:34:24,756 --> 00:34:27,598
something in Salem,
Massachusetts, became a hysteria

612
00:34:27,638 --> 00:34:29,539
there. Everyone was blaming
everyone else. Everyone was

613
00:34:29,559 --> 00:34:31,760
accusing everyone else of being
a witch and therefore... Sort of

614
00:34:31,760 --> 00:34:32,860
people did get punished.

615
00:34:33,240 --> 00:34:37,122
The burning of witches in
history is actually a lot less

616
00:34:37,182 --> 00:34:40,042
common than people often think
it to be. In the period of James

617
00:34:40,183 --> 00:34:43,644
I Of England, which was, what,
the early 1600s, there was a

618
00:34:43,684 --> 00:34:45,544
witch finder general and all
this sort of stuff, and there

619
00:34:45,544 --> 00:34:48,025
were stories coming out of so
many witches executed.

620
00:34:48,025 --> 00:34:50,606
Well, there was a book, wasn't
there, that helped you find

621
00:34:50,666 --> 00:34:52,726
witches, and who is a witch, and
who...

622
00:34:52,846 --> 00:34:55,487
Yeah, that's right, that's
right. There was the various

623
00:34:55,527 --> 00:34:57,568
books that were around at the
time, but, I mean, there were

624
00:34:57,668 --> 00:35:00,369
fewer people actually punished.
For being witches than the

625
00:35:00,429 --> 00:35:03,030
historical image would suggest.
And the same is actually Salem.

626
00:35:03,070 --> 00:35:06,172
There was a few people involved,
but it became a classic story of

627
00:35:06,332 --> 00:35:06,812
witchcraft.

628
00:35:06,852 --> 00:35:10,054
Then you get alternatives to
witchcraft like voodoo and that

629
00:35:10,094 --> 00:35:11,815
sort of thing, which you
obviously find in different

630
00:35:11,855 --> 00:35:15,757
areas. You find it in New
Orleans with a lot of Cajun and

631
00:35:15,897 --> 00:35:18,839
Caribbean sort of religions and
philosophies and those sort of

632
00:35:18,839 --> 00:35:22,561
places. And they have witchcraft
and sticking pins in dolls and

633
00:35:22,541 --> 00:35:24,942
all that sort of stuff. So there
are various places you can go to

634
00:35:24,922 --> 00:35:27,824
in America to find out about
ancient or historical

635
00:35:27,884 --> 00:35:28,344
witchcraft.

636
00:35:28,464 --> 00:35:32,085
And existing current witchcraft.
Witchcraft is white witches, of

637
00:35:32,105 --> 00:35:35,726
course, who supposedly do good,
and there's the wise women or

638
00:35:35,746 --> 00:35:38,767
wise woman sort of concept of
someone you go see for advice,

639
00:35:39,047 --> 00:35:41,828
whether it's herbal advice or
whether it's a potion or

640
00:35:41,868 --> 00:35:44,649
something like that. The image
of a witch is like someone who's

641
00:35:44,669 --> 00:35:47,669
associated with Satan and flying
broomsticks and that sort of

642
00:35:47,669 --> 00:35:47,829
thing.

643
00:35:47,849 --> 00:35:49,450
We can go to Leviosa.

644
00:35:50,186 --> 00:35:53,327
But the idea of a satanic witch
is more story than, well,

645
00:35:53,407 --> 00:35:56,228
actually is story, rather than
reality. And the number's a lot

646
00:35:56,308 --> 00:35:59,729
lower than you think of than you
would be told in the movies. But

647
00:35:59,789 --> 00:36:01,830
you can travel any place in the
world, you'll probably find

648
00:36:01,870 --> 00:36:04,711
examples of witchcraft.
Australia has very few, as far

649
00:36:04,711 --> 00:36:05,211
as I know.

650
00:36:05,371 --> 00:36:07,212
Some of these people are just
called witches because they're

651
00:36:07,212 --> 00:36:09,412
rather unpleasant, not because
they do anything particularly

652
00:36:09,452 --> 00:36:12,753
magical. But it's one of the
examples of things that are a

653
00:36:12,833 --> 00:36:14,814
nice myth, a nice sort of
legend, a nice...

654
00:36:14,998 --> 00:36:18,600
Story which is supported by
media in one form or another to

655
00:36:18,620 --> 00:36:21,921
make it sound more exciting and
more prevalent in most cases a

656
00:36:22,182 --> 00:36:27,464
witch or as you know wise woman
was a pretty dull situation was

657
00:36:27,484 --> 00:36:30,206
a woman who realized that if you
had willow bark you could

658
00:36:30,366 --> 00:36:33,807
relieve pain with that and
things like yeah therefore yeah

659
00:36:33,847 --> 00:36:36,048
most witches are pretty mundane
if you can call them witches at

660
00:36:36,048 --> 00:36:39,090
all that's Tim Mendham from
Australian skeptics.

661
00:36:54,742 --> 00:36:58,283
And that's the show for now.
Space Time is available every

662
00:36:58,364 --> 00:37:01,845
Monday, Wednesday, and Friday
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663
00:37:02,145 --> 00:37:06,527
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664
00:37:06,787 --> 00:37:10,869
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665
00:37:10,949 --> 00:37:13,470
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666
00:37:13,550 --> 00:37:15,611
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667
00:37:16,371 --> 00:37:18,892
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668
00:37:18,932 --> 00:37:22,893
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669
00:37:23,014 --> 00:37:23,834
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670
00:37:24,522 --> 00:37:27,505
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671
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673
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675
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