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Pliny
"What is outside does not concern men to explore and is not within the grasp of the human mind to guess."

"That certain persons have studied, and have dared to publish, its dimensions, is mere madness"

"On summer days the sun approaches nearer to the top of the world owing to a narrow circuit of light the underlying parts of the earth have continuous days for six months at a time, and continuous nights when the sun has withdrawn in the opposite direction towards winter. Pythias of Marseilles writes that this occurs in the island of thule, six days voyage north from Britain

Pluto and Charon
Diascovery of the Kuiper belt pushed the concept of a pluto mission to #1 in the planetary decadal survey

Kuiper airborne Observatory; stellar occultaion prediction, atmosphere

Nitrogen, methane carbon monoxide triple point

Tectonic lumps in Charon, charon got bigger, freezing

volcanic activity in southern hemisphere, how?

water does not erupt above ice, but water mixed with 30 percent ammonia does

concentration of ammonia by water freezing first

orbt plane edge on, like saturn rings, twice every Pluto orbit, once every 124 years

transit light curve produced first map of pluto bright poles, dark equatorial band

icy surfaces do not remain bright in the Solar System; could they be evaporating and refreshing themselves in an atmosphere?

high axial tilt, arctic seasons

leaving perihelion, atmospheric pressure increasing, arctic summer

Powered by plutonium, some russian plutonium because Los Alamos was shut down due to an information breach.

1988: Alan stern suggests Pluto mission (all graduate students)

The hemisphere viewed by NH was not the hemishphere mapped by charon occultations, the charon-trailing hemisphere was caught as NH left, B+

CO, HCN observed by Alma

flowing nitrogen ice glaciers

glacial mountains or icebergs? ice floats in frozen nitrogen

wind streaks

hexagonal convection cells

heat flow 2-3 mW per square metre (modelled typical radiogenic material)

temperature ice base vs surface (400-600 m thick then convection is possible)

no craters

larger towards the centre

Sputnik planum is perhaps an impact crater filled with ice.

Rockies/Alps sized mountains

wright mons, a shield cryovolcano? Only one crater on the side

Pluto's tropical zone is wider than its arctic zone, and there is a tropical/arctic overlap region unlike anywhere on Earth

dark eqatorial band likely due to comprising Pluto's diurnal zone; it never has a long enough winter to gather up ice

models of Pluto's obliquity over millions of years suggest that Pluto may experience "superseasons" similar to Earth's ice ages, during which atmospheric pressure may approach martian levels

liquid nitrogen flow channels?

light->dark corresponds to crater count UV tholin formation means darker- older

charon, craterpoor likely due to tidal disruption early in the solar system

stain of tholin on the pole due to methane capture from Pluto's atmosphere

pock marks caused by sublimation?

sputnik could have formed from an impact, filled in from a subsurface ocean

ice plain is facing away from charon aligned with the tidal axis

cthulhu macula, the whale, part of the dark equatorial band

the heart has far fewer craters

mountains topped with methane snow

tartarus dorsa, mountains

On jul 4 2015, ten days before flyby, the team lost contact with New Horizons

Deep Space Network

The computer had been overloaded, requiring a huge number of programs to be reinstalled. Everything had to be perfect.

They needed weeks; they had days.

Alan Stern wrote a 130 page book to be declared an accredited journalist so he could receive flight plans from NASA.

Charon would pass in front of Pluto for a few years starting in the mid-eighties

allowed to map surface features and colors

Voyager 1 could have visited Pluto, but had to give that up to visit Titan

1988: Stern began to ponder the mission to Pluto.

needed support within NASA

Pluto was never a priority for the NASA policy committees.

Pluto= Methane, Charon=Water

haze layers in the atmosphere

American Geophysical Union (AGU)

AGU Pluto technical session May 1989

dinner at an italian restaurant evening after the session

Alan and 14 other scientists began to chat about what it would take

No mission was on the drawing board

Mars people, Venus, Cassini, comet sample return

Only two new planetary missions had commenced in the 1980s

They didn't call it lobbying

Pluto Underground (Mars Underground) more fitting?

galileo, broken cassini, overbudget. "Christmas trees"

smaller, cheaper, more directed missions

Pluto 350: First proof of concept: 15 years in space, flybys of Earth and Venus (requiring hardening for the inner region)

Science questions posed to the SSES

Pluto vs Triton?

Is it as varied as it seems?

ices a coating or a crust?

internally active?

seasonal variation?

darkest on the side facing charon?

why binary?

Pluto flyby ranked as a highest ranked candidate for the 1990s

"Not Yet Explored" stamp Oct 1991

JPL, pluto fast flyby 35 kg 2 instruments 7 years SSES deemed too skimpy

Dan Goldin, appointed 1992, faster better cheaper (FBC) but had unrealistic expectation

Rob Stehle could game the system as well as Alan Stern- he cornered Dan Goldin at a ceremony at the Academy to return an Oscar carried on the Space Shuttle

Goldin fired people often, so people seldom said no to him

350 was dropped for Fast Flyby

"development miracles" SESS woud see it as too incapable

staelhe realised he could not create a viable craft at less than 100 kg

400 m to 1 billion dollars

Goldin felt betrayed by the Pluto community, despite the fact that most in the Pluto community favoured 350

the expensive mars observer blew up in 1994, and served as the basis for FBC

With Mars the focus, Pluto was placed on the back burner. Any mission had to be less than $400 million

Alan then decided to turn to Russia for help, opening negotiations with them without permission

The Russians demanded a probe of their own to land on Pluto and sample its atmosphere

Then the Russians demanded a cost to the launch, which was technically illegal- Americans could not pay Russians for launches. So the Germans had to pay, and they demanded their own probe be added, to be dropped off at jupiter

The DOD refused to put an atomic powered engine on a Russian rocket

Goldin always gave money to study Pluto, but never gave money for a mission, keeping them in a holding pattern

"do it without nuclear power".

1996 Stern began to ponder if Goldin was toying with them

On the number of planets in the outer solar system" Stern 1991

Kuiper belt 1992

Pluto wasn't a curiosity, it was a sample of a new region of the Solar System

Pluto Kuiper Express

SDT: Science Definition Team, it signaled that NASA was serious about Pluto

A year to plan the case and the instrumentation

1998: New NASA director, Ed Wyler was not a Plutophile

Alan Stern recruited Eugene Shoemaker, the founder of the field of planetary geology

2000: Wyler became frustrated with budgets that constantly ballooned, and ordered a stop work order on all Pluto studies.

Declared Pluto mission studies dead.

goldin backed Wyler

Stern and the Underground started again, selling the idea to the public. People were infuriated

Jupiter gravity assist required a mission before 2007

Pluto getting farther and farther away from perihelion, and cooling, potentially losing its atmosphere

APL (Johns Hopkins) was emerging as a competitor to JPL

jPL had added unnecessary shielding to the PKE, doubling its costs (Jupiter encounter was pushed to Europa standard, even though it would not come anywhere near as close

Strern cajoled the Planetary Society into another letter writing campaign

Ted Nichols, a 17 year old, started a website and went to NASA headquarters himself, being grilled by burocrats who assumed someone had put him up to it

APL kept manager numbers down. their first interplanetary mission, NEAR, exceeded its mission goals, was under budget and ahead of schedule.

November 29 2000: Costed proof of concept delivered to NASA

Proposals for a $750 million mission were due on Mar 21st

After Alan's years leading the team for Pluto, both labs wanted him to lead the mission team

JPL promised to fight for the mission if it fell into political trouble; JPL refused

Waking in the night, Stern decided to go with the untested APL, even though it would likely render him persona non grata at JPL for the rest of his life

Having backed his team, Stern had to walk a knifedge between overreach and underreach

Feb 2001: Bush administration zeroed all funding for a Pluto mission, choosing Europa. Did JPL have a hand in it?

Thanks to an in with the senator for maryland, APL were able to remind NASA that they didn't actually have the authority to cancel missions, congress did. Suddenly the competition was back on

Lorri could obtain images 5 times beyond what NASA required, resolutions good enough to spot features the size of buildings

10 weeks on approach and ten weeks on departure, Lorri would have images better than hubble

32 times the data that PKE had promised

Hibernation was a planned factor in the mission, for the first time ever, cutting costs

antenna ten times less powerful than voyager. this would only increase the download time to Earth

Every science goal had two instruments, to ensure redundancy should one fail

Four teams presented proposals; NASA reviwed them for 2 months

It came down to APL vs JPL

JPL had a heavier craft, and had to cut a stage from the rocket to save costs, leading to a longer flight time

With eleven instruments, JPLs was a christmas tree

Wyler made the win conditional; move to Jan 2006, the last window for Jupiter assist, and said that not only would the budget have to be kept down, but they would have to meet nuclear launch approval.

And yet, New Horizons would be cancelled again by the Bush Administration. It was only reinstated if they could prove that it was top in the decadal survey, and they couldn't take part in the survey, even though backers of rival missions could.

Many NASA offiicals still wouldn't back New Horizons, preferring a mission to Europa.

JPL tried to sneak on a 300 million ion drive. Scherezade.

Hubble was the only telescope that could definitely locate moons of Pluto

in the 90s Stern had calculated that the P/C system had multiple stable orbits

Hal Levison discovered two new moons wtih Hubble

One of the instrumemnts on Hubble shorted out, and so all scheduled observations with that instrument were cancelled

NASA complained about the two weeks of Hubble time, but the team responded that NASA had demanded the mission extension in the first place.

The spacecraft went into safe mode thanks to an unforseen command overload; the reboot required weeks of work be conducted in three days, since core observations began on jul 7

Larry Esposito, Stern's competitor for the Pluto contract, was there, and so was Rob Stahele

Marc Buie performed the study of Pluto's surface during the charon occultations

Pluto's mantle is frozen water

Sputnik Planetia lies 3-4 km below the surrounding highlands

early impact basin

pattern reminiscent of convection cells

half a million years turnover

frozen nitrogen flows slowly pits on surface

Water ice is less dense than nitrogen ice; mountains jutting out of the sea may be icebergs

nitrogen glaciers and earthlike morrains can be seen in the surrounding mountains

subsurface ocean? Sublunr point; closer to the surface due to impact, gravity reorient may have resulted in mutual lock

cthulhu regio has a high density of craters, indicating age, mountains topped with methane snow

the material covering pluto is densest in the deep red regions

Piccard Mons and Wright Mons appear to have volcanic craters, and may be cryovolcanoes

the geological processes appear to move in slow motion compared to earth

ebcause pluto is on its side, the pole (which acts as an equator) is poor in nitrogen

more volatile ices mask the water bedrock, as they are more likely to rise into the atmosphere and then refreeze

pluto has blue skies

a temperature inversion, or layer of colder air, lies near the surface

ethylene, acetylene and ethane were found in the atmosphere as the sunlight passed through it

the temperature at the top of the atmosphere was unexpectedly cold, meaning the atmospheric escape was slowed by a factor of 10 thousand

astronomers predicted the "comet head" of Pluto's atmosphere to lie at 20 Rpl; instead it was at just 6 rpl, a consequence of low rate atmospheric escape

the tail extended to 400 rpl

the venetia Burney student dust counter

advanced students at the university of colorado

Pushed for by stern

despite fears of a collision, only a single dust particle was observed by the SDC during the flyby

1.2 particles per cubic km

Charon, deeply cratered anceint

Mordor macula, impact crater, tinted orange

vulcan planum, younger, possibly cryovolcanic lava flow

ancient resurfacing,when charon still had internal heat

hexagonal, possibly a mark of early heating

tinged with ammonia

ammonia molecules do not last in ultraviolet

replaced from the interior?

small satellites also contain water and ammonia, kindred spirits of an impact?

crater counts on satellites suggest 4 billion year age

MU69
early telescope images from occultations (adided by gaia) suggested it was a "double", though whether it was a binary, a contact binary, or a potato was not known cold classical

bilobate body; low velocity impact, little deformatin high albedo "collar" at "neck"

formed in same area, so same relative velocity

streaming instability

pits on the terminator, not likely to be craters since in a line (sublimation? collapsed pits?) gignerbread man

color expected for a cold classical

Herschfeld
crown was intended for a deity

must determine if the gold had been cut with silver without defacing it

water is displaced by volume, not mass. Equivalent volume of pure gold would displace less water

May have developed a planetarium and a mechanical model of the universe

moved a fully laden ship with a system of pulleys; after which Heiron made an official decree that Archimedes was to be believed in everything he said.

archimedes screw archimedes principle

one of the first people to unify mathematics and science

pure mathematics was his first love

Archimedes ("master of thought") may be an honorific rather than a name

absent minded professor

Friend of Heiron I of Syracuse

"forget his food and neglect his person, to the degree that he was occasionally had to be carried with absolute violence to bathe or have his body anointed." While being bathed, he would trace geometric circles with the soap and in the ashes of the heating fire.

Despite his supposed engineering miracles, he made no references to them himself, preferring more rarefied pursuit.

greek culture revolved around devotion to gods, but Archimedes makes no reference to any gods in his works

Syracuse was founded 5 centuries before Archimedes' birth, yet was very much a Greek city. Archimedes writes in a doric dialect

Because it acted as a barrier between Greek civilization and the earlier Phonecean civilization of carthage, Syracuse was noted for its large military

Aristarchus said that "The distance to the stars is to the diameter of Earth's orbit what the surface of a sphere is to its centre"

Archimedes interpreted this as "the distance to teh stars is to the diameter of Earth's orbit what the diameter of Earth's orbit is to the diameter of the Earth"

overestimated the diameter of the Earth at 1 million stadia (eratosphenes calculated 250,000 stadia (correct)

radius of orbit: No more than 10,000 earth diameters

25th to a 40th a finger width (poppy seeds, not sand grains)

To perform the crown measurement would have required a level of precision unavailable at the time (Galileo 1586)

The Syracusia weighed 2000 tons and was said to contain a library and a gymnasium, as well as a floor mosaic depicting the entire plot of the Iliad. Intended as a gift for the Greek king of Egypt

Archimedes levered it into the sea

Heiron II 263 BC one year into first punic war, sided with Rome over Carthage, leading to decades of peace

Heiron had gained power without wealth or military advantage, and without bloodshed

After the Battle of Cannae, pressure to side with Carthage mounted, leading to a Civil War and victory for the Carthage faction.

His most effective strategy was to employ multiple catapults with multiple ranges, thus ensuring that ships were continuously barraged no matter how close their approach.

Archimedes was said to have focused sunlight with mirrors to burn the sails of ships; whether this was physically possible has been debated for millennia

archemedes claw, a crane-like structure that could lever a ship's bow out of the water

Plutarch "began to wonder if they were fighting the gods" (no visible operators)

Unfortunately, Syracuse overplayed their hand; shortly after the battle, it held the Festival of Artemis and, in a bit to raise morale, everyone was given free wine, including the guards. Upon being informed of this by a Syracusian deserter, the Romans basically walked in.

Quite rationally, the Roman General, Marcellus, had ordered Archimedes life be spared in the sack of the city. Unfortunately, he was not. "Do not disturb my circles"

ifrah
Latin uses declensions for numbers below 5; after that, the numbers do not decline

the five barred gate (other tally marks)

the number 10,000 itself

Dijksterhuis
"From this day forth Archimedes is to be believed in everything he might say"

Questions
mass vs volume: Archimedes' principle what exactly does the planck length measure? Linde and vanchurin: universes or regions of the same universe? Apollonius given 24 greek letters

1989: before Voyager 2 arrived at Neptune, S Alan Stern, a fresh postdoc, approached Geoffrey Briggs, the head of NASA's Solar System Exploration Division

Briggs advised him to come back with a plan for goals vs costs

Pluto was crossing teh Milky way, making earth observations difficult

Tombaugh Regio, Sputnik Planum, nitrogen ice sea

regio pitted with sublimation pits and deformed by solid nitrogen flow

convection cycle half a million years

water ice peaks may be broken icebergs trapped in the nitrogen ice (water is less dense than frozen nitrogen

gravitational field measurements of the impact region of sputnik planum have suggested that Pluto has a liquid water mantle

gravity cannot explain pluto's geological activity- pluto charon are tidelocked

possibly radioactive decay?

MACHO-1997-BLG-41 Carina Nebula Rho Cassiopeiae Microlensing

Ogle
Unknown stable elementary particle(s) beyond the Standard Model of Particle Physics, so-called Weakly Interacting Massive Particle(s) (WIMP), have been thought of as a viable candidate of DM, but has yet to be detected either in direct experiments, collider experiments or indirect searches

are alternative viable candidate of DM

Microlensing is the most robust, powerful tool among various methods to probe a compact, macroscopic DM in the Milky Way

unless 10^-16 to 10^-11 solar masses, unlikely to be dominant dm if narrow mass spectrum

can directly probe mass (gravity strength) of a lensing object irrespective of whether a lensing object is visible or not

The Optical Gravitational Lensing Experiment (OGLE [63]) collaboration [41, 42] has been making invaluable long-term efforts, more than a decade, to make monitoring observations of million stars in the Galactic bulge fields. The OGLE team has been finding more than two thousands of microlensing events and obtained various constraints on exoplanetary systems, brown dwarfs, low-mass stars as well as presented even an indication of free-floating planets in inter-stellar space [43] [also see 44, 45, for the similar constraints from the MOA microlensing experiments].

The ultrashort-timescale events indicate Earth-mass “unbounded” (wide-orbit or free-floating) planets [43, 45]. However, the origin of such free-floating planets is poorly understood because it involves complicated physics ofstar formation, planetary system formation and interaction of planetary system with other stars planets. Hence we pay a particular attention to a possibility of whether PBHs can give an alternative explanation of the ultrashort-timescale events.

Clesse
after the detection of sev0eral black hole mergers by Advanced LIGO/VIRGO since September 2015 [4–7]: the possibility that Dark Matter could be constituted in part or entirely by Primordial Black Holes (PBH).

being non-luminous, non-relativistic and nearly collisionless.

mergers involving a PBH of mass mA ' 5 M� and a PBH with a mass smaller than the Chandrasekhar mass, 1.4 M�, which would be a clear indication of primordial origin. 200 mpc from earth

they have initially low spins that can only be enhanced by very rare mergers or by matter accretion.

BH have a stellar origin, conservation of angular momentum typically implies large spin values after contraction, eventually sped up by a subsequent accretion phase of a companion star

In June 2017, LIGO announced the detection of GW170104. It has been possible to reconstruct with good confidence the spin orientation of the heaviest black hole. It has been found to be anti-aligned with the orbital angular momentum and this led LIGO to claim for the discovery of a new population of black holes forming binaries through a capture process, just as expected for PBH.

microlensing across Andromeda dark matter halo, unlikely to be all stars

of any type of compact objects with masses in the range 0.05M� <∼ M <∼ 0.45. Such abundance is in strong tension with the expected stellar component within the lens galaxies, and so these observations point towards an important MACHO component.

MACHOs and WIMPs

Hawking
10 micrograms minimum (planck length radius) stellar mass black hole formation

Unwin and Scholz
While all three scenarios are unlikely, they are still favourable compared to the chance alignment of TNOs (acc. brown/bat)

The prospect of a planet forming near Uranus and Neptune before being scattered to its present orbit is low since in order to fall into a stable orbit the planet would need to be appropriately influenced by a passing star (or another mechanism)

We will argue that while there is a low probability of capturing an Earth mass PBH, it is no more improbable than capturing an FFP of similar mass.

We assume that the PBH velocity distribution is the same as the DM velocity distribution given by the Standard Halo Model. The local density of PBHs is related to the local DM density and the fact that PBHs comprise a fraction fPBH of this loca#l density

In case of the in situ formation, at a ∼ 500 AU there is typically insufficient time and material to build an Earth mass planet [26–28]. The prospect of a planet forming near Uranus and Neptune before being scattered to its present orbit is low since in order to fall into a stable orbit the planet would need to be appropriately influenced by a passing star (or another mechanism) [4, 29].

We find that the rates are comparable and thus conclude that the probability that an FFP is gravitationally captured by the Solar System in ambient space is roughly comparable to capturing a 5M⊕ PBH with fPBH ∼ 0.05.

if one is willing to entertain that the possibility that the TNO orbits indicate a captured planet, it is plausible that the gravitational source in the outer Solar System could instead be a PBH (once we establish evidence for such a PBH population)

OGLE [6] indicates fPBH � 1. If the rest is taken up by the DM component, PBHs accrete dense DM microhalos. This is fortunate since DM annihilation provide a potential detection route and in the absence of DM it would be likely impossible to detect an M⊕ PBH in the Solar System

Indeed, for a non-negligible fPBH and DM with a thermal crosssection hσvi0 ∼ 3×10−26cm3/s (i.e. classic WIMP DM) the other PBHs surrounded by DM give a diffuse gamma ray flux that is strongly excluded

On its own, a PBH of mass 5M⊕ has a Hawking temperature of 0.004 K, making it colder than the CMB, and since it’s radius is rBH ∼ 5 cm

Planet nine hypothesis
https://arxiv.org/pdf/1902.10103.pdf

In addition to period commensurability, the angular orbital elements must have the proper form so that the relevant resonance angle (a Fourier harmonic of the gravitational potential, also called a “critical argument”) oscillates (or “librates”) around a particular value, instead of steadily increasing or decreasing its value (a regime known as “circulation”).

KBOs residing on resonant orbits generally experience coherent exchange of orbital energy and angular momentum with Neptune, and can be long-term stable even at high eccentricities, thanks to a phaseprotection mechanism that allows KBO orbits to overlap the orbit of Neptune without being rapidly destabilized by close encounters

Drawing on the fact that these resonances are densely populated, Malhotra (1995) demonstrated that Neptune likely formed much closer to the sun, and must have experienced long-range outward migration, capturing resonant KBOs along the way. Subsequent characterization of resonant dynamics in the Kuiper belt further revealed that Neptune’s migration must have had a stochastic component, and likely occurred during a transient period of dynamical instability experienced by the outer solar system

The broader class of classical KBOs is often divided into dynamically ‘cold’ and ‘hot’ sub-populations, 11 where the distinction is based on their orbital inclinations, which show a bimodal distribution

First, such objects cannot be generated simply through interactions with Neptune, and require an additional source of external gravitational perturbations (Morbidelli and Levison, 2004). Second, because the orbital evolution of such objects is not contaminated by chaotic interactions with Neptune, they provide a particularly intelligible probe of dynamical evolution that unfolds in the far reaches of the solar system

we will refer to the population of objects with q 6 30 AU and a > 30 AU as Centaurs, although we note that a more general definition also includes objects with semi-major axes in between the giant planets

as the structure of the trans-Neptunian region came into sharper focus a little over a decade ago, the hitherto conventional, in-situ formation narrative of the solar system (e.g. Cameron 1988; Pollack et al. 1996) was gradually replaced with a strikingly dynamic evolution model, wherein the giant planets are envisioned to have formed closer to the sun and subsequently scattered onto their current orbits during a transient period of instability

Counterintuitively, a lower mass Planet Nine is brighter owing to its requirement for a smaller heliocentric distance to have the same dynamical effect.

Opik, E. J. 1932, ¨ Note on Stellar Perturbations of Nearby Parabolic Orbits. Proc. Amer. Acad., Arts Sci., 67, 169182

Oort, J. 1950, The Structure of the Cloud of Comets Surrounding the Solar System anda Hypothesis Concerning its Origin, Bull. Astron. Inst. Netherlands, 11, 91110

to the boundary specified by galactic tides (∼ 104−5 AU)

It is important to recognize that this model of Planet Nine formation must necessarily involve a two-step process. This is because outward scattering of Planet Nine facilitated by the giant planets places it onto a temporary, high-eccentricity (q ∼ 5 AU) orbit, which must subsequently be circularized (thus lifting its perihelion out of the planet-forming region) by additional gravitational perturbations arising from the cluster.

The difficulty with this scenario, however, is that the likelihood of producing the required orbit for Planet Nine is low. Li and Adams (2016) estimated the scattering probability for this process by initializing Planet Nine on orbits with zero eccentricity and semi-major axis a ≈ 100 − 200 AU, and found that stellar fly-by encounters produce final states with orbital elements a = 400−1500 AU, e = 0.4−0.9, and i < 60 deg only a few percent of the time. We note however, that the calculations of Brasser et al. (2006, 2012) obtain considerably more favorable odds of decoupling a scattered planetary embryo from the canonical giant planets and trapping it in the outer solar system, with reported probability of success as high as ∼ 15%, depending on the specifics of the adopted cluster model.

One limiting factor is that the scattering encounter must be sufficiently distant so that the cold classical population of the Kuiper Belt (which is likely primordial; Batygin et al. 2012) is not destroyed.