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Error code: DatasetGenerationError
Exception: CastError
Message: Couldn't cast
id: string
area: string
subject: string
area_title: string
subject_title: string
section: string
register: string
half: string
source_file: string
messages: list<item: struct<role: string, content: string>>
child 0, item: struct<role: string, content: string>
child 0, role: string
child 1, content: string
prompt_source: string
n_turns: int64
n_chars: int64
est_tokens: int64
text: string
to
{'id': Value('string'), 'area': Value('string'), 'subject': Value('string'), 'area_title': Value('string'), 'subject_title': Value('string'), 'section': Value('string'), 'register': Value('string'), 'half': Value('string'), 'source_file': Value('string'), 'text': Value('string'), 'n_chars': Value('int64'), 'est_tokens': Value('int64')}
because column names don't match
Traceback: Traceback (most recent call last):
File "/usr/local/lib/python3.14/site-packages/datasets/builder.py", line 1816, in _prepare_split_single
for key, table in generator:
^^^^^^^^^
File "/src/services/worker/src/worker/job_runners/config/parquet_and_info.py", line 613, in wrapped
for item in generator(*args, **kwargs):
~~~~~~~~~^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.14/site-packages/datasets/packaged_modules/json/json.py", line 343, in _generate_tables
self._cast_table(pa_table, json_field_paths=json_field_paths),
~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.14/site-packages/datasets/packaged_modules/json/json.py", line 132, in _cast_table
pa_table = table_cast(pa_table, self.info.features.arrow_schema)
File "/usr/local/lib/python3.14/site-packages/datasets/table.py", line 2369, in table_cast
return cast_table_to_schema(table, schema)
File "/usr/local/lib/python3.14/site-packages/datasets/table.py", line 2297, in cast_table_to_schema
raise CastError(
...<3 lines>...
)
datasets.table.CastError: Couldn't cast
id: string
area: string
subject: string
area_title: string
subject_title: string
section: string
register: string
half: string
source_file: string
messages: list<item: struct<role: string, content: string>>
child 0, item: struct<role: string, content: string>
child 0, role: string
child 1, content: string
prompt_source: string
n_turns: int64
n_chars: int64
est_tokens: int64
text: string
to
{'id': Value('string'), 'area': Value('string'), 'subject': Value('string'), 'area_title': Value('string'), 'subject_title': Value('string'), 'section': Value('string'), 'register': Value('string'), 'half': Value('string'), 'source_file': Value('string'), 'text': Value('string'), 'n_chars': Value('int64'), 'est_tokens': Value('int64')}
because column names don't match
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "/src/services/worker/src/worker/job_runners/config/parquet_and_info.py", line 1369, in compute_config_parquet_and_info_response
parquet_operations, partial, estimated_dataset_info = stream_convert_to_parquet(
~~~~~~~~~~~~~~~~~~~~~~~~~^
builder, max_dataset_size_bytes=max_dataset_size_bytes
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
)
^
File "/src/services/worker/src/worker/job_runners/config/parquet_and_info.py", line 948, in stream_convert_to_parquet
builder._prepare_split(split_generator=splits_generators[split], file_format="parquet")
~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.14/site-packages/datasets/builder.py", line 1683, in _prepare_split
for job_id, done, content in self._prepare_split_single(
~~~~~~~~~~~~~~~~~~~~~~~~~~^
gen_kwargs=gen_kwargs, job_id=job_id, **_prepare_split_args
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
):
^
File "/usr/local/lib/python3.14/site-packages/datasets/builder.py", line 1869, in _prepare_split_single
raise DatasetGenerationError("An error occurred while generating the dataset") from e
datasets.exceptions.DatasetGenerationError: An error occurred while generating the datasetNeed help to make the dataset viewer work? Make sure to review how to configure the dataset viewer, and open a discussion for direct support.
id string | area string | subject string | area_title string | subject_title string | section string | register string | half string | source_file string | text string | n_chars int64 | est_tokens int64 |
|---|---|---|---|---|---|---|---|---|---|---|---|
1faf678cbc397cb8 | astronomy_space | astrobiology | Astronomy and Space | Astrobiology | The Origin of Life and What Life Requires | prose | mtp | astronomy_space/astrobiology.txt | ## The Origin of Life and What Life Requires
Astrobiology asks whether life exists beyond Earth, and every part of the question depends on
premises drawn from a single example. This is the field's defining epistemic problem: with a sample
size of one, it is impossible to distinguish the requirements of life in general... | 497 | 134 |
93897bf8a71e354a | astronomy_space | astrobiology | Astronomy and Space | Astrobiology | The Origin of Life and What Life Requires | prose | mtp | astronomy_space/astrobiology.txt | What appears genuinely general is a short list. Life requires a source of free energy maintaining
a system away from thermodynamic equilibrium, a medium in which chemistry can occur, and a set of
elements capable of forming complex structures. Carbon's capacity for stable four-bonded chains and
rings is unusual and not... | 630 | 170 |
4adf485ac77f787c | astronomy_space | astrobiology | Astronomy and Space | Astrobiology | The Origin of Life and What Life Requires | prose | calib | astronomy_space/astrobiology.txt | The origin of life on Earth occurred early — within a few hundred million years of conditions
permitting it — which is suggestive but not conclusive about how likely the transition is. The
major open questions concern the sequence: whether metabolism or replication came first, where the
energy gradient was, and how the... | 582 | 157 |
93cde860ab609448 | astronomy_space | astrobiology | Astronomy and Space | Astrobiology | The Origin of Life and What Life Requires | table | calib | astronomy_space/astrobiology.txt | Requirements and origins:
the sample-size problem one example; requirements and contingencies are
confounded
free energy a gradient maintained away from equilibrium
a solvent water on Earth; ammonia and hydrocarbons as alternatives
complex chemistry carbon's four-b... | 1,216 | 328 |
fe8b47b5351e7355 | astronomy_space | astrobiology | Astronomy and Space | Astrobiology | The Origin of Life and What Life Requires | qa | mtp | astronomy_space/astrobiology.txt | Q: Searches for life often target liquid water specifically. The strongest justification is:
A. Life requires water as a matter of physical law
B. Water is an excellent solvent with unusual properties, it is abundant, and it is what our only
known example uses — so it is the best-motivated search target, though not ... | 699 | 188 |
647c12a0763aba5a | astronomy_space | astrobiology | Astronomy and Space | Astrobiology | Habitability and Extreme Environments | prose | mtp | astronomy_space/astrobiology.txt | ## Habitability and Extreme Environments
The habitable zone is defined as the orbital range where a planet with an Earth-like atmosphere
could sustain liquid water at its surface. It is a useful first filter and it is much narrower than
the actual range of habitable conditions, because it considers only surface water ... | 458 | 123 |
5f080755ad052ae0 | astronomy_space | astrobiology | Astronomy and Space | Astrobiology | Habitability and Extreme Environments | prose | calib | astronomy_space/astrobiology.txt | Stellar type shapes habitability substantially. Small cool stars are the most numerous, have very
long lifetimes, and place their habitable zone close in, which makes planets there easier to detect
and also tidally locked, with permanent day and night sides. Whether that is fatal depends on
atmospheric heat transport, ... | 588 | 158 |
0eee087e1411c5b4 | astronomy_space | astrobiology | Astronomy and Space | Astrobiology | Habitability and Extreme Environments | prose | mtp | astronomy_space/astrobiology.txt | The study of terrestrial extremophiles has repeatedly widened the envelope of conditions known to
support life. Organisms grow above the boiling point of water at pressure, below its freezing point
in brines, at pH values spanning most of the scale, at radiation doses that shatter chromosomes,
and kilometres undergroun... | 565 | 152 |
21275e4589115cb3 | astronomy_space | astrobiology | Astronomy and Space | Astrobiology | Habitability and Extreme Environments | table | mtp | astronomy_space/astrobiology.txt | Habitability:
habitable zone surface liquid water from starlight; a first filter only
the narrowness ignores subsurface and non-stellar heat sources
tidal heating orbital flexing as an energy source; independent of
distance from the star
radiogenic heating decay in th... | 1,440 | 389 |
dfdaa5948a7bd960 | astronomy_space | astrobiology | Astronomy and Space | Astrobiology | Solar System Targets | prose | calib | astronomy_space/astrobiology.txt | ## Solar System Targets
Mars is the most accessible target and the case for past habitability is strong. The surface
records long-lived standing water, clay minerals requiring sustained aqueous alteration, and river
and lake sediments. The present surface is hostile — thin dry atmosphere, ionizing radiation,
strongly ... | 560 | 151 |
1cf29ea82f9dac81 | astronomy_space | astrobiology | Astronomy and Space | Astrobiology | Solar System Targets | prose | calib | astronomy_space/astrobiology.txt | Europa and Enceladus are the icy moon targets, both with subsurface liquid water oceans in contact
with a rocky floor, which is the configuration that supplies chemical energy. Enceladus is
extraordinary because it vents ocean material into space through south polar plumes, and a
spacecraft can therefore sample the oce... | 538 | 145 |
58ab2b55d34be005 | astronomy_space | astrobiology | Astronomy and Space | Astrobiology | Solar System Targets | prose | mtp | astronomy_space/astrobiology.txt | Titan is the outlier and the more interesting case conceptually, because it tests whether the water
assumption is a requirement or a parochialism. It has a dense nitrogen atmosphere, an active
methane cycle with rain, rivers, and lakes of liquid hydrocarbon, abundant complex organic
chemistry produced in its atmosphere... | 592 | 160 |
67429007b5ad71fb | astronomy_space | astrobiology | Astronomy and Space | Astrobiology | Solar System Targets | table | mtp | astronomy_space/astrobiology.txt | Solar system targets:
Mars strong evidence of past surface water; hostile present
surface, shielded subsurface
the oxidizing surface perchlorates and radiation destroying organics
sample return the decisive step; the required instruments cannot be flown
Europa ... | 1,370 | 370 |
f8928eaf107af60a | astronomy_space | astrobiology | Astronomy and Space | Astrobiology | Biosignatures and Exoplanet Atmospheres | prose | mtp | astronomy_space/astrobiology.txt | ## Biosignatures and Exoplanet Atmospheres
A biosignature is an observable that is better explained by life than by anything else, and the
qualifier carries all the weight. Every proposed biosignature has abiotic pathways, so the inference
is comparative rather than definitive, and it depends on context — the same mol... | 393 | 106 |
f368faa551b1de2b | astronomy_space | astrobiology | Astronomy and Space | Astrobiology | Biosignatures and Exoplanet Atmospheres | prose | calib | astronomy_space/astrobiology.txt | Atmospheric disequilibrium is the strongest general principle. An atmosphere containing gases that
should react with each other requires continuous replenishment, and life is one mechanism that
maintains such disequilibrium. Earth's simultaneous abundance of oxygen and methane is the standard
example, since they react ... | 388 | 104 |
14760cbcf6da2b65 | astronomy_space | astrobiology | Astronomy and Space | Astrobiology | Biosignatures and Exoplanet Atmospheres | prose | calib | astronomy_space/astrobiology.txt | Exoplanet atmospheres are characterized by transmission spectroscopy: starlight passing through the
atmosphere during transit acquires absorption features from its constituents. The signal is
extremely small, the observations are photon-starved, and clouds and hazes mute the features, which
is why atmospheric detection... | 521 | 140 |
719dce60bd547abb | astronomy_space | astrobiology | Astronomy and Space | Astrobiology | Biosignatures and Exoplanet Atmospheres | table | calib | astronomy_space/astrobiology.txt | Biosignatures and detection:
the definition better explained by life than by anything else
abiotic pathways every candidate has them; context decides
disequilibrium coexisting gases that should react; the strongest general
argument
oxygen and methane the terrestrial exam... | 1,390 | 375 |
a59e376d9c9c3536 | astronomy_space | astrobiology | Astronomy and Space | Astrobiology | Technosignatures and Inference | prose | calib | astronomy_space/astrobiology.txt | ## Technosignatures and Inference
Searching for technology rather than biology changes the target from chemistry to artifacts.
Narrowband radio emission remains the canonical signature because such signals do not occur
naturally and propagate efficiently across interstellar distances. Optical pulses, waste heat in
the... | 498 | 134 |
b0f249f047c56031 | astronomy_space | astrobiology | Astronomy and Space | Astrobiology | Technosignatures and Inference | prose | calib | astronomy_space/astrobiology.txt | The Fermi question — given the age and size of the galaxy, why no evidence — has many proposed
resolutions and no way to choose among them. Life may be extremely rare. The transition to complex
life may be the bottleneck. Technological civilizations may be short-lived. Interstellar travel and
communication may be less ... | 606 | 163 |
2077fd126a0e9806 | astronomy_space | astrobiology | Astronomy and Space | Astrobiology | Technosignatures and Inference | prose | mtp | astronomy_space/astrobiology.txt | The Drake formulation is often misread as an estimate and is better understood as a decomposition.
Its value is in identifying which terms are measurable and which are not. The astronomical terms —
star formation rate, planet frequency, habitable-zone occurrence — have moved from speculation to
measurement over the pas... | 544 | 147 |
54f5784787392270 | astronomy_space | astrobiology | Astronomy and Space | Astrobiology | Technosignatures and Inference | table | mtp | astronomy_space/astrobiology.txt | Technosignatures and inference:
narrowband radio the canonical signature; no natural analogue
optical pulses nanosecond laser pulses outshining the star briefly
waste heat thermodynamically unavoidable for large energy use
industrial pollutants long-lived artificial molecules in an atmosphe... | 1,479 | 399 |
230f89ce61d1d42f | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | Radiation, Spectra, and Stellar Atmospheres | prose | calib | astronomy_space/astrophysics_and_stellar_evolution.txt | ## Radiation, Spectra, and Stellar Atmospheres
Nearly everything known about the universe beyond the solar system arrived as
electromagnetic radiation, so interpreting that radiation is the foundational skill of
astrophysics. A blackbody is an idealized perfect absorber and emitter whose spectrum
depends only on tempe... | 413 | 111 |
bfa13afcce68da5e | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | Radiation, Spectra, and Stellar Atmospheres | prose | mtp | astronomy_space/astrophysics_and_stellar_evolution.txt | Two laws govern blackbody emission. Wien's displacement law states that the wavelength of
peak emission is inversely proportional to temperature, so hot objects are blue and cool
ones red — this is why a star's colour measures its surface temperature and why infrared
astronomy studies cool objects. The Stefan-Boltzmann... | 775 | 209 |
cf282a86c5f878a9 | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | Radiation, Spectra, and Stellar Atmospheres | prose | mtp | astronomy_space/astrophysics_and_stellar_evolution.txt | Spectral lines carry more information than the continuum. Kirchhoff's laws describe when
each type appears: a hot dense source produces a continuous spectrum, a hot diffuse gas
produces emission lines, and a cool diffuse gas in front of a continuum source produces
absorption lines. A stellar spectrum shows absorption l... | 449 | 121 |
066ba4a952171dad | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | Radiation, Spectra, and Stellar Atmospheres | table | mtp | astronomy_space/astrophysics_and_stellar_evolution.txt | Radiation quantities:
Wien's law lambda_peak = 2.898e-3 m K / T
Stefan-Boltzmann F = sigma T^4; sigma = 5.67e-8 W/(m^2 K^4)
luminosity L = 4 pi R^2 sigma T^4
inverse square F = L / (4 pi d^2)
Doppler shift delta_lambda / lambda = v / c (non-relativistic)
cosm... | 686 | 185 |
707a0acf70244066 | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | Radiation, Spectra, and Stellar Atmospheres | prose | mtp | astronomy_space/astrophysics_and_stellar_evolution.txt | Stellar spectral classification, the sequence O B A F G K M, orders stars by surface
temperature from about 40,000 K down to under 3,000 K, extended by L, T, and Y for brown
dwarfs. The classification is historical — originally alphabetical by hydrogen line
strength before temperature was understood — which is why the ... | 736 | 198 |
53271419853ca740 | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | Radiation, Spectra, and Stellar Atmospheres | qa | calib | astronomy_space/astrophysics_and_stellar_evolution.txt | Q: Star A has twice the surface temperature of star B and half the radius. The ratio of
their luminosities L_A/L_B is:
A. 1 B. 4 C. 8 D. 16
Reasoning: L is proportional to R^2 T^4. The radius factor contributes (1/2)^2 = 1/4 and
the temperature factor 2^4 = 16, giving 16/4 = 4. Answer: B. | 295 | 79 |
b3b8c0bf5eee5cc7 | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | Stellar Structure and Energy Generation | prose | calib | astronomy_space/astrophysics_and_stellar_evolution.txt | ## Stellar Structure and Energy Generation
A star is a self-gravitating ball of plasma in hydrostatic equilibrium: at every radius,
the outward pressure gradient balances the inward weight of the material above. This
single condition, combined with an energy source, an energy transport mechanism, and an
equation of st... | 550 | 148 |
ff00663a06943c11 | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | Stellar Structure and Energy Generation | prose | calib | astronomy_space/astrophysics_and_stellar_evolution.txt | The energy source is nuclear fusion in the core, where temperature and density are high
enough to overcome the Coulomb barrier between nuclei. Even at fifteen million kelvin,
the core of the Sun, thermal energies are far below the barrier height, and fusion
proceeds only through quantum tunnelling — the reaction rate i... | 694 | 187 |
ff556782d5efabaf | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | Stellar Structure and Energy Generation | prose | mtp | astronomy_space/astrophysics_and_stellar_evolution.txt | Hydrogen burning proceeds by two channels whose relative importance depends on
temperature. The proton-proton chain dominates below about 18 million kelvin and powers
the Sun; its rate scales roughly as T^4. The CNO cycle uses carbon, nitrogen, and oxygen
as catalysts, dominates above that temperature in more massive s... | 527 | 142 |
56ade6cbfb28f54f | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | Stellar Structure and Energy Generation | table | calib | astronomy_space/astrophysics_and_stellar_evolution.txt | Stellar structure essentials:
hydrostatic equilibrium dP/dr = -G M(r) rho(r) / r^2
energy transport radiation where the opacity permits, convection where
the temperature gradient becomes too steep
mass-luminosity L proportional to M^3.5 on the main sequence
main-... | 853 | 230 |
3fb529811db7dc29 | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | Stellar Structure and Energy Generation | prose | calib | astronomy_space/astrophysics_and_stellar_evolution.txt | The mass-luminosity relation combined with fuel supply produces the most consequential
result in stellar astrophysics. Luminosity scales as roughly the 3.5 power of mass, while
available fuel scales linearly with mass, so lifetime scales as M divided by M^3.5, or
M^-2.5. A star ten times the Sun's mass has about three ... | 731 | 197 |
64857a55a8cab474 | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | The Hertzsprung-Russell Diagram | prose | mtp | astronomy_space/astrophysics_and_stellar_evolution.txt | ## The Hertzsprung-Russell Diagram
Plotting luminosity against surface temperature for a population of stars does not produce
a scatter; it produces well-defined sequences, and understanding why is understanding
stellar evolution. About ninety percent of stars lie along the main sequence running from
hot and luminous ... | 542 | 146 |
cc3f92c3d2b59f3e | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | The Hertzsprung-Russell Diagram | prose | calib | astronomy_space/astrophysics_and_stellar_evolution.txt | Above and to the right lie the giants and supergiants — cool but enormously luminous,
which by L = 4 pi R^2 sigma T^4 requires very large radii. Below and to the left lie the
white dwarfs, hot but very faint, hence very small. These regions are sparsely populated
not because such stars are rare in an absolute sense but... | 468 | 126 |
e48e9e2d468946aa | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | The Hertzsprung-Russell Diagram | prose | mtp | astronomy_space/astrophysics_and_stellar_evolution.txt | The diagram's greatest practical use is dating star clusters. Every star in a cluster
formed at approximately the same time from the same material, so they differ only in mass.
Massive stars exhaust their core hydrogen first and leave the main sequence, so as a
cluster ages, the main sequence burns down from the top. T... | 657 | 177 |
ab5d43807aafe0b3 | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | The Hertzsprung-Russell Diagram | table | mtp | astronomy_space/astrophysics_and_stellar_evolution.txt | HR diagram regions:
main sequence core hydrogen burning; 90% of stars; mass sequence
subgiant branch hydrogen exhausted in core, shell burning begins
red giant branch inert helium core contracts, envelope expands enormously
horizontal branch core helium burning; the red giant's stable successor
asy... | 745 | 201 |
3d38e37190602ebc | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | The Hertzsprung-Russell Diagram | prose | calib | astronomy_space/astrophysics_and_stellar_evolution.txt | The instability strip is where variable stars pulsate, and its most important
inhabitants are the Cepheids. A Cepheid's pulsation period is tightly correlated with its
luminosity, so measuring the period gives the absolute magnitude, and comparing with the
apparent magnitude gives the distance. This period-luminosity r... | 594 | 160 |
548c3e3ab2dbb74e | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | Stellar Death and Compact Objects | prose | calib | astronomy_space/astrophysics_and_stellar_evolution.txt | ## Stellar Death and Compact Objects
How a star dies is determined almost entirely by its mass, and the thresholds are sharp
because they correspond to physical limits rather than to gradual transitions. | 204 | 55 |
097efdb4be5e5369 | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | Stellar Death and Compact Objects | prose | mtp | astronomy_space/astrophysics_and_stellar_evolution.txt | Stars below about eight solar masses end as white dwarfs. After exhausting core hydrogen
and then helium, they lack the mass to compress the carbon-oxygen core to carbon-ignition
temperature. The outer envelope is expelled as a planetary nebula — a misleading name
from the era when their small discs resembled planets —... | 639 | 172 |
5802c5d9f955a71d | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | Stellar Death and Compact Objects | prose | calib | astronomy_space/astrophysics_and_stellar_evolution.txt | The Chandrasekhar limit, about 1.4 solar masses, is the maximum mass electron degeneracy
pressure can support. It is derived rather than measured: as mass increases, the electrons
become relativistic, and the pressure they supply grows too slowly with density to
resist further compression. A white dwarf pushed past thi... | 705 | 190 |
6db61ccfd4011552 | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | Stellar Death and Compact Objects | prose | calib | astronomy_space/astrophysics_and_stellar_evolution.txt | Stars above about eight solar masses proceed through successive burning stages — carbon,
neon, oxygen, silicon — each faster than the last, building an onion-shell structure with
an iron core at the centre. Iron is where fusion stops, because it has the highest binding
energy per nucleon, so fusing it consumes rather t... | 618 | 167 |
8e6cb98b4b82a721 | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | Stellar Death and Compact Objects | table | mtp | astronomy_space/astrophysics_and_stellar_evolution.txt | Stellar endpoints by initial mass:
< 0.08 M_sun brown dwarf; never ignites hydrogen
0.08 - 0.5 red dwarf; fully convective, lifetimes exceeding a trillion years
0.5 - 8 red giant, planetary nebula, white dwarf (C-O core)
8 - 20 core-collapse supernova, neutron star
20 - 40 ... | 628 | 169 |
61def04232024c08 | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | Stellar Death and Compact Objects | prose | mtp | astronomy_space/astrophysics_and_stellar_evolution.txt | Neutron stars are the densest observable matter, packing more than a solar mass into a
radius of about ten kilometres, so a teaspoon of neutron star material would weigh as
much as a mountain. They conserve the angular momentum and magnetic flux of their
progenitor cores, which is why they rotate hundreds of times per ... | 617 | 166 |
e35001f5e6a54c22 | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | Stellar Death and Compact Objects | prose | mtp | astronomy_space/astrophysics_and_stellar_evolution.txt | Black holes form when even neutron degeneracy fails. The event horizon at the
Schwarzschild radius, 2GM/c^2, is not a surface but a boundary beyond which no path leads
outward — three kilometres for a solar mass, and about ten million kilometres for the
supermassive black hole at the centre of a large galaxy. Black hol... | 578 | 156 |
52c9efc98f50a521 | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | Stellar Death and Compact Objects | transcript | mtp | astronomy_space/astrophysics_and_stellar_evolution.txt | [user] How do we actually know the mass of a black hole we can't see?
[assistant] tool_call astro.mass_methods({"object_class": "black_hole"})
[tool] {"methods": [{"name": "orbital_dynamics", "applies": "companion or stellar
orbits", "precision": "high"}, {"name": "gravitational_waves", "applies": "mergers",
"precision... | 715 | 193 |
ba03ed694e5093dc | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | Stellar Death and Compact Objects | prose | mtp | astronomy_space/astrophysics_and_stellar_evolution.txt | Orbital dynamics is the most direct and the most trustworthy. If anything orbits the
black hole — a companion star in an X-ray binary, or the stars circling the galactic
centre — then Kepler's third law gives the enclosed mass from the orbital period and
semi-major axis. The stars near the Milky Way's centre have been ... | 506 | 136 |
3a495b426b57fd46 | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | Stellar Death and Compact Objects | prose | calib | astronomy_space/astrophysics_and_stellar_evolution.txt | Gravitational waves give a remarkably clean measurement for merging pairs. The waveform's
frequency evolution during inspiral depends on a specific combination of the two masses
called the chirp mass, and the full waveform through merger and ringdown constrains the
individual masses and spins. This is measuring the mas... | 370 | 100 |
ed212ff2b67d7284 | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | Stellar Death and Compact Objects | prose | calib | astronomy_space/astrophysics_and_stellar_evolution.txt | For distant supermassive black holes, indirect methods take over. Reverberation mapping
measures the light-travel-time delay between variations in the central continuum and the
response of surrounding gas, giving the radius of that gas; combined with its orbital
velocity from line widths, that gives the mass — good to ... | 685 | 185 |
fbe2b80f75aca190 | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | Stellar Death and Compact Objects | prose | mtp | astronomy_space/astrophysics_and_stellar_evolution.txt | And for the two nearest supermassive examples, direct horizon-scale imaging now resolves
the shadow, whose angular size scales with mass and provides an independent check
consistent with the dynamical measurements. | 214 | 57 |
ba405bb1105c60e0 | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | Galaxies and Cosmology | prose | mtp | astronomy_space/astrophysics_and_stellar_evolution.txt | ## Galaxies and Cosmology
Galaxies are gravitationally bound systems of stars, gas, dust, and dark matter. Hubble's
morphological classification divides them into ellipticals, spirals, and irregulars, and
the scheme is descriptive rather than evolutionary despite the "early" and "late" type
terminology it inherited. E... | 644 | 174 |
f61b4e4b383a11be | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | Galaxies and Cosmology | prose | calib | astronomy_space/astrophysics_and_stellar_evolution.txt | The rotation curves of spiral galaxies provided the first strong evidence for dark
matter. Orbital velocity should decline with radius outside the visible mass, following
Kepler's laws as it does in the solar system. Instead, measured rotation curves stay flat
far beyond the visible disc, implying that mass continues t... | 730 | 197 |
f7275ccc3ec0cd72 | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | Galaxies and Cosmology | prose | calib | astronomy_space/astrophysics_and_stellar_evolution.txt | Modern cosmology rests on the observation that the universe is expanding. Hubble's law
relates recession velocity to distance, and running the expansion backward gives a hot
dense beginning about 13.8 billion years ago. The cosmic microwave background is the relic
radiation released when the universe cooled enough for ... | 580 | 156 |
3d8e608de4e9d595 | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | Galaxies and Cosmology | table | calib | astronomy_space/astrophysics_and_stellar_evolution.txt | Cosmological quantities:
Hubble's law v = H_0 d; H_0 ≈ 67-73 km/s/Mpc, and the disagreement
between measurement methods is an unresolved tension
age of universe ~13.8 Gyr
CMB temperature 2.725 K, blackbody to extraordinary precision
composition ~5% or... | 799 | 215 |
fec669fe524f688e | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | Galaxies and Cosmology | prose | calib | astronomy_space/astrophysics_and_stellar_evolution.txt | Dark energy is the name for whatever drives the observed acceleration of the expansion,
discovered in 1998 through Type Ia supernovae appearing fainter — and therefore more
distant — than a decelerating universe would place them. It behaves like a constant energy
density of empty space with negative pressure, which in ... | 691 | 186 |
5daff285d0a8a27d | astronomy_space | astrophysics_and_stellar_evolution | Astronomy and Space | Astrophysics and Stellar Evolution | Galaxies and Cosmology | prose | mtp | astronomy_space/astrophysics_and_stellar_evolution.txt | The recurring lesson of the last century of cosmology is that the constituents we
understand are the minority. Ordinary matter — everything made of atoms, including every
star, planet, and person — is about five percent of the energy content of the universe.
The rest is inferred entirely from its gravitational effects,... | 694 | 187 |
39253f4891738f43 | astronomy_space | cosmology | Astronomy and Space | Cosmology | Expansion and Cosmological Models | prose | mtp | astronomy_space/cosmology.txt | ## Expansion and Cosmological Models
Cosmology applies general relativity to the universe as a whole, and it becomes tractable
because of an assumption that observation supports: on scales above a few hundred million
light-years, the universe is homogeneous and isotropic — the same everywhere and in every
direction. T... | 486 | 131 |
ab4ed73374b14eb5 | astronomy_space | cosmology | Astronomy and Space | Cosmology | Expansion and Cosmological Models | prose | calib | astronomy_space/cosmology.txt | Hubble's observation that galaxies recede with velocity proportional to distance is the
foundational measurement. The relation is not a velocity through space but an expansion of
space itself, which matters for interpretation: there is no centre from which expansion
proceeds, every observer sees the same recession patt... | 483 | 130 |
e7ba0d34a4536c86 | astronomy_space | cosmology | Astronomy and Space | Cosmology | Expansion and Cosmological Models | prose | calib | astronomy_space/cosmology.txt | Cosmological redshift follows from the same picture and is distinct from a Doppler shift. As
light travels, space expands, and the wavelength stretches proportionally. The redshift
therefore measures the ratio of the scale factor now to the scale factor when the light was
emitted, which is why redshift is a direct meas... | 406 | 109 |
00cc369a414b4274 | astronomy_space | cosmology | Astronomy and Space | Cosmology | Expansion and Cosmological Models | table | calib | astronomy_space/cosmology.txt | Foundational relations:
cosmological principle homogeneous and isotropic on large scales
Hubble's law v = H_0 d; H_0 ≈ 67-73 km/s/Mpc
scale factor a(t); a = 1 today
redshift 1 + z = 1/a at emission
Hubble time 1/H_0 ≈ 14 Gyr; a rough age estimate
Friedmann... | 1,065 | 287 |
cda5d968e99f077d | astronomy_space | cosmology | Astronomy and Space | Cosmology | Expansion and Cosmological Models | prose | mtp | astronomy_space/cosmology.txt | The observable universe's radius exceeding the speed of light times its age is a point that
generates persistent confusion and has a straightforward explanation. Light emitted 13.8
billion years ago has travelled for that duration, and the space it crossed has expanded while
it travelled, so the emitting material is no... | 458 | 123 |
3436ac9731f88f99 | astronomy_space | cosmology | Astronomy and Space | Cosmology | Expansion and Cosmological Models | qa | mtp | astronomy_space/cosmology.txt | Q: A galaxy is observed at redshift z = 3. The universe has expanded by what factor since
that light was emitted?
A. 3 B. 4 C. 1/3 D. 9
Reasoning: The relation is 1 + z = a_now / a_then, so 1 + 3 = 4. The universe was one quarter
of its present size, and all wavelengths have been stretched by a factor of four. An... | 328 | 88 |
f0211ff9cd0db0ab | astronomy_space | cosmology | Astronomy and Space | Cosmology | The Hot Big Bang and Nucleosynthesis | prose | calib | astronomy_space/cosmology.txt | ## The Hot Big Bang and Nucleosynthesis
Running the expansion backward implies that the universe was denser and hotter in the past,
and the hot Big Bang model traces the consequences. At early times the universe was a dense
plasma in thermal equilibrium, and as it expanded and cooled, successive processes fell out of
... | 480 | 129 |
377dd6ed7aed2dbb | astronomy_space | cosmology | Astronomy and Space | Cosmology | The Hot Big Bang and Nucleosynthesis | prose | calib | astronomy_space/cosmology.txt | The sequence of epochs is set by the temperature at which each interaction becomes too slow
relative to the expansion to maintain equilibrium. Within the first second, the weak
interactions maintaining the neutron-to-proton ratio froze out, fixing that ratio at roughly
one to six. Between about one second and a few min... | 568 | 153 |
956fc1933e999095 | astronomy_space | cosmology | Astronomy and Space | Cosmology | The Hot Big Bang and Nucleosynthesis | prose | calib | astronomy_space/cosmology.txt | Big Bang nucleosynthesis produced the light elements and is one of the model's strongest
quantitative successes. Essentially all the helium-4 in the universe, about 24 percent by
mass, was made in those few minutes, along with trace deuterium, helium-3, and lithium-7. The
predicted abundances depend on a single free pa... | 667 | 180 |
e66d4c94be587158 | astronomy_space | cosmology | Astronomy and Space | Cosmology | The Hot Big Bang and Nucleosynthesis | table | calib | astronomy_space/cosmology.txt | The hot Big Bang timeline:
< 1e-32 s inflation (proposed); exponential expansion
1e-6 s quarks bind into protons and neutrons
1 s neutrinos decouple; the neutron-proton ratio freezes
1-200 s nucleosynthesis; helium-4, deuterium, helium-3, lithium-7
~50,000 yr matte... | 943 | 254 |
cff3cee211c86662 | astronomy_space | cosmology | Astronomy and Space | Cosmology | The Hot Big Bang and Nucleosynthesis | prose | mtp | astronomy_space/cosmology.txt | The lithium problem deserves mention because it is an honest anomaly. Predicted primordial
lithium-7 exceeds what is measured in the oldest stars by roughly a factor of three, a
discrepancy well outside the quoted uncertainties. Proposed explanations include stellar
processes depleting lithium in those stars, unknown n... | 595 | 160 |
b350e9410c373c47 | astronomy_space | cosmology | Astronomy and Space | Cosmology | The Cosmic Microwave Background | prose | mtp | astronomy_space/cosmology.txt | ## The Cosmic Microwave Background
The microwave background is relic radiation from recombination, when the universe became
transparent. Its discovery in 1965 as an unexplained excess noise in a radio antenna
decisively favoured the hot Big Bang over the steady-state alternative, which had no mechanism
to produce a th... | 337 | 91 |
33bd1f0a36ff3788 | astronomy_space | cosmology | Astronomy and Space | Cosmology | The Cosmic Microwave Background | prose | calib | astronomy_space/cosmology.txt | Its spectrum is the most perfect blackbody ever measured, matching a temperature of 2.7255
kelvin with deviations below a part in ten thousand. That precision is itself informative: it
means the early universe was in thermal equilibrium and that no substantial energy was
injected afterward, which constrains a range of ... | 337 | 91 |
0b91e847be66e70d | astronomy_space | cosmology | Astronomy and Space | Cosmology | The Cosmic Microwave Background | prose | mtp | astronomy_space/cosmology.txt | The temperature fluctuations are the payload. After removing the dipole caused by our own
motion, the residual variations are about one part in a hundred thousand, and their
statistical pattern encodes the composition and geometry of the universe. The fluctuations
arose from acoustic oscillations in the pre-recombinati... | 480 | 129 |
cf71c4e34f3764d9 | astronomy_space | cosmology | Astronomy and Space | Cosmology | The Cosmic Microwave Background | prose | calib | astronomy_space/cosmology.txt | The power spectrum of these fluctuations — the amplitude as a function of angular scale —
shows a series of peaks whose positions and relative heights are precise diagnostics. The
first peak's angular position measures the geometry, because it corresponds to a known
physical size at a known distance and the observed an... | 669 | 180 |
7f40e51b27df6262 | astronomy_space | cosmology | Astronomy and Space | Cosmology | The Cosmic Microwave Background | table | calib | astronomy_space/cosmology.txt | CMB observables:
temperature 2.7255 K; blackbody to better than 1 part in 10^4
dipole ~3.4 mK; our motion at ~370 km/s relative to the CMB frame
fluctuations ~1 part in 10^5 after dipole removal
angular power spectrum amplitude versus angular scale; the primary dataset
first... | 1,076 | 290 |
2518441f8c36af7d | astronomy_space | cosmology | Astronomy and Space | Cosmology | The Cosmic Microwave Background | prose | mtp | astronomy_space/cosmology.txt | The consistency between independent probes is what makes the concordance model credible.
The baryon density inferred from CMB peak ratios agrees with the value inferred from
primordial deuterium, which is a completely independent measurement of a completely different
phenomenon at a completely different epoch. The matt... | 528 | 142 |
aa84776d3a6efad0 | astronomy_space | cosmology | Astronomy and Space | Cosmology | Structure Formation, Dark Matter, and Dark Energy | prose | calib | astronomy_space/cosmology.txt | ## Structure Formation, Dark Matter, and Dark Energy
Structure grew from the tiny density fluctuations visible in the CMB through gravitational
instability: overdense regions attract more matter, becoming more overdense. The growth rate
is set by the competition between gravity and expansion, and it is slow — density ... | 517 | 139 |
33d06581a53b3809 | astronomy_space | cosmology | Astronomy and Space | Cosmology | Structure Formation, Dark Matter, and Dark Energy | prose | calib | astronomy_space/cosmology.txt | That timeline is impossible without dark matter, and this is one of the strongest arguments
for it. Ordinary matter was coupled to radiation until recombination, so its fluctuations
could not grow during that entire period — radiation pressure erased them. Dark matter, not
interacting with radiation, began growing much... | 548 | 148 |
21dd8ae920b46c65 | astronomy_space | cosmology | Astronomy and Space | Cosmology | Structure Formation, Dark Matter, and Dark Energy | prose | mtp | astronomy_space/cosmology.txt | The evidence for dark matter comes from several independent phenomena at different scales.
Galaxy rotation curves stay flat far beyond the visible disc rather than declining as Kepler's
laws would require. Velocity dispersions in galaxy clusters imply far more mass than the
luminous content. Gravitational lensing maps ... | 665 | 179 |
7708270cdf31867d | astronomy_space | cosmology | Astronomy and Space | Cosmology | Structure Formation, Dark Matter, and Dark Energy | table | mtp | astronomy_space/cosmology.txt | Dark sector evidence and properties:
rotation curves flat far beyond the luminous disc
cluster dynamics velocity dispersions imply excess mass
gravitational lensing maps mass directly; exceeds visible matter
CMB peaks require non-baryonic matter
structure formation growth timelin... | 1,268 | 342 |
48b197a5a5b766f5 | astronomy_space | cosmology | Astronomy and Space | Cosmology | Structure Formation, Dark Matter, and Dark Energy | prose | mtp | astronomy_space/cosmology.txt | Dark energy's problem is theoretical rather than observational. A cosmological constant is
the simplest explanation, corresponds to a constant energy density of the vacuum, and fits the
data. Quantum field theory's naive estimate of the vacuum energy exceeds the observed value by
something between fifty and a hundred a... | 746 | 201 |
b0ec3ca8aad0b546 | astronomy_space | cosmology | Astronomy and Space | Cosmology | Inflation and Open Questions | prose | mtp | astronomy_space/cosmology.txt | ## Inflation and Open Questions
Inflation proposes a brief period of exponential expansion in the first fraction of a second,
and it was introduced to solve three problems in the standard hot Big Bang. The horizon
problem is that regions of the CMB separated by more than about a degree could never have been
in causal ... | 685 | 185 |
6aee2602a8b79f24 | astronomy_space | cosmology | Astronomy and Space | Cosmology | Inflation and Open Questions | prose | mtp | astronomy_space/cosmology.txt | Exponential expansion addresses all three with one mechanism. A region small enough to have
been in causal contact is inflated to encompass the entire observable universe, explaining the
uniformity. Any curvature is stretched flat, as the surface of an inflating balloon becomes
locally flatter. And any pre-existing rel... | 360 | 97 |
ece8c98333fc27e1 | astronomy_space | cosmology | Astronomy and Space | Cosmology | Inflation and Open Questions | prose | mtp | astronomy_space/cosmology.txt | Inflation's most consequential feature is one it was not designed to provide: quantum
fluctuations during the inflationary period are stretched to macroscopic scales and become the
seed density perturbations from which all structure grew. This makes the specific statistical
properties of the CMB fluctuations a predicti... | 635 | 171 |
a30969659e2cd818 | astronomy_space | cosmology | Astronomy and Space | Cosmology | Inflation and Open Questions | table | mtp | astronomy_space/cosmology.txt | Open questions:
what is dark matter no confirmed detection despite decades of increasingly
sensitive experiments
what is dark energy the cosmological constant fits and is not explained
the Hubble tension early-universe and late-universe measurements of the
... | 1,203 | 325 |
42d85f55d29b171d | astronomy_space | cosmology | Astronomy and Space | Cosmology | Inflation and Open Questions | prose | calib | astronomy_space/cosmology.txt | The Hubble tension is the most active current disagreement and deserves the closing word.
Measurements of the expansion rate from the CMB, extrapolated forward using the standard
model, give roughly 67 kilometres per second per megaparsec. Direct measurements using the
local distance ladder — Cepheids calibrating Type ... | 868 | 234 |
a46d4aaf80d6ae0e | astronomy_space | high_energy_astrophysics | Astronomy and Space | High-Energy Astrophysics | Radiation Mechanisms | prose | mtp | astronomy_space/high_energy_astrophysics.txt | ## Radiation Mechanisms
High-energy astrophysics studies the most energetic processes in the universe, and
interpreting what is observed requires knowing which physical process produced the radiation.
The spectrum's shape is the primary diagnostic, because each mechanism produces a
characteristic form that persists ac... | 354 | 95 |
4533dd0a1728d983 | astronomy_space | high_energy_astrophysics | Astronomy and Space | High-Energy Astrophysics | Radiation Mechanisms | prose | calib | astronomy_space/high_energy_astrophysics.txt | Thermal emission from an optically thick source is a blackbody, whose spectrum depends only on
temperature. The peak wavelength moves inversely with temperature, so a source peaking in X-rays
is at millions of kelvin. Thermal bremsstrahlung — braking radiation from electrons deflected by
ions in a hot ionized gas — pro... | 444 | 120 |
738558c5a10c0986 | astronomy_space | high_energy_astrophysics | Astronomy and Space | High-Energy Astrophysics | Radiation Mechanisms | prose | mtp | astronomy_space/high_energy_astrophysics.txt | Synchrotron radiation comes from relativistic electrons spiralling in a magnetic field, and it
produces a power-law spectrum rather than a thermal one because the electron energy distribution
is itself a power law. This is the signature of non-thermal particle acceleration, and its
presence establishes that some proces... | 508 | 137 |
96053f93835fc33e | astronomy_space | high_energy_astrophysics | Astronomy and Space | High-Energy Astrophysics | Radiation Mechanisms | prose | mtp | astronomy_space/high_energy_astrophysics.txt | Inverse Compton scattering upscatters low-energy photons to high energy when they encounter
relativistic electrons, which is the reverse of ordinary Compton scattering where a high-energy
photon loses energy to an electron. It is how the highest-energy photons in many sources are
produced, and the synchrotron self-Comp... | 484 | 130 |
3af61408b7598bb3 | astronomy_space | high_energy_astrophysics | Astronomy and Space | High-Energy Astrophysics | Radiation Mechanisms | table | calib | astronomy_space/high_energy_astrophysics.txt | Radiation mechanisms and their signatures:
blackbody optically thick thermal; peak set by temperature alone
bremsstrahlung hot ionized gas; flat with an exponential cutoff
synchrotron relativistic electrons in a magnetic field; power law,
polarized; establishes non... | 1,202 | 324 |
56fbf6aecaf83e6e | astronomy_space | high_energy_astrophysics | Astronomy and Space | High-Energy Astrophysics | Radiation Mechanisms | prose | mtp | astronomy_space/high_energy_astrophysics.txt | The iron K-alpha line deserves particular attention because it is the most direct probe of
strong gravity available. Iron fluoresces at a known rest energy, and a line produced in an
accretion disc close to a black hole is broadened by Doppler shifts from orbital motion and
skewed by gravitational redshift, producing a... | 548 | 148 |
6941cbf17c975549 | astronomy_space | high_energy_astrophysics | Astronomy and Space | High-Energy Astrophysics | Radiation Mechanisms | qa | mtp | astronomy_space/high_energy_astrophysics.txt | Q: A source shows a power-law spectrum extending over several decades in frequency, with
significant linear polarization. The emission mechanism is most likely:
A. Blackbody
B. Synchrotron radiation from relativistic electrons in a magnetic field
C. Thermal bremsstrahlung
D. Atomic line emission
Reasoning: A blackbody ... | 668 | 180 |
a7a56257c2920b21 | astronomy_space | high_energy_astrophysics | Astronomy and Space | High-Energy Astrophysics | Accretion | prose | calib | astronomy_space/high_energy_astrophysics.txt | ## Accretion
Accretion onto a compact object is the most efficient energy-release process known apart from
matter-antimatter annihilation, and it powers most high-energy sources. Material falling toward
a compact object releases gravitational potential energy, and the efficiency depends on how deep
into the potential ... | 620 | 167 |
b0d88be189a27405 | astronomy_space | high_energy_astrophysics | Astronomy and Space | High-Energy Astrophysics | Accretion | prose | mtp | astronomy_space/high_energy_astrophysics.txt | Angular momentum is the obstacle that makes accretion structured rather than radial. Infalling
material almost always has some angular momentum, so it cannot fall directly in and instead
settles into an orbiting disc. Accretion then requires transporting angular momentum outward so
that material can move inward, and id... | 608 | 164 |
4dabdedcfcff2de2 | astronomy_space | high_energy_astrophysics | Astronomy and Space | High-Energy Astrophysics | Accretion | prose | mtp | astronomy_space/high_energy_astrophysics.txt | The Eddington limit sets the maximum steady accretion rate. As accretion luminosity rises, the
outward radiation pressure on infalling material grows, and at the Eddington luminosity it
balances gravity so that further accretion is halted. The limit is proportional to the accretor's
mass, which means a given source has... | 565 | 152 |
24bb9e3e32102bf1 | astronomy_space | high_energy_astrophysics | Astronomy and Space | High-Energy Astrophysics | Accretion | table | calib | astronomy_space/high_energy_astrophysics.txt | Accretion physics:
efficiency ~10% for a neutron star, 6-32% for a black hole depending
on spin; fusion is ~0.7%
angular momentum the obstacle; requires outward transport for inward flow
magnetorotational instability the transport mechanism; magnetic fields in
... | 1,443 | 390 |
4cc91ebfadf75df4 | astronomy_space | high_energy_astrophysics | Astronomy and Space | High-Energy Astrophysics | Accretion | prose | mtp | astronomy_space/high_energy_astrophysics.txt | The light-crossing argument deserves emphasis because it constrains source sizes without
resolving them. A source cannot vary coherently on a timescale shorter than light takes to cross
it, because different parts could not coordinate. A source varying on a timescale of
milliseconds is therefore smaller than a light-mi... | 530 | 143 |
7cf08bfbb5105547 | astronomy_space | high_energy_astrophysics | Astronomy and Space | High-Energy Astrophysics | Compact Object Systems and Transients | prose | calib | astronomy_space/high_energy_astrophysics.txt | ## Compact Object Systems and Transients
X-ray binaries consist of a compact object accreting from a companion star, and they divide by
the companion's mass in a way that determines the accretion mechanism. High-mass systems have a
massive companion whose strong stellar wind is captured, giving persistent emission. Lo... | 533 | 144 |
ffa812daae79b6a2 | astronomy_space | high_energy_astrophysics | Astronomy and Space | High-Energy Astrophysics | Compact Object Systems and Transients | prose | mtp | astronomy_space/high_energy_astrophysics.txt | Distinguishing a neutron star from a black hole accretor is done by the presence or absence of a
surface. A neutron star has one, so material accumulating on it eventually ignites in a
thermonuclear flash producing a type I X-ray burst, and its rotating magnetic field can produce
pulsations. A black hole has neither, s... | 506 | 136 |
21293b0e2ef150dc | astronomy_space | high_energy_astrophysics | Astronomy and Space | High-Energy Astrophysics | Compact Object Systems and Transients | prose | mtp | astronomy_space/high_energy_astrophysics.txt | Supernovae divide into two physically distinct classes despite a spectroscopic classification
that predates the understanding. Core-collapse supernovae occur when a massive star's iron core
exceeds its degeneracy limit and collapses, with the resulting neutrino burst and rebound
ejecting the envelope. Thermonuclear sup... | 582 | 157 |
f777a43478521b1f | astronomy_space | high_energy_astrophysics | Astronomy and Space | High-Energy Astrophysics | Compact Object Systems and Transients | table | calib | astronomy_space/high_energy_astrophysics.txt | Compact objects and transients:
high-mass X-ray binary wind accretion from a massive companion; persistent
low-mass X-ray binary Roche lobe overflow; often transient
type I X-ray burst thermonuclear flash on a neutron star surface; proves a
surface exists
pulsations ... | 1,596 | 431 |
65d6c116f22036bd | astronomy_space | high_energy_astrophysics | Astronomy and Space | High-Energy Astrophysics | Compact Object Systems and Transients | prose | calib | astronomy_space/high_energy_astrophysics.txt | The 2017 neutron star merger is worth stating as a case because it settled several questions at
once. Gravitational waves and a short gamma-ray burst arrived within two seconds, confirming that
compact object mergers produce short bursts and constraining the speed of gravitational waves to
match light to within one par... | 670 | 181 |
be714a360b862279 | astronomy_space | high_energy_astrophysics | Astronomy and Space | High-Energy Astrophysics | Active Galactic Nuclei and Jets | prose | calib | astronomy_space/high_energy_astrophysics.txt | ## Active Galactic Nuclei and Jets
An active galactic nucleus is a supermassive black hole accreting at a rate producing
luminosity comparable to or exceeding the host galaxy's stars. The energy source is accretion
rather than fusion, which is established by the efficiency required — the luminosity and the
variability... | 404 | 109 |
Broad-Domain Calibration & Instruction Supplement
~1M tokens of hand-authored text across 192 subjects in 9 areas, built to serve three jobs from one source: quantization calibration, MTP draft-head training (on a disjoint half), and light instruction tuning.
Version 0.1.0 · built 2026-08-09T17:45:53
| split | rows | tokens~ | size | contents |
|---|---|---|---|---|
corpus |
5,536 | 969,606 | 5.4 MB | raw authored samples + provenance; carries the calib/mtp half label |
instruct |
5,536 | 1,084,399 | 6.4 MB | the same samples as chat-format prompt/response pairs |
Topic distribution
| area | subjects | samples | tokens~ | share |
|---|---|---|---|---|
data_science_ml |
27 | 861 | 148,041 | 15.3% |
software_web |
24 | 699 | 118,985 | 12.3% |
humanities_business |
24 | 633 | 116,425 | 12.0% |
math |
22 | 614 | 106,933 | 11.0% |
physics |
21 | 616 | 106,368 | 11.0% |
embedded_hardware |
19 | 571 | 99,046 | 10.2% |
earth_life_sciences |
19 | 520 | 97,693 | 10.1% |
generative_art |
19 | 539 | 90,941 | 9.4% |
astronomy_space |
17 | 483 | 85,174 | 8.8% |
| total | 192 | 5,536 | 969,606 | 100% |
Sample registers
| register | samples | share |
|---|---|---|
prose |
4,245 | 76.7% |
table |
971 | 17.5% |
qa |
224 | 4.0% |
transcript |
96 | 1.7% |
Disjoint halves
Every row carries half, a deterministic, non-overlapping assignment (see below). Filter on it; do not re-split.
| half | samples | intended use |
|---|---|---|
calib |
2,704 | quantization calibration (imatrix / AWQ / GPTQ) |
mtp |
2,832 | MTP draft-head training |
What this is for
A quantization calibration corpus is only as good as its coverage: llama-imatrix, AWQ and
GPTQ all decide which weights matter from the activations a corpus produces, so whatever the
corpus never exercises gets quantized on the assumption that it does not matter. The usual
mixes — wiki text plus whatever logs happen to be available — are narrow in a way that is
invisible until the quant is worse at something the corpus never covered.
This is a deliberately broad supplement, hand-authored across 9 areas and 192 subjects, to sit alongside a domain corpus rather than replace it. It was written to serve three jobs from one source:
- Quantization calibration — feed the
calibhalf tollama-imatrix/ AWQ / GPTQ. - MTP draft-head training — train on the
mtphalf, next-token. - Light instruction tuning — the
instructsplit, already in chat format.
The two halves are disjoint, on purpose
Every corpus row carries half, either calib or mtp. The assignment is deterministic and
the two sets never overlap. This matters for a specific reason: a draft head trained on the
same text used to calibrate the quant it drafts for would show an inflated acceptance rate,
because part of what you would be measuring is memorization rather than draft quality. Keeping
them apart is what makes an MTP acceptance number mean something.
The split is seeded per source file, not globally, so adding new subjects later never reshuffles the existing assignment — anything already calibrated or trained on stays valid.
How it was written
Hand-authored, one file per subject, in four deliberately mixed registers so the activation statistics are not all from one kind of text:
| register | what it is |
|---|---|
prose |
expository explanation under a section heading |
table |
indented term/definition reference blocks — dense, low-redundancy token patterns |
qa |
exam-style question with options, reasoning, and a stated answer |
transcript |
short illustrative [user] / [assistant] / [tool] dialogues |
There are no raw chat-control tokens anywhere in the text (<|im_start|> and friends are
linted against). That is deliberate: llama-perplexity has no --parse-special, so a marker
embedded in the text tokenizes as a control token on one stack and as plain BPE on the other,
which quietly makes PPL/KLD numbers incomparable. This corpus is safe to use as an eval file.
Using it
Calibration corpus — write the calib half out as flat text:
from datasets import load_dataset
ds = load_dataset("pearsonkyle/broad-domain-supplement", split="corpus")
calib = ds.filter(lambda r: r["half"] == "calib")
with open("corpus.broad.calib.txt", "w") as f:
f.write("\n\n".join(calib["text"]))
llama-imatrix -m model-F16.gguf -f corpus.broad.calib.txt -o imatrix.gguf -c 4096
Interleave it with your in-domain corpus rather than concatenating: a token-budgeted calibrator samples the file, and a large block at the head can eat the whole budget.
MTP draft-head training — the disjoint half, next-token:
mtp = ds.filter(lambda r: r["half"] == "mtp")
text = "\n\n".join(mtp["text"]) # ~500k tokens
Instruction tuning — already chat-shaped:
from transformers import AutoTokenizer
inst = load_dataset("pearsonkyle/broad-domain-supplement", split="instruct")
tok = AutoTokenizer.from_pretrained("<your-model>")
rendered = tok.apply_chat_template(inst[0]["messages"], tokenize=False)
# authored prompts only (the question was written as a question, not templated):
authored = inst.filter(lambda r: r["prompt_source"] == "authored")
Filtering by topic — every row carries area and subject:
ml = ds.filter(lambda r: r["area"] == "data_science_ml")
Read this before using instruct
The instruct split's prompts come from two different places and the difference matters:
prompt_source: "authored"(~6%) — theqaandtranscriptrows. The question or user turn was written as a prompt. These are genuine instruction data.prompt_source: "templated"(~94%) — theproseandtablerows. The source text was written as continuous exposition, and the prompt is generated from the section heading and subject using a small set of templates. The responses are hand-written; the questions are not.
Templated prompts are fine for light instruction tuning and for teaching a model to answer
topically on demand. They are repetitive by construction, and a model trained on them heavily
will learn the template. If you want prompt diversity, filter to authored, rewrite the
prompts, or mix this with a real instruction set — do not treat all 5.5k rows as if a person
wrote 5.5k distinct questions. This is stated plainly because a dataset that quietly presents
templated prompts as authored ones is the kind of thing that is discovered later, in results.
Caveats
- Token counts are estimates.
est_tokensuses a measured 3.70 chars/token ratio, not a real tokenizer. Expect a few percent of drift; recount with your own tokenizer if it matters. Two figures in the table differ for real reasons rather than by mistake:instructtotals more thancorpusbecause it counts the generated prompts as well as the responses, and both sit slightly under the ~1.0M raw-file figure because section headers, the per-file metadata block, and blank separator lines are not part of any sample. - Single author, single voice. One person wrote all of it, so it is stylistically consistent in a way a scraped corpus is not. Good for controlled calibration, and it means the corpus does not represent stylistic diversity — do not use it to measure that.
- Breadth over depth. Each subject is a competent overview at roughly 5k tokens, not expert-level treatment. It is written to exercise vocabulary and reasoning patterns across many domains, which is what calibration needs; it is not a reference text.
transcripttool calls were never executed. They are illustrative dialogues written to look like tool use, kept as literal assistant text rather than lifted into a structuredtool_callsfield, because presenting authored text as a captured trace would be misleading.- No claim is made that the content is error-free. It is a written corpus, not a verified one.
Row schema
Shared by both splits:
| field | meaning |
|---|---|
id |
stable content hash of the sample |
area, subject |
directory-level topic and subject file (e.g. physics / quantum_information) |
area_title, subject_title |
human-readable forms |
section |
the ## Section heading the sample sits under |
register |
prose / table / qa / transcript — how it is written |
half |
calib or mtp — disjoint. Filter on this; do not re-split |
source_file |
path within calibration_supplements/broad/ |
n_chars, est_tokens |
size; tokens are a 3.70 chars/token estimate |
corpus split adds:
| field | meaning |
|---|---|
text |
the sample as authored, section heading included |
instruct split adds:
| field | meaning |
|---|---|
messages |
chat-format turns (user / assistant, plus tool for transcripts) |
prompt_source |
authored (the prompt is from the source) or templated (generated from the heading — see the note above) |
n_turns |
message count |
Reproducing
Generated with Quant-Tuner; see
docs/ternary_qat.md for the end-to-end pipeline and
src/quant_tuner/datasets/ for the exact builder used to publish this.
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