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Astronomy: explore STEM content (page 10 of 26) · openstem

All fields Software Mathematics Physics Chemistry Biology Engineering Astronomy Environmental Other Astronomy Astronomy groups

Explore STEM Content

Search the community's STEM library — free to study, yours to make your own.

Astronomy

Stars, orbits, cosmology and observation on openstem — flashcards, notes, quizzes and plots shared by the community. Study free, or clone anything into your library.

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Collection4 items

01Astronomy · L2 · Eclipse Mechanics: Umbra, Penumbra, and Types

02Astronomy · L2 · Eclipse Mechanics: Umbra, Penumbra, and Types

03Astronomy · L2 · Umbra, Penumbra, and Eclipse Type

+1 more

Astronomy

Astronomy · L2 · Eclipse Mechanics: Umbra, Penumbra, and Types

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Astronomy · L2 · Eclipse Mechanics: Umbra, Penumbra, and Types

Collection3 items

01Astronomy · L3 · Kepler's Laws & Orbital Mechanics

02Astronomy · L3 · Kepler's Laws & Orbital Mechanics

03Astronomy · L3 · Kepler's Laws & Orbital Mechanics

Astronomy

Astronomy · L3 · Kepler's Laws & Orbital Mechanics

@openstem

Astronomy · L3 · Kepler's Laws & Orbital Mechanics

Flashcards8 cards

How do galaxy rotation curves provide evidence for dark matter?1 / 8

For a spiral galaxy, Newtonian dynamics predicts orbital speed v(r) = √(GM(r)/r) should decline as r⁻¹ᐟ² beyond the visible disk (Keplerian falloff), once nearly all the mass is enclosed. Instead, observed rotation curves stay roughly flat (v ≈ constant) out to large radii, implying M(r) ∝ r — a mass distribution extending far beyond the visible stars and gas, in a roughly spherical 'halo'.

Astronomy

Astronomy · L5 · Dark Matter Candidates and Evidence

@openstem

Astronomy · L5 · Dark Matter Candidates and Evidence

Flashcards5 cards

Why do we have day and night?1 / 5

Earth spins around. The side facing the Sun gets daylight. The side facing away gets night.

Astronomy

Astronomy · L1 · Day and Night

@openstem

Astronomy · L1 · Day and Night

Collection4 items

01Astronomy · L2 · The Asteroid Belt and Kuiper Belt

02Astronomy · L2 · The Asteroid Belt and Kuiper Belt

03Astronomy · L2 · Two Belts, Two Kinds of Leftover Material

+1 more

Astronomy

Astronomy · L2 · The Asteroid Belt and Kuiper Belt

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Astronomy · L2 · The Asteroid Belt and Kuiper Belt

Collection3 items

01Astronomy · L3 · Black Holes & Neutron Stars

02Astronomy · L3 · Black Holes & Neutron Stars

03Astronomy · L3 · Black Holes & Neutron Stars

Astronomy

Astronomy · L3 · Black Holes & Neutron Stars

@openstem

Astronomy · L3 · Black Holes & Neutron Stars

Flashcards8 cards

Write the (scalar, single-lens-plane) gravitational lens equation and explain each term.1 / 8

β = θ − (D_ls/D_s) α̂(θ), where β is the source's true angular position (had it not been lensed), θ is the observed image position, α̂(θ) is the deflection angle produced by the lens mass at that impact parameter, and D_ls, D_s (and implicitly D_l) are angular-diameter distances between lens, source, and observer that rescale the raw deflection into an apparent angular shift.

Astronomy

Astronomy · L4 · Gravitational Lensing as a Quantitative Astrophysical Tool

@openstem

Astronomy · L4 · Gravitational Lensing as a Quantitative Astrophysical Tool

Collection4 items

01Astronomy · L1 · Satellites: Natural & Artificial

02Astronomy · L1 · Satellites: Natural & Artificial

03Astronomy · L1 · Natural vs. Artificial Satellites

+1 more

Astronomy

Astronomy · L1 · Satellites: Natural & Artificial

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Astronomy · L1 · Satellites: Natural & Artificial

Flashcards8 cards

What is the interstellar medium (ISM), and what are its main components by mass?1 / 8

The interstellar medium is the matter filling the space between stars within a galaxy. By mass, it is roughly 99% gas (mostly hydrogen, ~10% helium by number, trace heavier elements) and 1% dust (microscopic solid grains of carbon and silicates). Despite dust being a small mass fraction, it dominates the ISM's effect on starlight passing through it.

Astronomy

Astronomy · L4 · The Interstellar Medium: Gas, Dust & the 21 cm Line

@openstem

Astronomy · L4 · The Interstellar Medium: Gas, Dust & the 21 cm Line

Collection3 items

01Astronomy · L2 · Near-Earth Objects and Impact Risk

02Astronomy · L2 · Near-Earth Objects and Impact Risk

03Astronomy · L2 · Near-Earth Objects and Impact Risk

Astronomy

Astronomy · L2 · Near-Earth Objects and Impact Risk

@openstem

Astronomy · L2 · Near-Earth Objects and Impact Risk

Note~292 words · 1 min

Escaping the Atmosphere Earth's atmosphere is wonderful for breathing, but it makes life difficult for astronomers. It blurs and distorts starlight — the reason stars appear to twinkle — and it completely blocks many kinds of light before t

Astronomy

Astronomy · L2 · Space Telescopes

@openstem

Astronomy · L2 · Space Telescopes

Flashcards7 cards

What is a solar eclipse?1 / 7

When the Moon passes between the Sun and Earth, blocking some or all of the Sun's light.

Astronomy

Astronomy · L1 · Solar and Lunar Eclipses

@openstem

Astronomy · L1 · Solar and Lunar Eclipses

Quiz4 questions

Why does the Moon seem to change shape during the month?

AThe Moon actually grows and shrinksBWe see different amounts of its sunlit halfCClouds cover part of itDThe Moon spins very fast

Astronomy

Astronomy · L1 · The Changing Moon Quiz

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Astronomy · L1 · The Changing Moon Quiz

Flowchart12 objects

Astronomy

Astronomy · L2 · Solar and Lunar Eclipses

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Astronomy · L2 · Solar and Lunar Eclipses

Note~514 words · 3 min

Exoplanet atmospheres: transmission spectroscopy and the habitable zone Two of the most active questions in exoplanet science are what a planet's atmosphere is made of, and whether the planet could plausibly host liquid water. Both question

Astronomy

Astronomy · L4 · Exoplanet atmospheres: transmission spectroscopy and the habitable zone

@openstem

Astronomy · L4 · Exoplanet atmospheres: transmission spectroscopy and the habitable zone

Quiz3 questions

Where are new stars born?

AInside existing stars that explodeBIn giant clouds of gas and dust called nebulaeCFrom planets that become hot enoughDAt the centre of galaxies only

Astronomy

Astronomy · L2 · Star Life Cycles and Eclipses

@openstem

Astronomy · L2 · Star Life Cycles and Eclipses

Collection4 items

01Astronomy · L1 · Asteroids, Comets, and Meteors

02Astronomy · L1 · Asteroids, Comets, and Meteors

03Astronomy · L1 · From Meteoroid to Meteorite

+1 more

Astronomy

Astronomy · L1 · Asteroids, Comets, and Meteors

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Astronomy · L1 · Asteroids, Comets, and Meteors

Note~418 words · 2 min

From Core Collapse to a Neutron Star When the iron core of a massive star (initial mass roughly 8–20 M☉) exceeds the Chandrasekhar mass, electron degeneracy pressure can no longer support it against gravity. The core collapses in millisecon

Astronomy

Astronomy · L5 · Neutron Star Structure, the TOV Equation, and Pulsars/Magnetars

@openstem

Astronomy · L5 · Neutron Star Structure, the TOV Equation, and Pulsars/Magnetars

Flowchart11 objects

Astronomy

Astronomy · L2 · Umbra, Penumbra, and Eclipse Type

@openstem

Astronomy · L2 · Umbra, Penumbra, and Eclipse Type

Flashcards8 cards

State the equation of hydrostatic equilibrium for a star and explain what balances what.1 / 8

dP/dr = −Gm(r)ρ(r)/r², where P is pressure, ρ is density, m(r) is the mass enclosed within radius r, and G is the gravitational constant. It states that at every radius, the outward push of the pressure gradient exactly balances the inward pull of gravity on that shell of gas — without this balance, a star would either collapse or blow apart.

Astronomy

Astronomy · L4 · Stellar Structure Equations

@openstem

Astronomy · L4 · Stellar Structure Equations

Flowchart9 objects

Astronomy

Astronomy · L1 · Telescopes · flowchart

@openstem

Astronomy · L1 · Telescopes · flowchart

Flowchart14 objects

Astronomy

Astronomy · L4 · From blackbody temperature to observable stellar properties

@openstem

Astronomy · L4 · From blackbody temperature to observable stellar properties

Flashcards8 cards

How does an absorption line form in a stellar spectrum?1 / 8

A star's continuum radiation is generated deep in the photosphere, where the local temperature is highest along the line of sight to that depth. As photons travel outward, atoms/ions in cooler, overlying layers absorb photons at specific transition wavelengths, then re-emit them isotropically (in essentially random directions). Along the observer's line of sight, this removes photons at the transition wavelength preferentially (since the re-emission depth is on average cooler and the process effectively scatters flux out of the beam), producing a dip — an absorption line — relative to the surrounding continuum.

Astronomy

Astronomy · L5 · Stellar Atmospheres and Spectral Line Formation

@openstem

Astronomy · L5 · Stellar Atmospheres and Spectral Line Formation

Note~622 words · 3 min

Orbital mechanics: vis-viva, orbital energy, and Hohmann transfers Kepler's laws describe the shape and timing of an orbit; the vis-viva equation adds the missing piece — the instantaneous speed of a body anywhere along that orbit. It under

Astronomy

Astronomy · L4 · Orbital mechanics: vis-viva, orbital energy, and Hohmann transfers

@openstem

Astronomy · L4 · Orbital mechanics: vis-viva, orbital energy, and Hohmann transfers

Flashcards8 cards

What is the Kuiper Belt?1 / 8

A vast, disc-shaped region of icy bodies beyond Neptune's orbit, stretching from about 30 to 50 AU from the Sun. It's home to Pluto and many other small icy worlds.

Astronomy

Astronomy · L2 · Dwarf Planets and the Kuiper Belt

@openstem

Astronomy · L2 · Dwarf Planets and the Kuiper Belt

Flowchart11 objects

Astronomy

Astronomy · L3 · Gravitational Lensing · flowchart

@openstem

Astronomy · L3 · Gravitational Lensing · flowchart

Note~290 words · 1 min

An Expanding, Cooling Universe The Big Bang model holds that the observable Universe began about 13.8 billion years ago in an extremely hot, dense state and has been expanding and cooling ever since. It is not an explosion of matter into em

Astronomy