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Astronomy: explore STEM content (page 15 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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Note~313 words · 2 min

Why Accretion Disks Need Viscosity Gas accreting onto a compact object (white dwarf, neutron star, or black hole) generically carries angular momentum and settles into a rotating disk rather than falling straight in. To actually accrete, th

Astronomy

Astronomy · L5 · Accretion Disks: The Eddington Limit and the Alpha-Disk Model

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Astronomy · L5 · Accretion Disks: The Eddington Limit and the Alpha-Disk Model

Flashcards8 cards

What are right ascension and declination, and what do they measure?1 / 8

The two coordinates of the equatorial system, used to fix a position on the celestial sphere the way longitude and latitude fix a position on the ground. Right ascension measures east-west position around the celestial equator; declination measures north-south position above or below it.

Astronomy

Astronomy · L3 · Celestial Coordinates & Precession

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Astronomy · L3 · Celestial Coordinates & Precession

Quiz4 questions

What causes an aurora?

ALightning from thunderstormsBCharged particles from the Sun colliding with atmosphere gasesCLight reflecting off the MoonDCity lights bouncing off clouds

Astronomy

Astronomy · L1 · Northern Lights (Auroras) Quiz

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Astronomy · L1 · Northern Lights (Auroras) Quiz

Quiz4 questions

Why are Type Ia supernovae described as a 'delayed' enrichment source, unlike core-collapse supernovae?

AThey occur instantly after star formation beginsBThey require a white dwarf progenitor to first form, then accrete or merge over a broad range of further timescales before explodingCThey only occur in galaxies older than the Milky WayDThey are not actually a source of chemical enrichment

Astronomy

Astronomy · L5 · Galactic Chemical Evolution

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Astronomy · L5 · Galactic Chemical Evolution

Flowchart16 objects

Astronomy

Astronomy · L5 · Gravitational Waves: Quadrupole Radiation, Chirp Signals, and Detection · flowchart

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Astronomy · L5 · Gravitational Waves: Quadrupole Radiation, Chirp Signals, and Detection · flowchart

Flowchart7 objects

Astronomy

Astronomy · L1 · Saturn's Rings · flowchart

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Astronomy · L1 · Saturn's Rings · flowchart

Flowchart13 objects

Astronomy

Astronomy · L2 · How the Solar System Formed · flowchart

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Astronomy · L2 · How the Solar System Formed · flowchart

Note~263 words · 1 min

A Thin, Cold, Rusty World Mars gets its nickname from iron oxide (rust) dust that coats its surface. Its atmosphere is a fraction of Earth's — only about 1% of Earth's surface pressure — and almost entirely carbon dioxide. That thin atmosph

Astronomy

Astronomy · L2 · Mars in Depth

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Astronomy · L2 · Mars in Depth

Note~220 words · 1 min

Not All Asteroids Stay in the Belt Most asteroids stay confined to the asteroid belt between Mars and Jupiter, but some have orbits that carry them much closer to Earth. Any asteroid or comet whose path brings it within about 195 million km

Astronomy

Astronomy · L2 · Near-Earth Objects and Impact Risk

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Astronomy · L2 · Near-Earth Objects and Impact Risk

Note~287 words · 1 min

Born From a Cloud of Gas Stars begin their lives inside nebulae — enormous clouds of gas and dust drifting through a galaxy. Gravity slowly pulls together the densest clumps of gas, and as material falls inward, the clump heats up and spins

Astronomy

Astronomy · L2 · The Life Cycle of Stars

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Astronomy · L2 · The Life Cycle of Stars

Quiz4 questions

Why are millisecond pulsars, rather than ordinary (slower) pulsars, used as PTA clocks?

AThey are easier to detect at radio wavelengthsBTheir extraordinarily stable rotation allows timing residuals to be measured with ~100 ns precision over yearsCThey emit exclusively in gravitational wavesDThey have the strongest magnetic fields of any pulsar class

Astronomy

Astronomy · L5 · Pulsar Timing Arrays

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Astronomy · L5 · Pulsar Timing Arrays

Collection4 items

01Astronomy · L5 · Neutron-Capture Nucleosynthesis: the s-process and r-process

02Astronomy · L5 · Neutron-Capture Nucleosynthesis: the s-process and r-process

03Astronomy · L5 · s-process or r-process?

+1 more

Astronomy

Astronomy · L5 · Neutron-Capture Nucleosynthesis: the s-process and r-process

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Astronomy · L5 · Neutron-Capture Nucleosynthesis: the s-process and r-process

Quiz4 questions

What is the key empirical argument that a magnetar's emission is powered by its magnetic field rather than by rotation?

AMagnetars have no measurable spin periodBThe rotational spin-down luminosity L_sd = 4π²Iṗ/P³ falls well short of the observed persistent X-ray luminosityCMagnetars are not neutron stars at allDMagnetars rotate faster than millisecond pulsars

Astronomy

Astronomy · L5 · Magnetar Physics

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Astronomy · L5 · Magnetar Physics

Flowchart15 objects

Astronomy

Astronomy · L4 · What Supports the Core?

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Astronomy · L4 · What Supports the Core?

Quiz4 questions

What does a telescope mainly do?

AMakes new starsBCollects more light than our eyes canCChanges the color of the skyDMoves stars closer

Astronomy

Astronomy · L1 · Telescopes Quiz

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Astronomy · L1 · Telescopes Quiz

Quiz4 questions

A planet transiting a star causes a fractional flux dip of ΔF/F = 0.01 (1%). If the star has radius R★ = R☉, what is the planet's radius?

AR_p = 0.1 R☉ ≈ ~11 R⊕BR_p = 0.01 R☉ = 1.1 R⊕ (approximately)CR_p = 0.5 R☉ = 55 R⊕ (approximately)DR_p = R☉ (the planet equals the star in size)

Astronomy

Astronomy · L5 · Exoplanet Detection, Hubble's Law, and the H–R Diagram

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Astronomy · L5 · Exoplanet Detection, Hubble's Law, and the H–R Diagram

Quiz4 questions

Tidal acceleration across a body of radius R at distance d from a mass M scales as:

AGM/d²B2GMR/d³CGMR²/d⁴DIt does not depend on d

Astronomy

Astronomy · L4 · Tidal Forces, Roche Limit & Tidal Locking — 4 Q

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Astronomy · L4 · Tidal Forces, Roche Limit & Tidal Locking — 4 Q

Note~131 words · 1 min

Getting Ready to Go Landing people on the Moon didn't happen all at once. It took years of smaller missions, each one teaching skills needed for the next, bigger challenge. Three Programs, One Big Goal Before Apollo could land on the Moon,

Astronomy

Astronomy · L1 · Humans on the Moon

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Astronomy · L1 · Humans on the Moon

Quiz4 questions

The Salpeter initial mass function, dN/dM ∝ M^(−2.35), implies that:

AEvery star-forming region produces exactly the same number of high- and low-mass starsBLow-mass stars vastly outnumber high-mass stars at birthCHigh-mass stars vastly outnumber low-mass stars at birthDOnly stars near 1 solar mass ever form

Astronomy

Astronomy · L4 · Stellar Populations & the Initial Mass Function — 4 Q

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Astronomy · L4 · Stellar Populations & the Initial Mass Function — 4 Q

Note~334 words · 2 min

Radiation from an Accelerating Quadrupole General relativity predicts that accelerating mass distributions radiate energy as ripples in spacetime curvature — gravitational waves — propagating at the speed of light. Because gravitational mon

Astronomy

Astronomy · L5 · Gravitational Waves: Quadrupole Radiation, Chirp Signals, and Detection

@openstem

Astronomy · L5 · Gravitational Waves: Quadrupole Radiation, Chirp Signals, and Detection

Flowchart15 objects

Astronomy

Astronomy · L3 · Timeline of the Early Universe

@openstem

Astronomy · L3 · Timeline of the Early Universe

Flashcards8 cards

Why must astronomers observe stars near the Galactic Center in the near-infrared rather than visible light?1 / 8

Roughly 30 magnitudes of visual extinction from intervening interstellar dust in the Galactic plane make the Galactic Center essentially invisible at optical wavelengths. Near-infrared light is scattered and absorbed far less by dust, so adaptive-optics-corrected infrared imaging (e.g. at Keck and the VLT) is what makes it possible to resolve and track individual stars there at all.

Astronomy

Astronomy · L4 · The Galactic Center and Sagittarius A*

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Astronomy · L4 · The Galactic Center and Sagittarius A*

Quiz4 questions

What does one 'year' actually measure?

AHow long the Moon takes to orbit EarthBThe time Earth takes to travel once around the SunCHow long a day lastsDHow fast Earth spins

Astronomy

Astronomy · L1 · Why a Year Has 365 Days Quiz

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Astronomy · L1 · Why a Year Has 365 Days Quiz

Note~185 words · 1 min

Training for Space Becoming an astronaut takes years of hard training. Astronauts learn to fly spacecraft, fix equipment, do science experiments, and even go on spacewalks — all while preparing for a place with no air and almost no gravity.

Astronomy

Astronomy · L1 · Astronauts

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Astronomy · L1 · Astronauts

Flashcards8 cards

What is the horizon problem in standard (non-inflationary) Big Bang cosmology?1 / 8

The cosmic microwave background is observed to be nearly isotropic (uniform temperature to ~1 part in 10⁵) across the entire sky, including regions that — tracing light-travel distances back through a purely radiation/matter-dominated expansion — could never have been in causal contact before recombination. Without inflation, there is no physical mechanism to have equilibrated their temperatures: the horizon problem asks why causally disconnected regions look identical.

Astronomy

Astronomy · L5 · Inflationary Cosmology

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Astronomy · L5 · Inflationary Cosmology

Quiz5 questions

What shapes Earth's magnetosphere into a compressed dayside and a long nightside tail?

AEarth's rotationBPressure from the solar windCThe Moon's gravityDCosmic ray bombardment

Astronomy

Astronomy · L3 · Aurora & Magnetosphere Physics

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Astronomy · L3 · Aurora & Magnetosphere Physics

Collection4 items

01Astronomy · L3 · Habitable Zones & the Search for Life

02Astronomy · L3 · Habitable Zones & the Search for Life

03Astronomy · L3 · The Drake Equation Factor Chain

+1 more

Astronomy

Astronomy · L3 · Habitable Zones & the Search for Life

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Astronomy · L3 · Habitable Zones & the Search for Life

Quiz4 questions

Which of these is a natural satellite?

AA GPS satelliteBA weather satelliteCEarth's MoonDA TV satellite

Astronomy

Astronomy · L1 · Satellites: Natural & Artificial Quiz

@openstem

Astronomy · L1 · Satellites: Natural & Artificial Quiz

Quiz4 questions

The horizon problem asks why:

AThe universe is expanding at allBWidely separated, apparently causally disconnected regions of the CMB have nearly identical temperaturesCΩ is measured to be exactly 1DGalaxies are receding from us faster the farther away they are

Astronomy

Astronomy · L5 · Inflationary Cosmology

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Astronomy · L5 · Inflationary Cosmology

Collection4 items

01Astronomy · L5 · Schwarzschild Black Holes

02Astronomy · L5 · The Schwarzschild Black Hole: Horizon, Photon Sphere, and ISCO

03Astronomy · L5 · Formation of a Schwarzschild Black Hole

+1 more

Astronomy

Astronomy · L5 · Schwarzschild Black Holes

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Astronomy · L5 · Schwarzschild Black Holes

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