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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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Quiz4 questions

What is a Near-Earth Object (NEO)?

AAny object inside the asteroid beltBAn asteroid or comet whose orbit brings it close to Earth's orbitCA satellite orbiting EarthDA comet that has already impacted Earth

Astronomy

Astronomy · L2 · Near-Earth Objects and Impact Risk

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Collection3 items

01Astronomy · L4 · Variable Stars: Cepheids, RR Lyrae & Asteroseismology

02Astronomy · L4 · Variable stars: Cepheids, RR Lyrae, and asteroseismology

03Astronomy · L4 · Variable Stars: Cepheids & RR Lyrae — 4 Q

Astronomy

Astronomy · L4 · Variable Stars: Cepheids & RR Lyrae

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Quiz5 questions

The restoring force for p-modes is pressure (acoustic waves); the restoring force for g-modes is:

AMagnetic tensionBBuoyancy in a stably stratified regionCCentrifugal force from rotationDRadiation pressure alone

Astronomy

Astronomy · L4 · Asteroseismology & Helioseismology — 5 Q

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Quiz4 questions

What is gravity?

AA force that pushes objects apartBA force that pulls objects toward each otherCA kind of lightDA type of gas

Astronomy

Astronomy · L1 · Gravity Quiz

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Quiz4 questions

Which observation is most often cited as evidence favouring core accretion over disk instability for giant planet formation?

AGiant planets are found only in binary star systemsBGiant planet occurrence correlates strongly with host-star metallicityCAll giant planets orbit at exactly 5 AUDGiant planets are never found around Sun-like stars

Astronomy

Astronomy · L5 · Exoplanet Formation and Demographics

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Collection3 items

01Astronomy · L3 · Cosmic Rays & High-Energy Astrophysics

02Astronomy · L3 · Cosmic Rays & High-Energy Astrophysics

03Astronomy · L3 · Cosmic Rays & High-Energy Astrophysics

Astronomy

Astronomy · L3 · Cosmic Rays & High-Energy Astrophysics

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Quiz4 questions

Why is Mars known as the 'Red Planet'?

AIt is covered in iron oxide (rust) dustBIt reflects red light from the SunCIts atmosphere is made of red gasDIt is the closest planet to the Sun

Astronomy

Astronomy · L2 · Mars in Depth

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Flowchart8 objects

Astronomy

Astronomy · L1 · The Order of the Seasons

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Note~230 words · 1 min

Light Carries a Chemical Fingerprint Every element absorbs and emits light only at specific wavelengths, set by the fixed energy levels its electrons can occupy. That gives every element a unique pattern of spectral lines — a fingerprint th

Astronomy

Astronomy · L3 · Spectroscopy & Redshift

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Flashcards8 cards

What are planetary rings actually made of?1 / 8

Not a solid sheet, but countless individual particles — ranging from dust grains to boulder-sized chunks, mostly water ice mixed with some rock — all independently orbiting the planet in roughly the same plane.

Astronomy

Astronomy · L3 · Planetary Ring & Moon Systems

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Note~316 words · 2 min

The Raw Material: Giant Molecular Clouds Stars are born inside giant molecular clouds — vast reservoirs of cold (roughly 10-30 K), dense interstellar gas, mostly molecular hydrogen, laced with dust. Cold, dense gas is exactly what gravity n

Astronomy

Astronomy · L3 · Star Formation & Molecular Clouds

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Collection4 items

01Astronomy · L1 · Jupiter, the Giant Planet

02Astronomy · L1 · Jupiter, the Giant Planet

03Astronomy · L1 · Why Jupiter Looks the Way It Does

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Astronomy

Astronomy · L1 · Jupiter, the Giant Planet

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Flowchart11 objects

Astronomy

Astronomy · L3 · Galaxy Types & the Milky Way · flowchart

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Collection4 items

01Astronomy · L1 · Rockets

02Astronomy · L1 · Rockets

03Astronomy · L1 · A Rocket Launch, Step by Step

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Astronomy

Astronomy · L1 · Rockets

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Note~304 words · 2 min

Most of the Universe Is Invisible Ordinary matter — atoms, stars, planets, everything we can see and touch — makes up only about 5% of the Universe's total mass-energy. The rest is split between two poorly understood components: dark matter

Astronomy

Astronomy · L3 · Dark Matter & Dark Energy

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Flashcards8 cards

What are cosmic rays?1 / 8

Extremely high-energy charged particles — mostly protons, with some heavier atomic nuclei and electrons — travelling through space at speeds close to the speed of light.

Astronomy

Astronomy · L3 · Cosmic Rays & High-Energy Astrophysics

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Flashcards8 cards

What two parameters fully characterise a Kerr black hole, and what does the spin parameter represent?1 / 8

Mass M and spin angular momentum J, usually expressed through the dimensionless spin parameter a = J/(Mc), with 0 ≤ a ≤ GM/c² for a physical black hole. The spin parameter measures how close the hole is to its maximal ('extremal') rotation rate, a = GM/c², beyond which the horizon would cease to exist in the standard picture.

Astronomy

Astronomy · L5 · The Kerr Metric: Frame Dragging, the Ergosphere & the Penrose Process

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Note~137 words · 1 min

A Home That Circles Earth The International Space Station, or ISS, is like a giant laboratory and home built in space. It is big enough for astronauts to live and work for months, and it never lands — it just keeps circling Earth. A Day on

Astronomy

Astronomy · L1 · The Space Station

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Flowchart9 objects

Astronomy

Astronomy · L1 · From the Moon to Mars

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Quiz4 questions

According to Kepler's First Law, what shape are planetary orbits?

APerfect circlesBEllipses, with the Sun at one focusCStraight linesDSpirals that slowly shrink

Astronomy

Astronomy · L2 · Kepler's Laws of Planetary Motion

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Quiz4 questions

A black hole has mass M = 10 M☉. What is its Schwarzschild radius? (r_s,☉ ≈ 3 km)

A3 kmB30 kmC300 kmD3,000 km

Astronomy

Astronomy · L5 · Schwarzschild Black Holes

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Flowchart17 objects

Astronomy

Astronomy · L4 · From differential gravity to tidal locking

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Collection4 items

01Astronomy · L4 · Supernova Classification: Light Curves & Spectral Types

02Astronomy · L4 · Supernova Classification: Light Curves & Spectral Types

03Astronomy · L4 · Classifying a Supernova by Spectrum

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Astronomy

Astronomy · L4 · Supernova Classification: Light Curves & Spectral Types

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Collection3 items

01Astronomy · L2 · Light Pollution and Dark Skies

02Astronomy · L2 · Light Pollution and Dark Skies

03Astronomy · L2 · Light Pollution and Dark Skies

Astronomy

Astronomy · L2 · Light Pollution and Dark Skies

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Flowchart11 objects

Astronomy

Astronomy · L3 · The EM Spectrum in Astronomy · flowchart

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Collection3 items

01Astronomy · L5 · Exoplanet Formation Theory and Demographics

02Astronomy · L5 · Planet Formation Channels and What Exoplanet Demographics Reveal

03Astronomy · L5 · Exoplanet Formation and Demographics

Astronomy

Astronomy · L5 · Exoplanet Formation and Demographics

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Note~397 words · 2 min

Comparative planetary atmospheres and the energy-balance climate model A remarkably simple energy-balance argument — absorbed sunlight equals emitted thermal radiation — predicts a 'bare' equilibrium temperature for any planet. Comparing th

Astronomy

Astronomy · L4 · Comparative planetary atmospheres and the energy-balance climate model

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Note~487 words · 2 min

Stellar populations: the initial mass function and cluster dynamical evolution Stars are not born one at a time — they form together, hundreds to millions at once, out of a single fragmenting molecular cloud. The statistical distribution of

Astronomy

Astronomy · L4 · Stellar populations: the initial mass function and cluster dynamical evolution

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Flowchart13 objects

Astronomy

Astronomy · L3 · Solar System Formation: The Nebular Hypothesis · flowchart

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Flowchart9 objects

Astronomy

Astronomy · L2 · Newton's Cannonball Thought Experiment

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Explore STEM Content

Astronomy

Explore STEM Content

Astronomy

Astronomy · L2 · Near-Earth Objects and Impact Risk

Astronomy · L4 · Variable Stars: Cepheids & RR Lyrae

Astronomy · L4 · Asteroseismology & Helioseismology — 5 Q

Astronomy · L1 · Gravity Quiz

Astronomy · L5 · Exoplanet Formation and Demographics

Astronomy · L3 · Cosmic Rays & High-Energy Astrophysics

Astronomy · L2 · Mars in Depth

Astronomy · L1 · The Order of the Seasons

Astronomy · L3 · Spectroscopy & Redshift

Astronomy · L3 · Planetary Ring & Moon Systems

Astronomy · L3 · Star Formation & Molecular Clouds

Astronomy · L1 · Jupiter, the Giant Planet

Astronomy · L3 · Galaxy Types & the Milky Way · flowchart

Astronomy · L1 · Rockets

Astronomy · L3 · Dark Matter & Dark Energy

Astronomy · L3 · Cosmic Rays & High-Energy Astrophysics

Astronomy · L5 · The Kerr Metric: Frame Dragging, the Ergosphere & the Penrose Process

Astronomy · L1 · The Space Station

Astronomy · L1 · From the Moon to Mars

Astronomy · L2 · Kepler's Laws of Planetary Motion

Astronomy · L5 · Schwarzschild Black Holes

Astronomy · L4 · From differential gravity to tidal locking

Astronomy · L4 · Supernova Classification: Light Curves & Spectral Types

Astronomy · L2 · Light Pollution and Dark Skies

Astronomy · L3 · The EM Spectrum in Astronomy · flowchart

Astronomy · L5 · Exoplanet Formation and Demographics

Astronomy · L4 · Comparative planetary atmospheres and the energy-balance climate model

Astronomy · L4 · Stellar populations: the initial mass function and cluster dynamical evolution

Astronomy · L3 · Solar System Formation: The Nebular Hypothesis · flowchart

Astronomy · L2 · Newton's Cannonball Thought Experiment