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Astronomy: explore STEM content (page 13 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~266 words · 1 min

One Cloud, One Family About 4.6 billion years ago, the Sun and every planet in our Solar System formed together out of a single giant cloud of gas and dust, called a solar nebula. This idea — that the Sun and planets share a common origin —

Astronomy

Astronomy · L2 · How the Solar System Formed

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Astronomy · L2 · How the Solar System Formed

Flashcards8 cards

What is the overdensity field δ(x), and what role does it play in describing large-scale structure?1 / 8

The overdensity field is the fractional deviation of the local density from the cosmic mean:

Astronomy

Astronomy · L5 · Large-Scale Structure and the Cosmic Web

@openstem

Astronomy · L5 · Large-Scale Structure and the Cosmic Web

Quiz4 questions

A star shows a parallax angle of 0.05 arcseconds. What is its distance?

A0.05 parsecsB5 parsecsC20 parsecsD200 parsecs

Astronomy

Astronomy · L4 · The Cosmic Distance Ladder, Quantitatively — 4 Q

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Astronomy · L4 · The Cosmic Distance Ladder, Quantitatively — 4 Q

Note~648 words · 3 min

Tidal forces: differential gravity, the Roche limit, and tidal locking Tides are not caused by gravity pulling on a body — they are caused by gravity pulling unevenly across an extended body. This distinction explains everything from ocean

Astronomy

Astronomy · L4 · Tidal forces: differential gravity, the Roche limit, and tidal locking

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Astronomy · L4 · Tidal forces: differential gravity, the Roche limit, and tidal locking

Note~292 words · 1 min

Measuring the Unreachable No ruler can be laid across space, so astronomers measure distance with a ladder of methods, each rung calibrated by the one below it and each capable of reaching farther than the last. Rung One: Parallax As Earth

Astronomy

Astronomy · L3 · The Cosmic Distance Ladder

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Astronomy · L3 · The Cosmic Distance Ladder

Note~243 words · 1 min

A New Shape for the Solar System For centuries, astronomers assumed planets moved in perfect circles because circles were considered the 'perfect' shape. In the early 1600s, Johannes Kepler studied years of careful observations of Mars and

Astronomy

Astronomy · L2 · Kepler's Laws of Planetary Motion

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Astronomy · L2 · Kepler's Laws of Planetary Motion

Collection6 items

01Astronomy · L3 · Hubble's Law: Recession Velocity vs Distance

02Astronomy · L3 · Exoplanet Transit Light Curve

03Astronomy · L3 · Tidal Cycle: y = sin(b·x)

+3 more

Astronomy

Astronomy · L3 · Visualised Universe

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Astronomy · L3 · Visualised Universe

Flashcards9 cards

Define a biosignature, and give two examples of candidate gas-phase biosignatures.1 / 9

A biosignature is a substance, feature, or pattern whose presence provides evidence of past or present biological activity. Gas-phase examples include O₂/O₃ (a byproduct of oxygenic photosynthesis on Earth) and CH₄ in persistent coexistence with an oxidizing atmosphere (a byproduct of methanogenesis).

Astronomy

Astronomy · L4 · Astrobiology: Biosignatures, the Fermi Paradox & Habitability

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Astronomy · L4 · Astrobiology: Biosignatures, the Fermi Paradox & Habitability

Flowchart9 objects

Astronomy

Astronomy · L1 · Astronauts · flowchart

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Astronomy · L1 · Astronauts · flowchart

Flowchart9 objects

Astronomy

Astronomy · L3 · Nebula Types · flowchart

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Astronomy · L3 · Nebula Types · flowchart

Quiz4 questions

What determines the mass of a primordial black hole at the moment it forms?

AThe mass of the progenitor star that collapsedBThe horizon mass at the time the perturbation re-enters the causal horizonCThe current Hubble parameter H₀DThe redshift of recombination, z ≈ 1100

Astronomy

Astronomy · L5 · Primordial Black Holes

@openstem

Astronomy · L5 · Primordial Black Holes

Quiz4 questions

Why do rockets need so much fuel?

ATo keep the astronauts warmBTo create enough thrust to escape Earth's strong gravityCTo make the rocket heavier for stabilityDFuel isn't actually needed

Astronomy

Astronomy · L1 · Rockets Quiz

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Astronomy · L1 · Rockets Quiz

Flowchart11 objects

Astronomy

Astronomy · L1 · Natural vs. Artificial Satellites

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Astronomy · L1 · Natural vs. Artificial Satellites

Quiz4 questions

Who proposed that the Sun, not Earth, is the center of the solar system?

APtolemyBNicolaus CopernicusCIsaac NewtonDNeil Armstrong

Astronomy

Astronomy · L1 · Astronomers Who Changed How We See the Sky Quiz

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Astronomy · L1 · Astronomers Who Changed How We See the Sky Quiz

Flashcards8 cards

What is a strongly lensed quasar, and why does it produce multiple images with different arrival times?1 / 8

A quasar whose light passes close enough to an intervening massive galaxy to be strongly gravitationally lensed into multiple distinct images. Each image's light follows a different path length and passes through a different depth of the lens's gravitational potential (the Shapiro delay), so light from the same intrinsic brightness fluctuation in the quasar arrives at Earth through each image at a different time.

Astronomy

Astronomy · L5 · Strong-Lensing Time-Delay Cosmography & the Hubble Tension

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Astronomy · L5 · Strong-Lensing Time-Delay Cosmography & the Hubble Tension

Collection4 items

01Astronomy · L2 · Comparative Planetology

02Astronomy · L2 · Comparative Planetology

03Astronomy · L2 · Venus's Runaway Greenhouse Effect

+1 more

Astronomy

Astronomy · L2 · Comparative Planetology

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Astronomy · L2 · Comparative Planetology

Flashcards9 cards

What physically causes a tidal force? Why does it stretch a body rather than just pull on it?1 / 9

A tidal force is the DIFFERENCE in a gravitational field's strength across an extended body. The near side of a body feels stronger gravity from the perturber than the centre does, and the far side feels weaker gravity than the centre. Relative to the body's own centre of mass, this produces an outward stretch on both the near and far sides — a tidal bulge on two sides, not one.

Astronomy

Astronomy · L4 · Tidal Forces, the Roche Limit & Tidal Locking

@openstem

Astronomy · L4 · Tidal Forces, the Roche Limit & Tidal Locking

Quiz4 questions

What is the main difference between an asteroid and a comet?

AAsteroids are rock and metal; comets are ice, dust, and rockBAsteroids orbit the Sun; comets do notCComets are always bigger than asteroidsDThere is no real difference

Astronomy

Astronomy · L2 · Comets, Asteroids, and Meteoroids

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Astronomy · L2 · Comets, Asteroids, and Meteoroids

Flashcards8 cards

What is a 'hot Jupiter'?1 / 8

A gas giant comparable in mass to Jupiter or larger, but orbiting its star in only a few days — far closer than Mercury orbits the Sun, and hot enough that its outer atmosphere can reach thousands of kelvin.

Astronomy

Astronomy · L3 · Exosolar System Architecture

@openstem

Astronomy · L3 · Exosolar System Architecture

Quiz6 questions

What is the nebular hypothesis?

AThe idea that planets were captured one by one from other systemsBThe idea that the Sun and planets formed together from one collapsing cloudCThe idea that the Sun formed before the galaxyDThe idea that planets formed from asteroid collisions only

Astronomy

Astronomy · L2 · How the Solar System Formed Quiz

@openstem

Astronomy · L2 · How the Solar System Formed Quiz

Flowchart15 objects

Astronomy

Astronomy · L3 · The Drake Equation Factor Chain

@openstem

Astronomy · L3 · The Drake Equation Factor Chain

Flowchart14 objects

Astronomy

Astronomy · L4 · General relativity: the equivalence principle and classic tests · flowchart

@openstem

Astronomy · L4 · General relativity: the equivalence principle and classic tests · flowchart

Flowchart9 objects

Astronomy

Astronomy · L2 · Space Telescopes · flowchart

@openstem

Astronomy · L2 · Space Telescopes · flowchart

Note~471 words · 2 min

White dwarfs: electron degeneracy pressure and the Chandrasekhar limit A white dwarf is the exposed core left behind after a Sun-like star sheds its outer layers late in life. With fusion permanently extinguished, nothing thermal remains to

Astronomy

Astronomy · L4 · White Dwarfs: Electron Degeneracy Pressure & the Chandrasekhar Limit

@openstem

Astronomy · L4 · White Dwarfs: Electron Degeneracy Pressure & the Chandrasekhar Limit

Flashcards8 cards

What is a kilonova?1 / 8

A kilonova is a roughly day-to-week-timescale optical/infrared transient powered by the radioactive decay of freshly synthesised, very neutron-rich heavy nuclei ejected during a neutron star merger (NS-NS or NS-BH). It is named for its peak luminosity — roughly 1,000× a classical nova, though still ~1,000× fainter than a typical supernova — and was predicted theoretically well before being confirmed observationally alongside GW170817 in 2017 (as AT2017gfo).

Astronomy

Astronomy · L5 · Compact Object Mergers, Kilonovae, and r-Process Nucleosynthesis

@openstem

Astronomy · L5 · Compact Object Mergers, Kilonovae, and r-Process Nucleosynthesis

Flashcards9 cards

What is the initial mass function (IMF), in one sentence?1 / 9

The initial mass function is the distribution describing how many stars of each mass are born together out of a single star-forming episode — a statistical statement about the relative numbers of low-mass and high-mass stars produced, not a description of any single star's life.

Astronomy

Astronomy · L4 · Stellar Populations, the Initial Mass Function & Cluster Evolution

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Astronomy · L4 · Stellar Populations, the Initial Mass Function & Cluster Evolution

Flowchart9 objects

Astronomy

Astronomy · L4 · The interstellar medium: gas, dust, the 21 cm line, and extinction · flowchart

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Astronomy · L4 · The interstellar medium: gas, dust, the 21 cm line, and extinction · flowchart

Collection3 items

01Astronomy · L5 · Primordial Black Holes

02Astronomy · L5 · Primordial Black Holes: Formation and Dark-Matter Constraints

03Astronomy · L5 · Primordial Black Holes

Astronomy

Astronomy · L5 · Primordial Black Holes

@openstem

Astronomy · L5 · Primordial Black Holes

Flowchart9 objects

Astronomy

Astronomy · L3 · The Cosmic Distance Ladder · flowchart

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Astronomy · L3 · The Cosmic Distance Ladder · flowchart

Quiz4 questions

Recombination refers to the epoch when:

AGalaxies first formedBFree electrons combined with protons to form neutral hydrogen atomsCThe first stars ignitedDDark energy began to dominate the universe's expansion

Astronomy

Astronomy · L4 · The Cosmic Microwave Background — 4 Q

@openstem

Astronomy · L4 · The Cosmic Microwave Background — 4 Q

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