The Universe As It Really Is – 500 Practice Flashcards (ENGLISH)

500 Q&A practice flashcards drawn from the lecture notes on The Universe As It Really Is, covering topics from atoms and gravity to the Sun, the Solar System, the Milky Way, and the Cosmos.

In the introduction, physics is described as the hardware and biology as the software. Which pair of disciplines is described as central science bridging the physical and life sciences?

Chemistry.

What is the approximate age of the Earth as determined by Claire Patterson's mass spectrometry work?

About 4.54 billion years.

Which paradox did Olbers propose, later discussed in the Cosmos chapter, regarding the darkness of the night sky?

Olbers’ paradox: if the universe were infinite and static with many stars, the night sky should be as bright as the Sun.

What major cosmic event is proposed to explain the observable expansion of the universe?

The Big Bang.

What is the name of the 2015 discovery by LIGO that confirmed a major prediction of general relativity?

Detection of gravitational waves from merging black holes.

What is the primary source of the Sun’s energy according to the text?

Nuclear fusion of hydrogen into helium in the Sun’s core.

Which particle is said to give mass to other particles via interaction with a field?

The Higgs boson (through the Higgs field).

What is the term for the force that binds quarks together inside protons and neutrons?

The strong nuclear force (carried by gluons).

Which force carrier particles are associated with electromagnetism and gravity (the latter still hypothetical)?

Photons for electromagnetism; gravitons for gravity (the latter hypothetical).

What is the unit used to measure the amount of time in GPS satellites’ timing system?

Atomic clocks (cesium standard).

Which planet is known for having a retrograde rotation, spinning east to west?

Venus.

What is Kepler’s first law of planetary motion?

Planets orbit the Sun in ellipses with the Sun at one focus.

What is Kepler’s second law (the law of equal areas)?

A line joining a planet and the Sun sweeps out equal areas in equal times.

What is Kepler’s third law relating a planet’s orbital period to its distance from the Sun?

The square of a planet’s orbital period is proportional to the cube of its average distance from the Sun.

Which cosmological concept explains why the early universe could become uniform despite vast distances?

Cosmic inflation.

What is the background radiation that pervades the universe, a remnant from the early cosmos?

Cosmic microwave background radiation.

What kind of galaxy is the Milky Way typically classified as?

A barred spiral galaxy.

What is the name given to the central supermassive black hole at the Milky Way’s core?

Sagittarius A* (Sgr A*).

What is the Sun’s approximate radius inside the core region relative to its total radius?

Most of the Sun’s mass lies within about 1% of its radius (the core contains a large fraction of mass).

What is Haydn’s line of thought about the solar system’s formation involving a disk of gas and dust around the young Sun called?

Planetary disk (protoplanetary disk) leading to planetesimals and protoplanets.

What is a planetesimal?

Small solid bodies from which planets form, typically kilometer-scale or larger.

What is the Large Hadron Collider’s role in modern physics, as reflected in the notes?

To explore fundamental particles and forces by simulating high-energy collisions.

Which element is the lightest and comprises most of the visible matter in the universe?

Hydrogen.

What is an isotope?

Variants of an element with the same number of protons but different numbers of neutrons.

What is the octet rule?

Atoms tend to have a full outer shell of eight electrons to achieve stability.

What is an ionic bond?

Bond formed by transfer of electrons from a donor (cation) to an acceptor (anion).

What is a covalent bond?

Bond formed by sharing electrons between atoms.

What kind of bond involves a fair amount of sharing but with partial charges (polar covalent)?

Polar covalent bond.

What are van der Waals interactions?

Weak intermolecular forces due to transient dipoles; important in layered structures like graphite.

What is the difference between a noble gas outer shell and other elements?

Noble gases have complete outer shells and are largely unreactive.

What is the primary component of the Earth’s atmosphere today by percent?

Nitrogen (~78%) and oxygen (~21%).

Which two layers of the Sun are responsible for energy transport from the core to the surface?

Radiative zone and convective zone.

What phenomenon explains the bending of light in a gravitational field?

Gravitational lensing.

What is LIGO an acronym for, and what does it do?

Laser Interferometer Gravitational-Wave Observatory; detects gravitational waves.

What is the speed of light in a vacuum?

About 299,792 kilometers per second (approximately 186,282 miles per second).

Which measurement became the basis for a meter in modern physics?

The distance light travels in vacuum in 1/299,792,458 of a second.

What is the Doppler effect as it relates to astronomy?

Change in wavelength (redshift/blue shift) due to relative motion of source and observer.

What are Cepheid variables used for in astronomy?

Standard candles to measure distances to galaxies.

What is the term for a star that collapses into a compact object leaving behind a dense core?

A neutron star (or black hole in more massive cases).

What is a quasar?

A very luminous active galactic nucleus powered by a supermassive black hole.

What is a white dwarf?

A dense stellar remnant left after a low-to-intermediate-mass star exhausts its fuel.

What is Hawking radiation?

Theoretical radiation predicted to be emitted by black holes due to quantum effects near the event horizon.

What does the term 'redshift' indicate in cosmology?

The speeding away of distant galaxies, indicating the expansion of the universe.

What is the Schwarzschild radius?

The radius of the event horizon of a non-rotating black hole.

Who is credited with the first measurement proving the Big Bang’s background radiation?

Penzias and Wilson (discovered cosmic microwave background radiation).

What is inflation in cosmology?

A rapid exponential expansion of space in the early universe.

What is the cosmic baryon matter comprised of?

Ordinary matter made of baryons (protons and neutrons) and electrons.

What is dark matter?

Matter that does not emit, absorb, or reflect light, inferred from gravitational effects.

What is dark energy?

A hypothesized form of energy driving the accelerated expansion of the universe.

What is the Walker circulation associated with ENSO?

A large-scale atmospheric circulation in the Pacific affecting monsoons and rainfall.

What is the Coriolis effect?

Deflection of moving air and water due to Earth’s rotation.

What is the Hadley cell?

A circulation loop from the tropics to about 30° latitude, driving trade winds and rainfall.

What is the Ferrel cell?

A mid-latitude atmospheric circulation cell between Hadley and Polar cells.

What is the Polar cell?

A circulation cell in the high latitudes with cold air descending near the poles.

What drives the jet streams?

Temperature contrasts and the Coriolis force at the boundaries between Hadley, Ferrel, and Polar cells.

What is the primary greenhouse gas responsible for anthropogenic warming according to the notes?

Carbon dioxide (CO2).

What is the Sun’s tachocline?

A shear layer between the radiative and convective zones, likely the source of the Sun’s magnetic field.

What is the Kuiper Belt?

A disk-shaped region beyond Neptune populated by icy bodies and dwarf planets.

What is the Oort Cloud?

A hypothetical spherical shell of icy bodies surrounding the solar system, source of long-period comets.

Which planet has the most notable rings besides Saturn?

Jupiter (and to a lesser extent, Uranus and Neptune with rings).

What is the Grand Tack hypothesis?

A model where Jupiter migrates inward and then outward, reshaping the inner solar system.

What drives plate tectonics?

Mantle convection and the movement of rigid lithospheric plates.

What marks the boundary between Earth’s crust and mantle (the Moho)?

The Mohorovičić discontinuity.

What is the scale used to measure earthquakes?

The Richter scale (logarithmic scale of earthquake magnitudes).

What is the Voyager 1’s distance measure used for?

Distances in space across the solar system; not directly named, but related to light-year concepts.

What is the difference between protons and neutrons?

Protons are positively charged; neutrons are neutral; both reside in the nucleus.

What is the Eightfold Octet Rule?

Each atom tends to have eight electrons in its outer shell for stability.

Which element is responsible for the color of gold due to relativistic effects?

Gold’s yellow color arises from relativistic effects on electron orbitals.

What is the Intertropical Convergence Zone (ITCZ)?

A belt near the equator where trade winds converge, leading to heavy rainfall.

What is the role of corals in ocean ecosystems?

Corals build reefs that support biodiversity and protect coastlines.

What is a “dark matter” halo and why is it important?

A massive, invisible component inferred from gravitational effects that helps explain galactic rotation curves.

What is baryon acoustic oscillation?

A regular pattern in the distribution of galaxies caused by sound waves in the early universe.

What is the difference between orbital speed and rotational speed on a planet?

Orbital speed is motion around a star; rotational speed is spin around the planet’s axis.

What is a 'false vacuum' in cosmology?

A local minimum of the energy potential that is not the true lowest energy state.

Why is the ocean’s salinity important for life?

Salinity affects osmosis, water balance, and nerve function in organisms.

What is radiative transfer in stars?

Energy transport via photons passing through the star’s radiative zone.

What is the Sun’s convective zone?

The outer layer where hot plasma rises and cools, transporting energy to the surface.

What is the difference between a meteor, meteorite and meteoroid?

Meteoroid is the small rocky body; meteor is the streak of light as it enters the atmosphere; meteorite is the remnant that lands on Earth.

What is the role of neutrinos in stellar processes?

Neutrinos carry away energy during nuclear reactions in stars; they interact very weakly with matter.

What is the significance of the Hubble Space Telescope in cosmology?

Measured distant galaxies and clarified that the universe is expanding; provided data on Cepheid variables and distant supernovae.

What is the 'anthropic principle' as explained in the Cosmos section?

The idea that the universe’s laws permit life because life exists to observe them; life and constants seem fine-tuned for habitability.

What is the significance of the Kozai mechanism (noted as a contrast, but in context of dynamics)?

Gravitational interactions in multi-body systems can exchange angular momentum, altering orbits.

What is the main function of the ozone layer?

Absorbs most ultraviolet radiation from the Sun, protecting life on Earth.

What natural phenomenon explains the existence of seasons?

Axial tilt of the Earth (~23.4 degrees) causing varying sunlight with seasons.

What is the speed of the solar wind at Earth’s orbit?

About 400 to 800 km/s depending on solar activity (in the notes, solar wind is discussed around 218–219).

What is a ‘Cepheid’ variable star and why is it important for distance measurement?

A pulsating star whose period-luminosity relation allows distance estimation.

What is the Plank constant and its significance in quantum physics?

Planck’s constant (h) is fundamental to quantization of energy and underpins quantum mechanics.

What is the Cosmic Inflation's theoretical impact on the universe’s horizon and flatness problems?

Inflation solves the horizon and flatness problems by expanding space exponentially, smoothing density variations.

What is the difference between a 'solemn' black hole and a rotating (Kerr) black hole in terms of the event horizon?

A Kerr black hole has two horizons (outer and inner) due to rotation; Schwarzschild black holes are non-rotating with a single horizon.

What is the ‘Shot from the Sun’ in solar astrophysics referring to?

Solar flares and coronal mass ejections—massive energy releases from the solar surface.

What do the Hadley, Ferrel and Polar cells collectively explain?

Global atmospheric circulation patterns driving winds and climate zones.

What is the role of the strong force in atomic nuclei?

It binds quarks to make protons and neutrons and keeps nuclei stable against electrostatic repulsion.

What is the standard model of particle physics suited to describe?

The fundamental particles (quarks, leptons) and the three of the four forces (strong, weak, electromagnetic).

What major discovery solidified the concept of quarks?

Gell-Mann and Zweig proposed quarks (up, down, strange; later top, bottom, charm).

What is a Cepheid’s significance in measuring the scale of the universe?

Its period-luminosity relation provides a standard candle for distance measurements.

Which particle carries the weak force?

W+, W−, and Z bosons.

What is the solar eclipse’s classic test of General Relativity?

Gravitational deflection of starlight by the Sun, observed in 1919 (Eddington).

What is the Hubble constant roughly?

Approximately 70 kilometers per second per megaparsec.

What is the cosmological horizon problem?

Why distant regions of the universe have not yet exchanged information (light) given finite speed and age.

What is a neutron star’s typical radius?

About 12 kilometers.