Expansion, redshift, CMB, dark matter, dark energy, nucleosynthesis, inflation and the cosmic distance ladder.
40 cards · basic cards · AI-written, checked twice. Edit anything.
- What is Hubble's law?
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The recession velocity of a galaxy is proportional to its distance: v = H0 * d- What are the symbol and units of the Hubble constant?
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Symbol H0, units km/s per megaparsec- What is the approximate current value of H0?
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About 70 km/s/Mpc (measurements range 67-73 depending on method)- What is cosmological redshift?
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The stretching of light wavelengths due to the expansion of space itself- What does the redshift parameter z represent?
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The fractional change in wavelength: z = (lambda_observed - lambda_rest) / lambda_rest- How does recession velocity relate to redshift z at low redshifts?
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v approximately equals c times z (speed of light times the redshift)- What is the key difference between cosmological and Doppler redshift?
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Cosmological redshift results from space expansion; Doppler redshift from relative motion through space- In what year was the cosmic microwave background discovered?
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1964 by Arno Penzias and Robert Wilson- What is the temperature of the cosmic microwave background?
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Approximately 2.725 Kelvin- What does the CMB physically represent?
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Radiation released when electrons and protons recombined into neutral atoms in the early universe- What are CMB anisotropies?
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Small temperature variations across the sky, at a level of about 1 part in 100,000- What is the CMB dipole anisotropy?
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A large-scale temperature difference caused by the Milky Way's motion relative to the cosmic microwave background rest frame- What do small-scale CMB temperature fluctuations reveal?
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The seeds of galaxies and large-scale cosmic structure in the early universe- What is dark matter?
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Invisible matter that does not emit or absorb light but exerts gravitational effects- What do flat galaxy rotation curves tell us about dark matter?
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Galaxies rotate too fast at their edges to be held by visible matter alone, implying dark matter halos
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