A) Gas and dust B) Liquid water C) Plasma D) Rock formations
A) X-rays B) Visible light C) Radio waves D) Gamma rays
A) Ionization imbalance B) Microwave heating C) Radiative torque alignment D) Heat conduction
A) Molecular clouds B) Reflection nebulae C) Supernova remnants D) H II regions
A) Helium B) Hydrogen C) Oxygen D) Carbon
A) Gold B) Silicates C) Diamonds D) Platinum
A) Polycyclic aromatic hydrocarbons (PAHs) B) Carbon monoxide (CO) C) Methane (CH4) D) Carbon dioxide (CO2)
A) Red B) Blue C) Yellow D) Green
A) Reflection nebula B) Supernova remnant C) Dark nebula D) H II region
A) 1 billion (109) molecules/m3 B) 100 ions/m3 C) 10 quadrillion (1016) molecules/m3 D) 1 trillion (1012) molecules/m3
A) Cold dense phase B) Coronal gas C) Warm ionized medium D) Photodissociation region
A) 1% B) 10% C) 5% D) 50%
A) Neutron stars B) Red giants C) White dwarfs D) OB stars
A) O(105 K) B) ~ 106 K C) ~ 104 K D) < 300 K
A) ~ 1012 molecules/m3 B) ~ 1025 molecules/m3 C) ~ 1016 molecules/m3 D) ~ 100 ions/m3
A) Cold dense phase B) Very hot gas (T ~ 106 K) C) Warm intercloud phase D) Photodissociation region
A) Thermal pressure is more important than magnetic fields. B) All phases have equal density. C) Pressure varies significantly across different regions. D) The phases are roughly in pressure balance over most of the Galactic disk.
A) William Huggins B) Francis Bacon C) Edward Barnard D) René Descartes
A) Spectral lines from CO B) Ly-α photon from hydrogen C) Forbidden lines of O III D) 21-cm line of H I
A) Interstellar dust B) Primordial nucleosynthesis C) Cosmic rays D) Stellar nucleosynthesis during stellar evolution.
A) They create cold neutral medium. B) They decrease the density of the ISM. C) They reduce the number of hydrogen atoms. D) They convert surrounding gas into the warm ionized phase, increasing temperature.
A) Synchrotron radiation B) Bremsstrahlung radiation C) Inverse Compton scattering D) Photon emission from de-excitation
A) 21-cm line emission B) Millimetre wavelength lines C) Far infrared quasi-blackbody emission D) Dipole radiation
A) CO (carbon monoxide) B) N II C) H2 (molecular hydrogen) D) O III
A) Bremsstrahlung cooling B) Synchrotron radiation C) Collision with atomic nuclei D) Inverse Compton scattering
A) It influences their dynamics and structure. B) It prevents star formation in spiral arms. C) It compresses all ISM into a thin disk. D) It has no effect on the ISM.
A) It becomes entirely in the coronal phase. B) It remains unchanged from the rest of the galaxy. C) It only contains cold gas. D) It is profoundly modified by the central supermassive black hole.
A) Synchrotron radiation B) 21-cm line emission C) Far infrared quasi-blackbody emission D) Millimetre wavelength lines
A) Quasi-blackbody emission B) Synchrotron radiation C) Inverse Compton scattering D) Bremsstrahlung radiation
A) 2025 B) 2030 C) 2020 D) 2040
A) Scattering B) Absorption lines C) Emission lines D) Reddening
A) Simple hydrocarbons. B) Buckminsterfullerene (C60) or 'buckyballs'. C) Carbon monoxide. D) Only hydrogen and helium molecules.
A) Victor Hess B) Edward Barnard C) Slipher D) Mary Lea Heger
A) Refraction B) Telescope lens C) Spectroscopy D) Photography
A) Inverse Compton scattering B) Synchrotron radiation C) Bremsstrahlung radiation D) Fine structure cooling
A) They cool down the ionized gas. B) They reduce the number of photons with energy below the Lyman limit. C) They increase the density of molecular clouds. D) They contribute to the heating of the warm neutral medium.
A) Paschen-alpha transition B) Lyman-alpha transition C) Brackett-alpha transition D) Balmer-alpha transition
A) Bremsstrahlung radiation B) Synchrotron radiation C) Far infrared quasi-blackbody emission D) Dipole radiation from spinning nanometre-sized grains
A) Infrared emission B) Bremsstrahlung radiation C) Synchrotron radiation D) Gamma-ray photons
A) 500 parsecs B) 30,000 parsecs C) 100 parsecs (300 light years) D) 10,000 parsecs
A) 1000 km/s B) 50 km/s C) 200 km/s D) 500 km/s |