Final Flashcards
What causes an aurora
When a solar storm comes toward us, some of the energy and small particles can travel down the magnetic field lines at the north and south poles into Earth’s atmosphere. There, the particles interact with gases in our atmosphere resulting in beautiful displays of light in the sky. Oxygen gives off green and red light
Brown dwarf
brown dwarf, astronomical object that is intermediate between a planet and a star. Brown dwarfs usually have a mass less than 0.075 that of the Sun, or roughly 75 times that of Jupiter
What’s the difference between stars and massive planets
Stars generate their own light and heat through nuclear fusion in their cores. They emit energy in the form of light and electromagnetic radiation, which makes them visible from great distances. On the contrary, planets do not produce light. Instead, they reflect light from their parent stars.
Population I vs Population II stars
Population I stars are younger stars found in the disk of the galaxy that contain lots of atoms heavier than helium (metals), while population II Stars are older, metal-poor stars found in a galaxy’s nuclear bulge, halo, and globular clusters.
what importance do supernovaes have on earth
Supernovae are considered one of the original sources of the elements heavier than iron in the Universe. Even the iron in your blood can be traced back to supernovae or similar cosmic explosions from long before our Sun had formed. Supernovae are thus essential to life.
difference between white dwarf neutron star and black hole
white dwarf - a low-mass star that has exhausted most or all of its nuclear fuel and has collapsed to a very small size; such a star is near its final state of life
black hole - a region in spacetime where gravity is so strong that nothing—not even light—can escape
neutron star - a compact object of extremely high density composed almost entirely of neutrons
why is the rotational speeds of the arms of galaxies an indicator of black matter
The rotational speeds of spiral galaxy arms are an indicator of dark matter because they don’t match the distribution of luminous matter or what’s expected from Kepler’s laws. This suggests that there’s an additional, invisible mass component, or dark matter, in the galaxy.
What is dark matter
nonluminous mass, whose presence can be inferred only because of its gravitational influence on luminous matter; the composition of the dark matter is not known
What is dark energy
an energy that is causing the expansion of the universe to accelerate; the source of this energy is not yet understood
How do we estimate the age of the universe
By measuring the Hubble constant, which is the current expansion rate of the universe, scientists can extrapolate backwards in time to calculate the universe’s age.
By measuring different parameters of the oldest stars, scientists can calculate the age of the universe
How do you measure the mass of a supermassive black hole
Scientists can calculate the mass of a supermassive black hole by measuring the speed of orbiting material, such as stars or gas, around it
The faster the gas rotates around the black hole, the more massive it is.
The heavier the black hole, the faster nearby stars will move due to its gravitational pull.
How do we know that the universe is expanding? Accelerating?
The discovery of galactic redshift, the period-luminosity relation of Cepheid variables, and a newfound ability to gauge a star or galaxy’s distance eventually played a role in astronomers observing that galaxies were getting farther away from us over time, which showed how the universe was expanding. (Dark matter is accelerating the expansion)
Big Bang
the theory of cosmology in which the expansion of the universe began with a primeval explosion (of space, time, matter, and energy)
Fermi paradox
Where are the aliens? If life and intelligence are common and have such a tremendous capacity for growth, why is there not a network of galactic civilizations whose presence extends even into a “latecomer” planetary system like our own?
what is the importance of cosmic microwave background radiation
Cosmic microwave background (CMB) radiation is a faint, almost uniform glow that fills space in the observable universe, and it’s a vital source of information about the early universe.
It’s the oldest and farthest light that any telescope can detect, and it’s considered one of the most promising ways to understand the universe’s origins and evolutionIt has the temperature predicted by the Big Bang theory, which is why it’s considered landmark evidence of the theory’s correctness. Astronomers use the patterns in CMB light to study the universe’s composition and age, understand the origins of galaxies, and search for signs of the Big Bang’s earliest moments.
