Astrophysics Flashcards
What is the structure of the universe?
Universe → Galaxies → Solar Systems → Stars, Planets, Moons, Asteroids, and Comets
Define a galaxy.
A collection of billions of stars
What is the Milky Way?
Our galaxy
What is a light year?
Distance light travels in one year (9.46×10^12 km)
What is a nebula?
A cloud of gas and dust that collapses due to gravity
What leads to the formation of a protostar?
Increasing temperature and pressure leading to nuclear fusion
What is the main sequence star?
Stable stage where outward pressure from fusion balances gravity
What happens when hydrogen runs out in a star?
It becomes a Red Giant/Supergiant and heavier elements fuse
What is the end stage for small-medium stars?
White Dwarf → Black Dwarf
What is the end stage for large stars?
Supernova → Neutron Star or Black Hole
Define a black hole.
A region of space with gravity so strong that not even light can escape
How is a black hole formed?
From the collapse of massive stars after a supernova
What is the event horizon?
The boundary beyond which nothing can escape from a black hole
What does the Big Bang Theory propose?
The universe began as a singularity about 13.8 billion years ago and has been expanding
What is cosmic microwave background radiation (CMB)?
Remnant heat from the Big Bang
What does redshift indicate?
Galaxies moving away have light shifted to the red end of the spectrum
What is Hubble’s Law?
v = H0d, where v = recession velocity, H0 = Hubble constant, d = distance from Earth
What does apparent magnitude measure?
How bright a star appears from Earth
What is absolute magnitude?
Brightness of a star if it were 10 parsecs away
Define a parsec.
A unit of distance equal to 3.26 light-years
What is Newton’s Law of Gravitation?
F = G(m1m2/r^2), where F = force, G = gravitational constant, m1,m2 = masses, r = distance
What role does gravitational force play in orbits?
Provides the centripetal force for orbital motion
What are natural satellites?
Moons (e.g., Earth’s Moon)
What are artificial satellites used for?
Communication, GPS, and observation
What is a geostationary orbit?
Satellites appear stationary relative to Earth, orbiting once per day
True or False: The universe is expanding.
True
List three advantages of satellites in social contexts.
- Revolutionize global communication
- Inspire innovation and encourage STEM education
- Improve quality of life through weather and navigation
List three disadvantages of satellites in social contexts.
- Raise privacy concerns due to surveillance
- Exacerbate digital and social inequality
- May not be prioritized in developing nations
List three political advantages of satellites.
- Enable global communication
- Promote peaceful relations between nations
- Enhance national security
List three political disadvantages of satellites.
- Create geopolitical dependencies
- Increase risks of conflict in space
- Divert funds from pressing political issues
List three health advantages of satellites.
- Improve healthcare access through telemedicine
- Help track global health crises
- Contribute to medical advancements
List three health disadvantages of satellites.
- Pose risks from space radiation exposure
- Cause psychological stress in professionals
- Hazards from space debris collisions
List three environmental advantages of satellites.
- Monitor deforestation and greenhouse gases
- Aid in understanding ecosystems
- Provide early warnings for natural disasters
List three environmental disadvantages of satellites.
- Pollute Earth’s orbit with space debris
- Contribute to greenhouse gas emissions
- Harm ecosystems through mining for materials
