Scale of the Universe
What is the universe made of?
All matter, space, and time.
What are the three main shapes of galaxies?
Spiral, Elliptical, Irregular.
What is a wave?
A disturbance that spreads from where it was created.
What is the speed of light in space?
About 670,000,000 mph.
In a transverse wave, how do particles move compared to the direction of the wave?
Particles move perpendicular to the wave’s direction.
Put these in order from smallest to largest: planet, galaxy, solar system, universe, star
Planet - Star - galaxy - solar system - universe
What shape is the Milky Way galaxy?
A barred spiral.
What’s the difference between transverse and longitudinal waves?
Transverse = particles move perpendicular; Longitudinal = particles move parallel.
Which EM wave is larger than a building?
Radio waves.
In a longitudinal wave, how do particles move compared to the wave’s direction?
Particles move parallel to the wave’s direction.
How old is the universe?
~13.8 Billion Years
What is Sagittarius A*?
A black hole at the center of the Milky Way.
What is a pulse wave?
A sudden disturbance where only one or a few waves are generated (e.g., pebble, thunder).
What EM wave is mostly absorbed by Earth’s atmosphere but is needed for life?
Ultraviolet (UV).
Give an example of a transverse wave and a longitudinal wave.
Transverse → light or water waves; Longitudinal → sound waves.
What is a galactic cluster?
A large group of galaxies bound by gravity (50+ galaxies).
What are star clusters? Name two types.
Groups of stars bound by gravity; Globular clusters and Open clusters.
Why can’t sound waves travel through space?
They need a medium (matter), and space is a vacuum.
Which EM wave is used for medical imaging like bone scans?
X-Rays
What are the high-pressure and low-pressure regions called in a longitudinal wave?
Compressions (high pressure) and Rarefactions (low pressure).
What is the Local Group?
The group of about 54 galaxies that includes the Milky Way.
What is Proxima b?
The closest known exoplanet, orbiting Proxima Centauri, possibly in the habitable zone.
What two components make up an electromagnetic wave?
An electric field and a magnetic field.
What is a Gamma Knife used for?
To kill tumors in the brain using precise gamma radiation.
Why can light travel through space but sound cannot?
Light (a transverse electromagnetic wave) doesn’t need a medium, but sound (a longitudinal wave) requires a medium like air, liquid, or solid.