Galaxies Flashcards
What does the Big Bang Theory propose about the beginning of the universe?
The universe began as a dense point in space that rapidly expanded outward.
This theory suggests that all matter was contained in a singularity before the expansion.
What evidence did Edwin Hubble discover related to the universe?
Hubble’s observations of distant galaxies showed they were moving away from us.
What does the Doppler Red Shift indicate?
Light waves stretch as galaxies move away, indicating they are receding.
This phenomenon is used to measure the speed and distance of galaxies.
What is the Steady State Theory?
It hypothesized that the universe was expanding but not changing due to constant creation of new matter.
This theory has been disproven.
What is electromagnetic radiation (ER)?
Energy in waves that is all around us and takes on many forms, most of which we cannot see.
ER includes various types such as radio waves, microwaves, and visible light.
What is visible light?
A form of electromagnetic radiation (EMR) that travels at high speeds through space in wave-like patterns.
It is the portion of the electromagnetic spectrum that can be seen by the human eye.
What is the speed of light?
Approximately 300,000 kilometers per second.
This speed is used as a standard to measure distances in the universe.
True or False: The universe is constantly expanding.
True.
This is a key concept supported by the Big Bang Theory.
Fill in the blank: The light waves are ‘squashed’ when a galaxy is _______.
approaching.
This phenomenon is known as Blue Shift.
What does the term ‘Blue Shift’ refer to?
Light waves ‘squashed’ as galaxies approach.
This indicates that the object is moving closer to the observer.
What is an Alightyear?
The distance light travels in 1 year or about 9.5 trillion kilometers.
When you look at stars, what are you looking into?
The Past.
How do scientists estimate the age of the universe?
By observing the universe’s oldest stars and the intensity of their redshift.
How old is the universe estimated to be?
About 13.7 billion years old.
What event do scientists associate with the age of the universe?
The Big Bang.
What role does gravity play in the formation of galaxies?
Gravity pulls matter together, leading to the formation of galaxies.
What begins to form seconds after the Big Bang?
Matter.
What is a star?
A huge ball of gas that produces its own energy through nuclear reactions in its core.
What are stars primarily formed from?
Clouds of gas and dust, mostly made of Hydrogen and Helium.
What happens once a nuclear reaction begins in a star?
It gives off a variety of EMR, including light, infrared radiation, and ultraviolet radiation.
What are galaxies composed of?
Families of stars, gases, and space dust.
What galaxy is our Solar system part of?
The Milky Way Galaxy.
What forms when gravity pulls clusters of celestial bodies together?
Galaxies.
How many galaxies are estimated to be in our universe?
Billions.
What do galaxies group to form?
Galaxy clusters.
Fill in the blank: Stars are formed in clouds of gas and dust mostly made of _______.
Hydrogen & Helium.
True or False: The Milky Way is the only galaxy in the universe.
False.
What are the three main types of galaxies?
Spiral galaxies, elliptical galaxies, irregular galaxies
Barred spiral galaxies are a sub-classification of spiral galaxies.
Describe the shape of spiral galaxies.
Shaped like discs with arms spiraling from a central bulge.
What is the most common type of galaxy in the universe?
Spiral galaxies, including the Milky Way.
What do objects in a spiral galaxy revolve around?
The galaxy’s center, which is often a black hole.
How do stars and matter in elliptical galaxies move?
They revolve around the galaxy’s center in a variety of directions.
What is the appearance of elliptical galaxies?
They look a bit like footballs.
What are the characteristics of irregular galaxies?
They have shapes that are difficult to classify, such as long and thin or ring-like.
What is the largest type of galaxy?
Elliptical galaxies.
When did the solar system begin to form?
4.6 billion years ago.
What event triggered the formation of the solar system?
A nearby star went supernova and exploded.
What did the explosion of the nearby star contribute to?
It added massive amounts of energy to a cloud of gas and dust.
What was the result of the cloud of gas and dust collapsing?
It formed a spinning disk that created a star (our sun).
What caused material in the disk to form the inner terrestrial planets?
Gravity.
What are some similarities in the formation of galaxies and solar systems?
Both involve gravitational collapse and the formation of rotating disks.
What motions do galaxies and solar systems have in common?
They both exhibit orbital motions around their centers.
Why do the planets orbit the Sun rather than the black hole in the center of our galaxy?
The gravitational influence of the Sun is stronger on the planets at their distances.
