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Universe Growth
Universe Growth
Ideas shape human reality, while light and the electromagnetic spectrum explain cosmic phenomena, revealing mysteries about the universe’s expansion and nature.
Ideas shape human reality, while light and the electromagnetic spectrum explain cosmic phenomena, revealing mysteries about the universe’s expansion and nature.
Ideas
Ideas
Ideas are the invisible architecture upon which all human reality is built.
Ideas are the invisible architecture upon which all human reality is built.
Light
Light
Light is energy that moves as a wave and behaves as a particle
Light is energy that moves as a wave and behaves as a particle
We see objects because light reflects off or is emitted by them.
We see objects because light reflects off or is emitted by them.
However, visible light is just a tiny slice of a bigger thing called the electromagnetic spectrum.
However, visible light is just a tiny slice of a bigger thing called the electromagnetic spectrum.
The electromagnetic spectrum is a way of organizing all the different types of light waves
The electromagnetic spectrum is a way of organizing all the different types of light waves
Shorter wavelength means higher energy,
Shorter wavelength means higher energy,
while longer wavelength means lower energy.
while longer wavelength means lower energy.
Redshift
Redshift
When the light waves go away from us, they seem stretched apart.
When the light waves go away from us, they seem stretched apart.
When they get stretched, their wavelength gets longer,
When they get stretched, their wavelength gets longer,
pushing the color toward the red (redshift).
pushing the color toward the red (redshift).
In the beginning, energy was very high with very short wavelengths.
In the beginning, energy was very high with very short wavelengths.
As space stretched, so did the energy waves, weakening them.
As space stretched, so did the energy waves, weakening them.
This leftover radiation is the Cosmic Microwave Background, and it proves the Big Bang.
This leftover radiation is the Cosmic Microwave Background, and it proves the Big Bang.
Questions
Questions
Questions are the compasses that point toward the edges of our knowledge.
Questions are the compasses that point toward the edges of our knowledge.
Is the Universe so Uniform?
Why is the Universe so Uniform?
After the big bang, the universe was extremely uniform. Then gravity made masses clump together.
After the big bang, the universe was extremely uniform. Then gravity made masses clump together.
But at scales larger than about 300-600 million light-years, the universe is still strikingly uniform
But at scales larger than about 300-600 million light-years, the universe is still strikingly uniform
from any location and in any direction. We don’t know why.
from any location and in any direction. We don’t know why.
There’s no special spot, and no preferred way to orient a map.
There’s no special spot, and no preferred way to orient a map.
Is space expansion accelerating?
Why is expansion accelerating?
Empty space is not truly empty because particles are constantly popping in and out of existence in a vacuum,
Empty space is not truly empty because particles are constantly popping in and out of existence in a vacuum,
creating vacuum energy that may produce a repulsive gravitational effect we call dark energy.
creating vacuum energy that may produce a repulsive gravitational effect we call dark energy.
More empty space implies more dark energy, which leads to faster expansion and even more empty space.
More empty space implies more dark energy, which leads to faster expansion and even more empty space.
However, the math for this idea gives an answer that is 10¹²⁰ times too large, so we don’t actually know if dark energy comes from vacuum energy.
However, the math for this idea gives an answer that is 10¹²⁰ times too large, so we don’t actually know if dark energy comes from vacuum energy.
What is the cosmological constant?
What is the cosmological constant?
The cosmological constant is the simplest explanation for dark energy,
The cosmological constant is the simplest explanation for dark energy,
the unknown phenomenon driving the accelerated expansion of the universe.
the unknown phenomenon driving the accelerated expansion of the universe.
It is a constant energy density that fills empty space uniformly.
It is a constant energy density that fills empty space uniformly.
It does not dilute as the universe expands.
It does not dilute as the universe expands.
Is expansion related to the arrow of time?
Is expansion related to the arrow of time?
Time moves forward because the universe changes from an extremely uniform state to a less uniform one.
Time moves forward because the universe changes from an extremely uniform state to a less uniform one.
Without gravity, the arrow of time (the feeling that time moves forward from past to future) would almost disappear.
Without gravity, the arrow of time (the feeling that time moves forward from past to future) would almost disappear.
The laws of physics without gravity work exactly the same forward and backward.
The laws of physics without gravity work exactly the same forward and backward.
Videos
Videos
Dynamic visual stories to explain ideas in a way the brain processes quickly and intuitively, showing concepts in action.
Dynamic visual stories to explain ideas in a way the brain processes quickly and intuitively, showing concepts in action.
Galaxies are moving away from us as the universe expands,
Galaxies are moving away from us as the universe expands,
and that farther galaxies recede faster.
and that farther galaxies recede faster.
This expansion creates a horizon beyond which we cannot see,
This expansion creates a horizon beyond which we cannot see,
not because space ends there, but because the light cannot catch up.
not because space ends there, but because the light cannot catch up.
The universe is getting bigger because the space between galaxies is stretching,
The universe is getting bigger because the space between galaxies is stretching,
not because the galaxies are flying through empty space toward some outer edge.
not because the galaxies are flying through empty space toward some outer edge.
That means the universe does not need to be expanding into anything,
That means the universe does not need to be expanding into anything,
The universe is getting bigger over time.
The universe is getting bigger over time.
The explanation uses simple cosmology ideas to show how scientists know this from observations.
The explanation uses simple cosmology ideas to show how scientists know this from observations.
It helps people understand that the universe has been expanding since the Big Bang.
It helps people understand that the universe has been expanding since the Big Bang.
The expansion of the universe may not fit our current ideas as neatly as scientists thought.
The expansion of the universe may not fit our current ideas as neatly as scientists thought.
Modern cosmology still has big unanswered questions and mysteries to be solved.
Modern cosmology still has big unanswered questions and mysteries to be solved.
It is an easy reminder to stay humble about what we know about space.
It is an easy reminder to stay humble about what we know about space.
Books
Books
Vessels of ideas, imagination, and memory that let us enter another mind across time activating our inner world, preserving knowledge, shaping thought, and expanding consciousness.
Vessels of ideas, imagination, and memory that let us enter another mind across time activating our inner world, preserving knowledge, shaping thought, and expanding consciousness.
Visual map to understand universe’s fundamental questions
Visual map to understand universe’s fundamental questions
Listen audiobook (not available)
Listen audiobook (not available)
Or enjoy visiting a library or bookstore near you.
Or enjoy visiting a library or bookstore near you.
Glass plates revealed the key to unlock the cosmic distance scale.
Glass plates revealed the key to unlock the cosmic distance scale.
Or enjoy visiting a library or bookstore near you.
Or enjoy visiting a library or bookstore near you.
by Delia Schwartz-Perlov & Alex Vilenkin
by Delia Schwartz-Perlov & Alex Vilenkin
Complete, step-by-step tour of modern cosmology
Complete, step-by-step tour of modern cosmology
Watch video (not available)
Watch video (not available)
Listen audiobook (not available)
Listen audiobook (not available)
Or enjoy visiting a library or bookstore near you.
Life’s meaning arises from physics and purpose.
Life’s meaning arises from physics and purpose.
Or enjoy visiting a library or bookstore near you.
Or enjoy visiting a library or bookstore near you.