How Do We Know The Age Of The Universe?

Cosmoknowledge

16 Sept 201802:03

Summary

TLDRThe script delves into the estimation of the universe's age, believed to be approximately 13.7 billion years old. This figure is derived from the observation of galaxies' distances and velocities, which are receding from us at rates proportional to their distances, a concept rooted in the Big Bang theory. Scientists use the expansion rate to calculate the universe's history and age by examining the Cosmic Microwave Background (CMB), the relic radiation from the Big Bang. Observations from the WMAP and Planck spacecraft have refined our understanding, confirming the universe's age as of 2013.

Takeaways

🌌 The estimated age of the universe is approximately 13.7 billion years old.
📏 This age is determined by measuring the distances and radial velocities of galaxies, which are moving away from us.
🚀 The speed at which galaxies are receding is proportional to their distance, indicating an expanding universe.
⏳ Scientists can calculate the time elapsed since the Big Bang by understanding the universe's expansion rate.
🔍 The history of the expansion rate can be inferred from the current density and composition of the universe.
🌡 Observations of the Cosmic Microwave Background (CMB) are crucial for determining the universe's parameters.
🛰️ Two spacecraft, WMAP (Wilkinson Microwave Anisotropy Probe) and Planck, have measured the CMB across the sky.
🌟 The WMAP and Planck missions improved upon previous observations with greater sensitivity and resolution.
📊 As of 2013, data from these missions has set the age of the universe at about 13.7 billion years.
🎶 The script is accompanied by music, suggesting an educational or documentary format.

Q & A

What is the estimated age of the universe?
-The estimated age of the universe is around 13.7 billion years old.
How is the age of the universe calculated?
-The age of the universe is calculated by measuring the distances and radial velocities of other galaxies, most of which are moving away from us at speeds proportional to their distances. Scientists work backwards to the point of singularity using the known expansion rate to determine the time passed since the Big Bang.
What is the significance of the galaxies' movement in relation to their distances?
-The movement of galaxies away from us at speeds proportional to their distances is evidence of the universe's expansion, which helps in calculating the age of the universe.
What role does the expansion rate play in determining the universe's age?
-The expansion rate is crucial as it allows scientists to work backwards from the current state of the universe to the initial singularity, thus helping to calculate the time elapsed since the Big Bang.
Why is the history of the expansion rate important?
-The history of the expansion rate is important because it provides insights into how the universe has evolved over time, which is essential for accurately calculating its age.
What is the Cosmic Microwave Background (CMB) and how does it help in understanding the universe's parameters?
-The Cosmic Microwave Background is the relic radiation left over from the Big Bang. Observations of the CMB help cosmologists determine parameters such as the universe's density and composition, which are vital for understanding its history and age.
Which two spacecraft have significantly contributed to the study of the Cosmic Microwave Background?
-The Wilkinson Microwave Anisotropy Probe (WMAP) and the Planck spacecraft have made significant contributions to the study of the Cosmic Microwave Background, improving upon previous observations with greater sensitivity and resolution.
How did the Planck spacecraft improve upon WMAP's observations?
-The Planck spacecraft improved upon WMAP's observations by providing measurements of the Cosmic Microwave Background with greater sensitivity and resolution, leading to more accurate data on the universe's age and parameters.
What was the age of the universe as determined by the Planck spacecraft's data as of 2013?
-As of 2013, the Planck spacecraft's data set the age of the universe at about 13.7 billion years.
What does the term 'singularity' refer to in the context of the universe's history?
-In the context of the universe's history, 'singularity' refers to the initial state before the Big Bang, where all matter and energy were contained in an infinitely small, dense point.
How does the study of the universe's density and composition contribute to our understanding of its age?
-The study of the universe's density and composition helps scientists understand how the universe has expanded and cooled since the Big Bang, which in turn contributes to more accurate estimations of its age.

Outlines

00:00

🌌 Universe Age Calculation

The script discusses the estimation of the universe's age, which is believed to be around 13.7 billion years old. This estimation is derived from observing the distances and radial velocities of galaxies, which are moving away from us at speeds that increase with their distance—a phenomenon known as Hubble's Law. Scientists use the expansion rate to calculate the time elapsed since the Big Bang. Additionally, understanding the universe's expansion history is crucial and can be inferred from its current density and composition. Observations of the Cosmic Microwave Background (CMB), the radiation left from the Big Bang, help determine these parameters. Two spacecraft, the Wilkinson Microwave Anisotropy Probe (WMAP) and Planck, have significantly contributed to these measurements, with the latter improving upon the former's observations. As of 2013, the data collected has set the universe's age at approximately 13.7 billion years.

Mindmap

Keywords

💡Universe

The universe refers to the totality of space, time, matter, energy, and the phenomena occurring within it. It is the central theme of the video, discussing its age and the methods used to calculate it. The script mentions the universe's estimated age of 13.7 billion years, which is a fundamental concept in understanding the scale and history of the cosmos.

💡Age of the Universe

The age of the universe is a measure of the time elapsed since the Big Bang, the event that initiated the expansion of the universe. The video script provides the current scientific consensus of approximately 13.7 billion years, derived from observations of cosmic phenomena, and is crucial for understanding the timeline of the universe's evolution.

💡Big Bang

The Big Bang is the prevailing cosmological model explaining the origin of the universe. It suggests that the universe began as an infinitely dense and hot point (singularity) and has been expanding ever since. The script refers to the Big Bang as the starting point for calculating the universe's age and the basis for understanding its expansion.

💡Galaxies

Galaxies are vast systems of stars, dust, and dark matter bound together by gravity. In the script, galaxies are mentioned in the context of measuring their distances and radial velocities, which are essential for understanding the expansion of the universe and its age.

💡Expansion Rate

The expansion rate of the universe refers to the speed at which it is growing or stretching over time. The script explains that knowing this rate is crucial for scientists to work backward to the singularity and calculate the universe's age, highlighting the importance of this concept in cosmology.

💡Cosmologists

Cosmologists are scientists who study the origins, evolution, and eventual fate of the universe. The video script mentions that cosmologists use observations to determine the universe's parameters, such as its age, density, and composition, emphasizing their role in understanding cosmic history.

💡Cosmic Microwave Background (CMB)

The Cosmic Microwave Background is a remnant radiation from the early universe, often referred to as the 'afterglow' of the Big Bang. The script describes how observations of the CMB are used to understand the universe's history and determine its parameters, making it a key concept in the study of cosmology.

💡Wilkinson Microwave Anisotropy Probe (WMAP)

WMAP is a spacecraft that has measured the Cosmic Microwave Background across the full sky, providing valuable data on the universe's density and composition. The script mentions WMAP as one of the two spacecraft that have contributed to the current understanding of the universe's age.

💡Planck Spacecraft

The Planck spacecraft is another instrument that has measured the Cosmic Microwave Background with greater sensitivity and resolution than WMAP. The script notes that Planck improved upon WMAP's observations, indicating its importance in refining the age estimate of the universe.

💡Density

In the context of the universe, density refers to the distribution of matter and energy within a given volume. The script explains that the current density of the universe is a parameter studied by cosmologists to understand its expansion history and calculate its age.

💡Composition

The composition of the universe pertains to the relative amounts of different types of matter and energy it contains, such as ordinary matter, dark matter, and dark energy. The script mentions that understanding the universe's composition is essential for cosmologists to study its evolution and determine its age.

Highlights

The estimated age of the universe is around 13.7 billion years old.

This age is determined by measuring distances and radial velocities of galaxies.

Galaxies are observed to be moving away from us, with speeds proportional to their distances.

The expansion rate of the universe allows scientists to calculate its age from the Big Bang.

Understanding the history of the expansion rate is essential for age calculation.

Cosmologists study the Cosmic Microwave Background (CMB) to learn about the universe's expansion history.

The CMB is relic radiation from the Big Bang.

Two spacecraft, WMAP and Planck, have measured the CMB across the full sky.

WMAP stands for Wilkinson Microwave Anisotropy Probe.

Planck spacecraft improved upon WMAP's observations with greater sensitivity and resolution.

As of 2013, combined data from these spacecraft set the universe's age at about 13.7 billion years.

The universe's current density and composition are crucial for understanding its expansion history.

Scientists work backwards from the singularity to the Big Bang to calculate the universe's age.

The Big Bang theory is supported by observations of the universe's expansion.

The universe's expansion rate is a key factor in determining its age.

The study of the CMB provides parameters for understanding the universe's early state.

The CMB's anisotropies reveal information about the universe's composition and density.

Advancements in spacecraft technology have enhanced our understanding of the universe's age.