Galaxies Through Time: Discover How to Look Back in Time and Study the History of the Universe

SciTech Daily

23 Sept 202002:39

Summary

TLDRThe video discusses how telescopes allow us to look back in time by viewing distant galaxies at various stages of their evolution. Galaxies change over billions of years, growing, colliding, and forming new stars. By studying images of galaxies throughout the universe’s history, astronomers can observe patterns of mergers, growth, and the formation of supermassive black holes. However, early galaxy evolution remains unclear due to the expanding universe stretching the light from the first galaxies. NASA’s James Webb Space Telescope aims to detect this ancient light, filling in missing chapters of galactic evolution and answering fundamental questions about the universe.

Takeaways

🔭 Telescopes allow us to see distant galaxies and light from long ago, giving us a glimpse into the universe's past.
🌌 Galaxies evolve over time, growing, colliding, merging, and forming new stars.
🌀 The earliest galaxies we have observed are smaller and less structured compared to those in the nearby universe.
📈 By studying galaxies at different distances and eras, astronomers can trace patterns in galactic evolution.
💥 Some eras in the universe's history were marked by frequent mergers and new star formations.
🕳️ Growth into larger galaxies is often associated with the presence of supermassive black holes at their centers.
📖 The universe's galactic history is like a story, but the beginning is still largely unknown due to the limitations of current telescopes.
🌌 The universe is expanding, stretching the wavelength of light from the earliest galaxies, making them harder to detect.
🔭 NASA's James Webb Space Telescope is designed to detect the stretched light from the first galaxies, filling in gaps in our understanding.
❓ The telescope will provide insights into major questions such as how the universe works and how we came to be.

Q & A

What does viewing distant galaxies tell us about the past?
-Viewing distant galaxies allows astronomers to see light that was emitted long ago, essentially looking back in time. By observing these galaxies, we can study how they appeared and behaved in earlier eras.
How do galaxies evolve over time according to astronomers?
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Outlines

00:00

🔭 The Role of Telescopes in Studying Galaxies Over Time

Telescopes give us the ability to see galaxies far away and view light that was emitted long ago, allowing us to observe the universe at various stages throughout history. By looking at galaxies from different eras, astronomers have gathered evidence that they evolve over time. Galaxies grow, collide, merge, and form new stars. The earliest galaxies observed tend to be smaller and less structured than those closer to us. This raises the question of how galaxies have evolved over billions of years, leading to the formation of structures like our own Milky Way.

📖 Uncovering the Forces Behind Galactic Evolution

Astronomers aim to understand the forces that drive galactic changes by studying images of galaxies at different stages of the universe's history. These images create a 'galactic flipbook,' revealing patterns. Some periods of cosmic history were marked by intense star formation and galactic mergers, while others saw galaxies grow larger, often centered around supermassive black holes. These observations provide an overview of galaxy development, but the earliest phases of this story remain unknown, as the light from the first galaxies is beyond the reach of current telescopes.

🚀 The Challenge of Observing the First Galaxies

The universe is expanding, and as space stretches, so does the wavelength of the light emitted by the first galaxies. This phenomenon makes it difficult for even the most advanced telescopes to detect them. Understanding these early galaxies is crucial to comprehending the full story of the universe's evolution. Without knowledge of the universe's beginnings, key insights into galaxy formation and development remain missing.

🔍 NASA’s James Webb Space Telescope: A New Era in Cosmic Exploration

The James Webb Space Telescope was specifically designed to detect the ancient light from the first galaxies. By capturing this light, Webb will provide new data that fills in the gaps in our understanding of galactic history. It will also allow astronomers to examine the middle stages of galaxy evolution with greater detail, shedding light on some of the universe's most fundamental questions, such as how the universe operates and how life in our galaxy came to be.

Mindmap

Keywords

💡Galaxies

Galaxies are vast systems composed of stars, stellar remnants, gas, dust, and dark matter, bound together by gravity. In the video, galaxies are central to the theme as the evolution and growth of galaxies over time are explored. The script mentions how galaxies collide, merge, and form new stars, illustrating the dynamic processes that shape them.

💡Telescopes

Telescopes are instruments that allow astronomers to observe distant objects by gathering and magnifying light. The video highlights how telescopes enable us to see galaxies from different eras, which is essential for studying their evolution. Telescopes like the James Webb Space Telescope are mentioned as tools to detect ancient light from the earliest galaxies.

💡Light

Light, specifically from distant galaxies, plays a critical role in the video. It is described as a means to look back in time because the light from faraway galaxies was emitted long ago. This ancient light allows astronomers to study how galaxies evolved over billions of years. The concept of stretched light, or redshift, is introduced in relation to the expanding universe.

💡Galaxy evolution

Galaxy evolution refers to the changes that galaxies undergo over billions of years. The video outlines how galaxies grow, collide, and merge, eventually forming new stars and becoming larger and more structured. The evolution of galaxies from small, unstructured early forms to the complex systems we see today, such as the Milky Way, is a key theme.

💡Star formation

Star formation is the process by which dense regions of molecular clouds collapse and form new stars. The video references certain eras in the universe's history where there were bursts of star formation, contributing to the growth and evolution of galaxies. Star formation is a key factor in how galaxies grow and change over time.

💡Mergers

Mergers are events where two or more galaxies collide and combine to form a larger galaxy. The video highlights that some eras were significant for galaxy mergers, which played a crucial role in their evolution. These mergers can lead to new star formations and the growth of supermassive black holes at the centers of galaxies.

💡Supermassive black holes

Supermassive black holes are extremely dense objects found at the centers of most large galaxies, including the Milky Way. The video mentions that as galaxies grow, many develop supermassive black holes at their cores. These black holes influence galaxy structure and dynamics and are an important part of understanding galactic evolution.

💡Expanding universe

The expanding universe is the concept that space itself is stretching, causing galaxies to move apart from each other over time. This expansion also stretches the wavelength of light, a phenomenon called redshift, making it more challenging to detect the light from the earliest galaxies. The video explains that the expanding universe is why the light from the first galaxies is beyond the reach of many telescopes.

💡James Webb Space Telescope

The James Webb Space Telescope (JWST) is a powerful observatory designed to detect ancient, stretched light from the first galaxies. The video describes how this telescope will help fill in the 'blank pages' of the story of galaxy evolution by observing the earliest galaxies in greater detail. JWST is crucial for answering fundamental questions about the universe's history and structure.

💡Redshift

Redshift is the phenomenon where the wavelength of light is stretched as the universe expands, causing the light from distant galaxies to shift towards the red end of the spectrum. The video explains that redshift makes it harder to detect light from the first galaxies. The James Webb Space Telescope is specially designed to observe these redshifted, ancient light signals.

Highlights

Telescopes allow us to see light that was emitted long ago, enabling a look back in time.

Galaxies change over time, growing, colliding, merging, and forming new stars.

Distant, early galaxies tend to be smaller and less structured than nearby galaxies.

Astronomers can create a 'galactic flipbook' by viewing galaxies at different distances and eras.

Patterns in galactic evolution emerge, showing eras of star formation and mergers.

Some eras in the universe were marked by the growth of galaxies with supermassive black holes.

The earliest stages of the universe remain largely unknown due to the expansion of space.

The expansion of the universe stretches the light from the first galaxies, making it difficult to detect.

Understanding the early universe is crucial, as missing the beginning hampers comprehension of galactic evolution.

NASA's James Webb Space Telescope is designed to detect the ancient, stretched light from the first galaxies.

The James Webb Space Telescope will fill in gaps in our knowledge of galactic history.

Webb will provide detailed insights into the middle eras of galaxy evolution.

Galactic evolution helps answer fundamental questions about the universe, such as 'How does the universe work?'

Seeing the light from the first galaxies offers a more complete understanding of galaxy evolution.

The story of the universe and its galaxies is incomplete without the light from the earliest galaxies.