How small are we in the scale of the universe? - Alex Hofeldt

Summary

In 1995, scientists used the Hubble Telescope to capture an image of over 1,500 galaxies in a seemingly empty part of the sky. This Deep Field image revealed the vastness of the universe, showing galaxies that existed over 13 billion years ago. Later, an updated image, the eXtreme Deep Field (XDF), displayed 10,000 galaxies, many of them incredibly distant. These images provide insight into the universe's infancy and homogeneity, reminding us of how small we are yet capable of exploring and imagining the mysteries of the cosmos.

Takeaways

• 🔭 Scientists used the Hubble Telescope in 1995 to capture images of a seemingly empty part of the sky near the Big Dipper.
• 🌌 After ten days and 150 hours of exposure, the telescope revealed over 1,500 galaxies in a tiny portion of the universe.
• 🖊️ The area captured by the Hubble Telescope is comparable to the size of a ballpoint pen tip held at arm's length.
• 🌍 The image represented just a small fraction of the night sky, about one two-millionth of it.
• 🌞 The Milky Way contains 100 to 400 billion stars, including the Sun, while each galaxy in the Deep Field contains billions of stars.
• 🚀 Apollo 8 astronauts traveled 380,000 kilometers to the Moon, but that distance is minuscule compared to the vastness of space.
• 🌠 In the 2000s, scientists captured an even deeper image, known as the eXtreme Deep Field (XDF), showing 10,000 galaxies, some over 13 billion years old.
• ⏳ The Deep Field images act as time machines, allowing scientists to observe galaxies as they were less than a billion years after the Big Bang.
• 🧪 These images show that the universe is homogeneous, with different regions of the sky appearing similar despite vast distances.
• 🌌 The script highlights the enormity of the universe and humanity’s ability to wonder, explore, and question the vast unknown beyond our vision.

Q & A

What area of the sky did scientists point the Hubble Telescope at in 1995?

Scientists pointed the Hubble Telescope at an area near the Big Dipper, a dark spot in the sky free from light pollution.

Why was the Hubble Telescope's Deep Field experiment considered risky?

The experiment was risky because the telescope was aimed at an apparently empty part of the sky, with no guarantee that anything significant would be captured.

What did the Hubble Telescope capture in its first Deep Field image?

The Hubble Telescope captured over 1,500 distinct galaxies in a tiny sliver of the universe.

How small was the area of the sky observed by the Hubble Telescope compared to the whole sky?

The area observed was roughly the size of the tip of a ballpoint pen held at arm’s length, representing about one two-millionth of the night sky.

What is the significance of the Deep Field images in terms of understanding the universe?

The Deep Field images show a vast number of galaxies in a tiny region, allowing scientists to study the structure and distribution of galaxies across space and time, including those from over 13 billion years ago.

How far into the universe and back in time do the Deep Field images allow us to see?

The images allow us to see galaxies that existed over 13 billion years ago, less than a billion years after the Big Bang.

What did scientists discover when they took a second, longer exposure with the Hubble Telescope?

In a second exposure over four months, scientists observed around 10,000 galaxies, with the data contributing to the creation of the eXtreme Deep Field (XDF) image.

What is the significance of the eXtreme Deep Field (XDF) image?

The XDF combines over ten years of observations, showing galaxies so distant and faint that they are one ten-billionth as bright as what the human eye can see.

What does it mean when scientists say the universe is homogeneous?

It means that images taken at different parts of the sky look similar, suggesting that the universe has a consistent structure across vast distances.

How does the script encourage viewers to reflect on their place in the universe?

The script encourages viewers to contemplate the enormity of the universe and our small place within it, but also highlights humanity’s capacity to wonder, explore, and investigate the unknown.

Outlines

00:00

🔭 Hubble's Risky Endeavor

In 1995, scientists directed the Hubble Telescope toward a seemingly empty part of the sky near the Big Dipper, taking a risky gamble to explore the unknown. Over 150 hours of exposure revealed something extraordinary: over 1,500 galaxies captured in just a small fraction of the universe. The discovery marked a significant milestone in space observation, showing the potential of deep space imaging.

🖋️ A Tiny Perspective on a Vast Universe

The scale of the Hubble's Deep Field image is astonishing. If you hold a ballpoint pen at arm's length and focus on the tip, that's the tiny section of the sky that Hubble captured. In that small portion, over 3,000 galaxies were discovered, representing just a fraction of the universe—approximately one two-millionth of the night sky. This gives a humbling perspective of the vastness of space.

🌍 Humanity in Comparison to Cosmic Distances

A striking comparison is drawn between human measurements and cosmic distances. With an average height of 1.7 meters, lining up 7.5 million humans would equate to Earth's diameter of 12,700 kilometers. From the Moon to the Sun and beyond, these figures illustrate the enormous scales in the universe, with the Milky Way containing billions of stars—each galaxy captured by Hubble holding countless more.

🌌 Evolution of Hubble’s Deep Field Imaging

A decade after the first Deep Field image, the Hubble Telescope took another long exposure, revealing 10,000 galaxies. The Extreme Deep Field (XDF) image was created by compiling over ten years of data, showing galaxies so distant and faint that they are just one ten-billionth the brightness of what the human eye can see. The XDF allowed scientists to peer even further into the depths of space.

⏳ Time Travel through Space

Deep Field images act like time machines. Due to the finite speed of light, the light captured by Hubble comes from galaxies that existed over 13 billion years ago, less than a billion years after the Big Bang. These observations allow scientists to study the universe in its infancy, providing a window into the early formation of galaxies and the evolution of the cosmos.

🪐 The Homogeneous Universe

One of the key discoveries from the Deep Field images is the homogeneity of the universe. No matter where scientists pointed the Hubble Telescope, the images taken across different regions of the sky appeared similar. This uniformity, despite the vast distances involved, provides an incredible insight into the structure of the universe.

🌠 The Human Spirit of Exploration

Though humans are minuscule in comparison to the vastness of the universe, we possess a unique capacity to wonder, question, explore, and imagine. The Hubble Deep Field images remind us of the immensity beyond our vision and encourage us to reflect on our place within the cosmos. The next time you look up at the night sky, consider the incredible distances and mysteries that lie between the stars.

Keywords

💡Hubble Telescope

The Hubble Telescope is a space telescope launched by NASA in 1990, providing high-resolution images of space. In the video, the Hubble Telescope plays a central role as it captured the groundbreaking Deep Field image of over 1,500 galaxies. Its advanced optics allowed scientists to observe parts of the universe previously unseen, helping them study distant galaxies and the early universe.

💡Deep Field Image

The Deep Field Image refers to the long-exposure image taken by the Hubble Telescope, revealing over 1,500 galaxies in a small, seemingly empty part of the sky. This image highlighted the vast number of galaxies in the universe and served as a 'time machine' to observe galaxies from over 13 billion years ago. The concept illustrates the theme of cosmic exploration and the universe’s immense scale.

💡Galaxy

A galaxy is a massive system of stars, stellar remnants, interstellar gas, dust, and dark matter, bound together by gravity. In the video, galaxies are the primary objects captured in the Deep Field images, with each containing billions of stars. The video emphasizes how each tiny point of light in the images represents entire galaxies, underscoring the vastness of the universe.

💡Light Speed

Light speed refers to the constant speed at which light travels through space, approximately 299,792 kilometers per second. The video explains how the finite speed of light means that images of distant galaxies are actually glimpses into the past. This concept is crucial for understanding how the Deep Field images allow us to look back in time, revealing the universe as it was billions of years ago.

💡XDF (eXtreme Deep Field)

The eXtreme Deep Field (XDF) is an even more detailed image captured by the Hubble Telescope after the initial Deep Field image. It combines over 10 years of photographs, revealing 10,000 galaxies, some so distant they are one ten-billionth the brightness visible to the human eye. This development pushed the boundaries of what scientists could observe, contributing to our understanding of the early universe.

💡Big Bang

The Big Bang refers to the event that is believed to have created the universe approximately 13.8 billion years ago. In the video, it is mentioned when discussing how the Deep Field images allow scientists to observe galaxies as they appeared less than a billion years after the Big Bang. This concept is crucial for understanding the origins of the universe and how the Deep Field images help study its early stages.

💡Homogeneous Universe

A homogeneous universe is one in which, on a large scale, matter and energy are distributed uniformly. The video highlights how Deep Field images from different parts of the sky reveal similar structures, supporting the idea that the universe is homogeneous. This discovery is significant because it challenges expectations given the vast distances involved, contributing to our understanding of cosmic structure.

💡Finite Speed of Light

The finite speed of light means that light takes time to travel across space, and thus, we see distant objects as they were in the past. This concept is critical in the video as it explains why the Deep Field images function like 'time machines,' allowing us to see galaxies as they existed billions of years ago. The idea of looking back in time is central to the video’s exploration of the early universe.

💡Apollo 8

Apollo 8 was the first crewed spacecraft to orbit the Moon, traveling 380,000 kilometers from Earth in 1968. The video uses the distance of Apollo 8’s journey as a point of comparison to emphasize the vast scales involved in space exploration, particularly when considering the enormous distances to the galaxies observed in the Deep Field images.

💡Scale of the Universe

The scale of the universe refers to the enormous size and distance of objects in space, often difficult to comprehend. The video emphasizes this concept by comparing the area of the Deep Field image to the size of a ballpoint pen tip held at arm’s length. The idea is further illustrated through comparisons to human height, the Earth’s diameter, and distances in space, demonstrating the vastness of what the Hubble Telescope captured.

Highlights

In 1995, scientists used the Hubble Telescope to focus on a seemingly empty area near the Big Dipper for 10 days.

The Hubble Telescope captured an image of over 1,500 galaxies in a small area of the sky.

The image revealed that even a tiny portion of the sky contains an immense number of galaxies.

The Deep Field image represents a tiny speck of the universe, approximately one two-millionth of the night sky.

A comparison shows that the Deep Field view is like seeing galaxies at the size of the tip of a ballpoint pen held at arm’s length.

The Milky Way contains 100 to 400 billion stars, and every galaxy in the Deep Field image holds billions of stars.

Over 10,000 galaxies were observed in a subsequent long-exposure image called the eXtreme Deep Field (XDF).

The XDF image was created by combining over 10 years of photographs taken by the Hubble Telescope.

Some galaxies in the XDF are so distant that their light is one ten-billionth the brightness that the human eye can detect.

The Deep Field images allow scientists to study galaxies as they existed over 13 billion years ago.

These images give insight into the universe as it was less than a billion years after the Big Bang.

The Deep Field images show that the universe is homogeneous, meaning different parts of the sky look similar on a large scale.

The consistency across different regions of the sky is surprising, given the vastness of the universe.

The finite speed of light makes the Deep Field images a window into the ancient universe, showing galaxies in their infancy.

The Deep Field images remind us of our smallness in the universe, but also our capacity to wonder and explore beyond what we can see.

Transcripts

In the winter of 1995,

scientists pointed the Hubble Telescope at an area of the sky near the Big Dipper,

a spot that was dark and out of the way of light pollution from surrounding stars.

The location was apparently empty, and the whole endeavor was risky.

What, if anything, was going to show up?

Over ten consecutive days,

the telescope took close to 150 hours of exposure of that same area.

And what came back was nothing short of spectacular:

an image of over 1,500 distinct galaxies

glimmering in a tiny sliver of the universe.

Now, let's take a step back to understand the scale of this image.

If you were to take a ballpoint pen

and hold it at arm's length in front of the night sky,

focusing on its very tip,

that is what the Hubble Telescope captured in its first Deep Field image.

In other words,

those 3,000 galaxies were seen in just a tiny speck of the universe,

approximately one two-millionth of the night sky.

To put all this in perspective,

the average human measures about 1.7 meters.

With Earth's diameter at 12,700 kilometers,

that's nearly 7.5 million humans lined up head to toe.

The Apollo 8 astronauts flew a distance of 380,000 kilometers to the Moon.

And our relatively small Sun has a diameter of about 1.4 million kilometers,

or 110 times the Earth's diameter.

A step further,

the Milky Way holds somewhere between 100 to 400 billion stars,

including our Sun.

And each glowing dot of a galaxy captured in the Deep Field image

contains billions of stars at the very least.

Almost a decade after taking the Deep Field image,

scientists adjusted the optics on the Hubble Telescope

and took another long exposure over a period of about four months.

This time, they observed 10,000 galaxies.

Half of these galaxies have since been analyzed more clearly

in what's known as the eXtreme Deep Field image,

or XDF.

By combining over ten years of photographs,

the XDF shows galaxies so distant

that they're only one ten-billionth the brightness

that the human eye can perceive.

So, what can we learn about the universe from the Deep Field images?

In a study of the universe, space and time are inextricably linked.

That's because of the finite speed of light.

So the Deep Field images are like time machines to the ancient universe.

They reach so far into space and time

that we can observe galaxies that existed over 13 billion years ago.

This means we're looking at the universe as it was

less than a billion years after the Big Bang,

and it allows scientists to research galaxies in their infancy.

The Deep Field images have also shown that the universe is homogeneous.

That is, images taken at different spots in the sky look similar.

That's incredible when we think about how vast the universe is.

Why would we expect it to be the same across such huge distances?

On the scale of a galaxy, let alone the universe,

we're smaller than we can readily comprehend,

but we do have the capacity to wonder,

to question,

to explore,

to investigate,

and to imagine.

So the next time you stand gazing up at the night sky,

take a moment to think about the enormity of what is beyond your vision,

out in the dark spaces between the stars.