The Conversation contributed the article to Space.com's expert voices.

Sara is a research fellow at the university of technology.

It has been an exciting week with the release of photos of our universe. The images below give us a glimpse of distant galaxies that were 13 billion years old.

It's a great time to appreciate our first class ticket to the depths of the universe and how these images allow us to look back in time.

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The James Webb Space Telescope has its first photos.

Galaxy-studded image with black background of space.

The SMACS 0723 deep field image was taken with only a 12.5-hour exposure. Faint galaxies in this image emitted this light more than 13 billion years ago. (Image credit: NASA, ESA, CSA, and STScI)
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Modern time travel

Space researchers look back in time and it's what they do every day.

The speed of light is one of the best known rules of physics. When we talk about light, we're actually referring to the entire spectrum of the spectrum, which travels at an average speed of over one million miles per second.

Light is so fast that it seems to be instantaneous. It takes some time to travel across the universe.

The moon is seen as it was 1.3 seconds ago. It is only a small glimpse back in time. Light particles from the sun's surface travel just over eight minutes before they reach Earth.

The universe is more than 100,000 light-years long. The newborn stars seen in the image are thousands of light years away. The first ever writing is thought to have been invented in ancient Mesopotamia around 2,000 years ago.

Top half of the image is filled with stars and the lower half of the image contains a giant plume of orangey brown dust in the Carina Nebula.

The Carina Nebula is a birthplace for stars. (Image credit: NASA, ESA, CSA, and STScI)
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We look back in time to how things used to be. Light can be used to try to puzzle together the mystery of our universe.

What makes JWST spectacular

Space-based telescopes allow us to see light that can't be seen through the atmosphere. The Hubble Space Telescope uses both visible and visible parts of the spectrum.

The goal was to use a wide range of light. This is one of the reasons the JWST can see further back in time.

Diagram showing the JWST is optimised for longer wavelengths from visible light to infrared. Whereas Hubble is optimised for shorter wavelength covering some ultraviolet, visible and a little bit of infrared.

The electromagnetic spectrum with Hubble and JWST’s ranges. Hubble is optimised to see shorter wavelengths. These two telescopes complement each other, giving us a fuller picture of the universe. (Image credit: NASA, J. Olmsted (STScI))
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Galaxies emit a wide range of frequencies on the spectrum. Information about the different physics in a galaxy is given by all of these.

When we're close to the stars, their light hasn't changed much, and we can look at a wide range of wavelength to understand what's going on inside them.

We can't have that luxury when we're far away. Due to the expansion of the universe the light from the most distant galaxies has been stretched to longer and redder wavelength.

As the universe grew, some of the light that would have been visible to our eyes lost its energy. It is now in a different part of the spectrum. The phenomenon is called a cosmological red shift.

This is where the JWST is at its best. Hubble couldn't see the entire universe because it couldn't see the wide range of IR wavelength detected by the JWST. You have the most powerful time machine in the known universe if you combine this capability with the JWST.

Light age does not equal distance

The universe was only 100 million years old when the Bigbang happened.

We'll be able to see light from a long time ago. You're going to be hurt by the fact that the galaxies are not that far away. It would take 46 billion light-years to get there.

It's difficult to work on a large scale because of the discrepancy.

Dark energy is expanding the universe. It is thought to be a universal constant, acting equally in all areas of space time.

Dark energy affects the expansion of the universe. This is the reason why the universe is 93 billion light-years across.

We can see the effects of dark energy on a larger scale than we can on a small scale.

Sit back and enjoy

There is a remarkable time of technology in our lives. We didn't know there were other planets. We are spoilt for choice now that we know there are trillions.

We will be taking a journey through space and time each week. As NASA releases the latest news, you can stay up to date.

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