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How NASA’s James Webb telescope can see back in time

The Sun, March 21, 2022 7:00PM Kids News

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The James Webb space telescope, seen here separating from the Ariane 5 rocket in January, is so powerful it is expected to see stars and galaxies created after the Big Bang* some 250 million years ago. Picture: AFP Photo/NASA TV media_cameraThe James Webb space telescope, seen here separating from the Ariane 5 rocket in January, is so powerful it is expected to see stars and galaxies created after the Big Bang* some 250 million years ago. Picture: AFP Photo/NASA TV

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Storytellers, scientists and dreamers have always been fascinated by the idea of time travel – now NASA’s new James Webb telescope is the closest anyone has come so far.

The new instrument is the most powerful telescope ever built. It should give us unprecedented* views of the universe and it will technically be able to look back in time. The “time-travelling” aspect of the James Webb telescope is all to do with how long it takes light to travel through the universe.

Breaking News Breaking News =?UTF-8?Q?An_artist=E2=80=99s_impression_of_the_James_Webb_Space_Tel?=	=?UTF-8?Q?escope_in_operation=2E_Credit=3A_NASA_GSFC=2FCIL=2FAdriana_Manrique_?=	=?UTF-8?Q?Gutierrez?= media_cameraAn artist’s impression of the James Webb Space Telescope in operation. Credit: NASA GSFC/CIL/Adriana Manrique Gutierrez

How can a telescope time travel?

Webb is the biggest and most complex telescope of its kind, fitted with all sorts of sophisticated* technology.

Its aim is to uncover the hidden depths of our universe, peering at the faint light of early stars and galaxies created after the Big Bang* some 250 million years ago.

The advanced tech will be able to see through dense dust clouds that cover distant planets.

Getting past this point could help lead towards identifying signs of extraterrestrial* organisms*, but experts doubt we’ll find actual living aliens with it.

media_cameraThe James Webb space telescope is set to explore galaxies from the cosmic dawn to the present day. Picture: James Webb space telescope/NASA

Okay, probably no aliens – so can we get back to that time travel question?

It takes a really long time for light to travel, so we can basically look a long way back in time to when stars and planets formed after the Big Bang.

The light that reaches the James Webb telescope may have travelled millions of kilometres from a star that no longer even exists.

If we use the telescope to look far enough into the distance, light from close to the beginning of the universe will be visible.

Scientists think some parts of the universe will remain impossible to see.

media_cameraEngineers monitored the unfolding of the final mirror panel on January 8 at the beginning of the James Webb telescope’s deployment to study every phase of cosmic history. Picture: Bill Ingalls/NASA/AFP

That’s because the universe is thought to be expanding, so some light sources are constantly moving away from us.

That means their light may never be able to reach the James Webb telescope.

However, it is hoped that this powerful instrument will teach us about how the universe is expanding – a process that astronomers believe is driven by something called “dark energy*”.

The James Webb telescope should be able to image stars so accurately that it can measure the dark space between them.

Checking on these measurements could determine how fast the stars are moving apart and therefore how fast the whole universe is expanding.

media_cameraThe James Webb space telescope, being tested with its arms unfolded prior to launch. Picture: NASA

Is it possible to look back in time from an ordinary backyard?

The short answer is yes. You are technically looking back in time every time you look at the moon or catch a glimpse of the sun.

Light from the sun takes 8.3 minutes to reach Earth.

If the sun were to suddenly disappear, you wouldn’t notice for 8.3 minutes because its light would still be appearing on Earth after it had gone.

media_cameraThe “time-travelling” aspect of the James Webb telescope is all to do with how long it takes light to travel through the universe. Picture: NASA

The same happens when you look at the moon.

The lunar surface is around 384,000km away from Earth, so it takes 1.3 seconds for light to travel from the moon to observers on our planet.

When you look at the moon you’re not seeing it in the present but actually what it looked like 1.3 seconds before.

This story was originally published by The Sun and is reproduced here with permission.

GLOSSARY

  • unprecedented: never done, seen or known before, unheard of
  • sophisticated: advanced, revolutionary, innovative, leading-edge
  • Big Bang: astronomical theory that a cosmic explosion marked the start of the universe
  • extraterrestrial: anything that exists outside Earth and its atmosphere
  • organisms: living things, including plants, bacteria, fungus and microscopic cells
  • dark energy: in theory a mysterious, invisible universal force that repels gravity

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QUICK QUIZ

  1. What obscures visibility of some distant planets?
  2. What do astronomers believe is driving the expansion of the universe?
  3. How long ago was the Big Bang?
  4. How long does it take light from the sun to reach Earth?
  5. How far away is the moon from our planet?

LISTEN TO THIS STORY

CLASSROOM ACTIVITIES
1. Turn back time
If you could use this new telescope to look back in time, which era would you like to look at through the lens of the James Webb telescope?

Pick an era and draw what you might see (be as imaginative as you like and draw as much detail as possible). Write the era or time you are looking back on at the top of your picture.

You can use pencils, textas or whatever materials you have to complete your drawing.

Time: allow 25 minutes to complete this activity
Curriculum Links: Visual Arts; Science; Critical and Creative Thinking

2. Extension
If we knew the sun was going to suddenly disappear, what would you do in the 8.3 minutes you have left before darkness? Write a descriptive paragraph about this experience.

Time: allow 15 minutes to complete this activity
Curriculum Links: English; Science; Critical and Creative Thinking

VCOP ACTIVITY
A moment in time

Imagine you were one of the scientists looking through the James Webb telescope and you made an epic discovery. Light from the sun bounced off one of the satellites orbiting Earth and came back down the lens of the telescope, sending Gamma rays into your pupils. You blacked out for a moment and when you came to, you had the ability to look back in time on Earth as well. But what would be the benefits of looking back in time? How far back can you see? How do you know when it’s the past and when it’s the present?

Write a story about your newly discovered ability and what you can do with it.

Re-read your story aloud to listen to see if it makes sense and if you can up-level it even further.

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