Time travel: Can the James Webb Space Telescope really see the past?


The James Webb Space Telescope (JWST) made history on July 12 with the release of its first image, a gem-filled image that has been described as the deepest image of the universe ever taken, RT reports.

Besides looking at the farthest point across space ever observed, the James Webb Space Telescope has another trick in its mirrors. It can look back in time more than any other telescope, and observe distant stars and galaxies as they appeared 13.5 billion years ago, not long after the beginning of The universe as we know it.

How is this possible? How can a machine look “back in time”? It’s not magic, it’s just the nature of light.

On the Telescope website, NASA scientists explained: “Telescopes can be time machines. Looking into space is like looking back in time. It sounds magical, but it is actually very simple. Light needs time to travel across vast distances of space to reach us.” “

Scientists say: “All the light you see, from the flicker of distant stars to the glow from your desk lamp a few meters away, takes time to reach your eyes. So you’ll never notice it transferring from the desk lamp to your eyes.” However, when you look at things millions or billions of miles away, like most objects in the night sky, you see light that has traveled a very long way to reach you.

The Sun is located 93 million miles (150 million km) away on average, which means that light takes about 8 minutes and 20 seconds to travel from the Sun to Earth. Scientists explain: “When we look at the sun (although you should not be looking directly at the sun) you see it as it appeared more than 8 minutes ago, not as it looks now – in other words, you are looking 8 minutes in the past.”

The speed of light is so important to astronomy that scientists prefer to use light years, rather than miles or kilometers, to measure great distances in space. A light year is the distance that light can travel in one year: about 5.88 trillion miles, or 9.46 trillion kilometers, for example, the North Star, Polaris, is located about 323 light years from Earth, when you see this star you see light its age Over 300 years old.

To look really far into the past, astronomers need telescopes like the JWST. Not only can the James Telescope zoom in on distant galaxies to observe visible light coming from millions of light years away, it can also pick up wavelengths of light invisible to the human eye, such as infrared waves.

Many things, including humans, emit heat as infrared energy, and this energy cannot be seen with the naked eye. But when infrared waves are detected with the right equipment, they can reveal some of the hardest-to-find things in the universe. Because infrared has a much longer wavelength than visible light, it can pass through dense, dusty areas without being scattered or absorbed, according to NASA, many stars and galaxies too far away, too faint or dark to be seen as visible light emitting energy. Thermal radiation can be detected as infrared.

This is one of the most used tricks on the JWST telescope. Using infrared sensors, the telescope can roam the dusty regions of space to study the light that was emitted more than 13 billion years ago by the oldest stars and galaxies in the universe.

This is how JWST took its famous deep field image, and this is how it will try to look further back in time, to the first hundreds of millions of years after the Big Bang. The stars that the telescope will report may actually be long dead Today, however, as its ancient light makes a long journey through the cosmos, JWST treats our eyes with a unique display of time travel.

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