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Tuesday, 20 September 2022

Can the James Webb Space Telescope really see the past?

Can the James Webb Space Telescope really see the history? 

Scientists want to use Webb to see the morning of the macrocosm. How is that possible? 

On July 12, the James Webb Space Telescope( JWST) made history by releasing its debut image a jewel- filled print that is been touted as the deepest print of the macrocosm ever taken. 


Besides looking further across space than any overlook before it, the James Webb Space Telescope has another trick up its glasses It can look further back in time than any other telescope, observing distant stars and worlds as they appeared13.5 billion times agone, not long after the morning of the macrocosm 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. 

" Telescopes can be time machines. Looking out in space is like looking back in time," NASA scientists explained" It sounds magical, but it's actually veritably simple Light needs time to travel across the vast distances of space to reach us." 

All of the light you see — from the shake of distant stars to the gleam from your office beacon a many bases down — takes time to reach your eyes. Luckily, light moves highly presto — roughly 670 million mph( 1 billion km/ h) — so you will noway notice it traveling from, say, the office beacon to your eyes. 

still, when you are looking at objects that are millions or billions of long hauls down — as utmost objects in the night sky are you are seeing light that has traveled a long, long way to reach you. 


Take the sun, for illustration. Earth's home star sits an normal of 93 million long hauls( 150 million kilometers) down. That means it takes light about 8 twinkles, 20 seconds to travel from the sun to Earth. So, when you look at the sun( although you should noway look directly at the sun), you are seeing it as it appeared further than 8 twinkles agone, not as it appears right now — in other words, you are looking 8 twinkles into the history. 

The speed of light is so important to astronomy that scientists prefer to use light- times, rather than long hauls or kilometers, to measure great distances in space. One light- time is the distance that light can travel in one time roughly5.88 trillion long hauls, or9.46 trillion km. For illustration, the North Star, Polaris, sits about 323 light- times from Earth. Whenever you see this star, you are seeing light that is further than 300 times old. 


So, you do not indeed need a fancy telescope to see back in time; you can do it with your own naked eyes. But to look truly far into the history( say, back to the morning of the macrocosm), astronomers need telescopes like JWST. Not only can JWST zoom in on distant worlds to observe visible light coming from numerous millions of light- times down, but it can also pick up wavelengths of light that are unnoticeable to mortal eyes, similar as infrared swells. 

numerous effects, including humans, emit heat as infrared energy. This energy can not be seen with the naked eye. But when infrared swells are viewed with the right outfit, they can reveal some of the hardest- to- discovery objects in the macrocosm. Because infrared radiation has a much longer wavelength than visible light does, it can pass through thick, fine regions of space without being scattered or absorbed, according to NASA. numerous stars and worlds that are too far, faint or obscured to see as visible light emit heat energy that can be detected as infrared radiation. 


This is one of JWST's handiest tricks. Using its infrared- seeing instruments, the telescope can blink past fine regions of space to study light that was emitted further than 13 billion times ago by the most ancient stars and worlds in the macrocosm. 

That is how JWST took its notorious deep field image, and that is how it'll essay to look indeed further back in time, to the first many hundred million times after the Big Bang. The stars that the telescope will reveal may actually be long-dead moment, but as their ancient light makes the lengthy trip across the macrocosm, JWST treats our mortal eyes to a one- of-a-kind time trip display. 

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