On July 12th, the James Webb Space Telescope (JWST) made history by releasing its debut image. pictures full of gems It is touted as the deepest picture of space ever taken.
Not only does it see farther into space than any observatory before it, james webb space telescope It can go further in time than any other telescope, allowing you to observe distant stars and galaxies that appeared 13.5 billion years ago. universe as we know it.
How is this possible? How can a machine “go back in time”? It’s not magic. That’s just the nature of light.
“Telescopes can be time machines. Looking out into space is like looking back in time,” explains a NASA scientist. WebbTelescope.org“It sounds like magic, but it’s actually pretty simple. Light takes time to travel vast distances in space to reach us.”
Every light you see, from the twinkle of a distant star to the glow of a desk lamp a few feet away, takes time to reach your eyes. Luckily, light travels incredibly fast (about 670 million mph (1 billion km/h)). So, for example, you won’t notice light reaching your eyes from a desk lamp.
But, like most objects in the night sky, when you’re looking at an object that’s millions or billions of miles away, you’re looking at light that has traveled a very long way to reach it.
took Sun, for example. Earth’s home star is an average of 93 million miles (150 million kilometers) away. So it takes about 8 minutes and 20 seconds for light to travel from the sun to the earth.So when you look at the sun (though you should don’t look directly at the sun), which is displayed in the state it was displayed more than 8 minutes ago, rather than in the state it is currently displayed in. So it was displayed 8 minutes ago.
of 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 light can travel in one year. Approximately 5.88 trillion miles (9.46 trillion km). For example, Polaris Polaris is about 323 light-years away from Polaris. earthWhenever you look at this star, you are looking at light that was over 300 years old.
So you don’t need a fancy telescope to go back in time. You can do it with your own naked eye. But to really look into the distant past (such as the beginning of the universe), an astronomer needs a telescope like his JWST. JWST can zoom in on distant galaxies and observe visible light coming from millions of light-years away, as well as pick up wavelengths of light invisible to the human eye. Infrared wave.
Many things, including humans, give off heat as infrared energy. This energy is invisible to the naked eye. But looking at infrared waves with the right instruments can reveal some of the most elusive objects in the universe. Because infrared radiation has much longer wavelengths than visible light, it can pass through dense, dusty regions of the universe without being scattered or absorbed. NASAMany stars and galaxies are too distant, too hazy, or too visible as visible light to emit thermal energy that can be detected as infrared radiation.
This is one of JWST’s most useful tricks. Using its infrared-sensing instruments, the telescope can peer into dusty regions of the universe’s past and study the light emitted by the universe’s oldest stars and galaxies more than 13 billion years before her. increase.
This is how JWST got its famous deep field imagery and how it tries to explore further back in time. first billion years later big bangThe stars that the telescope reveals may actually be dead today, but as those ancient lights make their long journey across the universe, JWST will give our human eyes a unique time travel experience. used for display.
Originally published in Live Science.
Comments
Post a Comment