By the time the light reaches our telescopes, its original wavelength will have shifted from the visible or ultraviolet to the infrared. The Hubble space telescope has managed to capture the shortest wavelength infrared rays stretched from the bluest of light of faraway galaxies.
Webb will knock it out of the park in terms of how deep into space—and how far back in time—it can catch distant galaxies in the act of growing up.
If life exists outside of Earth, it will release distinct chemical signatures, such as by breathing carbon dioxide and photosynthesizing out oxygen, that can transform a planet. Webb can detect infrared wavelengths for fingerprinting chemicals such as water and methane present in the atmosphere of exoplanets, which are planets beyond our solar system.
Webb contains two instruments that will allow scientists to unravel the wavelengths of infrared signals from solar systems beyond ours—to unweave the colors of the infrared rainbow, so to speak. Since the first exoplanet discovery in , scientists have found thousands of exotic planets teeming in the universe. Hubble works with a much narrower band of infrared energies compared to Webb.
The Earth also emits background infrared radiation that would overwhelm the faint signals coming from the deep cosmos. The birthplaces of stars are full of dust. While they make for breathtaking photos, the dust blocks scientists from peering right into the heart of these clouds when they look at them with visible light.
Luckily, infrared light from stars can penetrate through the dust to give scientists a whole new take on an old view. The same principle explains why infrared light can penetrate even further through dusty galaxies than visible light.
And Webb might help scientists figure out how the dust cooks up a star, why stars form in clusters and how planets form around a star. Nothing can escape a black hole, not even light; so technically, black holes are invisible. Several galaxies are seen in the infrared view, much more distant than the columns of dust and gas.
Note the human reference at the bottom for scale. Hubble's mirror is a much smaller 2. Sunshield Size Webb's sunshield is about 22 meters by 12 meters It's about half as big as a aircraft. The sunshield is about the size of a tennis court. Orbit The Earth is million km from the Sun and the moon orbits the earth at a distance of approximately , km. Because Hubble is in Earth orbit, it was able to be launched into space by the space shuttle.
Webb will be launched on an Ariane 5 rocket and because it won't be in Earth orbit, it is not designed to be serviced by the space shuttle.
This will help Webb stay cool, which is very important for an infrared telescope. As the Earth orbits the Sun, Webb will orbit with it - but stay fixed in the same spot with relation to the Earth and the Sun, as shown in the diagram to the left.
Actually, satellites orbit around the L2 point, as you can see in the diagram - they don't stay completely motionless at a fixed spot. Because of the time it takes light to travel, the farther away an object is, the farther back in time we are looking. This illustration compares various telescopes and how far back they are able to see.
Essentially, Hubble can see the equivalent of "toddler galaxies" and Webb Telescope will be able to see "baby galaxies". One reason Webb will be able to see the first galaxies is because it is an infrared telescope.
The universe and thus the galaxies in it is expanding. When we talk about the most distant objects, Einstein's General Relativity actually comes into play. You arrive at the planet pinata party photos from your fourth birthday and even some of you as a toddler. But then you realize that before this, there are no pictures. Your life has been captured only from the time you were already out of babyhood.
Then someone comes and offers to reveal some earlier pictures of you as a baby. You probably would want to see them. Now imagine you were offered the chance to see such pictures for the whole universe. And that's exactly what the new and impressive James Webb Space Telescope, finally scheduled for launch on December 18, , promises to give us, in all likelihood drastically changing our understanding of the cosmos. Telescopes allow us to see faraway objects.
Most use mirrors to gather and focus light. And the bigger the mirror, the more powerful the telescope is. You find them on hills and in deserts but also mounted on satellites. Being in space means there is no more distortion due to the Earth's atmosphere.
This results in sharper and higher-resolution images. The accomplishments of the Hubble Space Telescope can probably give some convincing reasons.
Besides, it would be hard to talk about the James Webb without talking about the Hubble. It showed us how incredibly huge, dazzling and sometimes weird and even scary the universe can be. It provided stunning and colorful images of gas clouds that reminded us of animals, and of galaxies of all sorts and shapes. But the Hubble gave us much more than pictures: It also enabled us to give a better estimate of the age of the universe — about The Hubble was also crucial for confirming that, contrary to what many scientists previously believed, the universe is expanding at an accelerated rate.
Back to our photo album. The Hubble's Deep Field images gave us an unprecedented look at the oldest and remotest objects known so far in the universe, billions of light-years away. Because light takes time to travel long distances, we see very distant objects as they were billions of years ago. With the Hubble, we could go only as far back as the "toddler pictures" of the universe, around million years after the Big Bang. If this is what we accomplished with the Hubble, what wonderful new things will we be able to see and learn with the new James Webb Telescope, the biggest and most complex and elaborate space telescope ever built?
It has been almost 20 years since the James Webb's original planned launch date. Many technological advances and even new inventions were needed for the telescope's completion.
The project faced many challenges and delays, but it is now ready and definitely worth waiting for. Here is why. The Webb has the largest primary mirror that will ever have been sent into space. Consisting of 18 gold-plated hexagonal smaller mirrors, it's more than six times the size of the Hubble's. But it also has improved sensitivity and observes in infrared light, while the Hubble observes mainly in visible light, the sort you and I can see.
All warm bodies emit infrared radiation, even you and I. Infrared is also used in TV remotes, night vision cameras, and meteorology and weather satellites.
And being able to observe in infrared light means that the Webb can see much more distant and older objects. That is because, in part thanks to the Hubble, we know that the farther these objects are from us, the more their light shifts towards the infrared.
Discovering new things by building on previous discoveries: That is science. If we want to look at the very earliest stars and galaxies, we thus need to observe them in infrared light. The Webb will be the first telescope to see the most distant galaxies and get a glimpse of what the universe looked like around to million years after the Big Bang — the first "baby pictures" of the universe, perhaps the first galaxies.
But looking in infrared light has another benefit: It enables one to see through dust clouds. The tiny particles in these clouds are very good at blocking visible light.
We can't see through them with our eyes, just as we can't see any stars on a very cloudy night here. And neither can the Hubble. But infrared light is much less affected, so with the James Webb Telescope, we will be able to penetrate and look past these dust clouds not only to see what is behind them, but also to take a better look at the formation of stars and planets.
The Webb's gigantic size presents a huge challenge.
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