ジェイムズウェッブ宇宙望遠鏡（JWST） will specialise exclusively in infrared astronomy to study early 宇宙. It will search for optical/infrared signals from the early 星 and galaxies formed in the 宇宙 soon after the Big Bang for a better understanding of the formation and evolution of galaxies and the formation of 星 & 惑星の システム。 JWST will also study 惑星の systems and the origins of life. The much-awaited JWST is now scheduled to be launched on 18 December 2021.
Usually, one focusses a telescope at a target to observe. But at times you deliberately focus on nothing and that change the course of a field of study. Decision to focus ハッブル スペース telescope on nothing in the hitherto unexplored fields in the sky was one such incident that changed the course of astronomy.
の多くの画期的な成果の中で ハッブル スペース Telescope (HST), the deep field images taken over the course of 10 days in 1995 when it captured about 3000 images of galaxies at different stages of stellar evolution has revolutionised astronomy and changed our understanding of the 宇宙.
These deep field images were formed by the light that had travelled from the remotest locations of the 宇宙 for billions of light years through the expanding 宇宙 and had reached Earth now to be captured by the ハッブル telescope after originally emanating from the early 星 and galaxies formed soon after Big Bang about 13 billion years ago. So, as such deep field images denoted early 星 and galaxies as they were then billions of years ago. This was truly remarkable feat.
But, this technique of capturing primordial optical signals for developing understanding of early 宇宙 could not be an effective methodological tool due to the fact discovered in 1929 by Edwin ハッブル その 宇宙 is expanding and all galaxies are moving away from each other as evidenced by the redshift of 銀河’s spectrum to higher wavelengths in infrared (IR) region. But the ハッブル telescope is equipped to observe in UV, visible and near-infrared region hence the need for an exclusive infrared 展望台 in スペース.
ジェイムズウェッブ宇宙望遠鏡（JWST） is thus a successor to the ハッブル スペース telescope (HST) in the sense that the ジェームスウェッブ telescope aims to carry forward the ハッブル telescope’s legacy in the area of study of early 宇宙. JWST will operate exclusively in infrared astronomy and has following four key goals:
これらの理由から、 JWST needed to be different from ハッブル telescope in design and operation. It is a reflecting telescope designed to capture near-infrared radiations from ultra-deep fields with a large origami-style mirror that makes it 100 times more powerful than ハッブル。 実際には、 JWST は最もおおきい スペース telescope ever. To maintain its unprecedented infrared sensitivity, JWST has protection from infrared contamination from sun through a highly effective 5-layer sunshield. Further, to help maintain its very low operating temperature of 50 Kelvin (-223° C or -370° F), JWST will be placed in an オービット around the sun in the cold shadow of Earth all the time near the second Lagrange point (L2) of the Earth-Sun system at a distance of about 1.5 million km from Earth.
の配置 JWST near far off Sun-Earth system L2 オービット means, unlike ハッブル telescope which received several repairs and maintenance in the スペース, JWST will be completely on its own after launch therefore there is no scope of any error at all. Perhaps this explains why launch of JWST is almost eternally delayed.
今、 JWST is planned to be launched on 18 December 2021.
As on 02 November 2021, JWST has already safely arrived at its launch site in French Guiana and the technical team is preparing for lift off on 18 December.
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ソース：
- NASA 2021. Webb telescope – The Road to Launch and Beyond for NASA’s James Webb スペース Telescope. Posted 02 November 2021. Available online at https://www.nasa.gov/feature/goddard/2021/the-road-to-launch-and-beyond-for-nasa-s-james-webb-space-telescope
- NASA。 JWST –Webbに関する一般的な質問。 オンラインで入手可能 https://www.jwst.nasa.gov/content/about/faqs/faq.html
- NASA。 JWST –重要な事実。 オンラインで入手可能 https://jwst.nasa.gov/content/features/keyFactsInternational/
- ESA。 科学と探査。 Webb –さらに見る。 オンラインで入手可能 https://www.esa.int/Science_Exploration/Space_Science/Webb
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