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---------------------- 2736 - HUBBLE - 30 years of astronomy?
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- When Hubble first launched, its instruments could observe ultraviolet light with wavelengths shorter than the eye can see, as well as optical light with wavelengths visible to humans.
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- A maintenance mission in 1997 added an instrument to observe near infrared light, which are longer wavelengths than people can see. Hubble’s new infrared eyes provided two new major capabilities: the ability to see farther into space than before and see deeper into the dusty regions of star formation.
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- Near infrared observations were used to better understand how the universe works, from star formation to cosmology. The light we can see with our eyes is part of a range of radiation known as the electromagnetic spectrum. Shorter wavelengths of light are higher energy, and longer wavelengths of light are lower energy. The Hubble Space Telescope sees primarily visible light as well as some infrared and ultraviolet radiation.
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- The astronomer Edwin Hubble discovered in the early 1900s that the universe is expanding and that the light from distant galaxies was shifted to longer, redder wavelengths, a phenomenon called the redshift. The greater the distance, the larger the shift. This is because the further away an object is, the longer it takes for the light to reach us here on Earth and the more the universe has expanded in that time.
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- The Hubble ultraviolet and optical instruments had taken images of the most distant galaxies ever seen, known as the Northern Hubble Deep Field which were released in 1996. These images, however, had reached their distance limit due to the redshift, which had shifted all of the light of the most distant galaxies out of the visible and into the infrared.
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- One of the new instruments added to Hubble in the second maintenance mission was the Near Infrared Camera and Multi-Object Spectrometer. The near infrared cameras on the spectrometer observed regions of the Deep Field and discovered even more distant galaxies with all of their light in the near infrared.
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- A typical image in the infrared shows a gigantic star cluster in the center of our Milky Way. Our best measurement of the age of the universe is 13.7 billion years. The distance that light travels in one year is called a light year. The most distant galaxies observed were at a distance of almost 13 billion light years. This meant that the light that was detected had been traveling for 13 billion years and showed what the galaxies looked like 13 billion years ago, a time when the universe was only about 5% of its current age.
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- These early galaxies were some of the first galaxies ever created and were forming new stars at rates that were more than a thousand times the rate at which most galaxies form stars in the current universe.
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- Although astronomers have studied star formation for decades, many questions remain. Part of the problem is that most stars are formed in clouds of molecules and dust. The dust absorbs the ultraviolet and most of the optical light emitted by forming stars, making it difficult for Hubble’s ultraviolet and optical instruments to study the process.
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- The longer, or redder, the wavelength of the light, the less is absorbed. That is why sunsets, where the light must pass through long lengths of dusty air, appear red.
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- The near infrared, however, has an even easier time passing through dust than the red optical light. This allowed astronomers to look into star formation regions with the superior image quality of Hubble to determine the details of where the star formation occurs.
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- The dawning of the age of infrared was added into the HST in 1997 NASA had no plans for a future infrared space mission. That rapidly changed as the results became apparent. Based on this new data scientists learned that fully formed galaxies existed in the universe much earlier than expected.
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- The infrared images also confirmed that the expansion of the universe is accelerating rather than slowing down as previously thought. The infrared images were followed by the Hubble Ultra Deep Field images in 2005, which further showed the power of near infrared imaging of distant young galaxies.
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- On Hubble, a near infrared imager was added to the third version of the Wide Field camera which was installed in May of 2009. This camera used an improved version of the detector arrays that had more sensitivity and a wider field of view. The James Webb Space Telescope has much larger versions of the detector arrays that have more wavelength coverage than the previous versions.
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- The James Webb Space Telescope, scheduled to be launched in March 2021, followed by the Wide Field Infrared Survey Telescope, form the bulk of future space missions for NASA.
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- These next programs were all spawned by the near infrared observations by HST. They were enabled by the original investment for a near infrared camera and spectrometer to give Hubble its infrared eyes.
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- With the James Webb Space Telescope, astronomers expect to see the very first galaxies that formed in the universe.
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------------------ Other Reviews to learn more from the Hubble telescope:
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- 1770 - The Hubble Space Telescope is celebrating 25 years of space astronomy. One of its greatest discoveries in 1998 was that gravitational attraction of all the matter in the Universe was not causing cosmic expansion to slow down. Quite the opposite, Hubble’s view of the most distant supernovae explosions confirmed that cosmic expansion was accelerating
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- 1179 - What has Hubble Taught Us? The Hubble Space Telescope has been sending us astronomical images for over 20 years. The telescope was launched in the Discovery Space Shuttle in April, 1990. Astronomers have been studying Hubble’s images, and the data that created them, and have written over 7,000 scientific papers to date. Let’s look at some of the discoveries that have been made by this telescope orbiting the Earth.
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- 1173 - The Hubble Deep Field space telescope image is one of the most amazing discoveries in all of astronomy. The space telescope stares at a single, small spot in the darkest part of the sky. It stares for the longest time to get the longest time exposure and to collect photons that are as faint as possible.
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- 1047 - The Hubble Space Telescope took its pictures using a very long time exposure lasting 10 days or more. The Hubble camera used CCD’s, charge coupled devices, that can collect photons over that entire time of exposure. Our eyes can not do this. Photons fire nerve cells in the back of our eyes and send the image to the brain. We do not have the ability to collect the photons until the image gets bright enough to see. The Hubble camera has much greater sensitivity and can see very faint objects accumulating photons over a long period of time. Faint objects are very far away and strange things happen while the light is traveling those distances.
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- 857 - Hubble Deep Field Discoveries. Everyone has heard of and seen images of the Hubble Deep Field. These images were created by the Hubble Space Telescope staring at a single spot in the sky and taking a very long time exposure picture. If you missed it go to Sky in Google Earth to get the picture.
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- 772 - Hubble Space Telescope. This is the 17th anniversary of the Hubble Space Telescope. It was launched April 24, 1990. I have collected some 8 3-ring binders, full of Hubble pictures. The discoveries using Hubble’s instruments have made astronomy and physics a frontier of amazement for me.
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- 650 - The Hubble Space telescope is 16 years old this year. It was built in 1986 but not launched until 1990 on the Shuttle Discovery. It was designed to have a 20 year life and times about up. It needs another Shuttle visit for repairs if it is to last longer. The telescope weighs 22,500 pounds on Earth, 300 miles up in orbit, in free fall, it weighs nothing. It is 14 feet in diameter and 43 feet long containing a 94 inch (7.8 feet) mirror. Within its first 7 years in orbit it has been hit by over 800 pieces of space junk. There are over 23,000 objects over 4 inches long cataloged as orbiting space junk. So far the Telescope has transmitted 27,000,000,000,000 bytes of data to be analyzed by astronomers. They have published over 6,300 papers from its data. Here are some of its more significant discovers over these past 16 years.
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-606- Hubble Deep Field. The Hubble Space Telescope was launched in 1990. It weighed 22,500 pounds, 14 feet in diameter, 43 feet long, and orbits at 300 miles elevation. In 1993 a 94 inch mirror was repaired to solve some resolution problems. Cost of the program was $1,400,000,000 dollars.
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- May 10, 2020 2736
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